ABA increase the photosynthetic efficiency in Vitis vinifera cv. Malbec

MORENO D.; BERLI F.; BRESSAN-SMITH R.; BOTTINI R.

Huerta Grande

Congreso; I Reunión Conjunta de las Sociedades de Biología de la República Argentina; 2007

Sociedades de Biología de la República Argentina

ABA is a phytohormone that modulates the plant responses to different stresses (drought, temperature, salinity, UV-B). Tungstate (w) inhibits ABA biosynthesis by blocking the enzyme ABA-aldehyde oxidase. Malbec is the typical variety of red wines from Argentina, where the cultivated area is the highest in the world. The chlorophyll a fluorescence is used in order to know the photosynthetic efficiency. The objective of the work was to study the ABA effect on the photosynthesis in grapevine. Plants of Vitis vinifera cv. Malbec vineyard were sprayed every 7 days onto the leaves with ABA (250 ppm), W (165 ppm) and H2O (control), from 15 days before flowering until harvest. The ABA-treated plants showed greater Fv/Fm and lower NPQ with respect to W, which means greater photochemical efficiency. In addition, the ABA-treated plants presented greater content of Chl a and photoprotective pigments, that might be important at noon when excessive intensities of PAR and UV-B are registered. In the W treated plants the berries were smaller. These results suggest that ABA protected the Chl a by increasing the photoprotective pigments, allowing a greater photochemical efficiency. This effect, added to a possible improvement in the carbohydrate partition observed in this and other species by our group, would be responsible for the greater berry size promoted by a greater production and transport of assimilates.