Changes in Photosynthesis, Translocation and Distribution of 14C-assimilates during Leaf Development and the Rate of Contribution of Each Leaf to Fruit Growth in Tomato

Abstract

Changes in rates of photosynthesis, translocation, and distribution pattern of 14C-assimilates in leaves during their development and the contribution of individual leaves to the accumulation of photosynthates in various sinks were investigated by using tomato plants. The photosynthetic rate of the 3rd and 7th leaf gradually decreased with their ages, however, the amounts of photosynthates produced per leaf gradually increased with the increase of leaf area. Therefore, the amounts of photosynthates reached maximum just before full expansion of each leaf. Most of assimilates were distributed to near sink as a main sink. Furthermore, the relationship between source and sink likely changed with the developmental stages of roots, shoot and fruits resulting in difference in sink strengths. Thus, competitiveness among sinks changed according to the relative gradients between them and the source. The contribution of each leaf to the accumulation of assimilates by each sink was calculated by the total amount of assimilates and the sum of the distribution of 14C-assimilates from each leaf. The inflorescence was supplied 60-80% of its accumulation by 2 to 4 adjacent leaves. Furthermore, the maximum contribution rate from one leaf seemed to be about 30%. The peak efficiency of a leaf to supply a sink corresponded to the time when the sink was enlarging most rapidly. •• OE¾ ‰Ê ŽÀ‚Ì "-ˆç •E "ì 'å ‚Í,-t ‚©‚ç ‚Ì OEõ • ‡ •¬ŽY•¨ ‚¨‚ae‚Ñ‚¨‚ae‚Ñ•ª ‚©‚ç ‚Ì •… •ª ‚AE-³ ‹@-{ •ª ‚Ì "]-¬ ‚É ‚ae‚Á‚Ä•s ‚í ‚ê ‚é‚ª,Šî-{"I ‚É‚Í-t‚Å• ¶ ŽY‚³ ‚ê ‚Ä‚¢ ‚éOEõ• ‡ •¬ ŽY •¨ ‚ª "-ˆç "ì 'å ‚Ì OE´Ž' ‚Å‚ ‚é.OEõ • ‡ •¬ •ì-p ‚Ì •ê ‚Å‚ ‚é-t‚Ì OEõ • ‡ •¬"\ ‚Í-t 1989"N3OEŽ6"ú Žó-•. *OE» •Ý:-ì •Ø •E:'ƒ ‹AEŽŽOE± •ê •· ‰ª Žx•ê .-î ‚¨‚ae‚Ñ‚¨‚ae‚Ñ•ì •¨ ‚Ì • ¶ ˆç 'i ŠK‚É ‚ae‚Á‚ÄˆÙ‚È ‚é(3,12,13,14). ‹à ‚ç(6)‚Í ƒi ƒX‚Å,Še-tˆÊ ‚Ì OEõ• ‡ •¬-Ê ‚Í,-t ‚Ì "-ˆç ‚AE ‚AE‚à‚É'• 'å ‚µ‚Ä,‚» ‚Ì-t‚Ì "WŠJOEã3-t 'OOEオ •V ‚½‚É"W ŠJ‚· ‚鎞Šú ‚É•Å'å ‚É'B ‚µ,‚» ‚Ì OEã •™•X‚É'á ‰º‚µ‚Ä‚¢ ‚-‚± ‚AE‚ðŽ¦ ‚µ ‚Ä‚¢ ‚é. ‚Ü‚½,OEõ • ‡ •¬ŽY•¨ ‚Ì "]-¬•E •ª "z ‚à,-t ‚Ì-î‚ɉž‚ ¶ ‚Ä •Ï ‰»‚µ‚Ä‚¢ ‚-‚à‚Ì ‚AE •l ‚¦ ‚ç‚ê ‚é‚ª,-t ‚Ì-î ‚Ì •i •s ‚É"º ‚Á ‚Ä,-t Ž© •g ‚Ì •A•¨ •ã ‚Ì 'Š 'Î "I ‚ÈˆÊ 'u ‚¨‚ae‚Ñ‚¨‚ae‚Ñ-ð Š" ‚à•Ï ‰» 771