Effect of Light and Ontogenetic Stage on Sink Strength in Bean Leaves
- 1 September 1978
- journal article
- research article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 62 (3), 454-457
- https://doi.org/10.1104/pp.62.3.454
Abstract
Light (about 3000 ft-c) neither increased nor decreased the sink strength of young, rapidly expanding leaves of Phaseolus vulgaris L. cv. Black Valentine, as measured by the comparative rates of import of 14C-labeled photosynthates by sink leaves in the light vs. dark in short term experiments. Although irradiated sink leaves accumulated more 14C activity, the difference was fully accounted for by photosynthetic reabsorption of respiratory CO2 derived from substrates translocated to the sink leaves. Maximum sink strength was attained when the sink leaf reached 7-8 cm2 in area (9-10% of its fully expanded size). Thereafter sink strength declined rapidly and asymptotically to a near zero value at about 45 % final area. During this period, however, the rapid decline in translocation was offset by a rapid rise in the photosynthetic rate of the sink leaf, maintaining a near constant relative rate of dry weight increase until the sink leaf had expanded to about 17% of its final area. Although the increasing photosynthetic capacity was associated with a decreasing import capacity, suggesting that the rate of translocation to the sink leaf was controlled by the developing capacity of the sink leaf for photosynthesis, it was not possible to vary the total (true) translocation rate to the sink leaf by varying the photosynthetic rate of the sink leaf in short term light-dark experiments. Despite a high ratio of source to sink in these experiments, no evidence accrued that translocation into young bean leaves was ever sink-limited.This publication has 6 references indexed in Scilit:
- Source and Sink Leaf Metabolism in Relation to Phloem TranslocationPlant Physiology, 1978
- Effects of translocation and assimilate demand on photosynthesisCanadian Journal of Botany, 1976
- Structural and Physiological Changes in Sugar Beet Leaves during Sink to Source ConversionPlant Physiology, 1974
- Translocation of Labelled Assimilates in The Soybean III. Translocation and Other Factors Affecting Leaf GrowthAustralian Journal of Biological Sciences, 1964
- Translocation of Labelled Assimilates in the Soybean II. The Pattern of Translocation in Intact and Defoliated PlantsAustralian Journal of Biological Sciences, 1962
- REAGENTS FOR THE VAN SLYKE-FOLCH WET CARBON COMBUSTIONJournal of Biological Chemistry, 1951