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为了明确盐对种子发芽影响的渗透效应和离子效应共同作用方式以及量化种子发芽对盐的响应,以两个大麦(Hordeum vulgare)品种‘Cask’和‘County’为研究对象,设置4个恒定温度(5、12、20和27℃)、5个等渗的NaCl和聚乙二醇(PEG)浓度梯度(–0.45、–0.88、–1.32、–1.76和–2.20MPa,蒸馏水作对照),做常规发芽实验。结果显示:(1)两个品种在NaCl溶液中比在等渗的PEG溶液中发芽率高且发芽速度快;(2)NaCl和PEG分别作为渗透剂计算出的水势模型参数值差异很大,说明水势模型不能用来描述种子发芽对盐的响应;(3)大麦种子在盐溶液中的发芽速率与盐浓度成显著的负相关直线关系,因此我们修订了水势模型,将修订后的模型命名为盐度模型,用来量化盐对大麦种子发芽的影响。与水势模型计算出的发芽时间相比,盐度模型计算出的50%种子发芽时间与大麦种子实际发芽时间更接近;(4)大麦种子在等渗的NaCl和PEG溶液中发芽速率差异随着水势降低,先增加后降低。据此我们提出盐的渗透效应和离子效应共同作用于种子发芽的3种情况:第一种在低盐条件下,主要是渗透效应起负作用;第二种情况在中盐条件下,渗透效应和离子效应共同起作用,离子效用的正作用强于渗透效应的负作用;第三种情况在高盐条件下,离子效应逐渐开始起离子毒害的负作用。
In order to clarify the effect of osmotic effect and ion effect of salt on seed germination and quantify the response of seed germination to salt, four barley (Hordeum vulgare) varieties ’Cask’ and ’County’ (5, 12, 20 and 27 ° C), five isotonic NaCl and polyethylene glycol (PEG) concentration gradients (-0.45, -0.88, -1.32, -1.76 and -2.20 MPa, distilled water control) Conventional germination experiments. The results showed that: (1) The germination rate and germination rate of two varieties in NaCl solution were higher than those in isotonic PEG solution. (2) The parameters of water potential model calculated by NaCl and PEG as penetrants differed greatly, Which means that the water potential model can not be used to describe the response of seed germination to salt. (3) The germination rate of barley seed in salt solution has a significant negative correlation with salt concentration. Therefore, we revised the water potential model and named the revised model Salinity model is used to quantify the effect of salt on the germination of barley seeds. Compared with the germination time calculated by the water potential model, the 50% seed germination time calculated by the salinity model is closer to the actual germination time of barley seeds. (4) The difference of germination rate of barley seeds in isotonic NaCl and PEG solution Lower water potential, first increase and then decrease. Based on this, we propose that salt infiltration effect and ion effect act together on seed germination in three situations: the first one is under the low salt condition, the main one is the negative effect of osmotic effect; the second one is under the salt condition, the infiltration effect Together with the ion effect, the positive effect of ion action is stronger than the negative effect of osmotic effect. The third case is that the ion effect begins to play a negative role in ion poisoning under high salt conditions.