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

Abstract

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.

Subsoil constraints in Vertosols: crop water use, nutrient concentration, and grain yields of bread wheat, durum wheat, barley, chickpea, and canola

“…Therefore, maintenance of higher K and Ca concentrations in the salt-tolerant genotypes has been shown to be one of the mechanisms underlying their superior salt tolerance (El-Hendawy et al 2005). However, in the present study, cereals had a significantly lower concentration of Ca in the YML than chickpea.…”

Soybean Performance under Salinity Stress

“…Similar results were reported for tomato (Lapina and Popov 1970), pea (Hamada and El-Enany 1994), alfalfa (Winicov and Seemann 1990), sunflower (Ashraf 1999), sorghum (Netondo et al 2004), and wheat (El-Hendawy et al 2005). Differences in CCI among cultivars (Table 1, Figure 1) indicate that this trait can be also influenced by genetic constitution.…”

Spectral reflectance indices as a rapid and nondestructive phenotyping tool for estimating different morphophysiological traits of contrasting spring wheat germplasms under arid conditions

“…Measurements of LAI and CT both provide indirect indicators for various morphophysiological traits such as the water status of plants, the capacity of roots to access available soil water, and the main limitations of photosynthesis, growth, and production under water shortage conditions (El-Hendawy et al, 2005;Pask and Reynolds, 2013). Therefore, both parameters could be used to detect destructively ascertained morphophysiological traits in a rapid, low-cost, and nondestructive manner (Jin et al, 2013).…”

“…ca. 20-30 samples per hour using a Scholander pressure chamber) (Jongdee et al, 2002;El-Hendawy et al, 2005;Munjal and Dhanda, 2005;Gutierrez et al, 2010). Thus, the main goal of recent innovative breeding strategies is to look for easy, rapid, inexpensive, and nondestructive tools to assess agronomic and physiological traits of a large number of germplasms in a relative short time.…”