放牧制度对短花针茅荒漠草原主要植物种光合特性日变化影响的研究

Effects of the grazing systems on diurnal variation of photosynthetic characteristic of major plant species of desert steppe

以内蒙古苏尼特右旗短花针茅荒漠草原为研究对象,通过划区轮牧与自由放牧的比较试验,研究3种主要植物种短花针茅、无芒隐子草和碱韭光合特性日变化对不同放牧制度的响应。结果表明,1)短花针茅、无芒隐子草和碱韭光合速率、蒸腾速率和气孔导度均表现为双峰型,具有明显的"午休"现象。胞间CO2浓度表现为双谷型。2)在其他条件相同时,放牧方式的不同对主要植物种的净光合速率、蒸腾速率无影响,但对双峰值出现的时间有所影响。3)对照禁牧和划区轮牧较自由放牧提高荒漠草原疏丛型禾草无芒隐子草的气孔导度和胞间CO2浓度。

A comparison of rotational grazing and continuous grazing was conducted on Stipa breviflora desert steppe in the Sunit Right Banner of Inner Mongolia. The study on response of diurnal variation of photosynthetic characteristic of major plant species in different grazing system showed： 1） Double-peaks on the curves of diurnal changes of photosynthetic rates, transpiration rates and stomatal conductance of S. breviflora, Cleisto- genes songorica and Alliurn polyrhizum, and there was a distinct phenomenon of ＂noon break＂. There was a double-valley on the curves of diurnal changes of internal CO2 concentration. 2） The different grazing regimes had no effect on the net photosynthetic rate or transpiration of the main plant species, but doubled the peak time in other the same conditions. 3） Rotational grazing and banning grazing increased stomatal conductance and internal CO2 concentration of C. songorica.