不同浓度盐胁迫对黄瓜幼苗生长和生理代谢的影响

Growth and physiological metabolism of cucumber seedlings in response to different concentrations of salt stress

采用基质栽培,选用抗盐性较强的黄瓜品种新泰密刺为试验材料,研究了不同浓度(0、0.3%、0.6%、0.9%、1.2%)NaCl处理对黄瓜幼苗生长和光合特性等生理代谢的影响。结果表明,盐胁迫下,黄瓜幼苗株高降低,茎粗减少,净光合速率(P n)、气孔导度(G s)、气孔限制值(L s)、蒸腾速率(T r)和水分利用率(WUE)均减小,细胞间隙CO2浓度(C i)增大,细胞膜伤害率增大,丙二醛(MDA)和可溶性蛋白含量升高,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性增加,且随着盐胁迫浓度的升高各指标变化幅度增大。高浓度(0.9%、1.2%)NaCl处理下,叶片的生长受到明显抑制,幼苗存活率下降,各生理指标与对照相比发生显著变化。综合来看,0.3%NaCl处理对黄瓜幼苗生长和各生理指标影响较小,0.6%和0.9%NaCl处理下,黄瓜幼苗生物量显著下降,1.2%则达到了黄瓜幼苗生长的极限盐浓度。

A cucumber cultivar Xintai Mici was used in this experiment to study the effects of different concentrationsof NaCl （0, 0.3%, 0.6%, 0.9% and 1.2%） on growth and physiological metabolism of substrate-cultured cucumber （Cuc-umis sativus L. ） seedlings. Under NaCl stress, the photosynthetic rate （Pn）, stomatal conductance （Gs）, stomatal limitationvalue （Ls）, transpiration rate （Tr） and water use efficiency （WUE） decreased, and while the intercellular CO2 concentration（Ci）, cell membrane damage rate, malondialdehyde （MDA） and soluble protein contents increased, superoxide dismutase（SOD）, peroxidase （POD） and catalase （CAT） activities improved. The change of each index was more obvious with the in-crease of salt concentrations. High concentrations （0.9% and 1.2%） of NaCl stress inhibited the growth of leaves,lowered survival rates of seedlings, and each physiologicalindex significantly changed compared with control. In con-clusion, 0.3% NaCl treatment had little effect on thegrowth and physiological metabolism of cucumber seedlings,0.6% and 0.9% NaCl treatments caused biomass signifi-cantly decrease, and 1.2% NaCl might be the highest con-centration that cucumber seedling could tolerate.