模拟践踏和降雨对天祝高寒区垂穗披碱草有性繁殖的影响

Effects of Simulated Trampling and Rainfall on Sexual Reproduction of Elymus nutans in Tianzhu Alpine Meadow

为探究践踏和降雨及其两者交互作用对垂穗披碱草有性繁殖的影响,在天祝高寒草甸进行了为期2年的模拟践踏和降雨试验。试验结果表明,随着践踏强度的增加,垂穗披碱草的株高、穗长、每穗种子数、单位面积的生殖枝数、种子千粒重和种子产量均呈下降趋势;随着降雨量的增加,其株高和有性繁殖指标升高。降雨极显著影响了垂穗披碱草单位面积的生殖枝数、种子千粒重和种子产量,践踏极显著地影响了其株高、穗长和每穗种子数。藏羊重度践踏下穗长、每穗种子数、单位面积的生殖枝数、千粒重和种子产量分别比牦牛重度践踏高出8%、51%、23%、16%、113%,藏羊践踏抑制垂穗披碱草有性繁殖的作用小于牦牛践踏。经F检验,降雨对垂穗披碱草有性繁殖的影响最大,降雨和践踏的交互作用对其影响较小,降雨缓解践踏对垂穗披碱草有性繁殖的抑制作用。

In order to elucidate the effects of trampling, rainfall and their interaction on the sexual reproduction of E. nutans, a two-year simulation trail based on trampling and rainfall was conducted in Tianzhu alpine meadow. The results showed that plant height, panicle length, number of seeds per panicle and reproductive branches per unit area, and seed 1000-grain weight and yield exhibited a reduced tendency with the increase of trampling intensity. Furthermore, with the increase of rainfall, both plant height and sexual reproduction indexes of E. nutans were increased. The rainfall significantly affected the number of reproductive branches, 1000-grain weight and seed yield. The trampling significantly affected plant height, panicle length and number of seeds per panicle. The panicle length, number of seeds per panicle and reproductive branches per unit area, 1000-grain weight and seed yield were increased by 8%, 51%, 23%, 16% and 113%, respectively, by Tibetan sheep heavy trampling than that of yak. In addition, the inhibition of sexual reproduction of E. nutans induced by Tibetan sheep trampling was less than that of yak. F-test analysis showed that the rainfall had the greatest impact on sexual reproduction of E. nutans, while the interaction between rainfall and trampling had little influence on it. Moreover, the rainfall can alleviate trampling inhibited sexual reproduction of E. nutans.