[Photosynthetic characteristics of Sarcandra glabra]

To learn about the photosynthetic characteristics of Sarcandra glabra and provide the theoretic references for its better planting.

The photosynthetic parameters of twenty different provenances of Sarcandra glabra were determined by Li-6400 portable photosynthesis system, and the data was analyzed by Excel and SAS software.

The results showed that the light saturation point of different Provenances of S. glabra were almost about 800 micromol x m(-2) x s(-1), while the light compensation point of them were from 14.70 micromol x m(-2) x s(-1) to 48.68 micromol x m(-2) x s(-1). The curve of net photosynthetic rate had two peaks on sunny day, the first one was in the morning and the other one was in the afternoon. The photosynthetic "noon- break" of S. glabra appeared between 11:00-13:00, when the net photosynthetic rate goes down sharply. Intercellular CO2 concentration (C(i)), CO2 concentration (CO2S) and transpiration rate (T(r)) all have effect on the diurnal change of net photosynthetic rate (P(n)) of S. glabra, and the average correlation coefficient between P(n) and the parameters above were orderly as -0.89 (P < 0.01), -0.75 (P < 0.05) and 0.69 (P < 0.05);

S. glabra was a plant with characteristics of shade-tolerance, and through the way of covering, sprinkling for decreasing the surrounding temperature would be effective to reduce its "noon-break" time and increas its efficiency of photosynthesis.