The Translocation of Photosynthetic Products from Mesophyll into Midrib in Flue-cured Tobacco Plant : I. The effect of sinks on the translocation of total 14C

[摘要] The translocation of photosynthetically assimilated 14C from the mesophyll of intact leaf-detached leaf, rooted leaf, and the leaf attached to stem section, was investigated using the technique of spot feeding. Results obtained were summarized as follows: 1) In the intact leaf, it was observed that 14C was translocated from mesophyll basipetally into the midrib via the veins of 1st order of branching. Little 14C was detected in the apical part of the midrib and the mesophyll except the part to which 14CO2 was supplied. The amount of 14C in the midrib increased during the period of 15∼30 minutes after 14CO2 feeding, then increased slightly, attaining to about 3 % of the total 14C in the leaf. 2) In the detached leaf, most of the assimilated 14C remained in the part to which 14CO2 was supplied, and very small amount of 14C was observed in the midrib 180 minutes after 14CO2 feeding. 3) In the rooted leaf, 14C translocated into the roots increased during the period of 30∼60 minutes after 14CO2 feeding. About 1.5∼2 % of 14C was exported from the mesophyll during 60 minutes after 14CO2 feeding. 4) In the case of the leaf attached to the stem section, 5 and 10 cm in length, the 14C moved slowly from the mesophyll, and 14C-activity in the midrib and in the stem section increased during the period of 120∼180 minutes after 14CO2 feeding. On these basis, the relation of source and sinks to the translocation of photosynthetic products were discussed.

[学科分类] 农业科学（综合）