Next Article in Journal
Early and Late Season Nutrient Stress Conditions: Impact on Cotton Productivity and Quality
Next Article in Special Issue
Soil Management Strategies in Organic Almond Orchards: Implications for Soil Rehabilitation and Nut Quality
Previous Article in Journal
Development of Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Pyrenophora graminea in Barley Seeds
Previous Article in Special Issue
Effect of Regulated Deficit Irrigation on the Quality of ‘Arbequina’ Extra Virgin Olive Oil Produced on a Super-High-Intensive Orchard
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Physiological Influence of Water Stress Conditions on Novel HLB-Tolerant Citrus Rootstocks

by
Juan M. Arjona-López
1,*,†,
Lidia Aparicio-Durán
1,†,
Frederick G. Gmitter, Jr.
2,
Estefanía Romero-Rodríguez
1,
Jude W. Grosser
2,
Aurea Hervalejo
1 and
Francisco J. Arenas-Arenas
1
1
Department of Agri-Food Engineering and Technology, Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), “Las Torres” Center, Ctra. Sevilla-Cazalla de la Sierra km. 12.2, 41200 Seville, Alcalá del Río, Spain
2
Citrus Research and Education Center, Department of Horticultural Sciences, IFAS, University of Florida, Lake Alfred, FL 33850, USA
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Agronomy 2023, 13(1), 63; https://doi.org/10.3390/agronomy13010063
Submission received: 2 November 2022 / Revised: 16 December 2022 / Accepted: 20 December 2022 / Published: 24 December 2022

Abstract

:
Citrus are one of the most relevant fruit crops in the Mediterranean basin, which is the second-highest citrus-growing region in the world. However, these crops are mainly grown under Mediterranean semi-arid conditions, characterized by long periods of drought and torrential rain. In this work, we have assessed the response of three promising HLB-tolerant citrus rootstocks (Orange-14, UFR-1, and B11R3T27) to the application of four water stress conditions (Control, Mild water stress, Drought, and Flooding), comparing them with Carrizo citrange. Aerial plant symptoms were recorded during the experimental period, whereas plant water parameters, including stomatal conductance, leaf water potential, and relative water content, were obtained at the end of the assay. For all assessed rootstocks and variables, drought treatment was the most limiting factor, with Carrizo citrange being the most suitable rootstock under this condition. Flooding was the second restrictive treatment, in which UFR-1 was the least affected rootstock. Mid-water stress with 50% water requirements did not differ from the Control treatment, which can help save water resources in semi-arid regions. This information can be helpful for the citrus industry to increase the efficiency of citrus crops subject to water stress in semi-arid regions.

1. Introduction

Citrus crops are one of the most financially and socially relevant fruit crops in the Mediterranean and subtropical regions. Thus, Mediterranean basin countries rank second in citrus production worldwide after China, with over 26 million tons [1]. In the Mediterranean region, citrus crops are grown chiefly under a semi-arid climate, and irrigation systems are thus required to obtain optimum production [2,3]. Under Mediterranean semi-arid conditions, the rainfall regime is characterized by a high temporal variability with long periods of drought in summer [4], which further aggravate soil desertification in this region [5,6]. In addition, because the soils mostly feature high clay content, a reduced drainage rate is also apparent [7,8].
Low water availability for plants is a major abiotic factor for agricultural production [9]. Specific to citrus, the crops are highly sensitive to long-term drought, which may severely affect their growth and development [10]. Drought induces complete stomatal closure, consequently reducing the transpiration rate/net CO2 assimilation rate. It may also cause increased cell respiration and thereby affect the internal leaf temperature [11,12]. First, citrus plants close their stomata under water scarcity, thus reducing stomatal conductance, water transpiration, and photosynthetic capacity [13,14]. Should this negative abiotic stress continue, the growth, fruit production and/or juice quality of citrus trees decreases [15,16].
Similarly, citrus crops are described as vulnerable to long-term flooding or waterlogging conditions, which can cause major financial losses [17]. This abiotic stress reduces the availability of root oxygen, diminishing plant growth, stomatal conductance, and photosynthesis [3,18]. Therefore, fruit production and quality can decrease under long-term flooding conditions.
In semi-arid regions, accurate irrigation water application is an essential practice due to the fact that water resources are limited and must be optimized. The application of a short water stress period (mild water stress) can improve fruit production on trees because they grow faster upon re-watering than those that are watered extensively as per crop requirements; the application of a water stress period in orange trees led to a growth that was higher than in those that are not subject to water stress [19,20,21,22].
Furthermore, citrus orchards in the Mediterranean basin are threatened by the occurrence risk of emerging diseases. Huanglongbing, or citrus greening disease (HLB), caused by three phytopathogenic and phloem-restricted bacteria from the “Candidatus Liberibacter” genus [23,24], has been reported as the most destructive citrus disease in the world [25]. HLB pathogens are chiefly and biologically transmitted by psyllid insects Trioza erytreae and Diaphorina citri [26,27,28,29]. Although none of these bacterial species have been identified in the Mediterranean basin countries [30,31], T. erytreae has been spreading across citrus trees in mainland Spain and Portugal since 2014 and 2015, respectively [32,33,34,35], whereas D. citri was identified on mandarin and orange orchards in Israel in August 2021 [31].
As with other woody crops, farmers often graft their different citrus cultivars in the most grown rootstock. In the case of Spain, the top citrus producer and exporter in the Mediterranean basin, Carrizo citrange is the most commonly used citrus rootstock [36]. Research into new planting materials, such as rootstocks, is described as a long-term effective and sustainable tool to fight abiotic and biotic factors in citrus orchards, [37] including water stress and HLB, respectively. Currently, citrus breeding programs are continuously obtaining new rootstocks to tackle these issues, and more recently address tolerance to HLB. However, this new plant material needs to undergo a preliminary assessment against typical and set abiotic disorders in Mediterranean countries. Hence, the aim of this study was to evaluate the physiological responsiveness of three novel citrus rootstocks to water stress conditions (drought, flooding, and mild water stress) compared with Carrizo citrange.

2. Materials and Methods

2.1. Plant Material and Experimental Conditions

The response of a total of 128 plants from four citrus rootstocks (non-grafted) included Orange-14 (Citrus reticulata ‘Nova’ + C. maxima HBP × C. reticulata ‘Cleopatra’ + Poncirus trifoliata) [38], UFR-1 (C. reticulata ‘Nova’ + C. maxima HBP × C. reticulata ‘Cleopatra’ + P. trifoliata) [39,40,41] and B11R3T27 (P. trifoliata ‘Flying dragon’ × C. paradisi ‘Duncan’), [42] as well as the standard-comparative rootstock Carrizo citrange (C. sinensis ‘Washington’ × P. trifoliata) [43], which is commercially available in Spain under register number 16690003 [44], were evaluated. As far as the ploidy levels are concerned, Carrizo citrange and B11R3T27 are diploid hybrids, while Orange-14 and UFR-1 are tetraploid hybrids. Citrus plants obtained from in vitro culture conditions by Agromillora Group Nursery (Subirats, Barcelona, Spain), were provided at the age of six-month-old. Once the plant material was received, each citrus plant was transferred to a 1.6-L pot with peat moss Sphagnum substrate (Organic matter over dry matter = 85–90%; Electrical conductivity = 0.5 mS cm−1; pH = 6.5–7; N = 1%; P2O5 = 0.2%; and K2O = 0.9%). All plants were subsequently maintained over a fortnightly acclimation period under greenhouse conditions, during which all were irrigated thrice a week depending on water requirements (100% irrigation), and a nutritive solution was not applied because the peat moss substrate contained sufficient nutrients to support plant growth in a short experiment of duration. The experiment was performed in a greenhouse located in “Las Torres” center of the Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Alcalá del Río municipality, Seville, Spain (37°30′43.3′′ N; 5°57′47.4′′ W) in the spring-summer season (May–June) of 2021 (28.60 °C and 64.90%, averaged temperature and relative humidity, respectively).

2.2. Treatments of Water Stress and Experimental Design

Reference evapotranspiration was first recorded and obtained from the greenhouse station three days a week, and citrus crop evapotranspiration was calculated in order to apply precise irrigation on Monday, Wednesday, and Friday (Table 1). Hence, four water stress treatments were applied to this experiment: Control (plants were irrigated at 100% crop evapotranspiration), Mild water stress (MWS, plants were irrigated at 50% crop evapotranspiration), Drought (plants were not irrigated during the experiment), and Flooding (plants were placed under waterlogged conditions in planter boxes under waterlogged conditions). All plants were arranged using a random design, and eight replicates (n = 8) were used per treatment and rootstock, with each plant being the experimental unit and resulting in 16 treatment combinations. The experiment started following the acclimation period and on the first day of treatment application (D1) and was completed 30 days later (D30). We carried out deep periodical assessments of aerial symptoms and at the end of the experiment, we obtained the response of plant water relation parameters such as stomatal conductance, leaf water potential, and relative water content considering a previous preliminary work [45].

2.3. Assessment of Aerial Plant Symptoms

For each plant, above-ground symptoms on leaves were recorded to estimate the effect of irrigation treatments using a 0 to 4: symptoms scale: 0, plants without symptoms; 1, plants with 25% leaves affected by chlorosis; 2, plants with 50% leaves affected by chlorosis; 3, plants with over 50% leaves affected by chlorosis; and 4, fully desiccated and dead plants. This assessment process was performed on days 1, 10, 19, 22, 26, and 30, from the first water stress treatment application until the end of the experiment. All data obtained in this assessment process were used to calculate the standardized area under the abiotic stress progress curve (SAUASPC) [46], using the following equations:
AUASPC = i 1 n 1 y i + y i + 1 2 × ( t i + 1 t i )
where yi is an assessment of aerial plant symptoms at the corresponding evaluation day (i), and n is the total number of observations days.
SAUASPC = A U A S P C t
where t is the total number of assessment days.

2.4. Assessment Plant Water Relation Parameters

2.4.1. Stomatal Conductance

On the last day of the experiment (D30), stomatal conductance (gs) was measured from two leaves per plant for a total of three plants. For this, a Leaf Porometer SC-1 was used (Deacon Devices, Pullman, WA, USA) [47].

2.4.2. Leaf Water Potential

Leaf water potential (LWP) was recorded at D30 from one leaf per plant for a total of three plants. For this assessment process, a Pump-Up Scholander chamber (PMS Instrument Company, Albany, OR, USA) [48] was used.

2.4.3. Relative Water Content

Relative water content (RWC) was obtained from leaves on four plants per rootstock and treatment at the end of the experiment (D30). The assessment process was carried out on two leaves per plant, collecting two discs 1 cm in diameter per leaf. The group of four discs per plant was weighed using a digital precision electronic scale Series 5134 IN (Nahita, Columbus, OH, USA). All groups of discs were covered with distilled water for 4 h in dark conditions at room temperature and weighed again. Each group of discs was subsequently placed in a labeled paper envelope and dried at 80 °C for 24 h in an oven and weighed again. Finally, the RWC was calculated using the following equation [49]:
R W C = ( W D W ) ( T W D W ) × 100
where W is the fresh weight of the four discs per each citrus rootstock and treatment; TW is the weight of the four turgent discs after 4 h in distilled water; DW is the dry weight of the four discs under oven conditions.

2.5. Statistical Analysis

All data obtained to calculate SAUASPC and stomatal conductance were analyzed by two-way ANOVA (Analysis of variance), and LWP and RWC data were analyzed by one-way ANOVA using the free software R version 4.1.2 [50]. Mean separations were obtained using the LSD-Fisher test (p < 0.05) [51] through the “agricolae” package [52]. The figures were also plotted with the same free software version, using the “ggplot2” package [53].

3. Results

3.1. Plant Symptoms

Plant symptoms response with the SAUASPC reported statistical differences among citrus rootstocks and treatments. No citrus rootstock displayed any symptoms in the control treatment during the experiment assessment. Similarly, Carrizo citrange and UFR-1 showed the same response in the MWS treatment and control. A low symptoms incidence was identified in Orange-14 and B11R3T27 under MWS, without significant differences compared with the control response. Under drought conditions, Orange-14 displayed the highest symptoms rate compared with other citrus rootstocks and treatments, followed by UFR-1 and B11R3T27. On the contrary, the lowest symptoms incidence was shown by Carrizo citrange, with statistical differences compared with Orange-14 under drought conditions. Conversely, Carrizo was statistically on par with Orange-14 under flooding conditions (Table 2).

3.2. Plant Water Relation Parameters

3.2.1. Stomatal Conductance

Statistical differences were detected among citrus rootstocks and treatments assayed. The highest stomatal conductance values were achieved by Carrizo citrange in the treatment control, MWS and flooding, and by B11R3T27 under control conditions. The second highest response group was found in the rootstocks B11R3T27 under MWS and flooding conditions, and Orange-14 under control conditions. This response was followed by UFR-1 under control and MWS conditions, and Orange-14 under MWS conditions. Finally, the lowest significant stomatal conductance values were achieved under drought conditions for all rootstocks, and under flooding conditions for Orange-14 (Table 3).

3.2.2. Leaf Water Potential

For all citrus rootstocks, the lowest LWP response was obtained under the drought treatment followed by flooding treatment, but only statistical differences were found among the treatments in Carrizo citrange and Orange-14. Carrizo citrange showed the highest significant rate with MWS compared with the drought and flooding treatments, and without significant differences compared with the control. For Orange-14, the highest statistical LWP rate was achieved by control and MWS, compared with the lowest response, which was obtained in the drought and flooding treatments. UFR-1 and B11R3T27 did not show statistical differences among the treatments, and the highest response was accomplished in the MWS treatment for both rootstocks. Thus, Carrizo citrange, UFR-1, and B11R3T27 displayed higher values of LWP under MWS than control conditions (Figure 1).

3.2.3. Relative Water Content

Statistical differences were found in the relative water content results for each citrus rootstock. In all, the lowest significant RWC response was achieved by the drought treatment compared with the highest rate. Thus, Carrizo citrange, Orange-14, and UFR-1 displayed the two highest RWC results under the control and MWS conditions, without statistical differences between these conditions. In the case of B11R3T27, the highest statistical RWC rate was obtained under control conditions compared with the three other treatments assayed. An intermediate response was found for all rootstocks under flooding conditions, with significant differences with control and the MWS rate, except for Carrizo citrange, whereas the lowest statistical RWC result was achieved under drought conditions per citrus rootstocks compared with the other treatments, except in Carrizo citrange, which did not differ with the flooding treatment (Figure 2).

4. Discussion

In this work, we have characterized the physiological effect of four irrigation treatments on three new and one commercial citrus rootstocks, including flooding and drought conditions. In our study, drought and flooding treatment showed the highest symptom rate for all citrus rootstocks, except for Carrizo citrange, which was not significantly affected by the drought treatment. However, this comparative rootstock reported the highest symptoms under flooding treatment, during which UFR-1 was not significantly affected. In the literature, Carrizo citrange is reported to be an optimal candidate under drought conditions and provides an intermediate response under flooding conditions [54,55]. In addition and to our knowledge, the remaining rootstocks have not previously been tested against water stress conditions [54]. Nevertheless, previous research carried out by this group in the summer of 2020 pointed out that B11R5T60, another citrus rootstock obtained by the CREC, reported a better response under the application of water stress treatments than Carrizo citrange [45].
As with symptoms, the lowest stomatal conductance response was found under drought conditions for all rootstocks, followed by flooding treatment. Nevertheless, Carrizo citrange and B11R3T27 did not close completely their stomata under flooding conditions, probably this is an avoiding mechanism to tolerate flooding conditions.
Regarding LWP and RWC results, the drought condition was again the most limiting factor in all rootstocks for symptoms and stomatal conductance, as described above. In line with the results obtained for stomatal conductance, all rootstocks reduced their values of LWP under severe water deprivation; thus closing the stomata very rapidly [56]. Concerning RWC, this parameter could provide plant cell water status information [57,58]. Thus, all rootstocks displayed the lowest value under drought conditions; however, Carrizo citrange accomplished a higher rate of water content at this limiting water treatment than the others citrus rootstocks.
On the other hand, the mild water stress treatment did not negatively affect the development of citrus rootstocks and showed statistically comparable results to those of the control in all parameters. This incidence could be beneficial in semi-arid regions to save water in agriculture production, where irrigation requirements are a limiting factor for citrus crops in Spain [59].

5. Conclusions

Our work provides preliminary information for citrus growers selecting rootstocks in those regions with drought and flooding problems, such as semi-arid regions, where saving water resources is a priority. Under drought and flooding conditions, the optimal choice is Carrizo citrange and UFR-1, respectively. In addition, all these four rootstocks are suitable for adapting to mild water stress periods, reporting similar behavior as those with 100% water requirements, except for B11R3T27 for RWC. Thus, new citrus rootstocks are a preliminary option for saving water resources in semi-arid regions and increasing rootstock diversity to combat biotic factors, such as HLB, in those areas with this problem or its risk of occurrence. Consequently, all these citrus rootstocks need further characterization regarding their water requirements, fruit yield, and quality under field conditions.

Author Contributions

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

Funding

This research was funded by the research contract CEM 38/2018 from Agromillora Catalana.

Data Availability Statement

Not applicable.

Acknowledgments

We are highly thankful to Agromillora Group for providing the plant material, including Mariàngela Mestre and Joan Torrent.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. FAOSTAT. Food and Agriculture Organization (FAO) of the United Nations. 2022. Available online: http://www.fao.org/faostat/es/#home (accessed on 6 August 2022).
  2. Ruiz, I.; Almagro, M.; de Jalón, S.G.; Solà, M.D.M.; Sanz, M.J. Assessment of sustainable land management practices in Mediterranean rural regions. J. Environ. Manag. 2020, 276, 111293. [Google Scholar] [CrossRef] [PubMed]
  3. García-Sánchez, F.; Syvertsen, J.P.; Gimeno, V.; Botía, P.; Perez-Perez, J.G. Responses to flooding and drought stress by two citrus rootstock seedlings with different water-use efficiency. Physiol. Plant. 2007, 130, 532–542. [Google Scholar] [CrossRef]
  4. Merino, A.; López, L.; Hermida, L.; Sánchez, J.L.; García-Ortega, E.; Gascón, E.; Fernández-González, S. Identification of drought phases in a 110-year record from Western Mediterranean basin: Trends, anomalies and periodicity analysis for Iberian Peninsula. Glob. Planet. Change 2015, 133, 96–108. [Google Scholar] [CrossRef]
  5. Puigdefábregas, J.; Mendizabal, T. Perspectives on desertification: Western Mediterranean. J. Arid Environ. 1998, 39, 209–224. [Google Scholar] [CrossRef]
  6. Safriel, U.N. Status of Desertification in the Mediterranean Region. In Water Scarcity, Land Degradation and Desertification in the Mediterranean Region; Rubio, J.L., Safriel, U., Daussa, R., Blum, W.P.F., Eds.; NATO Science for Peace and Security Series C: Environmental Security; Springer: Dordrecht, The Netherlands, 2009; pp. 33–73. [Google Scholar]
  7. Kijne, J.W. Abiotic stress and water scarcity: Identifying and resolving conflicts from plant level to global level. Field Crops Res. 2006, 97, 3–18. [Google Scholar] [CrossRef]
  8. Holzapfel, E.A.; Pannunzio, A.; Lorite, I.; de Oliveira, A.S.S.; Farkas, I. Design and management of irrigation systems. Chil. J. Agric. Res. 2009, 69, 17–25. [Google Scholar] [CrossRef] [Green Version]
  9. Sharif, P.; Seyedsalehi, M.; Paladino, O.; Van Damme, P.; Sillanpää, M.; Sharifi, A.A. Effect of drought and salinity stresses on morphological and physiological characteristics of canola. Int. J. Environ. Sci. Technol. 2018, 15, 1859–1866. [Google Scholar] [CrossRef]
  10. Colmenero-Flores, J.M.; Arbona, V.; Morillon, R.; Gómez-Cadenas, A. Salinity and water deficit. In The Genus Citrus; Talon, M., Caruso, M., Gmitter, F.G., Eds.; Elsevier Inc.: Amsterdam, The Netherlands, 2020; pp. 291–309. ISBN 9780128121634. [Google Scholar]
  11. Hsiao, T.C. Plant Responses to water stress. Annu. Rev. Plant Physiol. 1973, 24, 519–570. [Google Scholar] [CrossRef]
  12. Arbona, V.; Iglesias, D.J.; Jacas, J.; Primo-Millo, E.; Talon, M.; Gómez-Cadenas, A. Hydrogel substrate amendment alleviates drought effects on young citrus plants. Plant Soil 2005, 270, 73–82. [Google Scholar] [CrossRef]
  13. Arbona, V.; Marco, A.J.; Iglesias, D.J.; López-Climent, M.F.; Talon, M.; Gómez-Cadenas, A. Carbohydrate depletion in roots and leaves of salt-stressed potted Citrus clementina L. Plant Growth Regul. 2005, 46, 153–160. [Google Scholar] [CrossRef]
  14. de Magalhães Erismann, N.; Caruso Machado, E.; Sant’ Anna Tucci, M.L. Photosynthetic limitation by CO2 diffusion in drought stressed orange leaves on three rootstocks. Photosynth. Res. 2008, 96, 163–172. [Google Scholar] [CrossRef] [PubMed]
  15. Brakke, M.; Allen, L.H. Gas exchange of Citrus seedlings at different temperatures, vapor-pressure deficits, and soil water contents. J. Am. Soc. Hortic. Sci. 1995, 120, 497–504. [Google Scholar] [CrossRef] [Green Version]
  16. Pedroso, F.K.J.V.; Prudente, D.A.; Carolina, A.; Bueno, R.; Machado, E.C.; Ribeiro, R.V. Drought tolerance in citrus trees is enhanced by rootstock-dependent changes in root growth and carbohydrate availability. Environ. Exp. Bot. 2014, 101, 26–35. [Google Scholar] [CrossRef]
  17. Ford, H.W. Water management in poorly drained citrus soils. In Proceedings of the First International Citrus Symposium, Riverside, CA, USA, 16–26 March 1968; Champan, H.D., Ed.; University of California Press: Riverside, CA, USA, 1968; Volume 3, pp. 71–76. [Google Scholar]
  18. Martínez-Alcántara, B.; Jover, S.; Quiñones, A.; Forner-Giner, M.A.; Rodríguez-Gamir, J.; Legaz, F.; Primo-Millo, E.; Iglesias, D.J. Flooding affects uptake and distribution of carbon and nitrogen in citrus seedlings. J. Plant Physiol. 2012, 169, 1150–1157. [Google Scholar] [CrossRef] [PubMed]
  19. Cohen, A.; Goell, A. Fruit growth and dry matter accumulation in grapefruit during periods of water withholding and after reirrigation. Funct. Plant Biol. 1988, 15, 633. [Google Scholar] [CrossRef]
  20. Li, S.-H.; Huguet, J.-G.; Schoch, P.G.; Orlando, P. Response of peach tree growth and cropping to soil water deficit at various phenological stages of fruit development. J. Hortic. Sci. 1989, 64, 541–552. [Google Scholar] [CrossRef]
  21. Huang, H.B.; Gao, F.F.; Xu, J.K.; Xie, Z.S. Effects of moisture stress on orange (Citrus sinensis L. Osbeck.) fruit development. Acta Hortic. Sin. 1986, 13, 237–344. [Google Scholar]
  22. Huang, H.B.; Gao, F.F.; Li, J.G. Fruit expansion growth in relation to water-uptake under climate changes. Acta Hortic. Sin. 1994, 21, 124–128. [Google Scholar]
  23. Jagoueix, S.; Bove, J.M.; Garnier, M. The phloem-limited bacterium of greening disease of citrus is a member of the α subdivision of the Proteobacteria. Int. J. Syst. Evol. Microbiol. 1994, 44, 379–386. [Google Scholar] [CrossRef] [Green Version]
  24. Texeira, D.C.; Ayres, J.; Kitajima, E.W.; Danet, L.; Jagoueix-Eveillard, S.; Saillard, C.; Bové, J.M. First report of a Huanglongbing-like disease of citrus in São Paulo State, Brazil and association of a new Liberibacter Species, “Candidatus Liberibacter americanus”, with the disease. Plant Dis. 2005, 89, 107. [Google Scholar] [CrossRef]
  25. Bové, J.M. Huanglongbing: A destructive, newly-emerging, century-old disease of citrus. J. Plant Pathol. 2006, 88, 7–37. [Google Scholar]
  26. McClean, A.P.D.; Oberholzer, P.C.J. Citrus psylla, a vector of the greening disease of sweet orange. South Afr. J. Agric. Sci. 1965, 8, 297–298. [Google Scholar]
  27. Capoor, S.P.; Rao, D.G.; Viswanath, S.M. Diaphorina citri Kuway., a vector of the greening disease of citrus in India. Indian J. Agric. Sci. 1967, 37, 572–579. [Google Scholar]
  28. Yamamoto, P.T.; Felippe, M.R.; Garbim, L.F.; Coelho, J.H.C.; Ximenes, N.L.; Martins, E.C.; Leite, A.P.R.; Sousa, M.C.; Abrahão, D.P.; Braz, J.D. Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae): Vector of the bacterium Candidatus Liberibacter americanus. In Proceedings of the Huanglongbing-greening International Workshop, Ribeiro Preto, Brazil, 16–20 July 2006; Pietersen, G., Le Roux, H.F., Eds.; Citrus Research International: Ribeiro Preto, Brazil, 2006; p. 96. [Google Scholar]
  29. Ajene, I.J.; Khamis, F.; Mohammed, S.; Rasowo, B.; Ombura, F.L.; Pietersen, G.; van Asch, B.; Ekesi, S. First report of field population of Trioza erytreae carrying the Huanglongbing-associated pathogen, Candidatus Liberibacter asiaticus, in Ethiopia. Plant Dis. 2019, 103, 1766. [Google Scholar] [CrossRef]
  30. Siverio, F.; Marco-Noales, E.; Bertolini, E.; Teresani, G.R.; Peñalver, J.; Mansilla, P.; Aguín, O.; Pérez-Otero, R.; Abelleira, A.; Guerra-García, J.A.; et al. Survey of huanglongbing associated with “Candidatus Liberibacter” species in Spain: Analyses of citrus plants and Trioza erytreae. Phytopathol. Mediterr. 2017, 56, 98–110. [Google Scholar] [CrossRef]
  31. EPPO, 2022. European and Mediterranean Plant Protection Organization. Available online: https://gd.eppo.int/ (accessed on 5 October 2022).
  32. Pérez-Otero, R.; Mansilla, J.P.; Del Estal, P. Detección de la psila africana de los cítricos, Trioza erytreae (Del Guercio, 1918) (Hemiptera: Psylloidea: Triozidae), en la Península Ibérica. Arq. Entomolóxicos 2015, 13, 119–122. [Google Scholar]
  33. Arenas-Arenas, F.J.; Duran-Vila, N.; Quinto, J.; Hervalejo, Á. Is the presence of Trioza erytreae, vector of huanglongbing disease, endangering the Mediterranean citrus industry? Survey of its population density and geographical spread over the last years. J. Plant Pathol. 2018, 100, 567–574. [Google Scholar] [CrossRef]
  34. Arenas-Arenas, F.J.; Duran-Vila, N.; Quinto, J.; Hervalejo, Á. Geographic spread and inter-annual evolution of populations of Trioza erytreae in the Iberian Peninsula. J. Plant Pathol. 2019, 101, 1151–1157. [Google Scholar] [CrossRef]
  35. DGAV, 2022. Direção-Geral de Alimentação e Veterinária. Available online: https://www.dgav.pt/ (accessed on 29 August 2022).
  36. Tallón Vila, C.I. Biotechnology applied to the genetic improvement of citrus rootstocks. In Development of a Protocol for Micropropagation and Adventitious Regeneration for Use in Generating Salt Toleran Mutant Lines; Universidad de Murcia: Murcia, Spain, 2015. [Google Scholar]
  37. Bowman, K.D.; Joubert, J. Citrus rootstocks. In The Genus Citrus; Talon, M., Caruso, M., Gmitter, F.G., Eds.; Elsevier Inc.: Amsterdam, The Netherlands, 2020; pp. 105–127. ISBN 9780128121634. [Google Scholar]
  38. Grosser, J.; Graham, J.; Hoyte, A. Continued development of rootstocks tolerant of the Phytophthora-Diaprepes complex via greenhouse screening. In Proceedings of the Florida State Horticultural Society, Palm Beach County, FL, USA, 3–5 June 2007; Volume 120, pp. 103–109. [Google Scholar]
  39. Grosser, J.W.; Omar, A.A.; Gmitter, J.A.; Syvertsen, J.P. Salinity tolerance of ‘Valencia’ orange trees on allotetraploid rootstocks. Proceeding Fla. State Hortic. Soc. 2012, 125, 50–55. [Google Scholar]
  40. Kunwar, S.; Grosser, J.; Gmitter, F.G.; Castle, W.S.; Albrecht, U. Field performance of ‘Hamlin’ orange trees grown on various rootstocks in Huanglongbing-endemic conditions. HortScience 2021, 56, 244–253. [Google Scholar] [CrossRef]
  41. Grosser, J.W. Citrus rootstock named “UFR-1”. United States Plant Patent Application Publication Publication Number: US 2015/0237782 P1, 20 August 2015. pp. 1–9. [Google Scholar]
  42. Project 18-029C. Evaluation of Citrus Rootstocks Response to HLB in Large-Scale Existing Field Trials. 2022. Available online: https://slideplayer.com/slide/17630075/ (accessed on 7 October 2022).
  43. Savage, E.M.; Gardner, F.E. The Troyer and Carrizo citranges. Calif. Citrogr. 1965, 50, 112–116. [Google Scholar]
  44. Oficina Española de Variedades Vegetales, Registro de Variedades, Ministerio de Agricultura, Pesca y Alimentación. 2022. Available online: https://www.mapa.gob.es/es/agricultura/temas/medios-de-produccion/semillas-y-plantas-de-vivero/registro-de-variedades/ (accessed on 29 August 2022).
  45. Aparicio-Durán, L.; Gmitter, F.G., Jr.; Arjona-López, J.M.; Calero-Velázquez, R.; Hervalejo, Á.; Arenas-Arenas, F.J. Water-stress influences on three new promising HLB-tolerant Citrus rootstocks. Horticulturae 2021, 7, 336. [Google Scholar] [CrossRef]
  46. Campbell, C.L.; Madden, L. V Temporal analysis of epidemics I: Descriptions and comparisons of disease progress curve. In Introduction to Plant Disease Epidemiology; Campbell, C.L., Madden, L.V., Eds.; Wiley: New York, NY, USA, 1990; pp. 161–202. [Google Scholar]
  47. Rewald, B.; Raveh, E.; Gendler, T.; Ephrath, J.E.; Rachmilevitch, S. Phenotypic plasticity and water flux rates of Citrus root orders under salinity. J. Exp. Bot. 2012, 63, 2717–2727. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  48. Scholander, P.F.; Bradstreet, E.D.; Hemmingsen, E.A.; Hammel, H.T. Sap pressure in vascular plants. Science 1965, 148, 339–346. [Google Scholar] [CrossRef]
  49. Morgan, J.M. Osmoregulation and water stress in higher plants. Annu. Rev. Plant Physiol. 1984, 35, 299–319. [Google Scholar] [CrossRef]
  50. R Development Core Team R. A Language and Environment for Statistical Computing. R Foundation for Statistical Computing; R Development Core Team R: Vienna, Austria, 2022; ISBN 3-900051-07-0. Available online: http://www.r-project.org/ (accessed on 29 June 2022).
  51. Steel, R.G.D.; Torrie, J.H. Principles and procedures of statistics: With special reference to the biological sciences; McGraw-Hill Book Company, Inc.: New York, NY, USA, 1960. [Google Scholar]
  52. de Mendiburu, F. Statistical procedures for agricultural research. Package “Agricolae”, version 1.4-4; Comprehensive R archive network, Institute for statistics and mathematics: Vienna, Austria, 2013.
  53. Wickham, H. Data Analysis. In ggplot2. Use R! Springer: Cham, Switzerland, 2016; pp. 189–201. [Google Scholar]
  54. Florida Citrus Rootstock Selection Guide, 4th Edition, 2022. Available online: https://crec.ifas.ufl.edu/extension/citrus_rootstock/tables.html (accessed on 7 October 2022).
  55. Aleza, P.; Forner-Giner, M.A.; Del-Pino, Á. El panorama varietal y los nuevos patrones. Análisis de la situación actual. In Una hoja de ruta para la citricultura española; García Álvarez-Coque, J.M., Moltó García, E., Eds.; Cajamar Caja Rural: Almería, Spain, 2020; pp. 151–166. ISBN 978-84-95531-49-0. [Google Scholar]
  56. Gomez-Cadenas, A.; Tadeo, F.R.; Talon, M.; Primo-Millo, E. Leaf abscission induced by ethylene in water-stressed intact seedlings of Cleopatra mandarin requires previous abscisic acid accumulation in roots. Plant Physiol. 1996, 112, 401–408. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  57. Bielsa, B.; Hewitt, S.; Reyes-Chin-Wo, S.; Dhingra, A.; Rubio-Cabetas, M.J. Identification of water use efficiency related genes in “Garnem” almond-peach rootstock using time-course transcriptome analysis. PLoS ONE 2018, 13, e0205493. [Google Scholar] [CrossRef] [Green Version]
  58. Verslues, P.E.; Agarwal, M.; Katiyar-Agarwal, S.; Zhu, J.; Zhu, J.-K. Methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status. Plant J. 2006, 45, 523–539. [Google Scholar] [CrossRef]
  59. Kahil, M.; Albiac, J.; Dinar, A.; Calvo, E.; Esteban, E.; Avella, L.; Garcia-Molla, M. Improving the performance of water policies: Evidence from drought in Spain. Water 2016, 8, 34. [Google Scholar] [CrossRef]
Figure 1. Mean leaf water potential (LWP; MPa) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment. Values in columns with different letters denote statistical differences among the treatments per citrus rootstock by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress; ns: not significant differences.
Figure 1. Mean leaf water potential (LWP; MPa) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment. Values in columns with different letters denote statistical differences among the treatments per citrus rootstock by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress; ns: not significant differences.
Agronomy 13 00063 g001
Figure 2. Mean relative water content (RWC; %) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment. Values in columns with different letters denote statistical differences among the treatments per each citrus rootstock by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress.
Figure 2. Mean relative water content (RWC; %) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment. Values in columns with different letters denote statistical differences among the treatments per each citrus rootstock by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress.
Agronomy 13 00063 g002
Table 1. Crop coefficients for irrigation water calculation during the experimental period.
Table 1. Crop coefficients for irrigation water calculation during the experimental period.
TimeEto (mm Day−1)KcEtc (mm Day−1)
D15.850.452.63
D35.360.452.41
D55.750.452.59
D96.780.453.05
D127.550.453.40
D156.700.453.02
D194.800.452.16
D224.130.451.86
D245.950.452.68
D267.200.453.24
D297.380.453.32
Eto: Reference evapotranspiration; Kc: crop coefficient; Etc: crop evapotranspiration
Table 2. Mean standardized area under the abiotic stress progress curve (SAUASPC) during the 30-day of assessment.
Table 2. Mean standardized area under the abiotic stress progress curve (SAUASPC) during the 30-day of assessment.
Treatment
RootstockControlMWSDroughtFlooding
Carrizo citrange0.00 ± 0.00 h0.00 ± 0.00 h0.20 ± 0.04 fg0.50 ± 0.08 cd
Orange-140.00 ± 0.00 h0.03 ± 0.03 h0.98 ± 0.08 a0.66 ± 0.10 bc
UFR-10.00 ± 0.00 h0.00 ± 0.00 h0.77 ± 0.11 b0.26 ± 0.06 ef
B11R3T270.00 ± 0.00 h0.03 ± 0.03 gh0.78 ± 0.10 b0.41 ± 0.07 de
Values with different letters denote statistical differences among citrus rootstocks and treatments by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress.
Table 3. Mean stomatal conductance values (mmol m−2 s−1) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment.
Table 3. Mean stomatal conductance values (mmol m−2 s−1) on four citrus rootstocks (Carrizo citrange, Orange-14, UFR-1, and B11R3T27) under four water conditions treatments (Control, MWS, Drought, and Flooding) at the end of the experiment.
Treatment
RootstockControlMWSDroughtFlooding
Carrizo citrange205.32 ± 20.82 a184.33 ± 12.77 ab43.32 ± 7.60 f172.63 ± 34.21 ab
Orange-14123.23 ± 15.02 cd98.00 ± 1.98 de41.67 ± 3.28 f36.23 ± 1.54 f
UFR-1102.00 ± 17.67 de97.87 ± 7.95 de46.17 ± 10.15 f69.35 ± 22.10 fe
B11R3T27187.28 ± 16.39 ab158.75 ± 13.46 bc44.93 ± 4.67 f117.48 ± 0.83 cd
Values with different letters denote statistical differences among citrus rootstocks and treatments by LSD-Fisher’s test (p < 0.05). MWS: Mild water stress.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Arjona-López, J.M.; Aparicio-Durán, L.; Gmitter, F.G., Jr.; Romero-Rodríguez, E.; Grosser, J.W.; Hervalejo, A.; Arenas-Arenas, F.J. Physiological Influence of Water Stress Conditions on Novel HLB-Tolerant Citrus Rootstocks. Agronomy 2023, 13, 63. https://doi.org/10.3390/agronomy13010063

AMA Style

Arjona-López JM, Aparicio-Durán L, Gmitter FG Jr., Romero-Rodríguez E, Grosser JW, Hervalejo A, Arenas-Arenas FJ. Physiological Influence of Water Stress Conditions on Novel HLB-Tolerant Citrus Rootstocks. Agronomy. 2023; 13(1):63. https://doi.org/10.3390/agronomy13010063

Chicago/Turabian Style

Arjona-López, Juan M., Lidia Aparicio-Durán, Frederick G. Gmitter, Jr., Estefanía Romero-Rodríguez, Jude W. Grosser, Aurea Hervalejo, and Francisco J. Arenas-Arenas. 2023. "Physiological Influence of Water Stress Conditions on Novel HLB-Tolerant Citrus Rootstocks" Agronomy 13, no. 1: 63. https://doi.org/10.3390/agronomy13010063

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop