子午岭林区白桦-辽东栎混交林光合生理生态特征研究

对黄土高原子午岭次生林区白桦林、辽东栎林和白桦-辽东栎混交林3种林分的土壤物理特性和叶片光合特性进行了研究。结果表明:(1)白桦-辽东栎混交林地的土壤水分明显改善,其土壤容重最小、土壤孔隙度最大,且均优于纯林,即混交林地有深层次的土壤水分可供利用,并改善了土壤的物理结构;(2)辽东栎林的光合速率和气孔导度最大,其次为白桦-辽东栎混交林,水分利用率(WUE)为混交林白桦>混交林辽东栎>辽东栎林>白桦林;(3)混交林中白桦、辽东栎的Fv/Fm和Fv/Fo值均较大,与纯林差异不显著;白桦林和辽东栎林的qP和NPQ值均大于混交林。

Photosynthetic Physiological and Ecological Characteristics of Betula platyphylla-Quercus liaotungensis Mixed Forests in Ziwuling Forest Area

Soil physical properties and leaf photosynthetic characteristics in three stands,Betula platyphylla forest,Quercus liaotungensis forest,and Betula platyphylla-Quercus liaotungensis mixed forest,which were located in the secondary zone of Ziwuling Forest of the Loess Plateau,were studied.It was shown that(1) Betula platyphylla-Quercus liaotungensis mixed forest had a remarkably improved soil moisture,the lowest soil bulk density and the highest soil porosity,and was superior over the pure forests,i.e.in the mixed forest there were available moisture in deeper soil and the soil structure got improved;(2) Quercus liaotungensis forest had the highest photosynthetic rate and the highest stomatal conductance and Betula platyphylla-Quercus liaotungensis mixed forest took the second place in photosynthetic rate and stomatal conductance,and the water use efficiencies of the plants in different forests decreased in the order of Betula platyphylla in the mixed forest,Quercus liaotungensis in the mixed forest,Quercus liaotungensis in the pure forest and Betula platyphylla in the pure forest;(3) In the mixed forest Betula platyphylla and Quercus liaotungensis had higher Fv/Fm and higher Fv/Fo and did not significantly differed from them in the pure forest in these two respects,and both the qP and NPQ in Betula platyphylla forest and Quercus liaotungensis forest were higher than those of the mixed forest.