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

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.