干旱胁迫下沙地樟子松脱落酸变化及生理响应

The ABA Change and Physiological Responses of Pinus sylvestris L. var. mongolica Litv. to Water Shortage

土壤水分是限制沙地樟子松生长发育的关键因子。采用根系渗透胁迫法（ＰＥＧ处理）和盆栽干旱处理。以幼苗根系及叶片中脱落酸（ＡＢＡ）含量的累积作为幼苗对干旱胁迫响应的指示剂．模拟沙地樟子松幼苗对干旱胁迫的生理生态响应。在干旱胁迫下．根部和叶片ＡＢＡ均可迅速积累．但叶片ＡＢＡ累积较根部滞后；同时测定干旱胁迫下气孔导度、蒸腾速率、净光合速率．认为ＡＢＡ增加可降低气孔导度、并伴随蒸腾速率、净光合速率下降。１％土壤含水量可能是沙地樟子松幼苗干旱胁迫的临界值。低于此临界值，幼苗生长受到限制。

Water shortage often restricts growth of Pinus sylvestris var. mongolica. The physiological responses of Pinus sylvestris var. mongolica to water shortage was studied under different concentration of PEG and water shortage in this paper. The ABA content of root and conifer leaf, stamatal conductance, net-photosynthesis rate and transpiration rate were measured and discussed. The result suggests that ABA can be synthesized in the drought root and the synthesized ABA can result in the closure of stoma. The increasing of conifer leaf ABA lagged root synthesized ABA. The respiration rate and net--photosynthesis, rate also reduced responding to the closure of stoma. With the root ABA content as an indicator. l% soil water content may be the critical soil water content that affect the physiology.