The effects of salt stress on growth physiology of selected okra (Abelmoschusesculentus L.) cultivars

Abstract

Salinity due to over-accumulation of NaCl is usually of great concern and it is the most injurious factor in arid and semi arid regions. Considering this feature, an experiment was conducted to evaluate the salinity stress responses of selected okra cultivators on Diffusive Resistance (DR) and Relative Water Content (RWC). The okra cultivars 'Haritha‘, 'EUOK2‘ and 'MI5‘ were used for this study. Sodium chloride (100mM) was used to create the salinity while, distilled water was used as control. Salt stress significantly increased the DR of the selected okra cultivars. The highest increase (5.1 scm-1)was obtained in the 'MI5‘ followed by 'Haritha‘(4.2scm-1) and 'EUOK2‘(3.6 scm-1). The highest increase found in the 'MI5‘ okra cultivar would have been due to tight closure of stomata in this cultivar compared to the others. The lowest value found in the 'EUOK2‘ would have been due to its inherent characteristic feature. The stomates of this cultivar would have kept opened relatively widely than the others. Salt stress significantly reduced the RWC of the selected okra cultivars. The highest reduction (58.7 %) was found in the 'MI5‘ followed by 'Haritha‘ (67.3 %) and 'EUOK2‘ (73.5 %). The 'EUOK 2‘ maintained relatively high amount of water in their leaf tissues under salinity stress. All these events indicate that 'EUOK 2‘ cultivar of okra had the ability to withstand salinity stress much better than the others. As a result, 'EUOK2‘ was recognized as the most salinity tolerant okra cultivar which could be grown in the salt affected areas of the sandy regosols.