通过降低空气湿度(从约30%减少到5%)、增加CO_(2)浓度(从400#mu#l CO_(2)/L增加到730#mu#l CO_(2)/L)、烫叶鞘破坏韧皮部等处理对谷子叶片光合速率日变化和水分利用效率(WUE)进行了研究,发现中午光合速率降低与光合产物积累有关;虽然低大气相对湿度(5%)使光合速率有所降低,但提高了WUE。而烫叶鞘使光合物质积累既抑制了光合速率,又降低了WUE。
The diurnal variations of photosynthetic rate and water use efficiency in Setaria italica leaves
Liao Jianxiong, Wang Genxuan
State Key Laboratory of Arid Agroecology of Lanzhou University.Lanzhou 730000,Gansu
Diurnal changes of photosynthetic rate in millet leaves were observed under low relative humidity (about 5% RH), high CO_(2) concentration (730 #mu#l CO_(2)/L) and assimilate accumulation by heat girdling of leaf sheath by CI-301 CO_(2) gas analyzer. It was found that the midday depressions of photosynthesis in nature conditions and low RH and high CO_(2) concentration treatments were significantly correlated with the accumulation of photosynthates. High CO_(2) concentration (730 #mu#l CO_(2)/L) can increase photosynthetic rate and decrease transpiration rate (E), so improve water use efficiency (WUE) greatly. Low relative humidity (5% RH) can decrease photosynthetic rate (P_(n)), but improve WUE too, it is why low RH decrease stomatal aperture and the E is more dependent on the stomata than P_(n); assimilate accumulation (heat girdling of leaf sheath) could decreased P_(n) and WUE.
廖建雄, 王根轩. 谷子叶片光合速率日变化及水分利用效率[J]. 生理学报 1999; 51 (4): .
Liao Jianxiong, Wang Genxuan. The diurnal variations of photosynthetic rate and water use efficiency in Setaria italica leaves. Acta Physiol Sin 1999; 51 (4): (in Chinese with English abstract).