Physiological responses induced by chromium+6 toxicity to Cucumis sativus L. and Macrotyloma unifloroum Lam

Abstract

The aim of the present study was to examine the possible effect of Chromium (Cr 6+ ) stress on the rate of germination, growth, total chlorophyll, protein, and proline content in the seedling of Macrotyloma unifloroum Lam. and Cucumis sativus L. Upon exposure to graded levels of Cr +6 toxicity by using liquid culture medium. Seedling of both plants exhibited a gradual decline in the growth, total chlorophyll content, protein content along with enhanced proline content with increasing levels of Cr +6 . Rate of germination was 68% in case of Macrotyloma unifloroum Lam. whereas 1% in Cucumis sativus L. at 100 ppm of Cr +6 . The root and shoot growth showed a decline trend with the rise in concentrations (5 to 20 ppm) in both the plants. It was noticed that Macrotyloma unifloroum was less affected by Cr +6 in comparison to Cucumis sativus. The study of biochemical analysis revealed that the total chlorophyll and protein content of Macrotyloma unifloroum and Cucumis sativus were reduced gradually with the rise in concentration (5-20 ppm) and also time duration (7- 21days). A decrease in proline content was observed at lower concentrations (5 ppm) of Cr +6 whereas at higher concentrations (20 ppm) enhanced proline content was reported in both the species, but comparatively more in Cucumis sativus. The outcome of the present study indicates that the effect of hexavalent chromium (Cr +6 ) on