The interactive effect of the elevated CO 2 and moisture stress on the photosynthesis in Brassica leaves at different canopy positions

Brassica produces important edible oil consumed in South Asian countries including India. Production of Brassica crop in India suffered because its growing area is largely rain fed and this crop experiences adverse stress effect at various stages of growth (Uprety and Rabha 1999). The interactive effect of the elevated CO2 and temperature on Brassica species was studied using Free Air CO2 enrichment (FACE) facility for CO2 enrichment. The interactive effect of CO2 and temperature on the plant was studied using leaves at different canopy positions. The contribution of a temperature, light and relative humidity. has been studied with the help of correlation analysis between these environmental factors and rate of photosynthesis in the top, middle and lower leaves of the canopy.