Characterization of the ecophysiological responses of three pomegranate cultivars to salinity

Abstract

In order to understand photosynthetic responses of pomegranate plants (Punica granatum L.) to salinity, an experiment was conducted with three varieties, 'Mollar de Elche', 'Valenciana', and 'Wonderful', irrigated with seven salt concentrations (0, 40, 60, 80, 100, 120, and 140 mM NaCl). At the end of the experiment, parameters of gas exchange, chlorophyll fluorescence, water relations, and sugar and chloride concentrations were measured in leaves. As the concentration of NaCl increased, the concentration of Cl − in leaves was elevated, and the CO2 assimilation rate, stomatal conductance, variable fluorescence/maximum fluorescence ratio, PSII quantum yield, and total soluble sugars decreased. In 'Valenciana', the decrease of the net assimilation of CO2 could occur due to the closure of stomata, while in 'Mollar' and 'Wonderful', this was due to damage caused by Cl − toxicity. The study of carbohydrates also suggests a different behavior of carbon metabolism in the three varieties.

Photosynthesis and chlorophyll fluorescence of Iranian licorice (Glycyrrhiza glabra l.) accessions under salinity stress

“…More tolerance in some accessions in the present study and better biochamical and physiological performance can be attributed to these mechanisms. The decrease in plant growth, under NaCl exposure, can be attributed to the changes in osmotic pressure by salinity, as a result of excessive ion accumulation in plants, followed by nutritional disequilibrium (Munns, 2002;Olmo et al, 2019). Leaf area influences photosynthetic performance and the buildup of photosynthetic products.…”

Physiological changes of pomegranate seedlings under salt stress and nitrogen fertilization

“…As for stomatal conductance and transpiration, the increase in electrical conductivity negatively affected the CO 2 assimilation rate (A), which decrease by 21.04% as the salinity of irrigation water increased from 0.3 to 6.3 dS m -1 (Figure 2D). This decrease in the CO 2 assimilation rate of pomegranate seedlings with the increase in salinity levels of irrigation water is directly related to the reduction of stomatal conductance, in addition to the increase in intercellular CO 2 concentration, clearly indicating that salinity may have increased mesophilic resistance to the entry of atmospheric CO 2 into carboxylation sites and/or reduced enzymatic activities associated with the photosynthetic carbon metabolism, and this effect is common in plants grown under saline conditions (Cruz et al, 2017;Olmo et al, 2019).…”

Growth, gas exchange, water relations, fresh and dry matter partitioning in young fig (Ficus carica L.) plants irrigated with saline water

“…The extent of stomatal closure induced by salinity has been shown to be genotype dependent (Zarei et al, 2016). The suppression of A and g s was documented after two weeks of salinization in -Salinity also affected the water relations of most woody Melgar et al, 2008;Olmo et al, 2019;Zarei et al, 2016). In olive, a crop that shares similar environmental and cultur-J o u r n a l o f H o r t i c u l t u r a l S c i e n c e (LWP) and relative water content occurred even at low levels of salinity , albeit symptoms of toxicity and permanent damage appeared at higher NaCl than those causing comparable damage in other fruit trees (Rhoades et al, 1992).…”

“…Woody species may adapt to salinity via a number of physiological mechanisms. A decrease in stomatal conductance (g s ), which reduces transpiration and increases water dium tolerance to salinity and leads to a reduced accumulation of toxic ions into the leaves and prolonged leaf longevity Khayyat et al, 2014;Melgar et al, 2008;Olmo et al, 2019;Sun et al, 2018). Both non-stomatal and stomatal factors were responsible for the short-term changes in leaf photosynthetic rate (A induced by exposure to salinity for one week (Golombek and Lüdders, 1993).…”