|
|
||||||||
|
Plant Physiology 77:617-620 (1985) © 1985 American Society of Plant Biologists Starch and Sucrose Synthesis in Phaseolus vulgaris as Affected by Light, CO2, and Abscisic Acid 1Biological Sciences Center, Desert Research Institute, P. O. Box 60220, Reno, Nevada 89506, Carnegie Institution of Washington, Department of Plant Biology, Stanford, California 94305-1297, Pflanzenphysiologie Institut, Untere Karspule 2, D 3400 Göttingen, West Germany
Phaseolus vulgaris L. leaves were subjected to various light, CO2, and O2 levels and abscisic acid, then given a 10 minute pulse of 14CO2 followed by a 5 minute chase with unlabeled CO2. After the chase period, very little label remained in the ionic fractions (presumed to be mostly carbon reduction and carbon oxidation cycle intermediates and amino acids) except at low CO2 partial pressure. Most label was found in the neutral, alcohol soluble fraction (presumed sucrose) or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate (slope = 0.35). Starch formation increased linearly with assimilation rate (slope = 0.56) but did not occur if the assimilation rate was below 4 micromoles per square meter per second. Neither abscisic acid, nor high CO2 in combination with low O2 (thought to disrupt control of carbon metabolism) caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO2 assimilation, with sucrose the preferred product at very low assimilation rates.
1 Research supported by National Science Foundation Grant No. PCM-8304775 and Department of Energy Contract No. DE-ECO8-84ER13234. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|