Proline and glycinebetaine confer cadmium tolerance on tobacco bright yellow-2 cells by increasing scorbate-glutathione cycle enzyme activities

Abstract

Cadmium (Cd) stress significantly decreased membrane integrity and impaired the ascorbate (ASC)- glutathione (GSH) cycle in tobacco Bright Yellow-2 cells. Exogenous application of proline and glycinebe- taine (betaine) significantly restored the membrane integrity and increased the activities of ASC-GSH cycle enzymes under Cd stress without maintenance of the rich ASC or GSH pools. Moreover, proline offered more efficient protection against Cd stress than betaine.