Relationship between sucrose accumulation and cell size in 4-CPA-treated melon fruits (Cucumis melo L.)

摘要

Sucrose content of the 55-day-old control melon (cv. Earls Knight Natsukei No. 2) fruit was 1.8 times greater than that of the 40-day-old control fruit. The number of cells larger than 200 #mu#m in the 55-day-old control fruit increased two-fold, compared with that of the 40-day-old control fruit. Using 4-chlorophenoxyaceticacid (4-CPA) treatment, fruit weight and flesh thickness tended to be greater with decline of flesh firmness. Sucrose content in the CPA fruits was _1.4 times more than that of thecontrol fruit. The number of cells larger than 200 #mu#m in the 40-day fruit treated with 4-CPA (40-day CPA fruit) was nearly the same as the number of the cells of the 55-day-old control fruit. Therefore, it is suggested that the increase in number of large cells caused by 4-CPA treatment of melon fruit at an early stage of fruit development increases the sink strength of cells, which promotes active import of sucrose from an early stage of fruit development.