Cold-inhibited phloem translocation in sugar beet
Experimental studies were undertaken on a simplified single source leaf-single sink leaf, or single source leaf-double sink leaf sugar beet system to investigate the responsive nature of the long-distance phloem translocation system to localized cooling perturbations on the source leaf petiole. Experiments were performed by using a steady state (/sup 14/C)-labelling system for the source leaf, and translocation into the sink leaf (leaves) was monitored with a Geiger-Mueller system. A specially designed Peltier apparatus enabled cooling of the source petiole to 1/sup 0/C (or other desired temperatures) at various positions on the petiole, over different lengths, and at different rates of cooling. Initial experiment were designed to test the predictions of a mathematical recovery model of translocation inhibited by cold. The results did not support the mathematical model, but did suggest that vascular anastomoses may be involved in the recovery response. Selective petiolar incision/excision experiments showed that anastomoses were capable of re-establishing translocation following a disruption of flow. Studies with two monitored sink levels suggested that the inhibition to slow-coolings was not due to reduced translocation through the cooled source petiole region, but rather, was due to a repartitioning of flow among the terminal sinks (sink leaves and hypocotyl/crown region above the heat-girdled root). This repartitioning occurred via a redirection of flow through the vascular connections in the crown region of the plant, and appeared to be promoted by rapid, physical signals originating from the cooled region of the petiole.
- Research Organization:
- California Univ., Davis (USA)
- OSTI ID:
- 6936706
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUGAR BEETS
LEAVES
BIOLOGICAL LOCALIZATION
CARBON 14 COMPOUNDS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRANSLOCATION
BEETS
DISTRIBUTION
FOOD
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
PLANTS
VEGETABLES
553006* - Agriculture & Food Technology- Other Agricultural Applications- (1987-)