Issue link: http://read.dmtmag.com/i/197178
SOILCOHEN & CELLAR REMI tory role. For example, increases in brassinosteroid levels have been correlated with ripening of grapes. Brassinosteroids have recently been found to increase endogenously after veraison in grape berries, and exogenous applications have hastened berry ripening. Auxins, cytokinins and giberellins are developmental hormones that participate in early berry development. These hormones can be imported into the berry, but they are mostly produced by seeds, and final berry size is therefore correlated with the number of seeds. In fact, seedless berries show lower concentrations of all of these hormones. These hormones are generally not considered to play a significant role in promoting grape ripening from veraison through maturity, as levels decline before veraison and remain nearly nondetectable during grape ripening. Endogenous levels of indole- 3-acetic acid (IAA), a common auxin, rises during the first phase of berry growth, but is thought to decline throughout lag phase and ripening, with the lowest levels in mature berries. In fact, auxins have been shown to slow ripening and act antagonistically to ABA. Grower applications of IAA just prior to veraison have been shown to prolong the lag phase; delay increases in berry volume, soluble solids and anthocyanins; and delay decreases in titratable acidity, when compared to the untreated control. Giberellin (GA) is associated with cell division and its levels are highest in flower tissues and grapes right after set, and decline after that, which is conducive to GA playing a role in early berry development (but a less significant role in ripening). However, some studies report a small increase in GA right before veraison, implying that GA may play important roles in controlling crucial ABA levels increase at the onset of veraison. Photo: Thinkstock decline dramatically between veraison and maturity. Exogenous ABA treatment, in the form of sprays, at or slightly before veraison has been shown to accelerate ripening and increase anthocyanin levels in grapes. ABA is mostly produced in leaves but moves via the phloem to grape clusters. Recent studies have indicated that some ABA may also be produced in grape skins themselves. ABA is involved in both sugar accumulation and also positively influences the accumulation of phenolic compounds. OTHER PGRS INVOLVED It is evident that ABA plays many complex roles in vine and grape physiology, and that the effects of ABA depend on the stage of vine and grape development. Many other hormones and biochemical processes are also involved in grape ripening. On the topic of grape ripening alone, other hormones are thought to be involved, either in an inhibitory or stimulaw w w. v w m m e d i a.com CHOOSE ALL AMERICAN We carry a complete line of wine bottles, corks and capsules in many colors, shapes and sizes – and our centrally located Pennsylvania warehouse services the eastern United States. All American has it all. For more information, please contact: Lissa McLaughlin (727) 321-8879 lmclaughlin@ allamericancontainers.com Roberta Parmelee (315) 585-6045 rparmelee @allamericancontainers.com www.aacwine.com Wine Warehouse in Belle Vernon, Pennsylvania • Sales Offices & Warehouses in Miami, Tampa, Atlanta, Puerto Rico, NJ and CA N ov - D ec 2013 | V INE YA RD & W INE RY M A N A G EM EN T 35