星星草光合蒸腾特性的季节变化

对松嫩碱化草地上人工种植生长一至三年的星星草和自然生长的天然星星草的光合蒸腾特性的季节变化进行了测定。星星草光合速率的季节变化是单峰曲线，抽穗期光合速率最大。星星草的蒸腾速率则随生育期进程逐渐减小，但单位面积草地上星星草群体蒸腾速率的季节变化为单峰曲线，一年生、二年生和三年生星星草的最大值在开花期，而天然星星草则在抽穗期。星星草水分利用效率的季节变化也是单峰曲线，峰值均在抽穗期。

SEASONAL CHANGES OF PHOTOSYNTHETIC AND TRANSPIRATION CHARACTERS OF PUCCINELLIA TENUIFLORA

We measured the seasonal changes of photosynthetic and transpiration characters of Puccinellia tenuiflora, both natural growth and one to three-year planted P. tenuifiora on alkalized Songnen grassland. The curve of seasonal changes of photosynthetic rate of P. tenuiflora is one-peaked. The pohotosynthetic rate at heading stage is the maximum. The transpiration rate of P. tenuiflora decreased with the progress of fertility period, but the curve of transpiration rate of P. tenuifiora population per unit grassland area is one-peaked. The maximum values of one-year, two-year and three-year P. tenuiflora are in florescence, the maximum value of natural growth P. tenuiflora is at heading stage. The seasonal changes of water use efficiency of P. tenuiflora is one-peaked curve, the maximum values are at heading stage.