Si对NaCl胁迫下金丝小枣叶片中矿质元素微域分布的影响

Effect of silicon on mineral element micro-distribution in leaf blade of Ziziphus jujuba cv. Jinsixiaozao under NaCl stress

为进一步揭示硅(Si)与金丝小枣(Ziziphus jujuba Mill.cv.Jinsixiaozao)耐盐性的关系,以金丝小枣品种2a生嫁接苗为试材,研究了NaCl胁迫下Si对其叶片中矿质元素相对含量的影响。X-射线能谱分析结果表明,与对照相比,盐胁迫下金丝小枣叶片各个组织的细胞中K、Na元素相对含量均显著升高,Cl元素相对含量小幅升高,Si、Ca、Mg元素相对含量在大多数组织的细胞中显著下降;K、Ca、Si元素与Na、Cl元素相对含量间的比值明显改变,其中K/Na在栅栏组织的细胞中显著下降,Ca/Na和Si/Na几乎在所有组织的细胞中均显著下降。与盐胁迫相比,盐胁迫下加Si,枣叶片大多数组织的细胞中Ca元素相对含量升高不明显,P元素相对含量变化很小,Mg元素相对含量持续降低,但Na、Cl、K、Si元素相对含量在枣叶细胞中均显著变化,其中在叶绿体主要分布的栅栏细胞中K元素相对含量升高的幅度与Na、Cl元素相对含量降低的幅度均超过28.0%,Si元素相对含量在除下表皮细胞以外的所有叶细胞中均成倍升高,同时,这几种元素相对含量间的比值也显著改变,尤以K/Na、Si/Na和Si/Cl显著增大最为突出。结果说明,Si影响盐胁迫下金丝小枣对矿质元素的选择性吸收与分配,改善盐胁迫下金丝小枣叶片中盐分离子的平衡及微域分布。

To gain a further insight into the relationship between added soluble Si and salt tolerance of this fruit, the influence of Si on mineral element micro-distribution in leaf blade of the fruit was studied with its two-year-old grafted seedlings. X- ray micro-analysis showecl that, compared with control, in cells of all tissues of leaf blade, the relative content of both potassium （K） and sodium （Na） significantly increased, whie relative chlorine （Cl） content slightly increased, but the relative content of Si, calcium （Ca） and magnesium （Mg） significantly decreased in most cells of the leaf blade. Moreover, the ratio of K, Ca and Si to Na and Cl evidently changed. K/Na ratio significantly decreased in ceils of palisade tissue, Ca/Na ratio and Si/Na ratio significantly decreased in cells of almost all tissues. Compared with those under salt stress without Si, under salt stress with added Si, although increase of relative Ca content in cells of most tissues of the leaf blade was not significant, variation of relative phosphorus content was very little, relative Mg content further decreased, relative content of Na, Cl, K and Si in ceils of the leaf blade significantly changed, both the increase of relative K content and the decreases of Na and Cl in cells of palisade tissue were more than 28.0 percent, the relative Si content increased twice, and ratios of the relative content of these elements significantly changed, especially the significant increases of K/Na , Si/Na and Si/Cl. Experimental results suggested that Si influences selective absorption and distribution of Z. jujuba Mill. ev. Jinsixiaozao to mineral elements under salt stress, and improves balance of salt ions and their micro-distribution in leaf blade of the fi＇uit under salt stress.