不同盐分处理对狼尾草和大油芒发芽与幼苗生长的影响

Effects of salt stress on the seed germination and seedling growth of Pennisetum alopecuroides and Spodipogon sibiricus

为了解盐渍化生境中r对策者发芽与幼苗期的盐分适应特征,本研究选用狼尾草(Pennisetum alopecuroides)和大油芒(Spodipogon sibiricus),按照NaCl∶Na2SO4∶NaHCO3为1∶1∶3(mol)配制复盐溶液,分6个处理(0、0.1%、0.2%、0.4%、0.8%和1.6%),分别进行种子发芽和幼苗生长单因素实验,比较了两种植物的发芽能力、胚生长和幼苗生长状况以及生理生化指标。结果表明:种子萌发阶段,随盐分浓度增大,狼尾草和大油芒发芽率、发芽指数和发芽势等均显著下降,低浓度(≤0.4%)时狼尾草的发芽能力小于大油芒,高浓度(≥0.8%)时则相反;狼尾草和大油芒胚芽长、胚根长及胚鲜重均显著下降,但大油芒胚生长受抑制的程度高于狼尾草;幼苗阶段,盐分显著抑制狼尾草和大油芒的幼苗生长,但大油芒受抑制的程度低于狼尾草,且狼尾草体内生理活性钙和丙二醛含量高于大油芒;可见,两种植物的耐盐能力在种子萌发阶段狼尾草强于大油芒,而幼苗阶段狼尾草又弱于大油芒,这体现了r对策者风险分摊的对策。

In order to understand the adaptive features of r-strategists at their germination and seedling stages under salt stress, Pennisetum alopecuroides and Spodipogon sibiricns were chosen as the objects, and two single-factor experiments of seed germination and seedling growth were conducted to compare the germination ability, embryo growth, and seedling growth of the plants as well as their physiological and biochemical properties under the salt treatments of 1 ： 1 ： 3 （mol） of NaCl： NaESO4 ： NaHCO3 at six levels （0.0% , 0.1%, 0.2%, 0.4%, 0.8%, and 1.6% ）. At germination stage, the germination rate, germination index, and germination vigor of P. alopecuroides and S. sibiricus decreased significantly with the increase of salt concentration. The germination ability of P. alopecuroides was less than S. sibiricus at low salt concentrations （ ≤0.4% ）, but in adverse at high salt concentrations （ ≥ 0.8% ）. With the increase of salt concentration, the plumule length, radicel length, and embryo weight of the two plants decreased significantly, but the inhibition degree was higher for S. sibiricus. At seedling stage, the growth of P. alopecuroides and S. sibiricus was significantly inhibited by the salts, hut the inhibition de- gree was lower for S. sibiricus than for P. alopecuroides, and the contents of physiological active calcium and malondialdehyde in P. alopecurroides were higher than those in S. sibiricus. These results suggested that P. alopecuroides had a stronger tion stage but a lower salt-resistance than S. sibiricus countermeasures of r-strategists. salt-resistance than S. sibiricus at germina- at seedling stage, implying the risk-sharing