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Title: PHOTOSYNTHETIC ACTIVITY DURING THE CELL CYCLE OF THE GREEN ALGA SCENEDESMUS QUADRICAUDA

Author
item MESZAROS, T - MICROBIO INSTI CZECH REP
item KAFTAN, D - MICROBIO INSTI CZECH REP
item PRASIL, O - MICROBIO INSTI CZECH REP
item SETLIK, I - MICROBIO INSTI CZECH REP
item WHITMARSH, CLIFFORD
item NEDBAL, L - MICROBIO INSTI CZECH REP

Submitted to: Photosynthesis Mechanism and Effects
Publication Type: Proceedings
Publication Acceptance Date: 10/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Photosynthesis provides the energy and building blocks for plant growth and productivity. The photosynthetic process is made up of a series of molecular reactions that convert light energy into chemical energy and carbon dioxide into carbohydrates. To improve photosynthetic performance we need to understand the how photosynthesis is regulated. This knowledge is the basis for using genetic tools to control photosynthesis for optimal performance under diverse environmental conditions. With this aim we studied the performance of algal cells during development. The results show that photosystem II is a key, regulatory element during a significant period of cell development. We have shown that electron transport is a limiting factor in photosynthesis prior to and during cell division. This study demonstrates a successful approach for measuring photosynthetic performance during cell division. The results show that the factors that control photosynthetic performance switch from one rate limiting that site to another during cell division. This information will help researchers understand complex regulation of photosynthesis during plant growth.

Technical Abstract: The photosynthetic activity of a green alga Scenedesmus quadricauda was investigated during synchronous growth in light/dark cycles. The rate of photosynthesis varied more than twofold during the cell cycle. The minimum photosynthetic activity coincided with a substantial increase in the proportion of inactive photosystem II centers, and with an increase in stacking of the thylakoid membranes. This study shows that the intermediate electron transport chain controls photosynthetic rates during the maximum rate of photosynthesis and that photosystem II controls the rate during cell division.