Remediation Of Saline-Sodic Land With Salt Tolerant Plant(Brassica Napus) And Nutrition Physiology Of The Plant Under Salt Stress

Content:Trials were conducted in moderate saline-alkaline lands with main component of chloride during 2002y-2004y, the site was located at the experimental base of "948" project, in BaYanNaoEr city, Inner Mongolia Province. Under the remediation with salt tolerant plants Brassica napus, soil samples of saline-alkaline land were collected from profiles as 0cm¹5cm, 15cm³0cm, 30cm⁶0cm, 60cm¹00cm and 1m depths in five fixed plots during 2002y to 2004y, temporal variations of soil salinity and nutrient including the EC (dSm-1) and pH value, soluble K⁺, Na⁺, Ca²+, Mg²+, Cl^-. CO₃²- and HCO₃²-, available N, available P and organic matter were investigated. The results demonstrated that after three-year-planting with the Brassica the total salinity of topsoil (0cm¹5cm) reduced 62.2%, the percentage of the content of Na⁺, Cl^- in the soil declined as 78.3% and 41.6% respectively, the total salinity in lm profile soil reduced 71.3%, the percentage of the content of Na⁺, Cl^- in lm profile soil declined 69.4% and 38.9% respectively. Simultaneously, the OM in all soil layers increased, the contents of available P reduced, but Brassica had not significant effect on the contents of available N, moreover, Brassica could increase the contents of available N, OM in lm profile soil. It indicated that salt tolerant plant Brassica could contribute to the remediation of saline-alkaline soil.The phosphorus uptake and transfer of salt tolerate plants (Brassica napes and Susana Canadian Peers) were severely influenced by the designed salinity (10 mM/L, 40 mM/L, 80 mM/L, 150 mM/L) in an alkaline medium (pH=8.5). The experiment using 32P-tracer technique in the greenhouse indicated that salinity inhibited phosphorus uptake of salt tolerate plants compared with no saline conditions and the stimulation of P uptake from 0.25 millmolar KH2PO4 of plants was associated with increased levels of salinity. The results showed that salinity greatly enhanced the P accumulation in roots and shoots of Brassica and Susana and promoted transport of P from roots to shoots and leaves. These results further showed that genetic difference exists among species that greatly influenced their P absorbabiity and salt tolerant abilityThe effect of salt stress and extra Ca on the concentrations of N, P, K⁺, Ca²+, Mg²+, Na⁺ and K and Na ratio, K and Na Selectivity ratio in the leaves, the shoots, and the roots; Chlorophyll, proline in the leaves and roots; the leaf cell ultrastructure of Brassica napes was investigated on young plant. The treatments, consisting of 0, 25 mM/L, 50 mM/L, 100 mM/L and 200mM/L NaCl and 10mM/L Ca (NO3)2 in half-strength Hoagland nutrient solution; were applied for one and a half months. Significant differences among the concentration of mineral elements in the tissues of the tested cultivars were found. The result illuminated that salinity restrained the growth of plants significantly and decreased fresh weight, destroyed the leaf cell ultrastructure; lessened the concentrations of K+, Ca2+, Mg2+, and K Na ration of the leaves, the shoots and roots significantly, but salinity promoted transport of P from roots to shoots and leaves. The concentrations of Na+ in the organs of plants increased with the the levels of NaCl, at the same time, the contents of proline in the roots and leaves and K. Na Selectivity ratio in the roots and shoots increase, however, the contents of N did not changed. Under salt stress, extra Ca could hasten the growth of plants and added the contents of Chlorophyll and protect the leaf cell ultrastructure, cut down the adverse influence of NaCl on the uptake and transport of K in the organs, reduced the concentrations of Na+, increased K Na ratio and K Na Selectivity ratio, but reduced the total P of plants .In the whole, extra Ca could enhance the salt tolerant ability of plants and improve the nutrition of plants under salt stress.