Changes in nucleic acids and endogenous hormones in the apical buds of terminal shoots during the crucial period of floral induction in loquat.

摘要

'Zaozhong No.6' and 'Jiefangzhong' loquat (Eriobotrya japonica Lindl.) trees grown in the field were used as the materials in this study. The crucial period of floral induction for apical shoots was determined by defoliating and spraying gibberellic acid (GA). The changes in nucleic acid and endogenous hormone contents in the apical buds of terminal shoots during the crucial period of floral induction were investigated. In 2006, the crucial period of floral induction for 'Zaozhong No.6' and 'Jiefangzhong' was from July 1 to July 8 and from July 18 to July 25, respectively. During the crucial period of floral induction, the content of RNA and the ratio of RNA/DNA for the two cultivars increased significantly; the content of ABA and the ratios of abscisic acid (ABA) to other hormones, including ABA/GA₃, ABA/zeatin (ZT) and BA/[GA₃+indoleacetic acid (IAA)] for the two cultivars showed an upward tendency. The increased RNA level and RNA/DNA ratio may be important physiological indexes which reflect the characteristics of the crucial period of floral induction.