Characterization of leaf senescence and pod development in soybean explants
P M Neumann1, A T Tucker, L D Noodén
1Botany Department, University of Michigan, Ann Arbor, Michigan 48109.
Plant Physiology
|May 1, 1983
Summary
Soybean leaf explants with pods show accelerated yellowing and abscission. Pod removal or zeatin treatment delays senescence, suggesting root-supplied minerals and cytokinin influence foliar senescence.
Area of Science:
- Plant Physiology
- Agricultural Science
Background:
- Soybean (Glycine max) leaf discs often remain green when detached.
- Intact fruiting plants experience leaf yellowing.
Purpose of the Study:
- To investigate soybean leaf senescence using excised explants with pods.
- To analyze the influence of pods and nutrients on foliar senescence.
Main Methods:
- Excised soybean leaf-stem-pod explants were maintained on distilled water or nutrient solutions.
- Stomatal resistance, chlorophyll, protein loss, and pod/seed development were monitored.
- Effects of pod removal, seed removal, and zeatin treatment were assessed.
Main Results:
- Podded explants exhibited accelerated leaf yellowing and abscission compared to intact plants.
- Senescence was delayed by removing pods/seeds or by adding mineral nutrients or zeatin.
- Pods on explants showed similar color changes to intact plants, accelerated on water but delayed by zeatin.
- Seed dry weight increased in explants, comparable to intact plants.
Conclusions:
- Soybean explants with pods are effective models for studying foliar senescence and pod development.
- Mineral and cytokinin flux from roots likely influences soybean foliar senescence.
- Increased stomatal resistance does not appear to be a primary cause of soybean foliar senescence.
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