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将当年生构树幼苗置于含有不同浓度(0.4、1、2、3、4g·kg-1)NaCl的土壤中,研究其生物量积累、叶片细胞质膜透性和K+、Ca2+、Na+、Cl-等离子的吸收、分布及运输,并观察盐害症状.结果表明:构树幼苗的叶片质膜透性随着NaCl浓度的增加和胁迫时间的延长而升高,根冠比随NaCl浓度的升高而增加,大于3g·kg-1的土壤盐胁迫对构树叶片的质膜透性及植株的生物量积累影响显著.构树幼苗各器官中Na+和Cl-含量随土壤NaCl浓度升高而显著增加,K+和Ca2+则随之降低,叶片各离子含量均明显高于根和茎.说明盐胁迫影响根系对K+和Ca2+的吸收,并抑制了它们向地上部分的选择性运输,使叶和茎的K+和Ca2+含量下降.构树通过吸收积累Na+和Cl-抵御土壤盐分带来的渗透胁迫,但过量的Na+和Cl-积累会造成单盐毒害.作为抗盐性较高的非盐生植物,构树地上部分的拒盐作用不显著.
The seedlings of A. mongolica were placed in soils with different concentrations of NaCl (0.4, 1, 2, 3 and 4 g · kg -1) to study their biomass accumulation, leaf plasma membrane permeability and K +, Ca 2+, Na + - plasma absorption, distribution and transportation, and observe the symptoms of salt damage.The results showed that the membrane permeability increased with the increase of NaCl concentration and prolongation of stress time, and the root / shoot ratio increased with the increase of NaCl concentration And the soil salt stress of more than 3g · kg-1 had a significant effect on the plasma membrane permeability of plantation leaves and the biomass accumulation of plants. The contents of Na + and Cl- in the organs of broussonetia papyrifera seedlings increased with the increase of soil NaCl concentration While the content of K + and Ca2 + decreased, and the contents of all ions in leaves were significantly higher than those in roots and stems, indicating that salt stress affected the uptake of K + and Ca2 + in roots and inhibited their selective transportation to aerial parts, The content of K + and Ca2 + decreased in stems, and the accumulation of Na + and Cl- absorbed the soil osmotic stress caused by the accumulation of Na + and Cl-, but excessive Na + and Cl- accumulation could cause single salt toxicity.As a salt-tolerant non- Plants, trees on the part of the role of salt rejection is not significant.