Abstract
The effects of foliar applied H2O2
on chlorophyll, carotenoids, the non-enzymatic defense system (ascorbic acid), malondialdehyde
(MDA) hydrogen peroxide (
H2O2) and growth were assessed in roots and shoots of pea (Pisum sativum L.)
plants exposed to excess cadmium. In addition, we evaluated the influences of H2O2
spraying on proline, soluble sugars and
soluble proteins contents. Excessive cadmium treatment caused reduction in the growth parameters (dry mass, pods and
seeds dry weights), chlorophyll and carotenoids contents, roots total free amino acids, roots soluble sugars as well as shoots
and roots soluble proteins levels but increased total free amino acids and soluble sugars contents in shoots. Concentrations
of hydrogen peroxide and MDA was enhanced under Cd treatment. The foliar treatment of H2O2
alleviated the detrimental
effects generated under Cd treatment that represented as increment in pea growth. H2O2
spraying increased photosynthetic
pigments, growth characteristics, soluble proteins, and ascorbic acid contents comparing to the control sets not receiving
H2O2.
Similarly, a higher up-regulation was detected in proline contents of Cd + H2O2 set than Cd group ones at 0.25 mM
Cd. Contrarily, malondialdehyde (MDA), soluble sugars and total free amino acids contents of Cd + H2O2 set revealed a
lower decrease than Cd group ones especially in roots. The results demonstrated that H2O2
treatment could inverse the harmful
effects of cadmium on growth, through inducing the non-enzymatic defense system (ascorbate), proline accumulation,
maintenance of chlorophyll in pea leaves and lowering the intensity of H2O2
and lipid peroxidation (MDA).