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Article

Biomass Allocation and Allometric Relationship of Salix gordejevii Branches in Sandy Habitats Heterogeneity in Northern China

by
Guan-Zhi Liu
1,†,
Kai Zhao
2,†,
Shi-Qi Zhang
3,
Yu-Mei Liang
2,
Yong-Jie Yue
3,
Guo-Hou Liu
1,* and
Fu-Cang Qin
2,4,*
1
College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
2
College of Desert Control Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010010, China
3
College of Forestry, Inner Mongolia Agricultural University, Hohhot 010010, China
4
Inner Mongolia Forestry Research Institute, Hohhot 010011, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work and should be considered co-first authors.
Sustainability 2024, 16(13), 5483; https://doi.org/10.3390/su16135483
Submission received: 26 May 2024 / Revised: 21 June 2024 / Accepted: 22 June 2024 / Published: 27 June 2024
(This article belongs to the Topic Climate Change and Environmental Sustainability, 3rd Volume)
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Abstract

:
The patterns of biomass allocation are crucial for understanding the growth, reproduction, and community functions of plant individuals. We investigated the allometric growth characteristics and biomass allocation patterns of Salix gordejevii fascicular branches in various habitats of the Hunshandake Sandy Land to delve into their adaptability to environmental changes and role in the carbon cycle. We discovered the following: (1) The base diameter-to-branch length of S. gordejevii fascicular branches exhibited allometric growth relationships in mobile dunes and interdune lowlands, whereas it showed isometric growth relationships in semifixed and fixed dunes. As the soil moisture gradient increased, the length growth rate of S. gordejevii fascicular branches became faster than the base diameter growth rate in mobile dunes, demonstrated isometric growth in semifixed and fixed dunes, and was slow in interdune lowlands. (2) The biomasses of S. gordejevii fascicular branches significantly varied across different habitats, with the biomass of each component showing an increasing trend as habitat conditions improved. This study revealed the resource utilization strategies and adaptability of S. gordejevii fascicular branches in different habitats, providing new insights into the carbon sink function of desert ecosystems in semiarid regions.

1. Introduction

In the field of plant ecology, the allocation of biomass among different organs is a core issue [1] that not only reveals the strategies of plant adaptation to environmental conditions [2] and also reflects the distribution of photosynthetic products among various organs [3]. The optimal partitioning hypothesis suggests [4] that plants prioritize resource allocation to organs that acquire limiting resources to maintain the highest growth rate [5,6,7]. For example, under limited light conditions, biomass tends to be allocated to leaves and branches, whereas in environments limited by nutrients or water, biomass is often allocated to roots [8]. However, given that the proportion of biomass allocation changes with plant size [9,10], the application of the optimal partitioning hypothesis is limited. Allometric growth theory offers a solution to this problem [11,12]. It considers the effects of genetic traits and environmental factors on biomass allocation, revealing the intrinsic laws of biomass distribution among plant organs [13]. This theory has been widely applied in biomass allocation research [14], and scholars have suggested integrating the optimal partitioning hypothesis with allometric growth theory. The biomass of plants and its allocation among various organs reflect the plant’s response to environmental resource utilization and are the basis for intraspecific differentiation strategies [15]. Although current research has mostly focused on different species or provenance levels [16,17,18,19], studies on intraspecific different site types remain scarce. Therefore, further exploration in this field will provide new insights to plant ecological research.
Allometry refers to the phenomenon wherein the relative growth rates of two traits in an organism are disproportionate and determined by the genetic characteristics of species and constrained by environmental factors [20,21]. It not only reveals the intrinsic laws of biomass allocation among plant organs, it also plays an important role in describing the structural and functional characteristics of biological components [22,23]. Existing studies have shown that allometric growth indices vary between different plant organs; this variation may be related to the growth patterns and structural characteristics of each organ [24,25]. Therefore, analyzing the allometric relationships among plant components is important for understanding the adaptive strategies of plants when they face environmental stresses [26]. Plant allometry is closely related to morphological changes, biomass allocation, resource utilization, and morphological adaptation to heterogeneous environments [27]. The allometric relationship between plant height and diameter plays an important role in estimating the maximum heights of different functional groups of plants, constructing biomass estimation models, and deriving allometric relationships between individual size and density [28]. Existing research covers a range of fields from individuals [29] to populations [30,31] and from ecosystems to evolutionary ecology, molecular biology, and theoretical physics, providing new perspectives for understanding the evolutionary importance of life. However, studies have concentrated on tree species, with allometric growth research based on the scale of shrub fascicular branches [32], especially for sandy shrublands, being lacking.
The Hunshandake Sandy Land, one of the four major sandy lands in Inner Mongolia, not only lies a mere 180 km straight-line distance from China’s capital, Beijing, it also plays a crucial role in ecological and environmental protection [33]. This vast sandy area is the frontline of sand prevention and control in Northern China, wherein the success of ecological restoration directly influences the ecological security and climate stability of Beijing and the North China region [34]. Salix gordejevii Y.L. Chang & Skvortsov, endemic to Mongolia and Northen China, a xerophytic shrub, can rapidly generate adventitious roots and form new branches when buried by shifting sands [35], becoming the pioneer or dominant species in mobile and semimobile dunes [36]. Given its outstanding performance as a windbreak and in sand fixation, it has become an indispensable living sand barrier in improving the ecological environment of sandy areas and reversing desertification [37,38]. Studying the allometric growth characteristics of S. gordejevii in extreme environments, such as the Hunshandake Sandy Land, is of great importance for ecology and environmental science [39]. Allometric growth, as a key indicator of plant adaptability and biomass allocation, can reveal how S. gordejevii adjusts its growth strategies in resource-limited desert environments [40]. By thoroughly understanding the growth patterns of S. gordejevii, we can predict and manage the restoration of desert ecosystems, thus providing a scientific basis for desertification control [41]. Furthermore, research on the allometric growth and biomass allocation of S. gordejevii can help us understand the adaptation mechanisms of plants against the backdrop of global climate change, hence offering important references for the formulation of ecological protection and sustainable development strategies. Therefore, the study of the allometric growth of S. gordejevii is not only an exploration of the ecological adaptability of a single species, it is also a comprehensive contribution to maintaining biodiversity and ecological balance.
This study focuses on S. gordejevii in different habitats of the Hunshandake Sandy Land. It employed allometric growth theory to analyze the allometric relationships between the branch length and base diameter of S. gordejevii fascicular branches, examined their component biomass and allocation patterns, and discussed the allometric relationships between component biomasses. Its aim is to reveal the resource allocation strategies of S. gordejevii fascicular branches and hence provide a scientific basis for ecological restoration in sandy lands.

2. Materials and Methods

2.1. Overview of the Study Area

The study area is located in the central–eastern part of the Inner Mongolia Plateau at the northern foot of the Yin Mountains and southern end of the Xilingol Grassland’s Hunshandake Sandy Land. Its geographical coordinates are N41°50′–43°50′ and E111°45′–117°42′. The average elevation of the sampling site is 1100 m (a.s.l.). The Hunshandake Sandy Land features various types of sand dunes, including mobile, semifixed, and fixed dunes and interdune lowlands, with the majority of sand dunes being fixed or semifixed. The region encompasses two major river systems, namely, the Xilamulun and Luan Rivers, with 16 springs and over 500 lakes of various sizes providing abundant water resources and favorable moisture conditions. The annual precipitation in the study area is 200–400 mm and is mainly concentrated during the July–September period. Hunshandake Sandy Land belongs to the semi-arid desert steppe area with a single vegetation type and coverage rate of about 50%, mainly herbaceous plants, including S. gordejevii, Cleistogenes squarrosa, and Artemisia frigida.

2.2. Methods

2.2.1. Plot Establishment

Four types of typical natural dune environments were selected within the study area —mobile, semifixed, and fixed dunes and interdune lowlands—with three plots for each type. These plots have not been subjected to considerable human disturbance. S. gordejevii occupied a dominant position in the community composition of each plot. Through exhaustive field surveys, detailed site condition information for each plot, including aspect, slope, and geographical coordinates, were collected and systematically organized (Table 1).

2.2.2. Sample Collection and Index Measurement

Three 4-year-old superior S. gordejevii shrubs of different site types were selected as research samples. The determination of plant age was based on the growth ring counting method, and S. gordejevii shrubs with healthy growth, no pests or diseases, and typical morphology were selected. At each site, we conducted detailed measurements of these shrubs, including basal diameter, fascicular branch length, number of branches at each level, total number of plants, overall plant height, and leaf length and width, among other indices. This approach was taken to obtain the biomass of different levels of branches and leaves as well as that of branches. The measurements also included stem biomass, leaf biomass, and total twig biomass. In this study, the branches near the ground of a shrub were defined as primary branches, and we studied the allometric growth patterns of the shrub at branch level. We considered the stem of primary branches as the stem and measured branches as subbranches.
We applied the allometric growth equation y = bxa to describe the relationship between the branch length and basal diameter of S. gordejevii fascicular branches as well as the aboveground biomass (stems, leaves, and branches). By log-transforming the variables, we obtained the equation log(y) = log(b) + alog(x), ensuring that the data conformed to a normal distribution [42]. Here, y and x represent interdependent variables, such as stem biomass and root biomass; b is the allometric constant, which represents the intercept of the trait relationship; and a is the allometric exponent, which indicates the slope of the correlation.
The value of slope a was determined through standardized major axis (SMA) analysis [43], which decides whether a correlation is isometric (a is close to the theoretical value of 1.0) or allometric (a significantly deviates from the theoretical value of 1.0). We used Pitman’s method to calculate the confidence interval of the slope and Warton and Weber’s method to assess the heterogeneity of regression slopes. When the slopes showed homogeneity, we calculated a common slope and used analysis of variance to test for differences in intercepts and slopes.

3. Results

3.1. Characteristics of Fascicular Branch Length and Basal Diameter and Analysis of Allometric Growth

3.1.1. Frequency Distribution of Branch Length and Basal Diameter

In this study, we conducted detailed measurements of the active fascicular branches of S. gordejevii under different site conditions and plotted the frequency distribution curves of basal diameter and branch length (Figure 1). The results showed that in mobile dunes, fixed dunes, and interdune lowlands, the basal diameter distribution of S. gordejevii exhibited the characteristics of an approximately normal distribution, whereas in semifixed dunes, the frequency distribution of basal diameter showed a right-skewed trend.
Specific frequency analysis indicated that in mobile dunes, approximately 75% of the basal diameters of S. gordejevii fascicular branches were between 7.9 and 12.4 mm; in semi-fixed dunes, approximately 65% of the basal diameters ranged from 8.0 to 12.8 mm; in fixed dunes, approximately 69.4% of the basal diameters were distributed between 9.0 and 14.0 mm; and in interdune lowlands, approximately 62.2% of the basal diameters were within the range of 9.0–14.0 mm.
The data regarding the distribution of branch lengths at various sites also showed characteristics close to those of a normal distribution. In mobile dunes, approximately 76.7% of the lengths of S. gordejevii fascicular branches were distributed between 84.0 and 154.0 cm; in semifixed dunes, approximately 82.5% of the branch lengths were between 136.0 and 182.0 cm; in fixed dunes, approximately 65.3% of the branch lengths were between 173.0 and 228.0 cm; and in interdune lowlands, approximately 80% of the branch lengths were between 224.0 and 306.0 cm.

3.1.2. Allometric Growth of Fascicular Branch Length and Basal Diameter

In this study, we conducted an in-depth analysis of the allometric growth relationship between the length and basal diameter of S. gordejevii fascicular branches (Table 2, Figure 2). Our analysis results showed that when the influence of site types was not considered, the regression slopes between the length and basal diameter of all fascicular branches were significantly higher than the theoretical value (p < 0.01), indicating that the length of S. gordejevii fascicular branches increases faster than the basal diameter.
The further fitting analysis of the branch length and basal diameter data obtained under the conditions of different site types revealed slopes that ranged from 0.519 to 1.270, revealing the absence of a uniform slope applicable to all site types.
Through the multiple comparisons of slopes, we found that the slopes of other site types were significantly lower than those of mobile dunes (p < 0.05). Specifically, the slope of mobile dunes was 1.270, which was significantly higher than the theoretical value. The slopes of semifixed and fixed dunes were 0.912 and 0.977, respectively, neither of which differed significantly from the theoretical value (p > 0.05) and did not significantly differ from each other. Meanwhile, the slope of interdune lowlands was 0.519, which was significantly lower than the theoretical value (p < 0.05) and did not differ significantly from those of semifixed and fixed dunes (p > 0.05).

3.2. Biomasses of Fascicular Branch Components and Analysis of Allometric Growth

3.2.1. Adaptation and Allocation of Component Biomass under Habitat Heterogeneity

We explored the adaptability and allocation of component biomass under heterogeneous habitats. Analyzing the biomass of various components (stem, leaves, and branches) of S. gordejevii fascicular branches at different site types revealed significant differences in biomass (Figure 3). Specifically, as soil moisture content increased, the biomass of stems increased; the overall biomass of leaves also increased but decreased between fixed and semi-fixed dunes; and the biomass of branches showed an overall increasing trend.
The further analysis of the biomass allocation ratios of the components of S. gordejevii fascicular branches revealed significant differences in allocation ratios at different types of sites (Figure 4). The biomass allocation ratio of stems was highest in mobile dunes, whereas it was lowest in interdune lowlands. The biomass allocation of leaves in mobile and fixed dunes and interdune lowlands showed no significant difference (p > 0.05) but was significantly lower than that in semi-fixed dunes (p < 0.05). The biomass allocation of branches did not significantly differ between semifixed and fixed dunes (p > 0.05) but was smallest in mobile dunes and largest in interdune lowlands.

3.2.2. Allometric Relationships between the Biomasses of Components (Stems, Leaves, and Branches)

We analyzed the allometric relationships between the biomasses of various components (stems, leaves, and branches) of S. gordejevii fascicular branches (Table 3, Figure 5). We found significant differences in the accumulation rates of biomasses among these components across different site types. Initially, we observed a highly significant difference (p < 0.01) between stem and leaf biomasses with a regression slope of 1.215, which was significantly higher than the theoretical value (p < 0.05). This result suggests that the accumulation rate of leaf biomass is faster than that of stem biomass.
When differences in site types were considered, the fitting results of leaf biomass to stem biomass showed no significant difference between semifixed and fixed dunes. However, the slope of interdune lowlands was significantly lower than of mobile dunes (p < 0.05). No significant differences were found between the slope of mobile dunes and theoretical value (p > 0.05).
The further analysis of the relationship between branch and stem biomasses revealed a highly significant correlation (p < 0.01, Table 4) and a regression slope of 1.574, which was far greater than the theoretical value (p < 0.01). SMA analysis (Table 4, Figure 6) revealed a common slope of 1.384 across different site types that lacked a significant difference from the theoretical value (p > 0.05), suggesting that the accumulation rate of stem biomass is equal to that of branch biomass regardless of site type. The theoretical value was significantly lower than the slopes of mobile, semifixed, and fixed dunes (p < 0.05) but was not significantly different from the slope of interdune lowlands (p > 0.05). A comparison of intercepts revealed that for a given amount of stem biomass, the investment in branch biomass was smallest in mobile dunes and largest in interdune lowlands, with that in semifixed and fixed sandy lands in between the investments in mobile dunes and interdune lowlands.
Additionally, a correlation was observed between leaf and branch biomasses (p < 0.01, Table 5) with a regression slope of 0.921, which was not significantly different from the theoretical value (p > 0.05). Analysis across different site types revealed no common slope (Table 5, Figure 7). Multiple slope tests indicated that the slope of fixed dunes was significantly lower than the theoretical value (p < 0.05) and was significantly different from those of mobile and semi-fixed dunes. No significant differences between other site types nor from the theoretical value were found (p > 0.05).
Lastly, a highly significant difference was found between the total biomass of fascicular branches and stem biomass (p < 0.01, Table 6, Figure 8), with 60% of the total fascicular branch biomass being stem biomass. The common slope across different site types was 0.957, which was significantly lower than the theoretical value (p < 0.05). This finding indicates that regardless of site type, the accumulation rate of stem biomass is greater than that of the total biomass. Although the slopes of mobile and fixed dunes were not significantly different from the theoretical value (p > 0.05), the theoretical value was significantly lower than the slopes of semi-fixed dunes and interdune lowlands (p < 0.05). Intercept drift test results showed that the intercept for interdune lowlands was significantly greater than that for mobile dunes and fixed dunes (p < 0.05) and did not significantly differ from that for semi-fixed dunes (p > 0.05). Significant differences were found among mobile, semifixed, and fixed dunes (p < 0.05).
We delved into the allometric growth relationship between the branch and total biomasses of S. gordejevii fascicular branches. The results revealed a highly significant difference between branch and total biomasses (p < 0.01, Table 7, Figure 9) with a common slope of 0.660 across different site types. This value was significantly lower than the theoretical expected value (p < 0.01). This finding implies that regardless of site type, the accumulation rate of the branch biomass of S. gordejevii fascicular branches was greater than that of the total biomass.
Specific to different site types, the slopes of mobile, semifixed, and fixed dunes were all significantly lower than the theoretical value (p < 0.01), whereas that of interdune lowlands was not significantly different from the theoretical value (p > 0.05). The intercept drift between mobile and fixed dunes and interdune lowlands based on the common slope was significant (p < 0.01), whereas no significant differences were found between other site types (p > 0.05).
Furthermore, a correlation was found between the total and leaf biomasses of S. gordejevii fascicular branches (p < 0.01, Table 8, Figure 10). Allometric growth analysis across different site types revealed that the slope of mobile dunes was significantly lower than the theoretical value (p < 0.05), whereas the slope of interdune lowlands was significantly higher than that of other site types and the theoretical value (p < 0.05). No significant differences were found between semifixed and fixed dunes nor between their slopes and the theoretical value (p > 0.05).

4. Discussion

4.1. Allometric Growth Relationship between Fascicular Branch Length and Basal Diameter

We observed a balance between vertical and horizontal growth directions from the perspective of S. gordejevii fascicular branches across different site types. This balance indicates that an allometric growth relationship exists between branch length and basal diameter. Multiple tests of the slopes revealed that except for mobile dunes, the slopes of other site types were significantly lower than those of mobile dunes, and the slope of mobile dunes was significantly greater than the theoretical value. Slopes did not significantly differ between semifixed and fixed dunes nor from the theoretical value. The slope of interdune lowlands was significantly lower than the theoretical value and lacked a significant difference from those of semifixed and fixed dunes.
The results suggest that when the S. gordejevii population in mobile dunes is in the growth phase of its life cycle, young fascicular branches have a high individual count, and their rapidly elongating branches can effectively perform photosynthesis and expand the range of seed dispersal. Although many studies have assumed that consistent with the geometric self-similarity model [44,45,46], the growth rates of plant height and basal diameter are similar in the juvenile stage or small individuals, our study found the allometric growth index to be significantly higher than the theoretical value, likely because S. gordejevii is a typical pioneer sand-fixing plant that is characterized by sand burial tolerance, easy asexual reproduction, and rapid growth. Although the Hunshandake Sandy Land is located in an arid region, it has abundant water resources and good moisture conditions [47]. Therefore, the allometric growth index was significantly higher than the theoretical value. This result indicates that mobile dunes provide suitable growth conditions and good genetic resources to S. gordejevii, enabling its rapid growth and development.
The slopes of semifixed and fixed dunes did not significantly differ from the theoretical value (p > 0.05), indicating an isometric growth relationship. The allometric growth index of the fascicular branch length to basal diameter of S. gordejevii in semifixed and fixed dunes reduced relative to that in mobile dunes. This reduction may be related to a delay in vertical growth or an acceleration in horizontal growth. The delay in vertical growth could be due to genetic constraints or factors, such as drought or freeze–thaw cycles that cause embolism or cavitation in conduits, thus affecting growth [48]. Horizontal growth might have accelerated because the fascicular branch populations at these two types of sites are in a stable phase; individuals are large; and the transition from primary to secondary growth has occurred, enhancing radial resistance to adverse factors. Given that stem growth is indeterminate and height growth is generally incremental and determinate, this situation might lead to accelerated lateral growth, thus reducing the allometric growth index.
In interdune lowlands, the slope between the fascicular branches and basal diameter of S. gordejevii was 0.519, which essentially aligns with the elastic and fractal network models. We likely obtained this result because trees resist morphological distortion caused by their own weight or require large diameters for support to maintain an erect and upright form. Additionally, as the thickness of the transport cross-section increases and transport distance shortens, resistance can be minimized during resource transport, thus facilitating resource delivery.
This study shows that the relationship between the branch length and basal diameter of S. gordejevii fascicular branches changed with the increase in the moisture gradient of sandy lands across different site types. In mobile dunes, the growth rate of branch length exceeded that of basal diameter; in semifixed and fixed dunes, the growth relationship between branch length and basal diameter was isometric; and in interdune lowlands, the growth rate of branch length was slower than that of basal diameter. In mobile dunes, S. gordejevii favors a vertical growth rate to perform photosynthesis and expand the space for seed dispersal. In interdune lowlands, S. gordejevii favors a lateral growth rate with the changes in soil conditions to balance morphological deformation caused by its own weight, maintain a vertical and straight form, and minimize resistance to resource transport. The adaptive responses in semifixed and fixed dunes are intermediate between those in mobile dunes and interdune lowlands. These findings are valuable for understanding how S. gordejevii adapts to different sandy land environments.

4.2. Biomass of Fascicular Branch Components and Allometric Growth Relationship

The biomass allocation of various components of S. gordejevii fascicular branches showed significant differences at different types of sites. Compared with that in fixed dunes, the biomass allocation of components in mobile dunes had a lower proportion of allocation to branches, a higher proportion of allocation to stems, and little difference in allocation to leaves. A similar allocation phenomenon was observed in fixed dunes and interdune lowlands. However, in semi-fixed dunes, the biomass allocation of components was balanced. This characteristic is conducive to the rapid growth of S. gordejevii. Compared with interdune lowlands, semi-fixed dunes exhibited a lower proportion of allocation to branches but a higher proportion of allocation to leaves with little difference in allocation to stems. The analysis results demonstrate that under poor moisture conditions, the component biomass of S. gordejevii tends to increase the biomass of stems and leaves, thus reducing allocation to branches. Furthermore, the fully sclerified, thick cuticle leaf anatomical structure of S. gordejevii may be closely related to its biomass allocation strategy, indicating that S. gordejevii growing in mobile dunes has strong drought resistance.
Studying the accumulation rates of the stem, branch, leaf, and total biomasses of S. gordejevii fascicular branches under different site conditions is an important method for revealing its ecological adaptation mechanisms and investigating its biological characteristics. Through SMA regression analysis, we found significant positive correlations between S. gordejevii fascicular branches across different sites and traits. The only exception was the lack of correlations between leaf and stem biomasses in semifixed and fixed dunes. Additionally, the allometric growth index between different traits was related to site type. Without considering site type, the accumulation rates of branch–stem biomass were similar and followed the isometric growth rule. With a certain input of stem biomass, the input of branch biomass was smallest in mobile dunes and largest in interdune lowlands. Its value in semifixed and fixed sandy lands was intermediate between those in mobile dunes and interdune lowlands. However, the accumulation rates of branch and stem biomasses were greater than the total biomass accumulation rate, indicating the existence of allometric growth between total stem and branch biomasses, with the theoretical value being greater than the allometric growth coefficients. These traits are all related to site type. In mobile dunes, leaf–stem biomasses followed the isometric growth rule, whereas in interdune lowlands, the accumulation rate of leaf biomass was less than that of stem biomass, indicating an allometric growth relationship. In mobile and semi-fixed dunes and interdune lowlands, leaf–branch biomasses followed the isometric growth rule, whereas in fixed dunes, the accumulation rate of leaf biomass was less than that of branch biomass, showing an allometric growth relationship. In mobile dunes, the accumulation rate of leaf biomass was greater than that of total biomass. By contrast, in interdune lowlands, the accumulation rate of leaf biomass was less than that of total biomass. Meanwhile, in semifixed and fixed dunes, the accumulation rates of leaf and total biomasses demonstrated an isometric growth relationship.
The allometric growth relationships between different site types and other traits of S. gordejevii are closely linked. Overall, the biomass allocation strategy of S. gordejevii can be effectively adjusted by effectively controlling the accumulation rate of leaf biomass. That is, the main regulatory factor of the biomass allocation strategy of S. gordejevii fascicular branches is the accumulation rate of leaf biomass. The accumulation rate of leaf biomass was high in mobile dunes; low in semifixed and fixed dunes; and lowest in interdune lowlands. S. gordejevii fascicular branches adopt a growth strategy of increasing the accumulation rate of branch biomass in fixed dunes and increasing the accumulation rate of stem biomass in interdune lowlands to balance the reduction in the accumulation rate of leaf biomass. In this way, S. gordejevii can regulate the accumulation rate of leaf biomass, thus achieving improved growth results.

5. Conclusions

Coordinated development among different organs during the life cycle of plants is an important field of study. This physiological characteristic is influenced by various environmental factors, such as light intensity, moisture, and nutrients. Researching the allometric growth of plants in the vertical (i.e., plant height) and horizontal (i.e., basal diameter or crown width) directions is crucial for understanding the growth mechanisms of plants themselves. The study of the allometric growth relationships of biomasses among plant components is a hot topic. By investigating the allometric growth relationships of biomasses among plant components, we can not only enrich and optimize existing theories of resource utilization but also provide a scientific basis for multiscale biomass estimation. Notably, the size and number of leaves of annual branches directly determine the canopy morphology and growth mode of plants, which in turn affect the photosynthetic efficiency and carbon utilization capacity of plants. The balance between the size and number of leaves plays a vital role in revealing the differences in leaf size among various plants in nature as well as in the coexistence and maintenance of diversity of different species within the same habitat.
This study, by using S. gordejevii at different sites of the Hunshandake Sandy Land as material, analyzed the allometric growth characteristics and biomass allocation patterns of S. gordejevii fascicular branches. Understanding the adaptability of S. gordejevii to environmental changes and its role in the carbon cycle is of great importance. This study found the following: (1) The growth characteristics of S. gordejevii fascicular branches are significantly influenced by the soil moisture gradient, wherein the growth relationship between branch length and basal diameter demonstrates allometric growth in mobile dunes and interdune lowlands but isometric growth in semifixed and fixed dunes. (2) Biomass allocation exhibits a positive correlation with the soil moisture gradient across different habitats. In particular, in environments with low moisture, S. gordejevii tends to increase biomass allocation to stems to adapt to arid conditions. When moisture conditions improve, allocation to branches increases. (3) The total biomass allocation of S. gordejevii fascicular branches indicates that the biomasses of leaves and stems show an isometric growth relationship in mobile dunes, whereas they have an allometric growth relationship in interdune lowlands. This result suggests that S. gordejevii adapts to environmental changes by adjusting the biomass allocation of leaves and stems in different habitats.

Author Contributions

Conceptualization, G.-H.L. and F.-C.Q.; methodology, G.-H.L. and G.-Z.L.; software, K.Z.; validation, G.-Z.L. and K.Z.; formal analysis, K.Z., S.-Q.Z. and Y.-M.L.; investigation, K.Z., S.-Q.Z. and G.-Z.L.; resources, G.-H.L., F.-C.Q. and Y.-J.Y.; data curation, G.-Z.L., Y.-M.L. and K.Z.; writing—original draft preparation, K.Z.; writing—review and editing, K.Z. and G.-Z.L.; visualization, K.Z.; supervision, G.-H.L. and Y.-J.Y.; project administration, G.-H.L. and F.-C.Q.; funding acquisition, G.-H.L. All authors have read and agreed to the published version of the manuscript.

Funding

This work was funded by Natural Science Foundation of Inner Mongolia Autonomous Region (2021BS03023), National Natural Science Foundation of China (32360422), the Higher Educational Scientific Research Projects of Inner Mongolia Autonomous Region (BR230163), the Science and Technology Research Project of Colleges and Universities in Inner Mongolia Autonomous Region (NJZY21462), the Scientific Research Funding Project for Introduced High-level Talents of IMAU (NDYB2019-22), Inner Mongolia Natural Science Foundation Major Project ‘Natural Science Foundation-Study on the Mechanism of Gully Slope Erosion in Pisha Sandstone Area of the Yellow River Basin’ (2021ZD07); the basic scientific research project of colleges and universities ‘Study on the spatial and temporal variation characteristics of hydraulic erosion under different slope vegetation patterns in the coarse sand area of the Yellow River Basin’ (BR220109); Inner Mongolia Autonomous Region directly under the university basic scientific research business fee ‘Inner Mongolia Yellow River Basin sandy coarse sand area of forest and grass vegetation quality and efficiency of technological innovation team’ (BR22-13-10).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author or first author.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. West, G.B.; Brown, J.H.; Enquist, B.J. A general model for the structure and allometry of plant vascular systems. Nature 1999, 400, 664–667. [Google Scholar] [CrossRef]
  2. Hermans, C.; Hammond, J.P.; White, P.J.; Verbruggen, N. How do plants respond to nutrient shortage by biomass allocation? Trends Plant Sci. 2006, 11, 610–617. [Google Scholar] [CrossRef] [PubMed]
  3. Weiner, J. Allocation, plasticity and allometry in plants. Perspect. Plant Ecol. Evol. Syst. 2004, 6, 207–215. [Google Scholar] [CrossRef]
  4. Thornley, J.H. A balanced quantitative model for root: Shoot ratios in vegetative plants. Ann. Bot. 1972, 36, 431–441. [Google Scholar] [CrossRef]
  5. Gedroc, J.J.; McConnuaghay, K.D.M.; Coleman, M.C.S. Plasticity in root/shoot partitioning: Optimal, ontogenetic, or both? Funct. Ecol. 1996, 10, 44–50. [Google Scholar] [CrossRef]
  6. Bloom, A.J.; Chapin, F.S., III; Mooney, H.A. Resource limitation in plants-an economic analogy. Annu. Rev. Ecol. Syst. 1985, 16, 363–392. [Google Scholar] [CrossRef]
  7. Mccarthy, M.C.; Enquist, B.J. Consistency between an allometric approach and optimal partitioning theory in global patterns of plant biomass allocation. Funct. Ecol. 2007, 21, 713–720. [Google Scholar] [CrossRef]
  8. Gleeson, S.K.; Tilman, D. Allocation and the transient dynamics of succession on poor soils. Ecology 1990, 71, 1144–1155. [Google Scholar] [CrossRef]
  9. Poorter, H.; Jagodzinski, A.M.; Ruiz-Peinado, R.; Kuyah, S.; Luo, Y.J.; Oleksyn, J.; Usoltsev, V.A.; Buckley, T.N.; Reich, P.B.; Sack, L. How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents. New Phytol. 2015, 208, 736–749. [Google Scholar] [CrossRef]
  10. Chen, G.P.; Zhao, W.Z. Age class effect of metabolic index of Salix psammophila. Appl. Ecol. 2016, 27, 1870–1876. (In Chinese) [Google Scholar] [CrossRef]
  11. Enquist, B.J.; Niklas, K.J. Global allocation rules for patterns of biomass partitioning in seed plants. Science 2002, 295, 1517–1520. [Google Scholar] [CrossRef]
  12. Falster, D.S.; Duursma, R.A.; Ishihara, M.I.; Barneche, D.R.; FitzJohn, R.G.; Vårhammar, A.; Aiba, M.; Ando, M.; Anten, N.; Aspinwall, M.J.; et al. BAAD: A Biomass And Allometry Database for woody plants. Ecology 2015, 96, 1445. [Google Scholar] [CrossRef]
  13. Arhonditsis, G.B.; Shimoda, Y.; Kelly, N.E. Allometric Theory: Extrapolations From Individuals to Ecosystems. Encycl. Ecol. 2019, 2, 242–255. [Google Scholar] [CrossRef]
  14. Meng, H.; Yin, B.; Li, Y.; Zhou, X.; Zhang, Y.; Tao, Y.; Zhou, D. Differences and allometric relationships among assimilative branch traits of four shrubs in Central Asia. Front. Plant Sci. 2022, 13, 1064504. [Google Scholar] [CrossRef] [PubMed]
  15. Yang, X.; Zhang, W.; He, Q. Effects of intraspecific competition on growth, architecture and biomass allocation of Quercus liaotungensis. J. Plant Interact. 2019, 14, 284–294. [Google Scholar] [CrossRef]
  16. Li, Y.; Sun, J.; Li, J.; Wang, D.; Chen, S.; Xu, Y.; Cai, N. Biomass allocation and its allometric growth of Pinus yunnanensis seedlings of different families. J. Beijing For. Univ. 2021, 43, 18–28. [Google Scholar] [CrossRef]
  17. Fan, L.; Ding, J.; Ma, X.; Li, Y. Ecological biomass allocation strategies in plant species with different life forms in a cold desert, China. J. Arid Land 2019, 11, 729–739. [Google Scholar] [CrossRef]
  18. Müller, I.; Schmid, B.; Weiner, J. The effect of nutrient availability on biomass allocation patterns in 27 species of herbaceous plants. Perspect. Plant Ecol. Evol. Syst. 2000, 3, 115–127. [Google Scholar] [CrossRef]
  19. Cheng, D.; Ma, Y.; Zhong, Q.; Xu, W. Allometric scaling relationship between above- and below-ground biomass within and across five woody seedlings. Ecol. Evol. 2014, 4, 3968–3977. [Google Scholar] [CrossRef]
  20. Niklas, K.J.; Enquist, B.J. Canonical rules for plant organ biomass partitioning and annual allocation. Am. J. Bot. 2002, 89, 812–819. [Google Scholar] [CrossRef]
  21. Niklas, K.J.; Enquist, B.J. On the Vegetative Biomass Partitioning of Seed Plant Leaves, Stems, and Roots. Am. Nat. 2002, 159, 482–497. [Google Scholar] [CrossRef] [PubMed]
  22. Cheng, D. Study on the Correlation between Plant Biomass Allocation Pattern and Growth Rate. Ph.D. Dissertation, Lanzhou University, Lanzhou, China, 2007. (In Chinese). [Google Scholar]
  23. Li, C.; Li, G.; Xiao, C. Application of allometric relationship in terrestrial ecosystem biomass estimation. World Sci. Technol. Res. Dev. 2007, 29, 51–57. (In Chinese) [Google Scholar] [CrossRef]
  24. Wu, X.; Zheng, X.; Mu, X.; Li, Y. Differences in Allometric Relationship of Two Dominant Woody Species Among Various Terrains in a Desert Region of Central Asia. Front. Plant Sci. 2021, 12, 754887. [Google Scholar] [CrossRef]
  25. Gao, X.; Li, Z.; Yu, H.; Jiang, Z.; Wang, C.; Zhang, Y.; Qi, L.; Shi, L. Modeling of the height–diameter relationship using an allometric equation model: A case study of stands of Phyllostachys edulis. J. For. Res. 2016, 27, 339–347. [Google Scholar] [CrossRef]
  26. Vieilledent, G.; Vaudry, R.; Andriamanohisoa, S.; Rakotonarivo, O.S.; Randrianasolo, H.; Razafindrabe, H.N.; Rakotoarivony, C.; Ebeling, J.; Rasamoelina, M.S. A universal approach to estimate biomass and carbon stock in tropical forests using generic allometric models. Ecol. Appl. Publ. Ecol. Soc. Am. 2012, 22, 572–583. [Google Scholar] [CrossRef]
  27. Hulshof, C.; Swenson, N.G.; Weiser, M.D. Tree height–diameter allometry across the United States. Ecol. Evol. 2015, 5, 1193–1204. [Google Scholar] [CrossRef]
  28. Niklas, K.J. Plant allometry: Is there a grand unifying theory? Biol. Rev. 2004, 79, 871–889. [Google Scholar] [CrossRef]
  29. Yang, J.; Zhang, M.; Zhang, J.; Lu, H.; Hauer, R.J. Allometric Growth of Common Urban Tree Species in Qingdao City of Eastern China. Forests 2023, 14, 472. [Google Scholar] [CrossRef]
  30. Fan, G.; Zhang, J.; Huang, Y.; Shen, X.; Yu, P.; Zhao, X. Influence of population density on morphological traits and allometric growth of Corispermum macrocarpum. Acta Ecol. Sin. 2018, 38, 3931–3942. [Google Scholar] [CrossRef]
  31. Thomas, S.C. Asymptotic height as a predictor of growth and allometric characteristics in malaysian rain forest trees. Am. J. Bot. 1996, 83, 556–566. [Google Scholar] [CrossRef]
  32. Li, S.; Zheng, X.J.; Tang, L.S.; Li, Y. Morphological investigation of desert shrubs of China’s Junggar Basin based on allometric theory. J. Plant Ecol. 2011, 35, 471–479. (In Chinese) [Google Scholar] [CrossRef]
  33. Ma, W.; Wang, X.; Zhou, N.; Jiao, L. Relative importance of climate factors and human activities in impacting vegetation dynamics during 2000–2015 in the Otindag Sandy Land, northern China. J. Arid Land 2017, 9, 558–567. [Google Scholar] [CrossRef]
  34. Wang, H.Y.; Li, Z.Y.; Gao, Z.H.; Wu, J.; Sun, B.; Li, C.L. Assessment of land degradation using time series trend analysis of vegetation indictors in Otindag Sandy land. IOP Conf. Ser. Earth Environ. Sci. 2014, 17, 012065. [Google Scholar] [CrossRef]
  35. Gong, X.W.; Guo, J.J.; Fang, L.D.; Bucci, S.J.; Goldstein, G.; Hao, G.Y. Hydraulic dysfunction due to root-exposure-initiated water stress is responsible for the mortality of Salix gordejevii shrubs on the windward slopes of active sand dunes. Plant Soil 2021, 459, 185–201. [Google Scholar] [CrossRef]
  36. Su, H.; Li, Y.; Lan, Z.; Xu, H.; Liu, W.; Wang, B.; Biswas, D.K.; Jiang, G. Leaf-level plasticity of Salix gordejevii in fixed dunes compared with lowlands in Hunshandake Sandland, North China. J. Plant Res. 2009, 122, 611–622. [Google Scholar] [CrossRef] [PubMed]
  37. Zhang, R.L.; Liu, G.H.; Cui, X.P. Effects of Living Salix gordejevii Barrier on Wind-breaking and Sand-fixation in Hunshandake Sandland. J. Desert Res. 2006, 26, 717–721. [Google Scholar]
  38. Liu, B.; Zhang, R.; Liu, G. Research on the Effect of Wind-breaking and Sand-fixation of Salix gordejevii Living Sand Barriers in Hunshandake Sandy Land. J. Inn. Mong. For. Sci. Technol. 2010, 36, 12–15+20. [Google Scholar]
  39. Cui, X.; Liu, G.; Zhang, R. Root Distribution and Biomass of Salix gordejevii in Hunshandake Sandland. J. Desert Res. 2011, 31, 447–450. [Google Scholar]
  40. Cui, X.; Liu, G. Characteristics and Rules of Regeneration of Salix gordejevii in Hunshandak Sandland. J. Desert Res. 2012, 32, 60–64. [Google Scholar]
  41. Liang, Y.; Gao, Y.; Ren, A.; Chen, S.; Liu, N.; Liu, S. Quantitative characteristics of Salix gordejevii population in different sandy land habitats. Acta Ecol. Sin. 2000, 1, 81–88. [Google Scholar]
  42. Liu, G. Study on Allometric Growth and Ecological Adaptability of Salix gordejevii in Hunshandake Sandy Land. Ph.D. Dissertation, Inner Mongolia Agricultural University, Hohhot, China, 2017. (In Chinese). [Google Scholar]
  43. Zhu, J.D.; Meng, T.T.; Ni, J.; Su, H.X.; Xie, Z.Q.; Zhang, S.R.; Zheng, Y.R.; Xiao, C.W. Allometric relationships among leaf traits of mature forests in different climatic zones vary with functional types. Plant Ecol. 2011, 35, 687–698. (In Chinese) [Google Scholar] [CrossRef]
  44. Bourque, C.P.A.; Bayat, M.; Zhang, C. An assessment of height–diameter growth variation in an unmanaged Fagus orientalis-dominated forest. Eur. J. For. Res. 2019, 138, 607–621. [Google Scholar] [CrossRef]
  45. Zhou, X.J.; Wei, C.B.; Zhang, Q.S.; Yan, L.; Wen, Y.P. Joint analysis model of allometric growth relationship between multiple parts and the whole. Agric. Mech. Res. 2015, 37, 31–36. (In Chinese) [Google Scholar] [CrossRef]
  46. Ma, Y.Y.; Jiang, L.C. Error structure and error function of allometric growth model. For. Sci. 2018, 54, 90–97. (In Chinese) [Google Scholar] [CrossRef]
  47. Wu, X.-H. Rapid Vegetation Recovery in Hunshandake Sandy Land; Inner Mongolia University Press: Hohhot, China, 2003. [Google Scholar]
  48. Zhang, Y.J.; Hochberg, U.; Rockwell, F.E.; Ponomarenko, A.; Chen, Y.J.; Manandhar, A.; Graham, A.C.; Holbrook, N.M. Xylem conduit deformation across vascular plants: An evolutionary spandrel or protective valve? N. Phytol. 2023, 237, 1242–1255. [Google Scholar] [CrossRef]
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Figure 1. Distribution of the variables basal diameter and length of S. gordejevii fascicular branches in the four different site types.
Figure 1. Distribution of the variables basal diameter and length of S. gordejevii fascicular branches in the four different site types.
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Figure 2. Illustration of the allometric growth of the length and basal diameter of S. gordejevii fascicular branches.
Figure 2. Illustration of the allometric growth of the length and basal diameter of S. gordejevii fascicular branches.
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Figure 3. Visualization of the aboveground component biomass of S. gordejevii fascicular branches.
Figure 3. Visualization of the aboveground component biomass of S. gordejevii fascicular branches.
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Figure 4. Biomass allocation proportion of S. gordejevii overgrowing branches.
Figure 4. Biomass allocation proportion of S. gordejevii overgrowing branches.
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Figure 5. Allometric growth relationship between the leaf and stem biomasses of S. gordejevii fascicular branches.
Figure 5. Allometric growth relationship between the leaf and stem biomasses of S. gordejevii fascicular branches.
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Figure 6. Allometric growth relationship between the branch and stem biomasses of S. gordejevii fascicular branches.
Figure 6. Allometric growth relationship between the branch and stem biomasses of S. gordejevii fascicular branches.
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Figure 7. Allometric growth relationships between the leaf and branch biomasses of S. gordejevii fascicular branches.
Figure 7. Allometric growth relationships between the leaf and branch biomasses of S. gordejevii fascicular branches.
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Figure 8. Allometric growth relationship between the total and stem biomasses of S. gordejevii fascicular branches.
Figure 8. Allometric growth relationship between the total and stem biomasses of S. gordejevii fascicular branches.
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Figure 9. Allometric growth relationship between the total and branch biomasses of S. gordejevii fascicular branches.
Figure 9. Allometric growth relationship between the total and branch biomasses of S. gordejevii fascicular branches.
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Figure 10. Allometric growth relationship between the total and leaf biomasses of S. gordejevii fascicular branches.
Figure 10. Allometric growth relationship between the total and leaf biomasses of S. gordejevii fascicular branches.
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Table 1. Overview of site conditions of S. gordejevii plots.
Table 1. Overview of site conditions of S. gordejevii plots.
Site TypeGradientAspectElevationLongitudeLatitude
MD15°–30°Lee slope1275–1292 m115°36′7189″42°54′2529″
SD12°–25°Lee slope1267–1341 m115°41′7402″42°53′9269″
FD—Gentle1302–1314 m115°58′2208″42°29′4476″
DS—Gentle1323–1330 m115°57′2117″42°41′4752″
Note: MD denotes shifting sandy land; SD denotes semifixed sandy land; FD denotes fixed sand land; DS denotes interdune lowland.
Table 2. SMA analysis of the allometric growth of the length and basal diameter of S. gordejevii fascicular branches.
Table 2. SMA analysis of the allometric growth of the length and basal diameter of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Slope Multiple TestIntercept
1234
MD590.650 **1.270 (1.086–1.484) **1   0.8088
SD300.503 **0.912 (0.696–1.194) NS*1  1.2699
FD460.509 **0.977 (0.791–1.206) NS*NS1 1.2533
DS100.354 *0.519 (0.281–0.961) ***NSNS11.8384
All1450.492 **1.574 (1.399–1.770) **     
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 3. Allometric growth analysis of the leaf and stem biomasses of S. gordejevii fascicular branches.
Table 3. Allometric growth analysis of the leaf and stem biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Slope Multiple TestIntercept
1234
MD430.520 **1.007 (0.810–1.250) NS1   −1.142
SD400.001 NS0.951 (0.683–1.325) NSNS1  −0.625
FD490.009 NS1.074 (0.805–1.433) NSNSNS1 −1.150
DS100.856 **0.512 (0.377–0.694) ********10.029
All1420.201 **1.215 (1.046–1.411) *     
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 4. SMA analysis of the allometric growth of the branch and stem biomasses of S. gordejevii fascicular branches.
Table 4. SMA analysis of the allometric growth of the branch and stem biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Intercept of the Common SlopeIntercept Drift Test
1234
MD580.518 **1.331 (1.107–1.602) **−1.4561   
SD400.117 *1.395 (1.029–1.890) *−1.147**1  
FD490.505 **1.553 (1.265–1.906) **−1.286***1 
DS100.434 *0.842 (0.471–1.505) NS−1.087**NS*1
All1570.480 **1.574 (1.404–1.764) ** 
Common slope1.384 (1.229–1.570) NS
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 5. SMA analysis of the allometric growths of the leaf and branch biomasses of S. gordejevii fascicular branches.
Table 5. SMA analysis of the allometric growths of the leaf and branch biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Slope Multiple TestIntercept
1234
MD550.520 **1.105 (0.914–1.336) NS1   −0.328
SD350.569 **0.937 (0.744–1.18) NSNS1  −0.086
FD350.494 **0.655 (0.511–0.841) *****1 −0.034
DS100.528 *0.619 (0.346–1.106) NSNSNSNS10.045
All1350.640 **0.921 (0.831–1.021) NS     
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 6. SMA analysis of the allometric growth of the total and stem biomasses of S. gordejevii fascicular branches.
Table 6. SMA analysis of the allometric growth of the total and stem biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Intercept of the Common SlopeIntercept Drift Test
1234
MD600.974 **0.970 (0.930–1.013) NS0.1541   
SD400.809 **0.841 (0.729–0.970) *0.263**1  
FD490.918 **0.988 (0.908–1.074) NS0.217****1 
DS100.968 **0.851 (0.735–0.985) *0.283**NS*1
All1590.915 **1.008 (0.962–1.055) NS     
Common slope0.957 (0.924–0.994) *
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 7. Standardized major axis analysis of the allometric growths of the total and branch biomasses of S. gordejevii fascicular branches.
Table 7. Standardized major axis analysis of the allometric growths of the total and branch biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Intercept of the Common SlopeIntercept Drift Test
1234
MD600.535 **0.690 (0.577–0.825) **1.2001   
SD400.476 **0.603 (0.477–0.763) **1.090**1  
FD490.743 **0.636 (0.549–0.738) **1.142NSNS1 
DS100.603 **1.010 (0.617–1.655) NS1.079**NSNS1
All1590.693 **0.618 (0.561–0.674) **     
Common slope0.660 (0.594–0.728) **
Note: “**” denotes significance at p < 0.01. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
Table 8. SMA analysis of the allometric growths of the total and leaf biomasses of S. gordejevii fascicular branches.
Table 8. SMA analysis of the allometric growths of the total and leaf biomasses of S. gordejevii fascicular branches.
Site TypeSample SizeR2Slope (95% Confidence Interval)Slope Multiple TestIntercept
1234 
MD560.448 **0.730 (0.597–0.893) **1   1.326
SD400.099 *0.794 (0.584–1.079) NSNS1  1.106
FD420.327 **0.949 (0.732–1.229) NSNSNS1 1.165
DS100.823 **1.663 (1.187–2.329) ********10.426
All1480.493 **0.731 (0.651–0.210) **     
Note: “**” denotes significance at p < 0.01. “*” denotes significance at p < 0.05. “NS” denotes nonsignificance. The “R2” column indicates the significance of the regression relationship. The “Slope (95% CI)” column indicates the significance of the difference between the allometric growth index and the theoretical value. The “Slope multiple comparison” column indicates the significance of the intergroup differences of the slope. The “Intercept drift test” column indicates the significance of the differences in intercept drift, and the same applies below.
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Liu, G.-Z.; Zhao, K.; Zhang, S.-Q.; Liang, Y.-M.; Yue, Y.-J.; Liu, G.-H.; Qin, F.-C. Biomass Allocation and Allometric Relationship of Salix gordejevii Branches in Sandy Habitats Heterogeneity in Northern China. Sustainability 2024, 16, 5483. https://doi.org/10.3390/su16135483

AMA Style

Liu G-Z, Zhao K, Zhang S-Q, Liang Y-M, Yue Y-J, Liu G-H, Qin F-C. Biomass Allocation and Allometric Relationship of Salix gordejevii Branches in Sandy Habitats Heterogeneity in Northern China. Sustainability. 2024; 16(13):5483. https://doi.org/10.3390/su16135483

Chicago/Turabian Style

Liu, Guan-Zhi, Kai Zhao, Shi-Qi Zhang, Yu-Mei Liang, Yong-Jie Yue, Guo-Hou Liu, and Fu-Cang Qin. 2024. "Biomass Allocation and Allometric Relationship of Salix gordejevii Branches in Sandy Habitats Heterogeneity in Northern China" Sustainability 16, no. 13: 5483. https://doi.org/10.3390/su16135483

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