PARENT SESSION

Symposium S6D Crop photosynthesis, agricultural biotechnology
Thursday September 2nd, 2004 10:20 AM-12:20 PM Room 510A
Chair: Vince DeLuca
Co-Chair: Maurice Ku

The Control of Stomatal Aperture and Its Impact on Photosynthesis, Transpiration and Crop Yield. Yang Wang¹, Jifeng Ying¹, Monika Kuzma¹, Angela Sample¹, Maryse Chalifour¹, Jiangxin Wan¹, Charlene McArthur¹, Tina Uchacz¹, Carlene Sarvas¹, David Dennis^*,1, Peter McCourt², Yafab Huang¹, ¹ Performance Plants, Kingston, Ontario, Canada² Department of Botany, Toronto, Ontario, Canada

ABSTRACT- Abiotic stresses have a major influence in determining crop yield. The most important of these is water stress, especially when it occurs at a time when the crop is flowering and setting seed. At Performance Plants we have been attempting to minimize water loss through the control of stomatal aperture while maintaining yield under both optimal and stress conditions. So far, most water stress tolerance technologies work under stress conditions but have a yield drag under optimal conditions. This new technology is based on the observation that mutant Arabidopsis plants that have an enhanced sensitivity to abscisic acid (ABA) are more tolerant to water stress. These plants have a complete knockout of the beta subunit of farnesyl transferase that is part of the signal transduction pathway in the guard cells of the stomata involved in the control of stomatal aperture. Transgenic plants in which the expression of the farnesyl transferase has been conditionally down-regulated show a more rapid response to the ABA signal during water stress and a more rapid return to normal when the stress is relieved on watering. The impact of this on yield, photosynthesis and transpiration will be described under both field and laboratory conditions.

KEY WORDS: stress