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14 C‐Studies on Apple Trees. I. The Effect of the Fruit on the Translocation and Distribution of Photosynthates
Author(s) -
Hansen Poul
Publication year - 1967
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1967.tb07178.x
Subject(s) - sorbitol , sugar , shoot , chromosomal translocation , sucrose , horticulture , labelling , botany , chemistry , malus , biology , food science , biochemistry , gene
The presence of fruits affects the translocation and distribution of photosynthates from apple leaves to other organs of the tree. An attempt has been made to study the relationship in greater detail by following the distribution of 14 C introduced in the form of 14 CO 2 on shoots with and without fruits, respectively. Determinations of the 14 C‐content were made on different parts of the shoot sampled at varying intervals after the introduction of the tracer. The l4 C‐labelling and the content of sorbitol and sugar in the leaves were determined by means of paper chromatography. A total of nearly 90 per cent of the 14 C taken up by the leaves can be transferred to a fruit close by, the majority during the first 4 to 5 days following the addition of the 14 C. The content of 14 C in the leaves is reduced more rapidly in shoots with fruits than in those without. Young leaves retain more of the added 14 C than do fully developed ones. The greatest changes with time are found in the methanol‐soluble 14 C‐compounds. Immediately following application, the leaves contain 58 to 80 per cent of the 14 C added in sorbitol, 7 to 9 per cent in sucrose, and 1 to 4 per cent in the form of glucose. Within 5 days after the introduction of 14 C the amount of 14 C‐sorbitol is reduced very considerably, while in certain cases the amount of 14 C‐glucose increases. The 14 C‐sorbitol content was higher in leaves from shoots without fruits than in those from fruit‐bearing shoots, and this applied also to the total contents of sorbitol and of glucose.