盐胁迫下荒漠植物柠条和油蒿的离子吸收及分配特征

Ion absorption and distribution in Caragana korshinskii and Artemisia ordosica seedlings under different NaCl stress

柠条(Caragana korshinskii)和油蒿(Artemisia ordosica)是生长在荒漠地区的两种典型的固沙先锋植物。本试验以生长三个月的柠条和油蒿幼苗为研究材料,经0-400 mmol·L-1NaCl溶液胁迫处理7d,检测其含水量变化、主要矿质离子含量变化及其在根茎叶的分布、积累和运输特征。结果表明:随着盐浓度的增加,柠条和油蒿的含水量均呈下降趋势,柠条的变化尤为显著;二者在离子吸收与分配上显著不同,柠条体内Na^+的含量是油蒿的2-3倍,表现为"吸钠排钾"的特征,而油蒿体内K^+的含量是柠条的2倍左右,具有"吸钾拒钠"的耐盐特征。此外,随着NaCl浓度增大,柠条体内Cl^-含量升高,K^+、Ca^(2+)、Si^(4+)含量降低,而油蒿体内只有C^l-含量增加趋势明显,其他离子则相对稳定。说明二者耐盐机制显著不同,在离子吸收与分配上存在互补互利的效应,而且这种互补性提高了他们的耐盐性。

Caragana korshinskii and Artemisia ordosica are two typical sand- fixation pioneer plants adopted in arid and semi- arid regions. In this study we collected three months old of C. korshinskii and A. ordosica seedlings in the laboratory. Then these seedlings were subjected to salt stress by soaked in 0,100,200,300 to 400mmol·L- 1Na Cl solutions for 7 d separately. We examined their water contents and main mineral ion contents changes in their roots,stems,and leaves during salt stress. The experiment results indicated that their water content,especially for C. korshinskii,reduced as Na Cl concentration increased. The Na＋content in C korshinskii was 2- 3 times of A. ordosica ＇s,which indicated that C. korshinskii absorbed Na＋and inhibited K＋to adapt to high salt stress as Na Cl concentration increased. By on the contrary,A. ordosica absorbed K＋and inhibited Na＋because of its K＋content was twice of C. korshinskii ＇s. In addition,the Cl-content of C. korshinskii increased significantly and the K＋,Ca2 ＋,Si4 ＋contents was cut down as Na Cl concentration increased in every tissue,but the mineral ions content of A. ordosica were relatively stable. Thus,the two plants mutually benefit from each other and cooperate to promote their resistance to salt stress.