Search Results (1,600)

Grain filling is a vital factor influencing both rice grain yield and quality, yet its underlying mechanisms remain poorly understood. In this study, we perform a functional analysis of the grain-filling defective mutant pex1 in rice. pex1 plants produce seeds that are floury, thick-branched, and exhibit a significantly slower grain-filling rate compared to the wild type. Further analysis reveals that the pex1 mutants accumulated more starch in the pericarp but exhibited a defect in starch accumulation in the endosperm during grain filling, indicating an impaired transport of photosynthetic products from the pericarp to the endosperm. Cells within the nucellar projection in the pex1 mutant appear irregular and loose loosely arranged, consistent with defective transfer of assimilates. Expression analysis reveals a downregulation of key grain-filling genes during the filling phase in the pex1 mutant compared to the wild type, which correlates with the reduced grain-filling rate. Subcellular localization suggests that OsPEX1 is associated with the endoplasmic reticulum. Our findings demonstrate that OsPEX1 plays a crucial role in grain filling. Full article

Photosynthesis is an essential plant biological process. The performance of photosynthesis in grafted plants is affected by either the scion or the rootstock. However, the effect of the scion, rootstock and their interaction in the scion–rootstock combinations on photosynthesis of the grafted trees was not clear. In this research, the photosynthesis was analyzed within 21 citrus scion–rootstock combinations derived from three navel oranges (Citrus sinensis cv. ‘Banfield’, ‘Chislett’ and ‘Powell’) grafted on seven rootstocks [(Swingle citrumelo (C. paradisi × Poncirus trifoliata), Carrizo citrange (C. sinensis × P. trifoliata), X639 (C. reticulata × P. trifoliata), MXT (C. sinensis × P. trifoliata), Hongju (C. reticulata), Ziyang xiangcheng (C. junos) and Trifoliate orange (P. trifoliata)]. Results indicated that photosynthesis of these grafted citrus plants was significantly affected by all the scion, rootstock and their interaction. The rootstock and scion–rootstock interaction had more effect on both chlorophyll fluorescence and photosynthetic parameters with lower p values than the scion. All the scions grafted on Swingle showed the highest electron transport rate at 132.24, 158.39 and 154.59 µmol electrons m⁻² s⁻¹, and a higher net CO₂ assimilation rate at 11.22, 10.77 and 11.69 µmol m⁻² s⁻¹, respectively. The rootstock is the predominant factor affecting the content of photosynthetic pigments, and the combinations using Ziyang xiangcheng as the rootstock had the highest content at 19.83, 20.97 and 20.39 μmol s⁻¹ Kg⁻¹ FW. Electron transport rate is probably the predominant factor determining the final photosynthesis of the grafted citrus trees. This research is the first to reveal the respective effect of the scion, rootstock and their interaction on photosynthesis of citrus scion–rootstock combinations and is valuable in enhancing the understanding of the different performances in citrus scion–rootstock combinations, which aids in selecting optimal scion–rootstock combinations. Full article

In this study, we aimed to evaluate physiological and agronomic traits in 120 sugarcane genotypes under early drought stress conditions in a field trial across various soil types. The experiment used a split-plot arrangement, with a randomized complete block design and two replications. Two different water regimes were assigned to the main plot: (1) non-water stress (CT) and (2) drought (DT) at the early growth stage, during which sugarcane was subjected to drought stress by withholding water for 4 months. The subplot consisted of 120 sugarcane genotypes. The stalk height, stalk diameter, number of stalks, photosynthetic traits including SPAD chlorophyll meter reading (SCMR) and maximum quantum efficiency of photosystem II photochemistry (Fv/Fm), and normalized difference vegetation index (NDVI) were measured at 3, 6, and 9 months after planting (MAP). Yield and yield component parameters were measured at 12 MAP. Drought treatments lead to significant changes in various physiological traits in the sugarcane. Clustering analysis classified 36 sugarcane varieties grown in sandy loam soil and 15 genotypes in loam soil into two main clusters. In sandy loam soils, Biotec4 and CO1287 exhibited outstanding performance in drought conditions, delivering high cane yields. Meanwhile, in loam soil, MPT13-118, MPT07-1, Q47, F174, MPT14-1-902, and UT1 exhibited the best drought tolerance. Under drought conditions, cluster 1 showed higher values for SCMR, NDVI, height growth rate (HGR), cane yield, and drought tolerance index compared to cluster 2. These findings suggest that breeders can utilize these genotypes to enhance drought resistance, and the identified physiological traits can assist in selecting stronger candidates for drought tolerance. Full article

This study compared the effects of two C3 forages (Italian ryegrass [RG], Timothy grass [TG]) and two C4 forages (Klein grass [KG], Bermuda grass [BG]) on growth performance, nutrient digestibility, and nitrogen (N) balance in Korean crossbred black goats to evaluate C4 warm-season forages as alternatives under changing climate conditions. Sixteen castrated goats (10 months old) were allocated to four treatments using a randomized complete block design. Diets contained 40% treatment-specific forage and 60% commercial concentrate. After adaptation periods, a 5-day metabolism trial measured performance and digestibility parameters. No significant differences occurred among treatments for growth performance or digestibility of dry matter, crude protein, neutral detergent fiber, ash, and non-fiber carbohydrate. C4 grasses showed significantly lower acid detergent fiber and ether extract digestibility than C3 grasses, with KG having the lowest ether extract digestibility. The KG group had higher N intake and absorption than the TG group, while BG showed lower urinary and total N excretion than KG. No differences existed in retained N, utilization efficiency, or biological value among groups. Both C3 and C4 forages supported comparable goat growth performance, providing a reference for utilizing different photosynthetic pathway forages under changing climatic conditions. Full article

Under refined management, high-yield cotton fields are approaching their maximum output. However, how to break this yield upper limit, specifically the source–sink relationship is still inadequately researched. This experiment was conducted to explore the interaction mechanism between yield formation and source–sink parameters (photosynthesis, nitrogen content, canopy structure and dry matter accumulation and distribution). The treatments consisted of a no cutting source and sink treatment (CK), cutting 1/2 leaves per plant (1/2L) and cutting 1/2 bolls per plant (1/2B) at the initial flowering stage (IFS), the flower and boll stage (FABS), and the full boll stage (FBS). The results showed that 1/2L treatment minimized yield losses to 2.3–5.9% by enhancing photosynthetic compensation, with FBS-1/2L showing the smallest reduction (2.3–2.9%) due to higher leaf N content and SPAD values, whereas, the 1/2B treatments resulted in significant yield losses attributable to fewer bolls, especially the FBS-1/2B treatments, which reduced yields by 35.7–41.9%, with a compensatory rate of only 8.1–14.3%. It is noteworthy that the compensation rates of IFS-1/2B and FABS-1/2B could reach 26.7–32.3% and 18.7–23.8% of their yields due to the higher leaf N content. In a word, the source damage can be buffered by physiological compensation, while the sink loss leads to yield collapse due to the irreversibility of reproductive development. Thus, the core regulator of high-yield cotton fields was sink strength. Accordingly, optimizing the sink quality was performed through moderate boll thinning at the IFS, enhancing water and fertilizer supply at the FABS and strengthening sink organ protection at the FBS in order to realize a breakthrough in yield limit. Full article

Pecan (Carya illinoinensis [Wangenh]. K. Koch) germplasm resources are abundant, yet the characteristics of each cultivar at the seedling stage remain insufficiently understood. This study systematically evaluated the growth parameters, photosynthetic traits, and anatomical structures of one-year-old grafted seedlings from five pecan cultivars: “Pawnee”, “Mandan”, “Nacono”, “Caddo”, and “Creek”. Principal component analysis (PCA) was employed to comprehensively assess 56 indicators. The results indicated that, in terms of vegetative growth, leaf area and biomass of “Nacono” and “Creek” were significantly greater than those of “Pawnee” (p < 0.05). “Mandan” ranked second. Additionally, the seedling quality index of “Creek” was markedly superior to all other cultivars (p < 0.05). Anatomically, “Pawnee” exhibited greater leaf thickness, more highly differentiated palisade tissue, and the development of the main vein. By contrast, “Mandan” displayed larger branch radius, cortex thickness, and pith radius, accompanied by finer vessels and large but sparsely distributed stomata (p < 0.05). Regarding photosynthetic performance, “Mandan” accumulated the highest concentrations of photosynthetic pigments and achieved the greatest photosynthetic efficiency, significantly outperforming the remaining cultivars (p < 0.05). The PCA-based comprehensive evaluation revealed that “Mandan” outperformed the other cultivars in seedling growth, making it the most suitable for promotion, followed by “Creek”, “Nacono”, “Caddo”, and “Pawnee”. This research offers a theoretical foundation for the breeding, promotion, and application of superior pecan cultivars. Full article

Ultraviolet B (UV-B) radiation is a key environmental factor that limits plant growth and development. High UV-B intensity is a typical environmental feature in Turpan-Hami (Tuha) Basin in Xinjiang, China. In this study, the altitude-dependent UV-B adaptation strategies of plants in Tuha Basin were analyzed. Chlorophyll (Chl) and flavonoid (Fla) play an important role in absorbing UV-B radiation, scavenging free radicals, and maintaining photosynthetic performance under UV-B stress. Principal component analysis indicated that the total chlorophyll (Chl t), Chl a, Chl b, and Fla contents and the Chl a/Chl b ratio are important indicators for evaluating plant tolerance to UV-B. Noticeably, with increased altitudes, the roles of Chl b, Chl a/Chl b, and Fla become markedly significant. The characteristics of stomata, epidermal hair, and wax layer are closely correlated with the UV-B amount that reaches leaves. Epidermal hair density and cuticle thickness in leaves decreased with increased altitudes, whereas hydrogen oxide (H₂O₂) was significantly accumulated, but superoxide anion (O₂⁻) remained unchanged. High altitude significantly increased the stomatal apparatus area, density and specific leaf area. Moreover, plants without epidermal hair had a larger stomatal apparatus area compared with plants with epidermal hair. However, the presence or absence of epidermal hair had no effect on cuticle thickness, H₂O₂ and O₂⁻ levels. The carbon (C), nitrogen (N), and hydrogen (H) contents were high in plant leaves at high altitude, but the sulfur (S) content and C/N ratio were low. Taken together, plants in Tuha Basin could cope with UV-B radiation by synergistically regulating epidermal structures and synthesis of secondary metabolites. Meanwhile, these plants could further allocate and reconstruct organic elements to optimize their resource distribution in adaptation to UV-B radiation with different altitudes. Full article

Subsurface drip irrigation can improve crop water and fertilizer use efficiency, but it can cause soil hypoxia. We report on experiments performed in Aksu Prefecture, Xinjiang (41°17′ N latitude, 80°17′ E longitude), from April 2023 to October 2024 using oxygenated drip irrigation from the surface to 50 cm depth in an apple (Malus pumila Mill.) orchard, to examine the effects of drip irrigation on inter-root hypoxia, tree growth, fruit quality, and yield. Compared with surface oxygenated drip irrigation (CK), irrigating at 10 and 30 cm increased soil water content in the root system, elevated gibberellin, zeatin ribosides, and indoleacetic acid contents and reduced abscisic acid contents in new shoot tips. Compared with CK, branch and leaf nitrogen, phosphorus, and potassium contents were increased with irrigation at depths of 10 and 30 cm. The leaf nitrogen (N), phosphorus (P), and potassium (K) contents were increased by 18.03%, 22.42%, and 16.63%, respectively, in the treatment with a burial depth of 30 cm. Among treatments, irrigation at 30 cm produced the highest average daily plant water potential, and irrigation at 50 cm was the lowest. Maximum leaf soil–plant analysis development (SPAD) values occurred when irrigated at 30 cm, and minimum values occurred at 50 cm. For both years, the largest range of light flux utilization occurred when irrigated at 30 cm and the lowest when irrigated at 50 cm. Significant correlations between indoleacetic acid (IAA), total gibberellin (GA), zeatin riboside (ZRs), leaf N content, leaf K content, plant water potential (PWP), net photosynthetic rate (Pn), SPAD, and apple yield were determined by partial mantel analysis. A significant correlation was found between abscisic acid (ABA), IAA, GA, leaf P and K content, and apple quality. Principal component analysis revealed a burial depth of 30 cm had the highest principal component composite score, indicating that this burial depth, and oxygenation and fertilization regime most favored apple growth, yield, and quality. Full article

The photochemical efficiency of photosystem II (PSII) was monitored in two-year-old seedlings from six Chilean woody sclerophyllous species differing in foliage habits (evergreen, deciduous, semi-deciduous) and leaf orientation. A common garden experiment was established in July 2020 in a Mediterranean-type climate site under two watering regimes (2 L⁻¹ seedling⁻¹ week⁻¹ for 5 months versus no irrigation). Chlorophyll a fluorescence rise kinetics (OJIP) and JIP test analysis were monitored from December 2021 to January 2022. The semi-deciduous Colliguaja odorifera (leaf angle of 65°) exhibited the highest performance in processes such as absorption and trapping photons, heat dissipation, electron transport, and level of photosynthetic performance (i.e., parameters PI_ABS F_V/F_M, F_V/F₀, and ΔV_IP). In contrast, the evergreen Peumus boldus (leaf rolling) exhibited the opposite behavior for the same parameters. On the other hand, the deciduous Vachelia caven (small compound leaves and leaf angle of 15°) showed the lowest values for minimal and maximal fluorescence (F₀ and F_M) and the highest area above the OJIP transient (S_m) during the study period. Irrigation decreased S_m and the relative contribution of electron transport (parameter ΔV_IP) by 22% and 17%, respectively, but no clear effects of the irrigation treatments were observed among species and dates of measurement. Overall, V. caven and C. odorifera exhibited the highest photosynthetic performance, whereas P. boldus seemed to be more prone to photoinhibition. We conclude that different foliar adaptations among species influence light protection mechanisms more than irrigation treatments. Full article

We present a computational approach for performing the Gaussian decomposition (GD) of experimental spectral data, called evolutionary Gaussian decomposition (EGD). The key feature of EGD is its ability to estimate the optimal number of Gaussian components required to fit a target function, which can be any experimental functional dependence. The efficiency and robustness of EGD are achieved through the use of the differential evolution (DE) algorithm, which allows us to tune the performance of the method. Based on statistics from the independent trials of DE, EGD can determine the number of Gaussians above which further improvement in fit quality does not occur. EGD works by collecting statistics on local minima in the vicinity of the estimated optimal number of Gaussians, and, if necessary, repeats this process several times during optimization until the desired results are obtained. The method was tested using both synthetic spectral-like functions and measured spectra of photosynthetic pigments. In addition to the local minima statistics, the most significant factors that affect the results of the analysis were the median and minimum values of the cost function. These values were obtained for each different number of Gaussian functions used in the evaluation process. Full article

An appropriate drip irrigation amount and the straw return method are important ways to save water and achieve efficient maize production in semi-arid areas. A 2-year controlled field plot experiment was performed with two factors: straw return (straw removal, straw mulching) and differing drip irrigation amounts (200, 350, and 500 mm). Changes in growth, development, photosynthesis, yield, the components, and the water-use characteristics of maize under the intercropping conditions of drip irrigation amount and straw return were studied. The results showed that an increase in drip irrigation favored an increase in the net photosynthetic rate (P_n), stomatal conductance (G_s), and intercellular carbon dioxide concentration (C_i) of maize, and promoted an increase in maize plant height and leaf area index, which resulted in the accumulation of more dry matter and increased the maize yield. Compared with straw removal, straw mulching maintained a higher photosynthetic capacity at the later stages of maize growth and development under irrigations of 200 and 350 mm; the average increase in P_n over two years ranged from 4.06 to 19.19%; and good plant growth was maintained, thereby leading to the accumulation of more dry matter, with the average increase over two years ranging from 0.51 to 27.22%. Straw mulching also significantly improved water-use efficiency (WUE) at 350 mm of irrigation, with the average increase in yield over two years ranging from 4.58 to 4.83%. Overall, straw mulching had a positive impact on maize when irrigation was low, and when it was high, straw mulching did not adversely affect maize. Therefore, irrigation combined with straw mulching technology may be used to improve maize yield and WUE in semi-arid areas of Jilin Province. Full article

Low inner leaves in the thick canopy of dense Chinese fir plantations frequently show premature senescence and dieback regardless of age. To elucidate the underlying mechanisms, a 28-day growth chamber experiment was conducted under dark conditions to induce leaf senescence. Changes in leaf area, photosynthetic performance, and the responses of carbon metabolism and the antioxidant defense system were analyzed. Leaf area decreased significantly with time in darkness. The photosystem II reaction center was damaged, and fluorescence parameters and chlorophyll contents decreased, resulting in reduced light energy capture and conversion efficiencies. Photosynthetic rate, apparent quantum yield, stomatal conductance, transpiration rate, and light use efficiency all decreased, while the light compensation point and intercellular CO₂ concentration increased. Antioxidant enzyme activities initially increased but eventually collapsed as the stress continued and H₂O₂ and malondialdehyde accumulated, causing membrane conductivity, i.e., membrane permeability, to increase by 122%. Meanwhile, reduced non-structural carbohydrates, especially total non-structural carbohydrates content, decreased by 45.32%, triggering sugar starvation and accelerating aging. Our study provided new physiological evidence for light-stress response mechanisms in Chinese fir. Specifically, it revealed that dark-induced leaf senescence was mainly caused by irreversible damage to the photosynthetic apparatus and oxidative stress, which together led to carbon starvation and ultimately death. Full article

Bonellia nervosa is an understory tree with reverse phenology in tropical dry forests (TDFs), where seasonal water and temperature stress typically shape plant phenology and trait expression. This species is heliophytic and phreatophytic, relying on high light availability and deep-water access during the dry season. However, the role of dry-season light variation in influencing leaf traits of species with inverted phenology remains poorly understood. We examined how plant size, reproductive stage, and canopy structure influence trait variation in B. nervosa during the dry season. We measured plant height and diameter, reproductive status, and canopy structure using hemispherical photographs to estimate canopy openness, leaf area index, and transmitted light. Leaf structural traits included specific leaf area (SLA), thickness, water content, and stomatal density, while photochemical performance was assessed via chlorophyll fluorescence and rapid light curves. Principal component analysis and linear regression were used to examine trait–environment relationships. Photosynthetic efficiency was not affected by plant size or reproductive status. No strong trait correlations were observed for leaf water content and stomatal density. A negative relationship between canopy openness, transmitted light, and SLA indicates structural leaf adaptation to light conditions, with lower SLA values occurring under reduced light. In B. nervosa, leaf traits are driven more by light than by water availability during the dry season. This suggests that reverse phenology in phreatophytic species is functionally decoupled from seasonal water stress. Full article

In order to identify saline–alkali-tolerant rapeseed varieties suitable for cultivation on moderately saline–alkali soils and to expand the use of such lands, six rapeseed varieties were selected as experimental materials. Field experiments were conducted to evaluate agronomic traits, photosynthesis, stress physiology, yield, and quality throughout the entire growth period. Statistical methods, including correlation analysis, principal component analysis, membership function analysis, and cluster analysis, were employed to evaluate and select saline–alkali-tolerant varieties. The results indicated that H62 and 20C14 yielded the highest seed production, reaching 2287.99 kg·hm⁻² and 2277.15 kg·hm⁻², respectively. During the mid-to-late growth stages, the majority of agronomic traits, photosynthetic parameters, and stress physiology indicators for 20C14 were significantly superior to those of the other varieties. The results of the principal component analysis showed that the total root length at maturity stage, root–shoot ratio at flowering stage, and proline content at maturity stage were the most important indicators for screening saline–alkali-tolerant rapeseed varieties. A comprehensive analysis of these indicators revealed the following descending order of saline–alkali tolerance among the varieties: 20C14 > 20C17 > 20C4 > H62 > H158 > 17C2. Cluster analysis was performed to classify the rapeseed into strong saline–alkali-tolerant type (20C14 and 20C17), moderate saline–alkali-tolerant type (20C4, H62, and H158), and weak saline–alkali-tolerant type (17C2). Consequently, 20C14 and 20C17 are recommended as suitable rapeseed varieties for cultivation on soda saline–alkali soils. Full article

Tomato (Solanum lycopersicum L.) production in greenhouse systems increasingly relies on integrated fertilization and soil management strategies to enhance yield, fruit quality, and resilience to biotic stressors. This study evaluated the combined effects of five fertilization regimes and two contrasting soil tillage systems—rotary tillage (RT) and conventional plowing (P)—on the performance of greenhouse-grown ‘Bacuni’ tomatoes. Experimental assessments encompassed biometric traits, photosynthetic pigments (chlorophyll and anthocyanins), carotenoid concentrations (carotenes and lycopene), soluble solids, and total dry matter contents, as well as agronomic variables including fruit weight, fruit number, and total yield. Incidence of key pests and diseases, alongside soil compaction levels, were also quantified. Fertilization with Nutriplant 20:20:20, as well as the application of Albit both resulted in a marked stimulation of vegetative growth, while the highest yields were recorded in P × Orgevit + Kerafol (6962.65 g plant⁻¹; +44.6% vs. control) and RT × Albit + Turboroot (6208.22 g plant⁻¹; +16.2% vs. control). Rotary tillage consistently improved nutrient uptake efficiency and yield relative to plowing, highlighting the role of soil structure in modulating plant performance. Treatments with Albit and Turboroot also enhanced resistance to Tetranychus urticae and Xanthomonas campestris, indicating a dual benefit for productivity and phytosanitary status. The results underscore the importance of harmonizing fertilization strategies with soil management practices to optimize greenhouse tomato production. Integrative approaches that combine biostimulants, organic amendments, and soil structural optimization offer a viable pathway toward high-yield, high-quality, and disease-resilient crops in controlled environment agriculture. Full article