Department of Botany, Sri Venkateswara University, 517 502 (A.P.), Tirupati, India.
Photosynth Res. 1981 Dec;2(4):297-300. doi: 10.1007/BF00056267.
Photosynthetic carboxylating enzymes and the effects of light and temperature on (14)CO2 efflux in two species of gymnosperm leaves were studied. The activity of RuBP carboxylase was high and that of PEP carboxylase was very low when compared to C4 plants. The CO2 compensation point was high. (14)CO2 efflux was greater in light than in darkness and the ratio (L/D) increased with increase in temperature and light intensity. The inhibitors of glycolate metabolism showed decreased (14)CO2 evolution in light while dark respiration was unaffected. It is concluded that both Cycas circinalis, L. and Cycas beddomei Dyer are C3 plants.
研究了两种裸子植物叶片中的光合羧化酶以及光和温度对 (14)CO2 释放的影响。与 C4 植物相比，RuBP 羧化酶活性很高，而 PEP 羧化酶活性非常低。CO2 补偿点较高。(14)CO2 释放量在光下大于在暗中，并且随着温度和光强的增加，比值（L/D）增加。糖酵解代谢抑制剂在光照下减少了 (14)CO2 的释放，而黑暗呼吸不受影响。结论是，苏铁和德氏苏铁都是 C3 植物。
