盐胁迫对3种沉水植物生物学指标及叶片中丙二醛含量的影响

Effects of NaCl stress on plant biology indicators and MDA content of 3 submerged plants

以沉水植物苦草、轮叶黑藻、狐尾藻为研究对象,分别研究了在不同盐度下3种沉水植物的生物学指标和生理状况,以期为沿海地区水系沉水植物构建提供依据。结果表明,在0.05mol/L盐度下轮叶黑藻、苦草出现生长抑制,株高、鲜质量下降,叶片中丙二醛含量增加,单株叶片面积减小,而狐尾藻在0.05mol/L盐度下生长良好,0.08mol/L盐度下出现株高、鲜质量下降,叶片中丙二醛含量增高的现象。因此,推荐盐度在0.05mol/L以下的水体,可以建植苦草和轮叶黑藻,盐度不高于0.08mol/L的水体可以建植狐尾藻。盐胁迫下沉水植物会表现为一定的抗逆性,会通过单株叶片面积减小、增加根冠比、叶片肉质化等措施来减少水分流失和保证机体的正常生理功能,但超过一定的阀值,抗逆性会减弱,导致沉水植物出现生长抑制或者死亡现象。在有一定盐度的水体进行沉水植物建植恢复,该沉水植物能够耐受的盐度高于水体的盐度,是保证沉水植物成活的基本前提。

Vallisneria, Hydrilla, Myriophyllurn were selected as target object to study the effect of salinity on biological indicators and physiological conditions of submerged plants. The research would provide reference to the construction of the submerged plants community in coastal areas. Results showed that 0.05 mol/L of salinity would suppress the plant height and fresh weight of Hydrilla, Vallisneria, the MDA content of leaves was increased and leaf area per plant was reduced. Meanwhile, Myriophyllum grew well under 0.05 mol/L of salinity, but it appeared certain degree of growth inhibition under 0.08 mol/L of salinity. Therefore, Vallisneria and Hydrilla were recom- mended to plant in water of salinity below 0.05 mol/L, Myriophyllum was recommended to plant in water of salinity 0.05-0.08 mol/L. Submerged plants presented certain resistance under the salt stress, they would decrease the leaf area per plant, increase the shoot/roots ratio, increase succulent leaves and through other measures to reduce the wa- ter loss and ensure their normal physiological function. While, when the salt stress exceeded the threshold level, the resistance of plant would be weakened, resulting the growth inhibition or mortality of submerged plants. Therefore, when applying the submerged plants to restore the salinity water, the salinity tolerance of submerged plants should be higher than the water salinity so as to ensure the survival of these plants.