Changes of Ethylene Evolution, ACC Content, Ethylene Forming Enzyme Activity and Respiration in Fruits of Highbush Blueberry.

Abstract

We measured ethylene evolution, ACC content, ethylene forming enzyme (EFE) activity, and respiration in highbush blueberry (Vaccinium corymbosum L.) from flowering to harvest to assess the role of ethylene in the processes. Cultivars used were 'Collins' (early maturing), 'Berkeley' (mid-season), and 'Dixi' (late maturing). Ethylene evolution increased at both petal-fall and maturation stages, and was higher in the early stage than in the late stage. Ethylene at petal fall was produced by the calyx and ovary parts, but not the corolla. This indicates that ethylene evolution in flowering is correlated with pollination or fertilization or both. Ethylene evolution rate in the maturation stage was high between the blue pink (BP) peel color in 'Collins', and mature green (MG) stage in 'Berkeley', and green pink (GP) stage in 'Dixi'. Ethylene evolution was higher for 'Collins' than for the others in both years and higher in 1995 than in 1994. The pattern of EFE activity was not similar to that of ethylene evolution except in 'Collins'. Therefore, the correlation between ethylene evolution and EFE activity in the maturation stage was different with each cultivar. Berry ACC content was high at GP stage in three cultivars before ethylene evolution increased.