Agrotechnology

Effect of elevated CO2 and water stress on tomato at flowering stage

International Conference on Agricultural & Horticultural Sciences

September 14-15, 2012 Hyderabad International Convention Centre, India

Mamatha H, N.K. Srinivasa Rao and Laxman R.H

Posters: Agrotechnol

Abstract:

Thirty five days old seedlings of Tomato (SolanumlycopersicumL.)cv.ArkaAshishwere transplanted in open top chambers (Bangalore, India) during rabi 2010. Water stress was imposed by withholding irrigation three weeks at flowering stage (49 DAT).Photosynthesis,stomatal conductance, transpiration and stomatal density were characterized in response to CO 2 enrich - ment and water stress conditions.Irrespective of soil moisture status the net photosynthetic rate (Pn) of tomato leaves exposed to elevated CO 2 (550ppm) was greater than ambient CO 2 (380 ppm). Reduction in Pn was observed when water was withheld at both CO 2 concentrations but reduction at ambient CO 2 concentration was proportionately greater (14.78%) as againstthe plants grown at elevated CO 2 which recorded 12.10 percent reduction in Pn at water stress condition as compared to well watered plants. The stomatal conductance and transpiration decreased with increasing CO 2 concentration due to partial closure of stomata. El - evated CO 2 had negative correlation on stomatal density. Stomatal density on adaxial surface was 24 percent lower and abaxial surface was 28 percent lower in elevated CO 2 than in ambient CO 2 concentration.Stomatal density of the plants grown under elevated CO 2 and water stress recorded 23 percent decline as compared to plants grown at ambient CO 2 condition. Results indi - cate that elevated CO 2 had beneficial effects under water stress conditions, by decreased stomatal conductance and transpiration.