Endogenous hormones and fructan metabolism in Chrysolaena

Chrysolaena obovata (Asteraceae) of the Brazilian Cerrado accumulates inulin-type fructans in the rhizophores, the underground reserve organs of cauline origin. Rigui et al. sample plants in the field and find correlations with the dry and wet seasons throughout the phenological cycle between fructan content and composition, fructan enzyme activities and expression, and ABA and IAA contents. During sprouting, high IAA concentrations and plant growth occur concomitantly with low ABA concentration and inulin hydrolysis. Conversely, as plants enter the dormancy phase, high ABA concentration occurs in parallel with low fructan synthesis. The results suggest that the co-ordinated action of carbohydrate metabolism and hormone synthesis enables C. obovata to survive unfavourable field conditions.