阴山扁蓿豆光合特性对模拟牦牛、藏羊践踏和降水的短期响应

发布时间：2018-07-14 18:40

【摘要】：为明晰牦牛和藏羊践踏对阴山扁蓿豆光合特性的分异影响,在天祝高寒草地采用模拟降水和践踏双因子控制试验,研究了阴山扁蓿豆单叶面积、叶绿素含量、叶片气体交换参数变化对短期模拟牦牛、藏羊践踏和降水的响应。结果表明,随着模拟牦牛和藏羊践踏强度的增加、模拟降水量的降低,阴山扁蓿豆单叶面积、叶绿素含量、蒸腾速率(T_r)、叶片气孔导度(G_s)和净光合速率(P_n)均呈下降趋势,胞间CO_2浓度(C_i)呈上升趋势。相同降水量下,藏羊和牦牛轻度践踏强度下阴山扁蓿豆蒸腾速率、叶片气孔导度和净光合速率均高于对照,胞间CO_2浓度低于对照。与对照相比,牦牛重度践踏处理下阴山扁蓿豆单叶面积、叶绿素含量、蒸腾速率、叶片气孔导度和净光合速率的降幅和胞间CO_2浓度的升幅均大于藏羊重度践踏处理。单一的模拟降水或模拟践踏极显著地影响了各测定指标,且两者共同作用对阴山扁蓿豆单叶面积、蒸腾速率、叶片气孔导度、净光合速率和践踏末期叶绿素含量的影响达极显著水平。综合可得,牦牛和藏羊轻度践踏可促进阴山扁蓿豆光合作用,重度践踏严重抑制了阴山扁蓿豆光合作用,且牦牛践踏对阴山扁蓿豆光合能力的抑制作用大于藏羊践踏。
[Abstract]:In order to understand the effect of yak and Tibetan sheep trampling on photosynthetic characteristics of alfalfa bean in Yinshan Mountain, simulated precipitation and trampling control experiments were used to study the single leaf area and chlorophyll content in Tianzhu alpine grassland. Response of leaf gas exchange parameters to the short-term simulated yak, Tibetan sheep trampling and precipitation. The results showed that with the increase of simulated yak and Tibetan sheep trampling intensity, the simulated precipitation decreased, the single leaf area, chlorophyll content, transpiration rate (Tr), stomatal conductance (GSP) and net photosynthetic rate (PN) of alfalfa bean decreased. The concentration of intercellular CO2 was increasing. Under the same precipitation, the transpiration rate, stomatal conductance and net photosynthetic rate of leaves of Tibetan sheep and yak were higher than those of the control, and the concentration of intercellular CO _ 2 was lower than that of the control. Compared with the control, the decrease of single leaf area, chlorophyll content, transpiration rate, stomatal conductance and net photosynthetic rate of leaves and the increase of intercellular CO2 concentration in Yak were higher than those in Tibetan sheep. The single simulated precipitation or simulated trample significantly affected each index, and the combined effects on the single leaf area, transpiration rate and stomatal conductance of alfalfa bean were studied. The effect of net photosynthetic rate and chlorophyll content at the end of trampling was very significant. It can be concluded that light trampling of yak and Tibetan sheep can promote photosynthesis of alfalfa bean in Yinshan Mountain, and severe trampling seriously inhibits photosynthesis, and the inhibitory effect of yak trample on photosynthetic ability of Alfalfa bean in Yinshan Mountain is greater than that on Tibetan sheep.
【作者单位】：甘肃农业大学草业学院草业生态系统教育部重点实验室中美草地畜牧业可持续发展研究中心甘肃省草业工程实验室;
【基金】：国家自然科学基金(31360570)资助
【分类号】：S812

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