四翅滨藜生理生化特征对盐胁迫的响应

采用温室盆栽试验研究四翅滨藜(Atriplex canescens)幼苗株高、地径、生物量、净光合速率、蒸腾速率、气孔导度、叶绿素含量、抗氧化酶活性及丙二醛含量对不同浓度NaCl和Na_2SO_4(0、100、200、300和400mmol·L~(-1))胁迫的响应,以探讨四翅滨藜对不同种类及不同浓度盐渍环境的适应机制及其耐盐机理。结果显示:(1)随着盐分浓度的升高,四翅滨藜幼苗的株高、地径及生物量增量呈现出先升高后降低的趋势,低盐浓度下2种盐均促进幼苗生长,盐浓度超过400mmol·L~(-1)时,NaCl对幼苗生长具有明显抑制作用。(2)2种盐处理下,四翅滨藜幼苗净光合速率(Pn)和叶绿素含量(Chl)随盐浓度增大而升高,即2种盐均对幼苗Pn和Chl含量具有促进作用,且Na_2SO_4的促进效果大于NaCl;而幼苗蒸腾速率(Tr)和气孔导度(Gs)随盐浓度升高呈先增大后减小的趋势,且Na_2SO_4的促进作用强于NaCl。(3)与对照相比,四翅滨藜幼苗的丙二醛、SOD、POD酶活性在NaCl和Na_2SO_42种盐处理下,随着盐浓度的升高均呈现出不同程度的增大,且增大幅度总体表现为NaClNa_2SO_4。研究表明,四翅滨藜在NaCl和Na_2SO_4胁迫下,叶绿素的分解速率以及发挥作用的渗透调节物质均有差异,使得幼苗叶片健康程度不同,导致叶片光合能力大小的差异,最终表现为植株的生长差异;四翅滨藜具有较强的耐盐能力,而且对Na_2SO_4的适应能力强于NaCl。

Physiological and Biochemical Responses of Atriplex canescens Seedlings to Salt Stress

The physiological and biochemical characteristics of Atriplex canescens seedlings under NaCl and Na₂SO₄ stress(0, 100, 200, 300 and 400 mmol·L^-1)was studied.The results shows that: (1) with the increase of salt concentration, the plant height, ground diameter and biomass increment were increased first and then decreased. Low salt concentration of the two kinds of salt promoted the growth of seedlings to some extent, when the concentration of salt reaches 400 mmol·L^-1, NaCl treatment inhibited the growth obviously. (2) Under the two kinds of salt treatments, the net photosynthetic rate and chlorophyll content of A. canescens seedlings increased with the increase of salt concentration, both of the two salts promoted the P_n rate and Chl content of seedlings, and the promotion degree of Na₂SO₄ was greater than that of NaCl. While the transpiration rate and stomatal conductance of A. canescens seedlings increased first and then decreased with the increase of the salt concentration, and the promotion degree of Na₂SO₄ was greater than that of NaCl. (3) Compared with the control, the malondialdehyde, SOD and POD of A. canescens seedlings were increased differently with the increase of the concentration of NaCl and Na₂SO₄ treatments, and the increase of NaCl treatment was greater than that of Na₂SO₄ treatment. The results showed that the resistance of A. canescens to Na₂SO₄ was stronger than that of NaCl.