To determine the effects of gamma radiation on the photosynthetic pigments, sugar content and total carbon gain, seeds of Cullen corylifolium (L.) Medik. were irradiated with variable doses (0, 2.5, 5, 10, 15, and 20 kGy) at the rate of 1.65 kGy h-1 from 60Co gamma source. Cullen corylifolium represents an important Chinese medicine with adequate levels of secondary metabolites, thus we hypothesized that gamma irradiation could modulate primary metabolites which could supplement secondary metabolite levels. The seeds were then transferred to field for biochemical analysis at different developmental stages; pre-flowering, flowering and post-flowering. Gamma dosage at 10 kGy resulted in a significant increase in concentration of chlorophyll a (61.17%), chlorophyll b (93.18%) and total chlorophyll (71.66%), suggesting that low doses of radiation could activate photosynthetic pigment system while at 15 and 20 kGy dose resulted in depletion of such parameters. Sugar and total C analysis of plants irradiated at 10 kGy demonstrated significantly maximum (216.01%) sugar content in leaves at all developmental stages and significantly minimum (46.13%) and (57.81%) in plants raised from seeds irradiated at 15 and 20 kGy respectively. Effective stimulatory dose for C. corylifolium ’11062’ is 10 kGy. In contrast, the carotenoid content of the plants exposed to 15 and 20 kGy was maximum than control. Significance of such stimulation correlated with increasing C mass of the plant concerned is discussed in the light of newer aspects in research.

Cadmium and Mercury induced varying responses in Abelmoschus esculentus L. in relation to enzymes (ascorbate peroxidase (APX, 1.11.1.11), catalase (CAT, 1.11.1.6), glutathione reductase (GR, 1.6.4.2) and superoxide dismutase (SOD, 1.15.1.1) which are most related to the levels of Hg and Cd applied and concentrations of thiol groups already present or induced upon treatment. In the present investigation varying concentrations of CdCl2 and HgCl2 (0, 0.05, 0.10, 0.50, 1 and 2mM respectively) applied to plant in the soil shows a significant increase in ascorbate peroxidase, glutathione reductase and superoxide dismutase activities, and the respective metal accumulation. It reveals a mechanism for constant detoxification of H2O2 that have to be associated with adaptations and ultimate survival of this plant species during stress conditions. A reduction of catalase activities was observed on exposure to these metals, which is supposedly due to the inhibition of enzyme synthesis. Root length, shoot length, number of leaves showed an enhancement with 0.05 mM CdCl2 dose then a gradual decline with the increase in concentrations. The results indicate that A. esculentus is tolerant to high concentrations of these metals, a property related to a differential activation of its enzymatic antioxidant system, and also reveal that this species has a higher capacity of Cd absorption.