To counteract abiotic stress-induced devastating effects on plants, an imperative shotgun approach is the action of exogenously applied potential osmoprotectants such as proline. This experiment was carried out to evaluate the effects of exogenous application of different concentrations of proline as foliar spray on growth, chlorophyll contents, gas exchange characteristics, chlorophyll fluorescence and mineral ion accumulation of two eggplant cultivars viz., L-888 and Round grown under saline regimes. Fifty seven-day old plants were subjected for 15 days to varying levels of proline [0 (water spray), 10 and 20 mM] under control and saline (150 mM NaCl) conditions. Salt stress reduced growth, net CO2 assimilation rate (A), transpiration rate (E), water use efficiency (A/E), non-photochemical quenching (NPQ), electron transport rate (ETR), efficiency of photosystem II (Fv/Fm), shoot and root K+ and Ca2+ ions, while increased sub-stomatal CO2 concentration (Ci) and Ci/Ca ratio while non-significant effect was observed on chlorophyll contents and photochemical quenching (qN) of both eggplant cultivars. However, exogenous application of proline counteracted the adverse effects of salt stress on shoot fresh weight, a/b, A/E ratio, E and shoot Na+ of both eggplant cultivars. Overall, proline was not effective in alleviating the undesirable effects of salt stress on morphological and physiological attributes of both eggplant cultivars under saline and non-saline regime.
Keywords: Salt stress, Proline, eggplant, mineral nutrients, gas exchange characteristics
1. Introduction
Most of the environmental constraints drastically influence plant growth and development that lead to reduction in crop yield (Cramer et al., 2011; Shahbaz et al., 20...
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... exchange characteristics, chlorophyll fluorescence as well as Ca2+ and K+ ions of both eggplant cultivars, while in contrast, salt-induced increase was observed in the accumulation of Na+ ions as well as sub-stomatal CO2 concentration (Ci) and Ci/Ca ratio of both eggplant cultivars. Foliar-applied varying levels of proline remained ineffective in improving growth and photosynthetic attributes, inorganic nutrients (Na+, K+ and Ca2+) of both eggplant cultivars under control and saline regimes. However, exogenous application of proline (20 mM) counteracted the adverse effects of salt stress on shoot fresh weight, a/b, A/E ratio, E and shoot Na+ of both eggplant cultivars. Overall, proline was not effective in alleviating the undesirable effects of salt stress on morphological and physiological attributes of both eggplant cultivars under saline and non-saline regime.