NaCl胁迫对宁夏4种灌木生长及光合特性的影响

Effects of Salt Stress on Growth and Photosynthetic Characteristics of Four Shrubs in Ningxia

以黑果枸杞、沙棘、银水牛果和柽柳的幼苗为研究对象,研究不同NaCl浓度(0、250mmol/L、500mmol/L、750mmol/L和1 000mmol/L)对宁夏4种常见耐盐植物生长及光合作用的影响。结果表明,(1)当NaCl浓度达到750mmol/L时,沙棘植株死亡,当浓度增加到1 000mmol/L时银水牛果植株死亡,黑果枸杞和柽柳也出现不同程度的盐害症状;(2)4种灌木的株高与基径增长量在NaCl胁迫下均呈下降趋势,高浓度盐胁迫明显抑制了4种灌木生物量(P<0.05),低浓度盐胁迫对黑果枸杞和柽柳的生物量的影响不明显;(3)在NaCl胁迫下4种植物的净光合速率、蒸腾速率、叶绿素相对值均表现出不同程度的降低,并随着胁迫浓度的增加而下降,而水分利用效率则升高,NaCl胁迫对4种植物的光合特性有显著影响(P<0.05);(4)综合分析各树种生长和生理表现,沙棘耐盐性较弱,银水牛果具有中度耐盐性,黑果枸杞和柽柳可忍受中高浓度的盐胁迫。

A pot experiment was carried out, in which NaC1 was added to simulate different salt stress condition with five different levels （0, 250mmol/L, 500mmol/L, 750mmol/L and 1 000mmol/L）, to study the changes of growth and photosynthetic characteristic of four shrubs in Ningxia （Lycium ruthenicum Murr. , Hippophae rhamnoides Linn. , Shepherdia argentea, and Tamarix chinensis Lour. ）. The results showed that ： （ 1 ） The Hippophae rhamnoides were dead under the treatment of 750mmol/L NaCl, and thoseShepherdia argentea were dead under the treatment of 1 000mmol/L NaC1, while Lycium ruthenicum and Tamarix chinensis showed different degrees of salt damaged under 1000mmol/L NaCl stress. （2） The height and biomass accumulation of NaCl stressed seedlings decreased as the salt concentration increased, heavy salt stress severely impeded biomass growth of all four shrubs （P〈0. 05 ）, yet light salt stress merely effected on that of Lycium ruthenicum Murr. and Tamarix chinensis Lour. （3） The net photosynthetic rate （Pn）, transpiration rate （Tr） and chlorophyll relative value of four plants showed different degrees of decrease, and decreased further along with the stress aggravated, while the water use efficiency had an increasing trend. When the concentration exceeds 250mmol/L, the photosynthetic characteristlcs of four plants were significantly different from that of the control （P〈0. 05 ）. （4） Based on the analysis of growth and photosynthetic characteristic, the results indicate that the L. ruthenicum and T. chinensis salt are high- ly salt tolerant, and the S. argentea is moderately salt tolerant.