ABA Combined with UV-B enhances fruit quality with negative effects on yield in Vitis vinifera L. cv. Malbec

BERLI F.; ALONSO R.; BOTTINI R.

Shangai

Congreso; XXI International Plant Growth Substances Association (IPGSA) Meeting; 2013

Plant Growth Regulation Society of America (PGRSA) and the Japanese Society for the Chemical Regulation of Plants (JSCRP)

We have shown that ABA activates defense against solar ultraviolet-B (UV-B), i.e. triggering biosynthesis of phenols that filter the harmful radiation and acting as antioxidants. ABA levels in berry skins were not related to UV-B, although they fluctuated noticeably during fruit ontogeny, rising at the onset of ripening (veraison), likely regulating maturation. The present work reports the interaction between elevated solar UV-B levels perceived by high altitude vineyards (1450 m a.s.l.) and ABA applications on berry quality indicators and fruit yield. Determinations were done on field-grown grapevines (Vitis vinifera L. cv. Malbec) at different developmental stages during three seasons (2009, 2010 and 2011). Grapevines were exposed to normal (+UV-B) or to UV-B filtered sunlight (-UV-B) from 15 days before flowering until harvest. These treatments were combined with weekly sprays to leaves and berries of 1 mM ABA (+ABA) or H2O (-ABA) from 30 days before veraison. Results were evaluated as concentration (berry size dependent) and in absolute amounts (per berry basis), in order to understand the physiological effects. Berry skins antioxidant capacities, anthocyanins and total polyphenols were increased by +UV-B combined with +ABA (significant interaction effect), and the effects were higher as concentration. Also, +UV-B and +ABA interact to reduce berry growth, berries number, and sugar accumulation, without affecting sugar concentration. In conclusion, fruit quality indicators were increased by +UV-B and +ABA with negative effects on yield.