SEASONAL-VARIATION IN RIBULOSE 1,5-BISPHOSPHATE CARBOXYLASE ACTIVITY AND ITS RELATIONSHIP WITH LEAF PROTEIN-CONTENT AND NET PHOTOSYNTHETIC RATE IN TROPICAL DECIDUOUS TREE SPECIES

The ribulose 1,5-bisphosphate carboxylase (RuBPC) activity, protein co ntent and net photosynthetic rate (P-N) were estimated at monthly inte rvals from September 1990 to August 1991 in Chukrasia tabularis, Dolic handrone atrovirens, Eugenia jambolana, Gmelina arborea, Lannea coroma ndelica, Terminalia arjuna and Terminalia bellerica. The leaves of all these tree species showed significantly higher RuBPC activity during summer than in winter, when it was expressed on the basis of chlorophy ll (Chl) content. RuBPC exhibited seasonal variations in its activity and these differed from one tree species to the other. When expressed on the basis of leaf area, the activity of RuBPC correlated with prote in content, but not with P-N.