盐胁迫下苗期与拔节期碱茅植株生长及与离子关系的比较研究

 用不同浓度NaCl溶液处理碱茅植株，测定和比较苗期与拔节期植株的生物量，K、Na与Cl含量和吸收与运输速率。苗期与拔节期植株的地上生物量分别在66及134mmol／L浓度下达最大值，根系生物量在66mmol／L下达最大值，根／冠比在苗期随盐浓度增加线性降低，而拔节期显著低于苗期且不受盐浓度影响。拔节期植株Na、Cl含量及由此产生的渗透调节能力、以及K，Na与C1的吸收与运输速率均高于苗期，而K／Na比及对K离子的选择性则低于苗期，两生长期植株K含量无显著差异。苗期与拔节期植株对K都存在着选择性吸收与运输，且吸收与运输速率与相对生长率呈显著正相关；苗期植株的Na与Cl吸收与运输速率与相对生长率无关，而拔节期呈显著正相关。从盐胁迫下，K、Na与Cl离子含量变化及由此产生的渗透反应分析，Cl主要用于维持植株的“基础”渗透势，在高胁迫下也参与渗透调节；Na主要用于维持植株的渗透调节；而K从数值上不参与渗透调节，在维持植株的“基础”渗透势中的作用也较小。

A COMPARATIVE STUDY ON THE GROWTH OF SALT-TREATED Pucciinellia Tenuiflora AT THE SEEDING AND ELONGATING STAGES AND ITS RELATIONS WITH IRONS

The potted plants of Puccinellia tenuiflora were respectively treated with different concentrations of NaCl solutions. Biomass, K, Na and Cl contents, absorption and transportation rates from plant roots to shoots at the seedling and elongating stages were measured and compared.The maximum shoot biomass of the seedlings and elongating plants was appeared under the treatment of 66 and 134 mmol/L, and maximum root biomass was under that of 66 mmol/L. The ratio of plant roots to shoots at seedling stage were linearly decreased with the increase of the NaCl concentration, while those at elongating stage were lower than that at seeding stage, and has no significant changes with the cnange of salt concentrations. Na and Cl contents in both shoots and roots, and Na and Cl caused osmoregulation capacity in shoots, absorption and roots, transport rates of K, Ma and Cl from roots to shoots were higher during elongation stage than that during seedling stage. However K/Na ratios, selectivity of K over Na calculated by selective ratio was lower during elongation stage than during seedling stage. Absorption and transportation rates of plants to K during seedlings and elongation, and to Na and Cl during elongation had significant correlation with their relative growth rate (RGR), while those to Na and Cl during seedlings had no correlation with RGR. Based on numerical change of K, Na and Cl contents, it is inferred that ions played different roles during osmoregulation under stress. Cl was used to maintain "basic osmotic potential" of shoots relative to the control solution without strees, and also to maintain osmoregualtion. K did not significantly cause osmoregulation, numerically, and played a little role in maintenance of "basic osmotic potential" of shoots.