A rapid dehydration leaf assay reveals stomatal response differences in grapevine genotypes. (22nd January 2014)

• Record Type: Journal Article
• Authors: Hopper, Daniel W; Ghan, Ryan; Cramer, Grant R
• Is Part Of: Horticulture research. Volume 1(2014)
• Publication Date: 2014-01-22
• Subjects: Drought -- Plant genetics -- Stomata; Horticulture -- Research -- Periodicals; 635.072
• DOI: 10.1038/hortres.2014.2
• Languages: English
• ISSNs: 2052-7276

Abstract

Abstract: A simple and reliable way of phenotyping plant responses to dehydration was developed. Fully-developed leaves were detached and placed in a closed plastic box containing a salt solution to control the atmospheric water potential in the container. Three hours of dehydration (weight loss of the leaf) was optimal for measuring changes in stomatal response to dehydration. Application of the plant hormone abscisic acid (ABA) prior to leaf detachment decreased the amount of water loss, indicating that the assay was able to detect differences based on a stomatal response to dehydration. Five different Vitis genotypes ( V. riparia, V. champinii, V. vinifera cv. Shiraz, V. vinifera cv. Grenache and V. vinifera cv. Cabernet Sauvignon) with known differences in drought tolerance were screened for their dehydration response and the results obtained corresponded to previous reports of stomatal responses in the vineyard. Significant differences in stomatal density along with differences in the amount and rate of water lost indicate differences in dehydration sensitivity among the genotypes screened. Differences in stomatal response to ABA were also detected. Shiraz had the lowest stomatal density and the highest ABA sensitivity among the genotypes screened, yet Shiraz lost the most amount of water, indicating that it was the least sensitive to dehydration. Despite having the highest stomatal density and intermediate stomatal sensitivity to ABA, V. riparia lost the smallest amount of water, indicating that it was the most sensitive to dehydration. The assay presented here represents a simple and reliable phenotyping method for plant responses to leaf dehydration. Physiology: gauging dehydration tolerance in grape leaves: A simple, new assay allows researchers to measure dehydration responses in grape leaves in a highly controlled manner. Developed by Grant Cramer and colleagues at the University of Nevada in Reno, NV, USA, the method should help viticulturists and geneticists screen grapevine subtypes for differences in drought tolerance and water use. The researchers detached leaves from the vines of various Vitis grapes—including 'Shiraz', 'Grenache' and 'Cabernet Sauvignon'—and immediately placed the leaves in closed, plastic boxes containing a salt solution, which helps to control atmospheric water potential. They tracked water loss for 3 h and observed significant and reproducible differences in dehydration sensitivities. These differences, as revealed by the new assay, were largely driven by the dehydration response of tiny pores in the grape leaves known as stomata, which open to allow for gas exchange and close to prevent water loss.