盐胁迫对竹柳幼苗生理响应及结构解剖的研究

为了解盐胁迫对竹柳(Salix spp.)幼苗生长的影响,采用土培方法,对NaCl胁迫下半年生竹柳扦插苗的成活率、生理响应和根叶部结构进行研究。结果表明,在0.25%Na Cl胁迫(轻度盐胁迫)下竹柳能正常生长,而在0.5%NaCl(中度、重度盐胁迫)下生长受到抑制,推断竹柳的耐盐阈值是0.5%。随着NaCl浓度的增大,叶片相对含水量、叶绿素a含量、叶绿素总含量和叶绿素a/b均呈下降趋势;但叶绿素b含量、脯氨酸含量和MDA含量呈升高趋势。在轻度盐胁迫下,叶片SOD活性和可溶性蛋白含量均升高,在中、重度盐胁迫下显著下降。从根叶解剖结构来看,叶片、角质层、栅栏组织厚度和根部周皮和直径在轻度盐胁迫时最大,但在中度盐胁迫时叶片栅栏组织细胞长度减小且排列越来越疏松,根部输导组织细胞不正常。这表明竹柳在轻度胁迫时具有一定的耐盐性,但在中高度盐胁迫下生长不良。

Effect of NaCl Stress on Physiological Responses and Anatomical Structure of Salix spp. Seedlings

In order to understand the effects of NaCl stress on the seedling growth of Salix spp., the survival rate, physiological response and anatomical structure of half-year-old Salix spp. seedlings were studied under salt stress by pot-culture method. The results showed that the growth of seedlings was well treated with 0.25% NaCl (light salt stress), while it was inhibited treated with more than 0.5% NaCl (moderate and severe salt stress). It was deduced that the salt tolerant threshold of Salix spp. was 0.5%. The relative water content, the content of Chl a, Chl a+b and Chl a/b decreased as salt stress enhanced, while the Chl b, proline and malondialdehyde (MDA) contents increased gradually. The activity of superoxide dismutase (SOD) and soluble protein content increased under light salt stress, but significantly declined under moderate and severe salt stress. The thickness, cuticle, palisade tissue of leaf and the diameter and periderm of root were the biggest treated with 0.25% NaCl, while under moderate salt stress, the cell length in palisade tissue of leaf decreased with loose arrangement and the cells in transfusion tissue of root was abnormal. Therefore, it was suggested that Salix spp. had tolerance to light salt stress, and undergrowth at moderate and severe salt stress.