| In the present study, the potted plants of the two-year-old Myrica rubra were subjected to 25℃(control),"biqi"and"dongkui": 2±2℃, 10±2℃(low temperature stress), 35±2℃, 40±2℃(high temperature stress), 400μmol·m-2·s-1 PDF and 12 hours photoperiod during 6 days and recovered during 6 days at 25℃at the same light regime, were determined in 2d,4d,6d separately. The effects of temperature stress on the operation of photosynthetic apparatus and the protective mechanism in leaves of Myrica rubra were studied. The main results of this study are as follows:1,Compared with 25℃, the net photosynthetic rate (Pn), apparent photosynthetic quantum yield (AQY), carboxylation efficiency (CE), Chlorophyll content, photochemical efficiency (Fv/Fm) and photochemical quenching (qP) all declined under temperature stress. All dates come back, and can be restored to the control level after stress disarmament at 10℃and 35℃treatment, but 2℃and 40℃treatment can not be restored. The results show that temperature treatment is significant on the impact of Myrica rubra leaves, photosynthetic apparatus were hurt with 2℃and 40℃.2,Photorespiratory rate and nophotochemical quenching of Myrica rubra leaves increased with temperature treatment. This results show that photorespiration and xanthophyll cycle were the major protective mechanism under temperature stress in Myrica rubra leaves.3,The result of the detection on Myrica rubra leaves showed that respiratory rate increased and can be restored to the control level after stress disarmament. It made out that Myrica rubra could change respiratory rate to improve stress resistance and adapted itself to stress.4,It showed by comparison that Pn, AQY, CE, Fv/Fm and Fo of"biqi"were more susceptible than those of"dongkui"to low temperature, but the situation changed as to high temperature. It could come to a conclusion that"biqi"is low temperature resistance and"dongkui"is high temperature resistance.
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