不同盐胁迫对唐古特白刺种子萌发和幼苗生长的影响

Effects of salt stress on seed germination and seedling growth of Nitraria tangutorum

为揭示唐古特白刺种子萌发、幼苗更新过程中对盐渍环境的耐受性及生态适应性,以不同浓度(0,2,4,6,12,18,28,36g·L-1)的盐溶液(NaCl,MgSO4,盐渍土壤)处理河西走廊中部荒漠地带唐古特白刺(Nitraria tangutorum)种子,研究不同盐对种子吸水、萌发和幼苗生长的影响.结果表明,唐古特白刺种子萌发期对不同盐的耐受性不同,随NaCl、MgSO4浓度的升高,种子萌发率呈现不同程度的降低,盐渍土壤溶液对萌发率影响较小.唐古特白刺幼苗的伤害度随NaCl和MgSO4浓度的升高而加大,6g·L-1 NaCl,2g·L-1和6g·L-1 MgSO4的胁迫下伤害度达到最大,三种盐对种子萌发和幼苗生长的抑制、伤害效应依次是NaCl>MgSO4>盐渍土壤.种子萌发可耐受的NaCl和MgSO4胁迫临界阈值分别为6g·L-1和28g·L-1,幼苗可耐受的NaCl和MgSO4胁迫临界阈值分别为6g·L-1和12g·L-1.在轻度盐渍化的生境,唐古特白刺种子能正常萌发,重度盐渍化土壤不利于种子萌发和幼苗建植.破除种子的休眠、土壤保墒和低盐渍化土地种植,是保证唐古特白刺种子萌发、幼苗存活和建植的关键.

To reveal the tolerance of seed germination,seedling regeneration of Nitraria tangutorum to saline environment and their ecological adaptability,seed germination and seedling growth of N.tangutorum following different concentration of the NaC1,MgSO4 and saline soil solution are studied.The results show that water uptake rate of seed increase firstly and then decrease,and germination percentage decrease with increasing NaC1 and MgSO4 concentration,whereas there are insignificant effect of saline soil solution on germination percentage.The effect of salt stress on seed germination and seedling growth is NaCl＞MgSO4 ＞ saline soil solution.Seed germination and seedling growth of N.tangutorum are significantly affected by higher concentrations of NaC1 and MgSO4,in which the lowest permeability threshold of germination are 6 g·L-1 and 28 g·L-1,for seedling are 6 g·L-1 and 12 g·L-1,respectively; seed germination can tolerate stress of higher concentrations of saline soil solution.The results imply that N.tangutorum can survive in a slightly saline soil habitat,suggesting that breaking seed dormancy,keeping soil moisture and low salinity are the key to guarantee survival of N.tangutorum.