engleski

Early Brassica Crops Responses to Salinity Stress: a Comparative Analysis between Chinese cabbage, White cabbage and Kale

Soil salinity is severely affecting crop productivity in many countries, particularly in the Mediterranean region. To evaluate early plant responses to increased salinity and characterize tolerance markers, three important Brassica crops - Chinese cabbage (B. rapa ssp. pekinensis), white cabbage (B. oleracea var. capitata) and kale (B. oleracea var. acephala) were subjected to short-term (24 h) salt stress by exposing them to NaCl at concentrations of 50, 100 or 200 mM. Physiological parameters (root growth, photosynthetic performance parameters, and Na+/K+ ratio), biochemical parameters (proline content, and lipid peroxidation as indicated by malondialdehyde, MDA, levels) and phytohormone levels (abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs) and brassinosteroids (BRs)) in the plants' roots and leaves were then measured. The crops' tolerance was positively correlated with levels of the stress hormone abscisic acid (ABA) and negatively correlated with levels of jasmonic acid (JA) and jasmonoyl-L-isoleucine (JA-Ile). Furthermore, salinity induced contrasting changes in levels of the growth-promoting hormones BRs. The crop’s tolerance was positively correlated with levels of BR precursor typhasterol while negatively with the bioactive BR brassinolide. Principal Component Analysis revealed correlations in observed changes in phytohormones, biochemical and physiological parameters. Overall, the results show that kale is the most tolerant to salt stress when Chinese cabbage was found to be the most sensitive species of the three species studied. The data obtained provide holistic indications of the spectrum of tolerance mechanisms involved.

stress response ; cabbage ; phytohormones

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