Vol. 75 No: 1

Title:
The role of leaves in citrus fruitlet abscission: Effects on endogenous gibberellin levels and carbohydrate content

Authors:
J. MEHOUACHI, D.J IGLESIAS, F.R. TADEO, M. JAGUSTI, E. PRIMO-MILLO and M. TALON

pp: 79-85

Abstract:
In satsuma (Citrus unshiu, cv. Clausellina) mandarin trees, defoliation shortly after anthesis of old (previous season) or young (current season) leaves increased fruitlet abscission (up to 60%) during the following 12 weeks. Defoliation also advanced the beginning of abscission. In foliated plants, maximum rates of abscission were reached 41 d after anthesis (DAA), whereas in plants without old or young leaves maximum abscission rates occurred 32 and 54 DAA, respectively. Gibberellin (GA) and carbohydrate concentrations were determined by GC-MS and HPLC, respectively. Defoliation did not substantially modify the endogenous levels of the active GA1, although the precursors and products of this GA changed mostly at 32 DAA. Thereafter, GA concentrations were similar in foliated and defoliated plants. Carbohydrate concentrations were low, and the highest differences were observed at 21 DAA. At this time, sucrose and hexoses were slightly lower and higher, respectively, in fruitlets on defoliated plants. Higher abscission rates of fruitlet of leafless inflorescences were also associated with reduced amounts of sucrose and higher hexose concentrations during this period. The data suggest that removal of either old or young leaves advanced and increased abscission, and reduced the sucrose/hexose ratio of fruitlets during the initial period of fruit set.

Full text: JHSB Subscribers     ISHS members & other users
(PDF 408704 bytes)

Translate:

Go back to previous page