湿地松种子萌发对模拟水分胁迫的响应

Responses of Germination of Pinus Elliottii Seeds to Simulating Water Stress

采用聚乙二醇(PEG-6000)高渗溶液人工模拟水分胁迫,研究湿地松(Pinus elliottii)种子对水分胁迫的生态响应。结果表明:随着水分胁迫的加重,湿地松种子的萌发率、相对萌发率、发芽势、发芽指数、幼苗高度、根长与生物量等指标均呈现不同程度的下降趋势;通过建立水分胁迫与种子萌发率的回归方程,求解得出湿地松种子萌发的耐旱临界值是-0.68MPa,耐旱极限值是-1.14MPa;水分胁迫对湿地松种子萌发初期影响较大,会延迟其萌发时间,分别为1～8d不等;幼苗的根系在轻中度水分胁迫下生长较为稳定,表现出对干旱的适应性;水势为-0.8MPa时湿地松种子进入浅度休眠状态来适应干旱环境,通过建立水势与生物量的回归方程预测在-1.07MPa下湿地松生物量降至为0。

The artificial water stress treatment was conducted with polyethylene glycol（PEG-6000） hypertonic solution,so that we can find the response of seeds of Pinus elliottii to water stress.The results indicate that： with water stress increased,P.elliottii seed germination rate,relative germination rate,germination potentiality,germination index,seedling shoot length and root length,biomass had a decreasing tendency in different degrees;By established linear regression equation of seed germination under water stress,we can predict the drought tolerance critical value is-0.68 MPa and limited value is-1.14 MPa;The water stress had great impact on seed germination of P.elliottii early and will delay its germination time ranging from 1~8 d,respectively;The root of P.elliottii had a more stable growth under light water stress,showing adaptability to drought.When the concentration of PEG-6000 decrease to-0.8 MPa,the P.elliottii seed can not sprout into seedlings,aimed to adapt to drought environment,under-1.07 MPa the biomass decreased to 0 directly.