Growth, ion content, gas exchange, and water relations of wheat genotypes differing in salt tolerances

2005 ◽  
Vol 56 (2) ◽  
pp. 123 ◽  
Author(s):  
Salah E. El-Hendawy ◽  
Yuncai Hu ◽  
Urs Schmidhalter
Keyword(s):  
Salt Tolerance ◽  
Leaf Area ◽  
Water Relations ◽  
Genotypic Variation ◽  
Turgor Pressure ◽  
Mineral Nutrient ◽  
Genotypic Differences ◽  
Wheat Genotypes ◽  
Spad Value ◽  
Osmotic Potentials

Although the mechanisms of salt tolerance in plants have received much attention for many years, genotypic differences influencing salt tolerance still remain uncertain. To investigate the key physiological factors associated with genotypic differences in salt tolerance of wheat and their relationship to salt stress, 13 wheat genotypes from Egypt, Australia, India, and Germany, that differ in their salt tolerances, were grown in a greenhouse in soils of 4 different salinity levels (control, 50, 100, and 150 mm NaCl). Relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), photosynthesis, chlorophyll content (SPAD value), and leaf water relations were measured at Days 45 and 60 after sowing. Mineral nutrient content in leaves and stems was determined at Day 45 and final harvest. Salinity reduced RGR, NAR, photosynthetic rate, stomatal conductance, water and osmotic potentials, and K+ and Ca2+ content in stems and leaves at all times, whereas it increased leaf respiration, and Na+ and Cl– content in leaves and stems. LAR was not affected by salinity and the effect of salinity on SPAD value was genotype-dependent. Growth of salt-tolerant genotypes (Sakha 8, Sakha 93, and Kharchia) was affected by salinity primarily due to a decline in photosynthetic capacity rather than a reduction in leaf area, whereas NAR was the more important factor in determining RGR of moderately tolerant and salt-sensitive genotypes. We conclude that Na+ and Cl– exclusion did not always reflect the salt tolerance, whereas K+ in the leaves and Ca2+ in the leaves and stems were closely associated with genotypic differences in salt tolerance among the 13 genotypes even at Day 45. Calcium content showed a greater difference in salt tolerance among the genotypes than did K+ content. The genotypic variation in salt tolerance was also observed for the parameters involved in photosynthesis, and water and osmotic potentials, but not for turgor pressure.

Genetic variability in sunflower cultivars under drought. II. Growth and water relations

1986 ◽  
Vol 37 (6) ◽  
pp. 583 ◽  
Author(s):  
C Gimenez ◽  
E Fereres
Keyword(s):  
Leaf Area ◽  
Carbon Balance ◽  
Genotypic Variation ◽  
Biomass Accumulation ◽  
Reproductive Period ◽  
Water Extraction ◽  
Genotypic Differences ◽  
Leaf Area Duration ◽  
Root Water Extraction ◽  
Yield Responses

Experiments were conducted between 1981 and 1983 at Cordoba, Spain, to determine the morphophysiological basis for the differences in yield responses to drought of eight sunflower genotypes. There was genotypic variation in most characters examined, particularly in maximum leaf area and in leaf area duration, biomass accumulation and distribution, and in root water extraction. Long-season genotypes had greater leaf area and produced more biomass under drought conditions, exploring the subsoil down to 270 cm. Short-season genotypes restricted water extraction to the top 180 cm of the soil profile and had about half of the leaf area duration of a long-season cultivar. Evidence is presented of small differences in osmotic adjustment among genotypes. The relations between leaf area and grain yield as well as calculations of a carbon balance for the reproductive period suggest genotypic differences in photosynthetic efficiency under drought.

Inheritance of coleoptile tiller appearance and size in wheat

2008 ◽  
Vol 59 (9) ◽  
pp. 863 ◽  
Author(s):  
G. J. Rebetzke ◽  
C. López-Castañeda ◽  
T. L. Botwright Acuña ◽  
A. G. Condon ◽  
R. A. Richards
Keyword(s):  
Leaf Area ◽  
Genetic Control ◽  
Genotypic Variation ◽  
Growth Stages ◽  
Genotypic Differences ◽  
Progeny Testing ◽  
Plant Leaf ◽  
Generation Means ◽  
Selection For ◽  
Seedling Leaf

Selection for rapid leaf area growth has the potential to increase wheat biomass, and both water-use efficiency and weed competitiveness early in the season. Several morphological components contribute to increased seedling leaf area, including rapid seedling emergence and production of longer, wider leaves. Early emergence of a large coleoptile tiller has also been demonstrated to increase plant leaf area and biomass in wheat and other grass seedlings. Yet little is known of the extent and nature of genotypic variation for coleoptile tiller growth in wheat. A random set of 35 wheat, barley, and triticale genotypes was evaluated in glasshouse and outdoor studies for seedling characteristics, including coleoptile tiller growth and total plant leaf area. Coleoptile tillers were produced more reliably for seedlings grown outdoors and when supplied with additional soil nitrogen. Genotypic differences in coleoptile tiller frequency and leaf area were large, ranging from 0 to 78% and from 0.0 to 1.4 cm2, respectively at very early growth stages. Australian commercial wheats tended to produce fewer coleoptile tillers of smaller size than overseas germplasm where the coleoptile tiller accounted for up to 12% of total seedling leaf area. This compared favourably with mainstem tiller leaf area, which ranged from 0 to 3.5 cm2 and accounted for up to 16% of plant leaf area. Broad-sense heritabilities were high for coleoptile tiller presence and size in favourable conditions (c. 75%) but low (c. 40%) for seedlings evaluated across nitrogen content-varying soils. Generation means analysis was used to investigate genetic control for coleoptile tiller growth across multiple populations. Significant (P < 0.05) differences were observed among generations for coleoptile tiller frequency and growth (numbers of leaves, leaf area, and biomass). These differences reflected strong additive genetic control with little evidence for any gene action × year interaction. Increases in coleoptile tiller frequency and mass were correlated with larger embryo size and wider seedling leaves to increase seedling leaf area (rg = 0.89). Comparisons between reciprocal F1 and F2 generation means indicated strong maternal effects for coleoptile tiller growth in some but not all crosses. Screening in favourable environments will increase heritability and aid in selection for progenies producing large coleoptile tillers. Evidence for additive genetic control should permit early generation selection but not without some progeny-testing for coleoptile tiller growth together with other early vigour components associated with increased plant leaf area.

scholarly journals Tolerance of Tepary and Navy Beans to NaCl During Germination and Emergence

HortScience ◽  
1991 ◽  
Vol 26 (3) ◽  
pp. 246-249 ◽  
Author(s):  
Steven H. Goertz ◽  
Janice M. Coons
Keyword(s):  
Salt Tolerance ◽  
Developmental Stage ◽  
Leaf Area ◽  
Tepary Bean ◽  
Navy Bean ◽  
Phaseolus Acutifolius ◽  
Bean Cultivar ◽  
Navy Beans ◽  
Osmotic Potentials ◽  
Better Than

Seeds of two tepary bean lines (Phaseolus acutifolius Gray var. latifolius) and one navy bean cultivar (P. vulgaris L. `Fleetwood') were tested with 0.0-, – 0.3-, –0.6-, -0.9-, -1.2-, or – 1.5-MPa NaCl solutions to determine their relative salt tolerance during germination and emergence. Developmental stage was not affected at – 0.3 MPa, but with salinities more negative than -0.9 MPa, `Fleetwood' developed more slowly than the tepary lines; no plants emerged at – 1.5 MPa. Teparies tended to maintain higher water and osmotic potentials than navy over the range of NaCl concentrations used, although turgor was similar for all three genotypes. Leaf area was reduced more in navy than in white tepary at – 0.6 and – 0.9 MPa. Dry weights of navy were higher than those of either tepary bean at all NaCl concentrations, although decreases at higher salinities relative to 0.0 MPa were greater for navy than for teparies. Root: shoot ratios were higher at – 0.3 MPa than at 0.0 MPa, but were lower at the higher NaCl concentrations for all three genotypes. Overall, tepary beans tolerated NaCl better than navy. The characteristic that best indicated differences in salt tolerance was developmental stage.

Genetic Potential for Salt Tolerance During Germination in Lycopersicon Species

HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 296-300 ◽  
Author(s):  
M.R. Foolad ◽  
G.Y. Lin
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Genotypic Variation ◽  
Control Treatment ◽  
Molar Ratio ◽  
Wild Accession ◽  
Salt Tolerant ◽  
Plant Introductions ◽  
Genetic Potential ◽  
Stress Levels

Seed of 42 wild accessions (Plant Introductions) of Lycopersicon pimpinellifolium Jusl., 11 cultigens (cultivated accessions) of L. esculentum Mill., and three control genotypes [LA716 (a salt-tolerant wild accession of L. pennellii Corr.), PI 174263 (a salt-tolerant cultigen), and UCT5 (a salt-sensitive breeding line)] were evaluated for germination in either 0 mm (control) or 100 mm synthetic sea salt (SSS, Na+/Ca2+ molar ratio equal to 5). Germination time increased in response to salt-stress in all genotypes, however, genotypic variation was observed. One accession of L. pimpinellifolium, LA1578, germinated as rapidly as LA716, and both germinated more rapidly than any other genotype under salt-stress. Ten accessions of L. pimpinellifolium germinated more rapidly than PI 174263 and 35 accessions germinated more rapidly than UCT5 under salt-stress. The results indicate a strong genetic potential for salt tolerance during germination within L. pimpinellifolium. Across genotypes, germination under salt-stress was positively correlated (r = 0.62, P < 0.01) with germination in the control treatment. The stability of germination response at diverse salt-stress levels was determined by evaluating germination of a subset of wild, cultivated accessions and the three control genotypes at 75, 150, and 200 mm SSS. Seeds that germinated rapidly at 75 mm also germinated rapidly at 150 mm salt. A strong correlation (r = 0.90, P < 0.01) existed between the speed of germination at these two salt-stress levels. At 200 mm salt, most accessions (76%) did not reach 50% germination by 38 days, demonstrating limited genetic potential within Lycopersicon for salt tolerance during germination at this high salinity.

Genotypic Variation in C and N Isotope Discrimination Suggests Local Adaptation of Heart-Leaved Willow

2021 ◽  
Author(s):  
Yi Hu ◽  
Robert D Guy ◽  
Raju Y Soolanayakanahally
Keyword(s):  
Isotopic Composition ◽  
Local Adaptation ◽  
N Uptake ◽  
Genotypic Variation ◽  
Carbon Isotopic Composition ◽  
Genotypic Differences ◽  
Clinal Variation ◽  
Trade Off ◽  
Uptake Efficiency ◽  
N Uptake Efficiency

Abstract Plants acquire multiple resources from the environment and may need to adjust and/or balance their respective resource-use efficiencies to maximize grow and survival, in a locally adaptive manner. In this study, tissue and whole-plant carbon isotopic composition (δ13C) and C/N ratios provided long-term measures of use efficiencies for water (WUE) and nitrogen (NUE), and a nitrogen isotopic composition (δ15N) based mass balance model was used to estimate traits related to N uptake and assimilation in heart-leaved willow (Salix eriocephala Michx.). In an initial common garden experiment consisting of 34 populations, we found population level variation in δ13C, C/N and δ15N, indicating different patterns in WUE, NUE and N uptake and assimilation. Although there was no relationship between foliar δ13C and C/N ratios among populations, there was a significant negative correlation between these measures across all individuals, implying a genetic and/or plastic trade-off between WUE and NUE not associated with local adaptation. To eliminate any environmental effect, we grew a subset of 21 genotypes hydroponically with nitrate as the sole N-source, and detected significant variation in δ13C, δ15N and C/N ratios. Variation in δ15N was mainly due to genotypic differences in the nitrate efflux/influx ratio (E/I) at the root. Both experiments suggested clinal variation in δ15N (and thus N uptake efficiency) with latitude of origin, which may relate to water availability and could contribute to global patterns in ecosystem δ15N. There was a tendency for genotypes with higher WUE to come from more water replete sites with shorter and cooler growing seasons. We found that δ13C, C/N, and E/I were not inter-correlated, suggesting that selection of growth, WUE, NUE and N uptake efficiency can occur without trade-off.

scholarly journals GENOTYPIC VARIATION ON THE ANTIOXIDATIVE RESPONSE OF COWPEACULTIVARS EXPOSED TO OSMOTIC STRESS

2017 ◽  
Vol 30 (4) ◽  
pp. 928-937 ◽  
Author(s):  
EDILENE DANIEL DE ARAÚJO ◽  
ALBERTO SOARES DE MELO ◽  
MARIA DO SOCORRO ROCHA ◽  
REBECA FERREIRA CARNEIRO ◽  
MAURISRAEL DE MOURA ROCHA
Keyword(s):  
Osmotic Stress ◽  
Genotypic Variation ◽  
Potassium Nitrate ◽  
Proline Content ◽  
Stress Factors ◽  
Cowpea Cultivars ◽  
Stages Of Growth ◽  
Antioxidative Response ◽  
Increased Activity ◽  
Osmotic Potentials

ABSTRACT The cowpea [Vigna unguiculata (L.) Walp.], also known as cowpea, is of fundamental socioeconomic importance to the northeast of Brazil, and has become one of the main sources of protein in the diet of the rural population. However, in this region, it has become necessary to identify genotypes that are better adapted to drought. In addition, research is needed regarding the action of substances that promote tolerance to stress factors. The aim of this study was to evaluate the antioxidative response of cowpea cultivars under osmotic stress conditions using potassium nitrate as an attenuator. Five osmotic potentials were tested in the substrate (0.0, −0.2, −0.4, −0.6, and −0.8 MPa), and three seed treatments (pre-soaking in distilled water, pre-soaking in potassium nitrate, and without pre-soaking) were tested in three cowpea cultivars (BRS Itaim, BRS Aracê, and BRS Potengi). The design was randomized with 45 treatments and four replications. The data were submitted to analysis of variance (P < 0.05), and in cases of significance, regression analysis was conducted to quantitate the factors. Our results indicate that an increase in proline content in cowpea plants may be seen as indicative of the intensity of water stress on germination and the initial stages of growth of the plant. The BRS Itaim cultivar best tolerates drought conditions with the application of potassium nitrate, given the increased activity of antioxidant enzymes such as superoxide dismutase, catalase, and ascorbate peroxidase.

scholarly journals Growth and Water Relations of Sun-cured Tobacco Irrigated with Saline Water

2003 ◽  
Vol 20 (6) ◽  
pp. 394-401
Author(s):  
G Angelino ◽  
S Ascione ◽  
C Ruggiero
Keyword(s):  
Water Relations ◽  
Irrigation Water ◽  
Saline Water ◽  
Turgor Pressure ◽  
Dry Matter Accumulation ◽  
Saline Irrigation ◽  
Crop Growth Rate ◽  
Leaf Surface Area ◽  
Net Assimilation ◽  
Plant Salt Tolerance

AbstractWe have investigated the effects of saline irrigation on growth and water relations of two sun-cured tobacco genotypes, Xp102 and Px107, which belong to the Xanthia and Perustitza tobacco ecotypes, respectively. We compared three commercial sea salt concentrations of the irrigation water (0.25%, 0.5%, and 1% w/v) plus a non-salinized control, corresponding to an electrical conductivity (ECw) of 4.4, 8.5, 15.7, 0.5 dS m-1 and osmotic potentials of -0.22, -0.35, -0.73, -0.02 MPa, respectively. The ECsoil increased with the salinity of the irrigation water. At high salinity (1%), the soil where Px107 plants were grown showed a significantly higher salinity compared to the soil of Xp102. For both genotypes, the soil water content increased at increasing salinity and during the growth season. Increasing salinity progressively reduced the leaf turgor pressure and enhanced the cellular osmotic adjustment. The latter resulted to be more pronounced in Px107 compared to Xp102 (0.36 vs. 0.20 MPa). At higher salinity (0.5% and 1%), both genotypes showed reduced leaf surface area, dry matter accumulation, water use, net assimilation rate (NAR) and crop growth rate (CGR). Px107 roots were more sensitive than shoot to salinity (3% reduction per dS m-1) and compared to Xp102 roots, which showed a reduced development only at 1% salinity. Assessment of plant salt tolerance according to the Maas and Hoffman model revealed a slope of 1-2% for both genotypes, indicating that these tobaccos are relatively more salt tolerant compared to other species.

scholarly journals Screening of ‘King’ Mandarin Hybrids as Tolerant Citrus Rootstocks to Flooding Stress

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 388
Author(s):  
Mary-Rus Martínez-Cuenca ◽  
Amparo Primo-Capella ◽  
María Ángeles Forner-Giner
Keyword(s):  
Water Relations ◽  
Growth Parameters ◽  
Chlorophyll Concentration ◽  
Co2 Assimilation ◽  
Poncirus Trifoliata ◽  
Control Treatment ◽  
Gene Expressions ◽  
Flooding Stress ◽  
Citrus Rootstock ◽  
Osmotic Potentials

This work compares the tolerance to long-term anoxia conditions (35 days) of five new citrus ‘King’ mandarin (Citrus nobilis L. Lour) × Poncirus trifoliata ((L.) Raf.) hybrids (named 0501XX) and Carrizo citrange (CC, Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.), the widely used citrus rootstock in Spain. Growth parameters, chlorophyll concentration, gas exchange and fluorescence parameters, water relations in leaves, abscisic acid (ABA) concentration, and PIP1 and PIP2 gene expressions were assessed. With a waterlogging treatment, the root system biomass of most hybrids went down, and the chlorophyll a and b concentrations substantially dropped. The net CO2 assimilation rates (An) and stomatal conductance (gs) lowered significantly due to flooding, and the transpiration rate (E) closely paralleled the changes in gs. The leaf water and osmotic potentials significantly increased in most 0501 hybrids. As a trend, flooding stress lowered the ABA concentration in roots from most hybrids, but increased in the leaves of CC, 05019 and 050110. Under the control treatment (Ct) conditions, most 0501 hybrids showed higher PIP1 and PIP2 expressions than the control rootstock CC, but were impaired due to the flooding conditions in 05019 and 050110. From this study, we conclude that 0501 genotypes develop some adaptive responses in plants against flooding stress such as (1) stomata closure to prevent water loss likely mediated by ABA levels, and (2) enhanced water and osmotic potentials and the downregulation of those genes regulating aquaporin channels to maintain water relations in plants. Although these traits seemed especially relevant in hybrids 050110 and 050125, further experiments must be done to determine their behavior under field conditions, particularly their influence on commercial varieties and their suitability as flooding-tolerant hybrids for replacing CC, one of the main genotypes that is widely used as a citrus rootstock in Spain, under these conditions.

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