硅盐互作下小獐毛植物体内元素分布及生理特性的研究

THE EFFECTS OF SILICON ON IONIC DISTRIBUTION AND PHYSIOLOGICAL CHARACTERISTIC OF AELUROPUS PUNGENS UNDER SALINITY CONDITIONS

以新疆泌盐植物小獐毛 (Aeluropuspungens)为材料 ,研究盐胁迫下小獐毛植物体元素吸收、分泌和过氧化物酶活性的变化以及硅对上述指标的影响。结果表明 :在盐分胁迫下 ,其植物体钠离子浓度升高 ,钙元素含量降低 ,其它元素含量变化不明显。叶片硅元素含量随盐胁迫而增加。同时 ,当盐分浓度由 0mmol·L-1 升至 1 2 0mmol·L-1浓度时 ,盐腺对各种离子的分泌作用表现为先加强 (60mmol·L-1 )后降低 (1 2 0mmol·L-1 )的趋势 ;其叶及根可溶性蛋白变化不明显 ,但过氧化物酶活性随盐胁迫而升高 ;可溶性蛋白含量叶片高于根部 ,而过氧化物酶活性根部高于叶片。同时盐胁迫对小獐毛根部及叶片含水量无明显影响。通过细胞化学定位结果显示 ,小獐毛叶表富含硅元素 ,硅元素在叶表排列沿叶脉方向呈线性分布 ;在其叶片盐腺上 ,硅元素分布于帽细胞顶部 ,在此过氧化物酶 (POD)活性也较强。元素分析结果显示 ,小獐毛体内富积硅元素。在较低的NaCl(60mmol·L-1 )浓度下 ,施用硅处理可减少叶片钠离子浓度 ,使地上部对钾、钠元素的相对选择性明显提高。在较高盐浓度 (1 2 0mmol·L-1 NaCl)下 ,加硅对叶片钠离子浓度的降低作用效果不明显。在盐胁迫下 ,加硅未能减少根中钠离子浓度 ,但可明显增加叶片POD活性。实验结果表明 ,盐?

The changes of ionic absorption, secretion and the activity of POD on Aeluropus pungens under salinity conditions and the effects of silicon nutri tion on those indices were studied using light microscopy, cytochemical localizatio n, and quantitative and qualitative analysis for ions and physiological indices. The results were as follows: Under salinity conditions, the Na + content incre as ed and the Ca 2+ content of the plant tissues decreased, while the other io ns rema ined constant, and the concentrations of silicon in leaves increased with increa sing salinity. The rate of ion secretion increased between 0 and 60 mmol·L -1 NaCl, and then declined when the NaCl concentrations in the roots reached 120 mmol·L -1 . The cont ent of soluble protein was unaffected but the POD activity was enhanced by the s alt treatment. The amount of soluble proteins were higher in the roots than that in the leaves, while on the POD activity, the situation was the contrast. The water content did not change within 120 mmol·L -1 NaCl. The cytochemical l ocation of Si distr ibution and POD activity techniques showed silica was distributed in rows along the leaf veins on the leaf surfaces, and some traces on the papillaes. On the s alt glands Si accumulated on the top of the cap cell where the strong POD activi ty was found. By analyzing the elements, it was found that silicon tended to a ccumulate on the tissues of Aeluropus pungens. The Na content and the select ive of Na, K of the shoots, which was not affected under 120 mmol·L -1 NaC l, was reduced under 60 mmol·L -1 NaCl by the addition of 3 mmol·L -1 Na 2SiO 3. However, the Na content remained un affected in the roots by the addition of Silicon to both salt concentrations. Th e above experiments demonstrated that halophyte Aeluropus pungens adapte d to sal inity conditions by adjusting water conditions, the ion distribution and POD act ivity on the plant tissues. The capacity of salt tolerance was improved, which w as due to the inhibition of the Na transport from roots to shoots and the increa sing abilities of antioxidative defense when silicon was added to the nutrient solutions.