engleski

Short term salinity response of selected Brassica crops

Soil salinity is one of the world wide problems affecting crop productivity. In order to evaluate early plant response to high salinity and characterise tolerance markers, three important Brassica crops: Chinese cabbage, white cabbage and kale were exposed to short term salt stress (24 h) in the range of NaCl concentrations (50, 100 and 200 mM). Physiological markers including Na+/K+ ratio and photosynthesis efficiency followed by biochemical stress markers such as proline, antioxidant enzymes and lipid peroxidation (MDA) as well as phytohormones (ABA, SA, JA, JA-Ile, brassinosteroids and IAA) were measured. Significant increase in proline and MDA contents, which are usually reported as strong biomarkers of abiotic stress, were obtained in roots and leaves tissue of Brassica crops, although photosynthetic efficiency was reduced only in Chinese cabbage. In parallel, osmoregulation through increased levels of ABA was shown to be one of the most dominant markers of salinity response among Brassicas. Contrary, levels of jasmonates (JA and JA-Ile) were significantly lower upon high salt in roots and leaves of cultivars. Salinity affected accumulation of growth promoting hormones brassinosteroids and IAA. Levels of brasinolide where significantly increased in roots and leaves of Chinese cabbage compared to other two Brassica crops and similar pattern was observed for active IAA. Salinity induced successive increase in IAA precursors (TRP, IPyA, IAM and IAN) in roots and leaves of three Brassicas but levels of active IAA were significantly higher only in leaves of Chinese cabbage followed by increased level of catabolic oxIAA. Performed PCA analysis revealed correlations among observed phytohormones, biochemical and physiological markers, and revealed Chinese cabbage as the most sensitive cultivar.

Brassica crops ; salinity stress ; phytohormones

nije evidentirano