Abstract: Photosynthetic rate in leaves of Rhodimyrtus tomentosa decreased by 43.7 as leaf water potentential declined from -1.25 MPa to -2.0 MPa at lower light intensity. The relation-ship between photosynthetic rate (PN, umol.m-2s-l) and light intensity (PAR, m mol • m-2s-l) was PN=2.13+17.96 PAR, r2=0.89 in leaves of Rhodomyrtus tomentosa with leaf water poten-tial -1.25 MPa. While the correspondencing relationship was PN= 0.37+15.49 PAR, T2=0.9 as leaf water potential decreased to -2.0 MPa. Ardisia quinquegona had lower photosynthetic rate and it decreased by 69.6% as leaf water potential declined from -1.06 MPa to -1.9 MPa.

Key words: Rhodomyrtus tomentosa