Abstract
In order to investigate the effect of ratio of non-photsynthetic organ to photosynthetic organs (C/F ratio) on the photosynthesis in mulberry tree, photosynthetic rates were compared in the following three plots at the same leaf order. Treatments were conducted early in July. A; Shoots were pruned to remain half number of leaves. B; Shoots were pruned in the same way as in A plot and all of the lateral buds were removed. C; untreated. The results obtained are as followrs; (1) Photosynthetic rate of the remained leaves was higher in A and B plot than C plot unti1 35 days after treatment. Photosynthetic rate of A plot exceeded B plot during the first 2 weeks after treatment, but thereafter, B plot was higher than A plot. (2) C/F ratio increased suddenly in A and B plots immediately after treatment, but ratio in A plot fell down gradually and reached the level of untreated one 35 days after treatment on the contrary, ratio in B plot rose after a little decrease. High correlation was recognized between photosynthetic rates and C/F ratios. (3) Content of 80% hot ethanol-soluble reducing sugar was highest in C plot except 35days after treatment. Ethanol-soluble reducing sugar content in B plot was higher than A plot in the first two weeks after treatment, but thereafter, A plot exceeded B plot. (4) The increased photosynthetic rate in the pruned trees was associated with the decreased sugar concentration in the remained leaves which was caused by the enbancement of assimilate translocation from the remained leaves to 1ateral buds or other organs.
