PARENT SESSION
Poster Session 12: Physiology
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

The impact of ABA, CK and nitrogen deficit on stomatal responses in Arabidopsis thaliana.

Younas, Yasmin^*,1, Neuman, Dawn¹, ¹ University of Nevada, Las Vegas, Las Vegas, NV, U.S.A.

ABSTRACT- As plants develop, their appearance is continuously being modified by environmental conditions. The mechanisms through which plants receive and respond to environmental input or "signals" are extremely complex. Some of these signals are sensed by stomata and changes in the degree of stomatal opening reflect the cumulative effect of many physiological responses of a leaf to its surroundings. Located on leaf surfaces, stomata open and close, providing an effective barrier to the movement of water vapor and CO₂ into and out of the leaf. There is also increasing evidence of a phytohormonal role--specifically abscisic acid (ABA) and cytokinin (CK)--in the interaction of stomata with their environment. A review of the literature has also indicated that nitrogen (N) may be an important regulatory molecule in stomatal responses to ABA and CK, although this has not yet been carefully tested. Our lab is currently investigating the interaction between these two key plant hormones coupled with nitrogen concentration as part of this regulatory system in plants. For these studies we are using Arabidopsis as our model system. ABA, synthesized primarily in mature leaves, is known to close stomata and is considered to be an inhibitory hormone exhibiting an antagonistic response to CK. There are some reports that CK's are able to reopen ABA-closed stomata although this occurrence is poorly understood and does not appear to happen consistently. For this project we are attempting to precisely test and clarify these interactions.

Key words: Stomatal Response, Abscisic Acid, Cytokinin, Nitrogen Deficit