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Sugar transport in isolated corn root protoplasts
1Central Research and Development Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898.
Plant Physiology
|December 1, 1984
Summary
Corn root protoplasts preferentially absorb glucose over sucrose, exhibiting distinct uptake kinetics and temperature sensitivities. This study clarifies sugar transport mechanisms in Zea mays L. roots.
Area of Science:
- Plant Physiology
- Biochemistry
- Molecular Biology
Background:
- Understanding sugar uptake in plants is crucial for crop yield and nutrient allocation.
- Corn (Zea mays L.) root protoplasts offer a model system to investigate monosaccharide and disaccharide transport.
- Differential sugar transport mechanisms can impact plant growth and development.
Purpose of the Study:
- To investigate and compare the uptake kinetics of glucose and sucrose in isolated corn root protoplasts.
- To determine the influence of external concentration, pH, and temperature on sugar transport.
- To elucidate differences in sugar uptake between corn root and soybean cotyledon protoplasts.
Main Methods:
- Isolation of protoplasts from corn (Zea mays L.) roots.
- Measurement of glucose and sucrose uptake rates under varying substrate concentrations, pH, and temperatures.
- Kinetic analysis (Michaelis-Menten) to determine uptake parameters (K(m)).
- Assessment of inhibitor effects on sugar transport.
Main Results:
- Corn root protoplasts exhibited preferential uptake of glucose over sucrose and other hexoses.
- Glucose uptake displayed biphasic kinetics (saturable and linear components, K(m) = 7 mM), while sucrose uptake was linear.
- Glucose uptake showed a sharp temperature optimum at 42°C, whereas sucrose uptake was less temperature-sensitive, peaking above 50°C.
Conclusions:
- Distinct transport mechanisms govern glucose and sucrose uptake in corn root protoplasts.
- Kinetic and thermal properties suggest specialized transporters for glucose in corn roots.
- Observed differences highlight tissue-specific sugar transport strategies in plants.
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