Radiosensitivity Studies and Radiostability of Ribulose-1,5 Bis-Carboxylase and Gas Exchange Characteristics in Wheat, Garden Pea, Field Pea, Spinach, and Okra

Gamma radiation may be perceived as a stress like any other abiotic stress viz., temperature, nutrient, water, and salinity, and may affect plant growth and metabolism. However, radiation response may vary depending on the dose of exposure and with the genetic makeup of the field crop. Protein synthesis and degradation which are fundamental to the efficiency of the enzyme systems and to the normal plant growth and development may also get altered. An experiment was conducted to measure the effect of seed gamma irradiation at 0, 0.005, 0.025, and 0.05 kGy on the growth and development of five field crops viz., wheat, garden pea, field pea, spinach, and okra. Interspecies variation in seedling emergence capacity, plant vigor and mass, leaf development and economic yield in response to gamma irradiation was observed across the investigated field crops. Leaf photosynthetic rate, transpiration rate, stomatal conductance, and Rubisco activity were measured to be relatively less radiation sensitive and were more radiation stable than the nitrate reductase (NR) activity. The present study clearly shows that carbon metabolism is less sensitive to gamma radiation stress than nitrogen metabolism. It may also imply that under radiation stress, the growth of any plant species may be much more affected than the seed/grain yield.