不同生长时期羊草大针茅光合速率与气温关系的比较研究

A COMPATATIVE STUDY ON RELATION BETWEEN PHOTOSYNTHETIC RATE OF ANEUROLEPIDIUM CHINENSE AND STIPA GRANDIS AND AIR TEMPERATURE AT THEIR DIFFERENT PERIODS OF GROWTH

本文对羊草(Aneurolepidium chinense)和大针茅(Stipa grandis)营养枝生长初期、盛期和后期的光合速率-气温关系进行了比较研究。结果表明:羊草的相对光合速率-气温关系是一条三次函数曲线,大针茅则是一条三次项趋于零的四次函数曲线;羊草光合作用的低温补偿点低于大针茅,而高温补偿点则高于大针茅;光合作用-气温曲线斜率,即温度系数,两种植物间有差异,但不显著。光合作用的高温补偿点和最适温度,即温度饱和点,都以生长盛期最高,生长后期又低于初期。光合作用的半饱和温度和近饱和温度,也以生长盛期最高;生长后期与初期相比较:曲线处于下降阶段时,两种牧草的这一温度均是后期低于初期;曲线处于上升阶段时,大针茅仍是后期低于初期。羊草则是后期高于初期。

This paper focuses on the relation between photosynthetic rates andair temperature in A.chinense and S. grandis in the beginning, the peakand the late period of their growth. The results are as follows. For A.chinense, the relation between photosynthetic rate and tempera-ture shows a curve of cubic function, wheweas for S. grandis it is a cur-ve of quartic function. Compared with A.chinense,the compensation pointof photosynthesis at lower temperature in S. grandis is higher, and athigher temperature, this value is lower in S. grandis than in A.chinense.But the slopes for the two curves show little difference. At different growth stages,the indices for photosynthesis mentionedabove show a little change. They reach the highest values of compensa-tion point of photosynthesis at higher temperature and the optimal tempe-rature at the peak growth stage. Compared with the beginning stage, the-se values for the late growth stage are lower. At the half-saturation and near-saturation points, the air temperatureof photosynthetic rate is highest in peak growth stage. At the other twostages,the late stage is lower than the beginning for the two species inthe decreasing section of the curve and in increasing section of the curvefor S.grandis, it is the same with the decreasing section, but for A.chinense,it is just the opposite.