Abstract

Stomata conductance (g_s), Shoot water content (SWC), chlorophyll pigments (chl a,b) and enzymes involved in anti-oxidant photo-protection were determined in two mungbean genotypes (Kawmay-1 and VC2010) under greenhouse conditions. The two genotypes were subjected to water deficit stress (20, 40 and 80% of field capacity) and two root-knot nematode (Meloidogyne javanica) infection levels (non-infected and infected at 15000 juveniles per pot). Both water deficit and nematode infection resulted to a fast decline in the chlorophyll pigments, g_s and SWC in both genotypes; however, VC2010 was recorded as being comparatively resistant. Increase in antioxidant enzymes activity was detected for superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and polyphenol oxidase (PPO) in both stresses, but this activity was more pronounced in water deficit stress than nematode infection, especially at 40% field capacity. APX and PPO production peaks recorded at 20% of irrigation in VC2010 were highest. This revealed that VC2010 genotype was tolerant to environmental stresses compared to Kawmay-1. It was conceived from the present study that water deficit stress significantly hampered the physiological representatives of plant health, while on the other hand enzymatic alterations to cope with the biotic and abiotic stresses in plants could be used for better tolerability and plant health. The results indicated that oxidative damage (ROS) produced under environmental stress can be minimized by increasing the antioxidant enzymatic activities in mungbean.

Key words: Enzymatic activities, Nematode infection, Mungbean, reactive oxygen species (ROS), stomata conductance, water deficit.