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Ribulose-1,5-bisphosphate carboxylase activity of Populus tremuloides Michx. bark tissues
1Faculty of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, New York 13210, USA.
Tree Physiology
|June 1, 1986
Summary
Populus tremuloides bark contains active Ribulose-1,5-bisphosphate (RubP) carboxylase, comparable to leaf activity. This indicates young bark tissues are photosynthetically capable, supporting observed photosynthesis rates.
Area of Science:
- Plant Physiology
- Biochemistry
- Forest Ecology
Background:
- Photosynthesis is crucial for plant growth and carbon fixation.
- Ribulose-1,5-bisphosphate (RubP) carboxylase is a key enzyme in photosynthesis.
- The photosynthetic competence of bark tissues is not fully understood.
Purpose of the Study:
- To isolate and characterize RubP carboxylase from Populus tremuloides bark.
- To compare the activity of bark RubP carboxylase with that of leaf tissues.
- To assess the photosynthetic capacity of young Populus tremuloides bark.
Main Methods:
- One-step Sephadex G-100-120 column chromatography for enzyme isolation.
- Measurement of RubP carboxylase specific activity (micromol CO2 mg-1 chlorophyll min-1).
Main Results:
- RubP carboxylase was successfully isolated from Populus tremuloides bark.
- The isolated enzyme exhibited a specific activity of 1.3 micromol CO2 mg-1 chlorophyll min-1.
- Bark RubP carboxylase activity was found to be comparable to that of leaf tissues.
Conclusions:
- Young Populus tremuloides bark tissues are photosynthetically competent.
- Sufficient RubP carboxylase is present in bark to account for observed photosynthesis rates.
- Bark tissue should be considered in studies of Populus photosynthesis.