Fertilization and water stress interactions in young Eucalyptus grandis plants

2006 ◽  
Vol 36 (4) ◽  
pp. 1028-1034 ◽  
Author(s):  
Corina Graciano ◽  
Juan J Guiamet ◽  
Juan F Goya

We determined whether fertilization with N and P affects water relations, and thereby water-stress tolerance, in young Eucalyptus grandis plants. To assess whether fertilization enhances osmotic adjustment under drought, 3-month-old E. grandis were planted in pots and fertilized with either N (1 g of urea) or P (12 g of calcium super phos phate). The soil was watered to attain one of two conditions: field capacity and –0.8 MPa. P fertilization when plants were well watered conditions increased solute accumulation, which might confer better performance under water stress. However, under water-stress conditions, nonfertilized and N-fertilized plants showed osmotic adjustment, while P-fertilized plants did not. P fertilization increased dry-mass allocation to leaves and decreased allocation to roots even under water-stress conditions. N-fertilized plants increased allocation to roots and maintained allocation to leaves under water-stress conditions in comparison with control plants, so they were not affected by water stress as much as P-fertilized plants were. This may explain why P fertilization increased growth when water was not limiting but had no effect under drought conditions. In the long term, changes in dry-mass allocation caused by P fertilization might increase susceptibility to water deficit.

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1344
Author(s):  
Hana Ghouil ◽  
Domingo Sancho-Knapik ◽  
Amira Ben Mna ◽  
Nabil Amimi ◽  
Youssef Ammari ◽  
...  

Climate change models predict an increase in aridity, especially in the regions under Mediterranean-type climates such as the Mediterranean Basin. However, there is a lack of ecophysiological studies supporting the selection of the more drought-adapted ecotypes for reforestation programs. In this study, we analyzed the anatomical and functional adaptations of 18-month-old seedlings to drought on 16 Quercus suber L. populations from the southeastern rear edge of the species distribution in northern Tunisia growing in a common garden, in order to identify the most appropriate material to use in reforestations. The results evidenced that populations from more xeric habitats displayed the highest leaf dry mass per area (LMA) and lowest leaf area (LA) values, together with the largest increase in the bulk modulus of elasticity (Δε) in response to drought (i.e., elastic adjustment). On the other hand, some populations with intermediate values of aridity, LMA and LA displayed the sharpest increase in proline concentration (ΔPro), with a concomitant increase in osmotic potential at full turgor (Δπo) (i.e., osmotic adjustment). Therefore, two different strategies seem to drive the within-species variation of the studied Q. suber populations in response to water scarcity: (i) a water saver strategy for improving water stress tolerance through the maximization of the elastic adjustment; and (ii) a water spender strategy for maintaining water absorption and photosynthetic activity under moderate water stress through the maximization of the osmotic adjustment. We concluded that the higher elastic adjustment, together with reduced LA and increased LMA, implied a better performance under drought stress in the populations of Q. suber from more xeric habitats, which can be considered the most drought-adapted ecotypes and, consequently, the most appropriate for reforestation programs under an eventual increase in aridity.


1994 ◽  
Vol 24 (12) ◽  
pp. 2404-2408 ◽  
Author(s):  
Jorge H. Lemcoff ◽  
Ana B. Guarnaschelli ◽  
Ana M. Garau ◽  
María E. Bascialli ◽  
Claudio M. Ghersa

Osmotic adjustment was studied in 6-month-old seedlings of Eucalyptuscamaldulensis Dehnh., Eucalyptustereticornis Smith, Eucalyptusviminalis Labill., and Eucalyptusgrandis Hill ex Maiden. Because osmotic adjustment is related to water-stress tolerance, it can be used as a selection criterion of material adapted to drought. Half of the individuals of each species were submitted gradually to water stress, while the rest were maintained in soil at field capacity. Twenty-five days later the effect of stress on the development of osmotic adjustment was analyzed. All species had adjusted osmotically. The lowest osmotic adjustment was observed in E. camaldulensis and E. grandis (14.1% and 15.2%, respectively). Eucalyptusviminalis and E. tereticornis had values of 32.3% and 41.9%, respectively. Our results demonstrate that species differ significantly in their extent of osmotic adjustment under drought stress, and that it is possible to use this inductive plant feature as one of the criteria to select, during early developmental stages, Eucalyptus genotypes adapted to drought-prone environments. Some phylogenetic considerations are presented.


2013 ◽  
Vol 40 (5) ◽  
pp. 466 ◽  
Author(s):  
Oumelkheir Belkheiri ◽  
Maurizio Mulas

Atriplex halimus L. is known in the Mediterranean basin and along the coastal areas of Sardinia for its adaptability to salinity, although less information is available on the resistance of this species to water stress in absence of salinity. The effect of water stress on growth and water utilisation was investigated in two Atriplex species: A. halimus originating of south Sardinian island and the exotic species Atriplex nummularia Lindl., originating in Australia and widely used in land restoration of arid areas. Water stress was applied to young plants growing in 20 L pots with a sufficient water reserve to store a potentially sufficient water reserve to maintain substrate near to field capacity (30%) between irrigations. Watering was at 70% (control) or 40% (stress) of field capacity. In order to simulate the grazing by livestock, four plant biomass cuttings were conducted at times T0, T1, T2 and T3, corresponding to one cutting at the end of well watered phase (T0) before water stress induction, two cuttings after cycles of 5 weeks each during full summer (T1) and late summer (T2) and one cutting during autumn (T3). All plants remained alive until the end of treatment although growth was strongly reduced. Leaf dry weight (DW) and water use efficiency (WUE) were determined for all cuttings; relative water content (RWC), turgid weight : dry weight ratio (TW : DW), water potential (Ψw), osmotic potential (Ψs), CO2 assimilation, osmotic adjustment (OA), abscisic acid (ABA) and sugar accumulation were determined for the late summer cutting at T2. Water stress induced a decrease in DW, RWC, Ψw, Ψs, TW : DW and CO2 assimilation for both species, but an increase in WUE expressed in terms of dry matter production and a high accumulation of ABA and total sugars mainly for A. halimus. This suggests a more developed adaptive mechanism in this selection. Indeed, the clone was selected from the southern part of the island, where natural populations of saltbush are more exposed to abiotic stresses, mainly the water stress generated not by salinity. A. nummularia showed a greater OA and a positive net solute accumulation as than A. halimus, suggesting that water stress resistance in A. halimus is linked to a higher WUE rather than a greater osmotic adjustment.


1989 ◽  
Vol 67 (6) ◽  
pp. 1681-1688 ◽  
Author(s):  
T. J. Tschaplinski ◽  
T. J. Blake

Organic solute concentrations of five hybrid poplar cultivars were compared to determine the relationship between water-stress tolerance, tissue solute concentration, and growth rate under field conditions. In the expanding foliage of the faster growing Populus deltoides Bartr. × P. balsamifera L. (Jackii 4), the saturated osmotic potential and turgor loss point osmotic potential were 0.18 MPa and 0.47 MPa lower, respectively, than in the slower growing P. deltoides × P. balsamifera (Jackii 7). The expanding foliage of Jackii 4 had higher (ca. 50%) concentrations of organic solutes, attributable mainly to salicyl alcohol, salicin, sucrose, and an unidentified compound. The coupling of high productivity and stress tolerance in Jackii 4 suggests that these may be compatible rather than competing attributes. Water-stress studies on P. deltoides Bartr. × P. nigra L. (DN 22) under greenhouse conditions demonstrated that stressed trees accumulated 4 times the soluble sugar concentrations of well-watered trees, lowering the saturated osmotic potential by 0.55 MPa and turgor loss point osmotic potential by 1.0 MPa. Leaves were the primary site of osmotic adjustment to water stress and roots showed no adjustment. The use of repeated drying cycles in planting stock may aid survival of postplanting stress in species capable of osmotic adjustment. The relationship between stress tolerance and solute concentrations in the greenhouse water-stress study paralleled that of the field study.


2017 ◽  
Vol 39 (4) ◽  
pp. 440-447 ◽  
Author(s):  
Daniel Teixeira Pinheiro ◽  
Denise Cunha Fernandes dos Santos Dias ◽  
Joyce de Oliveira Araújo

Abstract: Seeds vigor can influence seed performance under stress conditions. The objectives of this study were to evaluate the effect of water and thermal stress on germination and performance of melon seedlings, and to verify if germination under stress conditions is an efficient parameter to evaluate the vigor of these seeds. Four lots of ‘Golden Mine’ melon had their initial quality characterized by germination, first count, accelerated aging and seedling emergence tests. Germination under water stress was performed on a paper moistened with PEG 6000 solution at 0.06, -0.3, -0.6 and -0.9 MPa. The percentage and speed of germination, length and dry mass of the seedlings were evaluated. For the thermal stress experiment, cold test and germination at sub- (15 ºC) and supra-optimal (35 ºC) temperatures were performed, as well as at the ideal temperature (25 ºC). The germination of melon seeds under water stress induced by PEG 6000 at -0.3 and -0.6 MPa is an efficient method to detect differences in the physiological potential of lots of melon seeds, but these differences disappear under severe water stress (-0.9 MPa). Germination under sub-optimal temperatures also allows to identify differences in seeds performance and to classify them according to the vigor level.


2016 ◽  
Vol 14 (4) ◽  
pp. e0809 ◽  
Author(s):  
Morteza Ebtedaie ◽  
Akhtar Shekafandeh

The purpose of this study was to evaluate the biochemical responses to water stress tolerance of two pomegranate cultivars, ‘Rabbab’ and ‘Shishehgap’. After the establishment of rooted stem cuttings of both cultivars under greenhouse conditions, they were treated with four levels of deficit irrigations (100%, 75%, 50% and 25% of field capacity) in a completely randomized design with four replications. The results showed a significant difference between the two cultivars regarding antioxidant enzymes activities. In both cultivars, the water stress increased the activity of superoxide dismutase, catalase and ascorbate peroxidase. However, at high water deficit (25% field capacity, FC), ‘Rabbab’ showed significantly higher enzyme activity than ‘Shishehgap’. In each level of irrigation, there were not considerable differences in peroxidase activity between the two cultivars. An increment of 162% and 65.5% in soluble sugar was gained at 50% FC in ‘Rabbab’ and ‘Shishehgap’, respectively. ‘Rabbab’ showed better growth performance in each level of irrigation than ‘Shishehgap’. Therefore, it can be concluded that 'Rabbab', with lesser decline in leaf relative water content (RWC), a strong antioxidant system and accumulation of more soluble carbohydrates, can resist higher water stress than 'Shishehgap'.


Author(s):  
Slimani Afafe ◽  
Harkousse Oumaima ◽  
Mazri Mouaad Amine ◽  
Zouahri Abdelmajid ◽  
Ouahmane Lahcen ◽  
...  

Background: Plant strategies for adapting to drought could be improved by associations between plant roots and soil microorganisms, including arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPR). In this study, the impact of a selected AMF complex and a selected PGPR species on the growth of tomato (Lycopersicum esculentum Mill.) under induced water stress was evaluated. Methods: Three different inoculation treatments were applied to tomato seedlings (a complex of AMF composed mainly of Glomus genus a Bacillus sp. PGPR treatment and a combination of both) and three different water levels (75%, 50% and 25% of field capacity). Result: A significant damaging impact of drought on tomato growth parameters and root mycorrhizal colonization, although the presence of microbes stimulated tomato plants growth and decreased the impact ofdrought stress. Indeed inoculated plants presented greater heights, fresh and dry weights, leaves number and area; greater water status; and greater proteins, sugars and chlorophylls contents either with the AMF complex or the Bacillus sp. in normal and drought stress conditions compared to the non-inoculated plants. However dual inoculation recorded the highest values under all water levels treatments.


Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 559 ◽  
Author(s):  
Lin ◽  
Lin ◽  
Wu ◽  
Chang

Water deficits during the growing season are a major factor limiting crop production. Therefore, reducing water use during crop production by the application of regulated deficit irrigation (RDI) is crucially important in water resources. There are few reports on the biostimulants used for growth and water use efficiency (WUE) in maize (Zea mays Linn.) under RDI. Therefore, the influence of betaine and chitin treatments, alone and in combination, on maize cultivar ‘White Pearl’ was assessed by observing changes in the physiology and morphology of plants exposed to RDI. Plants were grown in plastic pots in greenhouses and maintained under full irrigation (FI) for 1 week until imposing RDI and biostimulants. Plants were then subjected to FI (no water deficiency treatment, field capacity >70%) and RDI (field capacity <50%) conditions until the end of each experiment. Plant agronomic performance, photosynthesis parameters, and WUE values were recorded weekly for 8 weeks and three individual experiments were carried out to assess the efficacy of biostimulants and irrigation treatments. Betaine (0, 50, and 100 mM/plant) was foliage-treated every 2 weeks during Experiment 1, but chitin (0, 2, and 4 g/kg) was applied to the soil at the beginning of Experiment 2. The optimal concentration of each chemical alone or in combination was then applied to the plants as Experiment 3. A factorial experiment design of two factors with different levels under a completely randomized arrangement was used in this investigation. Betaine (50 mM) or chitin (2 g/kg) treatments alone significantly elevated total fresh weight (63.03 or 124.07 g/plant), dry weight (18.00 or 22.34 g/plant), and cob weight (3.15 or 6.04 g/plant) and boosted the water-stress tolerance of the maize under RDI compared to controls. However, a combination treatment of 50 mM betaine and 2 g/kg chitin did not increase plant height, fresh shoot and root weights, dry cob weight, and total dry weight under RDI compared to controls. Soil-plant analysis development (SPAD) values (>30) were effective in detecting plant growth performance and WUE values under RDI. These findings may have greater significance for farming in dry lands and offer information for further physiological studies on maize WUE and water stress tolerance


2016 ◽  
Vol 18 (2) ◽  
pp. 71-78 ◽  
Author(s):  
KK Sarkar ◽  
MA Mannan ◽  
MM Haque ◽  
JU Ahmed

An experiment was conducted to study the effects of water stress on physiological parameters associated to drought tolerance in soybean at the Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh during January to April, 2015. Four soybean genotypes namely i) BU Soybean 1 ii) Binasoybean 1 iii) Galarsum and iv) BARI Soybean 5 were grown in two watering regimes viz. control (80% of the field capacity) and water stress (50% of the field capacity). Genotypic variability was found in water stress tolerance in soybean. Highest accumulation of leaf proline, sugar and water content and lower accumulation of malondialdehyde were found in Binasoybean 1 compared to other genotypes. Lowest yield reduction was found in Binasoybean 1. Binasoybean 1 showed relatively higher drought tolerance whereas BARI Soybean 5 was found susceptible to yield. It was found that higher water stress tolerance in Binasoybean 1 was associated with better water relations and higher accumulation of sugar and proline and lower accumulation of malondialdehyde content in leaf.Bangladesh Agron. J. 2015, 18(2): 71-78


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