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United States Department of Agriculture

Agricultural Research Service


Location: Horticultural Crops Research

2009 Annual Report

1a. Objectives (from AD-416)
1. Investigate leaf anatomy and morphology of well-watered and water-stressed grapevines using light and electron microscopy. 2. Monitor berry ripening and fruit quality characteristics of well watered and water stressed grapevines.

1b. Approach (from AD-416)
Research will be conducted on two cultivars in a greenhouse and drought conditions will be simulated. Leaves will be tagged on the vines of both cultivars to determine leaf age. During the dry-down and re-watering cycles, the physiological, anatomical, and morphological characteristics will be measured in both cultivars to assess drought resistance. Prior to sampling tissues for all microscopy studies, photosynthesis, dark respiration, and stomatal conductance will be measured on leaves of well-watered and water-stressed grapevines. Fruit quality characteristics such as Brix, pH, titratable acidity, color etc., will be measured to examine ripening behavior and quality characteristics during dry-down and re-watering cycles. Documents Grant with Washington State University. Formerly 5358-21000-034-32G (12/2008).

3. Progress Report
Having no qualified graduate student and delayed funding precluded us from initiating this project. Notwithstanding such obstacles, we used potted vines of Cabernet Sauvignon, Grenache, and Zinfandel prepared earlier to collect preliminary data on physiological and anatomical drought adaptive features for identifying drought resistant cultivars. ABA levels decreased with increasing water levels. As expected, stomatal conductance increased with increasing soil moisture levels. In a similar pattern, leaf water potential was highest at the highest soil moisture levels. The leaves followed reticulate venation pattern in which veinlets circumscribed small areas of mesophyll known as areola confining free vein endings of different density. Between the two cultivars, Zinfandel and Grenache subjected to two water regimes (42% and 29% soil volumetric water content) Zinfandel appeared to be more tolerant to low moisture levels as indicated by their high stomatal conductance. After hiring a qualified graduate student, these features will be reexamined with more rigorous experiments using all three cultivars. Along with all the physiological measurements, anatomical measurements including surface morphology, leaf anatomical parameters, amount of wax, and vein density will be measured in all three varieties and identify drought resistant cultivars. Methods of ADODR monitoring included meetings, e-mail, and phone calls.

4. Accomplishments

Last Modified: 06/27/2017
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