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The effects of water stress on leaf PEPCases in Mesembryanthemum cordifolium

Tang Li, Shi Jiaonai

Shanghai Institute of Plant Physiology, The Chinese Academy of Sciences. Shanghai 200032

Abstract

Mesembryanthemum cordifolium is a facultative CAM plant. We found in this plant that: 1. Water stress elevated leaf PEPCase activity (Fig．1), the content of PEPCase protein (Fig．4) and mRNA encoding PEPCase (Fig．5). 2. Rewatering lowered the leaf PEPCase level (Fig．1). 3. PEPCases of stem and leaf were affected in the same way either by water stress or by rewatering (Fig．2). Therefore, it is possible that the shifting from C3 to CAM occurred in all green parts of the plant when water stressed. 4. There was a 300 kD minor PEPCase isoenzyme besides the 250 kD major one (Fig．2). They changed in the same way during water stress and rewatering (Fig．2). 5. The PEPCase activity in lower leaves was higher than in the upper young leaves.

Key words: phosphoenolpyruvate carboxylase;Facultutive CAM plant;Water stress;Mesembryanthemum cordifolium

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Citing This Article：

Tang Li, Shi Jiaonai. The effects of water stress on leaf PEPCases in Mesembryanthemum cordifolium. Acta Physiol Sin 1997; 49 (2): (in Chinese with English abstract).