Implication of Carbohydrates and Gibberellins in Photosynthesis Regulation in Citrus through Leaf/Fruit Ratio Manipulation
To investigate the effect of leaf/fruit ratio (NL/F) on citrus leaf photosynthetic assimilation (A) , carbohydrates concentrations and gibberellins levels variation, experiments were conduced on Okitsu Satsuma mandarin cv. in 2003 autumn. The (NL/F) of bearing shoots were adjusted. The exchange of assimilate between the shoot and the rest of the tree was prevented by girdling the base of the shoot. Our results show a significant limitation of (A) when (NL/F) is higher with a simultaneous increase of sucrose and starch in both leaves and shoots, whereas source-limiting conditions, induced by the smallest leaf/fruit ratios (NL/F=1-5-10), had the opposite effect. Gibberellins quantification showed an increase of GA1 and GA19 when (NL/F) is high and an increase of GA4, GA8 and GA20 when (NL/F) is lower, with no apparent effects on GA9 and GA9, levels. These suggest that source-limiting conditions favour the 13hydroxylation gibberellins biosynthesis pathway when carbohydrates accumulation induced by limited-sink conditions favour the 3-hydroxylation and/or the non13-hydroxylation gibberellins biosynthesis pathways. The role of carbohydrates and gibberellins as signals inhibiting or promoting photosynthesis will be discussed as well as the possible interactions between the hormone and sugars.
Leaf/Fruit ratio Photosynthesis Carbohydrate Gibberellins
Rym Bouhlal Domingo J. Iglesias Mehdi Ben Mimoun Rachid Hellali Manuel Talon
Departement Agronomic et Biotechnologies Vigitales, Institut National Agronomique de Tunisie (INAT), Centra de Gendmica y Postcosecha, Institute Valenciano de Investigaciones Agrarias (/. V. I. A. ) 46 Departement Agronomic et Biotechnologies Vigitales, Institut National Agronomique de Tunisie (INAT),
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
805-808
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）