CHANGES IN ANTIOXIDANT ENZYME ACTIVITIES AND HYDROGEN PEROXIDE CONCENTRATION IN LITCHI CHINENSIS DURING FLORAL DIFFERENTIATION
Floral differentiation is induced by low temperatures and enhanced by autumn and winter drought. Antioxidant enzyme activities, hydrogen peroxide concentration, leaf water content, maximum photochemical efficiency of PS 2 (Fv/Fm) and SPAD value in Litchi chinensis Sonn. cvs. Nuomici and Feizixiao during the chilled and drought-induced floral differentiation from Nov. to Feb. 2006 were studied, with the aim to show the physiological changes during the stress-induced floral differentiation. The results showed that the SPAD value indicating chlorophyll concentration increased before and then decreased after the emergence of panicle primordia in Nuomici, while in feizixiao SPAD values slowly rose during the period. Leaf water content in both cultivars decreased to the lowest level when panicle primordia emerged and increased thereafter. Fv/Fm decreased with the drop of temperature, and were higher in Feizixiao than in Nuomici. Activities of SOD and POD in the two cultivars increased at first and then decreased before panicle primordia emerged. But after that, the enzyme activities in Nuomici increased and remained at stable levels, while that in Feizixiao increased to a high level but decreased thereafter. APX activity in Nuomici increased during the whole stage while in Feizixiao it increased then decreased but still remained at a higher level. On the whole, APX activities in the floral induction stage were lower than those in the panicle developmental stage. A sudden increase in H2O2 concentration in the two cultivars was found when panicle primordia emerged. H2O2 concentration before panicle emergence in both cultivars was lower than that after panicle emergence.
Zhou, B.Y., Chen, H.B., Huang, X.M., Wu, G.L., Hu, Z.Q. and Gao, Z.G. (2010). CHANGES IN ANTIOXIDANT ENZYME ACTIVITIES AND HYDROGEN PEROXIDE CONCENTRATION IN LITCHI CHINENSIS DURING FLORAL DIFFERENTIATION. Acta Hortic. 863, 453-460
litchi, floral differentiation, antioxidant enzyme