NaCl胁迫对5个引自北美的树种叶肉细胞超微结构的影响

为明确美国白蜡(Fraxinus americana L.)、茶条槭(Aceginnala Maxim.)、红桤木(Alnus rubra Bong.)、水紫树(Nyssa aquatica L.)和美国皂荚(Gleditsia triacanthos L.)5个引自北美的树种的耐盐性,采用水培方法、利用透射电镜技术对0(对照)、4和8 g·L-1 NaCl胁迫处理后5个树种1年生苗叶肉细胞超微结构的变化进行了观察和比较.观察结果表明:正常条件(0g·L-1NaCl)下,5个树种叶肉细胞在叶绿体形态、嗜锇颗粒数量等方面略有差异,但均未发生质壁分离现象.经NaCl胁迫处理后,5个树种叶肉细胞中的叶绿体和细胞核受到不同程度的损伤,表现为叶绿体膜消失,类囊体片层结构肿胀,叶绿体降解,嗜锇颗粒增大或增多,细胞核的核膜消失、核染色质凝聚；且随NaCl质量浓度的提高,损伤程度均逐渐加剧.4和8g·L-1NaC1胁迫条件下,美国皂荚、茶条槭和水紫树的叶肉细胞发生质壁分离现象,而红桤木、美国白蜡和水紫树的叶肉细胞内出现环状片层.根据观察结果,推测红桤木和美国白蜡对NaCl胁迫的耐性较强,美国皂荚和茶条槭也有一定的耐性,而水紫树的耐性最弱.

Effect of NaCl stress on ultrastructure of mesophyll cells of five tree species introduced from North America

In order to definite the salt tolerance of five tree species introduced from North America,such as Fraxinus americana L.,Acer ginnala Maxim.,Alnus rubra Bong.,Nyssa aquatica L.and Gleditsia triacanthos L.,using water culture method,the ultrastructure of mesophyll cells of one-year-old seedlings of them after treated with 0(CK),4 and 8 g·L-1NaCl was observed and compared by TEM technique.The observation results show that under normal condition(0 g·L-1NaCl),mesophyll cell of five tree species has slight difference in chloroplast morphology and osmiophilic granule number,and so on,but no occurrence of plasmolysis.Generally,chloroplasts and cell nuclei of mesophyll cells of five tree species are injured at different degrees after stressed by NaCl,it is presented as disappearance of chloroplast membrane,swelling of thylakoid lamella structure,chloroplast degradation,osmiophilic granule increase or bigger,disappearance of cell nuclear membrane,nuclear chromatin condensation.And with rising of NaCl concentration,the injure degrees of chloroplasts and cell nuclei are gradually severe.Under 4 and 8 g·L-1NaCl stress condition,the plasmolysis appears in mesophyll cells of G.triacanthos,A.ginnala and N.aquatica,while the annulate lamellae appear in mesophyll cells of A.rubra,F.americana and N.aquatica.According to the observation results,it is conjectured that the tolerance to NaCl stress of A.rubra and F.americana is stronger while that of N.aquatica is the weakest,and G.triacanthos and A.ginnala also possess a certain tolerance to NaCl stress.