不同钾和硼水平对棉花叶片逆境生理及其细胞壁硼的影响

为了揭示钾、硼对棉花叶片细胞膜及硼利用的影响,本试验以棉花作为研究材料,采用营养液培养方式,研究了不同钾、硼处理叶片逆境下细胞膜及与细胞壁结合的硼比例的变化。结果表明,施钾水平为20 mg·L^-1时,缺硼(0 mgB·L^-1)阻碍棉花地上部生长和干物质的积累,且与正常硼(0.2 mgB·L^-1)相比,叶片逆境生理指标均显著升高,束缚态硼相对含量、R值(半束缚态硼/自由态硼)、细胞壁提取率和叶片总细胞壁硼占叶片硼的比例均有所升高;施钾水平为2 mg·L^-1时,缺硼叶片逆境生理指标、自由态硼和半束缚态相对含量及R值较正常硼处理也均显著升高,但束缚态硼相对含量和叶片总细胞壁硼占叶片硼的比例降低。因此,适钾与低钾时,缺硼均会明显破坏细胞膜透性。适钾条件下,缺硼导致细胞壁增厚,在细胞壁与果胶多糖结合的硼的比例升高;而低钾时,缺硼对于叶片细胞壁提取率无显著影响,进入叶片细胞质的硼的比例升高,但与果胶多糖结合的硼的比例降低。

Effect of Different Levels of Potassium and Boron on Stress Physiology and Cell Wall Boron Content of Cotton Leaf

To find out the effect of potassium(K) and boron(B) on cotton leaf cell membrane and B distribution and utilization, the membrane relative permeability, MDA, Pro, the content of free B, semi-bound B and bound B and the content of B in cell wall of cotton leaf were analyzed under different K levels with solution culture method in this study. The results showed that in normal K(20 mgK·L^-1), B deficiency(0 mgB·L^-1) hindered the normal growth and dry mass of shoots, in addition, the membrane relative permeability, the content of MDA and Pro significantly increased compared with the normal B(0.2 mgB·L^-1), and the relative concentration of bound B, R value, cell wall material and the ratio of total cell wall B/leaf B increased by 10.32%, 21.28%, 31.35% and 31.35%, respectively. In contrast, under low K(2 mgK·L^-1) supply, B deficiency produced a very significant decrease in the relative concentration of bound B and the ratio of total cell wall B/leaf B. The above results showed that under either K-deficient or K-sufficient condition, B deficiency damaged the cotton leaf cell membrane and cell membrane permeability. In normal B-supplied plants, lacking of B induced more B into the cytoplasm, but increased the proportion of B that combined with the pectic polysaccharides in cell wall. However, under K-deficient treatment, the proportion of B cross-linked pectic polysaccharides in cell wall decreased.