PT  - JOURNAL ARTICLE
AU  - Christine Böttcher
AU  - Paul K. Boss
AU  - Christopher Davies
TI  - Increase in Cytokinin Levels during Ripening in Developing <em>Vitis Vinifera</em> Cv. Shiraz Berries
AID  - 10.5344/ajev.2013.13053
DP  - 2013 Aug 19
TA  - American Journal of Enology and Viticulture
PG  - ajev.2013.13053
4099  - http://www.ajevonline.org/content/early/2013/08/14/ajev.2013.13053.short
4100  - http://www.ajevonline.org/content/early/2013/08/14/ajev.2013.13053.full
AB  - This paper describes the quantification of the phytohormones abscisic acid (ABA), and its metabolites, and a range of cytokinins and gibberellic acid (GA) species in the same grape (Vitis vinifera L.) berry pericarp developmental series. Some relatively minor differences in concentrations were observed for some ABA metabolites and GAs when compared to previous studies. The biologically active GAs 4 and 7 (along with precursor and inactive forms) were present before veraison but at very low concentrations after veraison. ABA levels peaked shortly after veraison, but high levels of dihydrophaseic acid before veraison and high levels of ABA glucose ester after veraison suggest that two different catabolic pathways are developmentally controlled. The analysis of the concentrations of certain cytokinins provided some previously unreported and surprising results as the concentration of isopentenyladenine increased rapidly at veraison and remained at elevated levels throughout ripening. The reason for this phenomenon is unknown, but a similar increase in the concentrations of some cytokinins has been observed during kiwifruit development and may be involved in the control of ripening and/or senescence.