单盐胁迫对蒙古扁桃种子萌发和幼苗生长的影响

Effects of single salt stress on seeds germination and seedlings growth of Amygdalus mongolica

目的研究单盐胁迫对蒙古扁桃Amygdalus mongolica种子萌发和幼苗生长的影响。方法以天然生长于祁连山自然保护区的濒危植物蒙古扁桃去内果皮的种子为研究材料,以不同浓度NaCl、Na_2SO_4、CaCl_2溶液模拟单盐胁迫条件,采用纸卷发芽的方法,测定发芽指标和幼苗生长指标。结果 3种盐在0.02~0.04 mol/L,蒙古扁桃种子发芽率、幼苗鲜质量、幼苗干质量呈增大趋势,在0.06~0.18 mol/L呈降低趋势;种子发芽指数、活力指数、饱和含水量、苗高、初生根长度、根长、次生根个数、幼苗根干质量随盐胁迫的加剧呈现显著下降趋势(P<0.05)。结论蒙古扁桃种子萌发和幼苗生长对盐碱的变化很敏感,NaCl、CaCl_2溶液处理下,种子萌发的半致死浓度(P_(50))均为0.12 mol/L,幼苗成长的P_(50)也均为0.10 mol/L,Na_2SO_4溶液处理下,种子萌发的P_(50)为0.10 mol/L,幼苗成长的P_(50)为0.06 mol/L,在高浓度单盐胁迫后,致使部分种子休眠而保持生活力,未能萌发的种子复水后萌发率高达82%~89%。

Objective To investigate the effects of single salt stress on seeds germination and seedlings growth of Amygdalus mongolica. Methods The single salt stress condition was simulated with various concentration of NaCl, Na2SO4, and CaCl2solutions; And the indexes of seeds germination and seedlings growth was tested under this condition according to the requirements of paper bed germination test. The study material used in this study was the seeds（without endocarp） of Amygdalus mongolicawhich was an endangered plant species from the Nature Reserve of Qilian Mountain. Results The germination rate of seeds, the fresh weight, and dry weight of the seedlings increased with the increase of the solution concentration when the concentration is in the range of 0.02—0.04 mol/L; The three indexes mentioned above decreased with the increase of the solution concentration when the concentration was in the range of 0.06—0.18 mol/L; And this correlation was consistent among all the three salts used in this study. Seeds germination index, seeds vigor index, saturated moisture content of the seeds, seedlings height, length of primary roots, root length, total number of the secondary roots, saturated moisutre content of the roots, and the root dry weight of the seedling decreased significantly when the condition of the salt stress was intensified（P〈0.05）. Conclusion The seeds of A. mongolica is very sensitive to the changes of the salt concentration and the results showes that when NaCl and CaCl2 solution is used, P（50） concentration for seeds germination is 0.12 mol/L, and for seedling growth is 0.10 mol/L; When Na2SO4 solution is used, the P（50） concentration for seed germination and for seedling growth is 0.10 mol/L and 0.06 mol/L respectively. Stress of high concentration of signal salt could make some seeds to be dormant, thus the viability of those seeds could be remained and the germination rate of the seeds which failed to germinate under the condition of single salt stress was up to 82%—89% after rewatering.