【目的】研究盐胁迫下柳树(Salix spp.)良种对盐胁迫的响应及耐盐阈值,可为深入研究其耐盐机制,建立遗传转化体系,扩大其在盐碱地的种植规模提供参考。【方法】以‘苏柳172’(S. ×jiangsuensis ‘J172’)组培苗为试验材料,采用 6个 NaCl 浓度梯度:0、50、100、150、200、250 mmol/L处理10~20 d,研究盐胁迫下‘苏柳172’组培苗形态、生理指标及抗氧化酶同工酶谱的变化。【结果】‘苏柳172’组培苗具有一定的耐盐性,其耐盐阈值为150 mmol/L,当NaCl浓度高于200 mmol/L时,其生长严重受害,甚至死亡。低盐胁迫下(50 mmol/L), ‘苏柳172’生长不受影响,除超氧歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT) 3种抗氧化酶活性,脯氨酸、谷胱甘肽(GSH)含量均有所提高外,其他指标均无显著变化。中盐胁迫(100~150 mmol/L)下,叶绿素(Chl)、可溶性蛋白(SP)含量出现轻微下降,相对电导率(REC)、丙二醛(MDA)、H₂O₂含量增加,GSH及3种抗氧化酶水平达到最大值,此时耐盐性最强。高盐胁迫(200~250 mmol/L)下,Chl、SP、GSH 含量都急剧下降,达到最小值,而REC、MDA达到最大值,3种抗氧化酶活性都显著下降,说明‘苏柳172’受到了严重的氧化胁迫。盐胁迫还导致其叶绿体和细胞质中CuZnSOD、线粒体中MnSOD同工酶及POD2、POD3、POD4等同工酶谱带的表达明显增强。【结论】该柳树良种具有一定的耐盐能力,其盐胁迫耐受阈值为150 mmol/L NaCl。

【Objective】Studying the response of Salix variety to salt stress and the threshold of salt tolerance could provide reference for further research salt resistance mechanism and expansion of planting scale in saline-alkali land.【Method】The tissue culture plantlets of S. ×jiangsuensis‘J172’(‘J172’) were treated with NaCl 0, 50, 100, 150, 200 and 250 mmol/L for 10-20 days under in vitro culture. The changes of morphology, physiological indexes and antioxidant enzyme isozyme bands in ‘J172’ plantlets were studied.【Result】‘J172’ plantlets had certain salt tolerance, and its salt tolerance threshold was lower than 150 mmol/L NaCl, its growth was seriously damaged and even death under higher than 200 mmol/L NaCl. Under mild salt stress (50 mmol/L NaCl), the growth of ‘J172’ plantlets were not affected, and the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), proline and glutathione (GSH) were mildly increased, other indexes were no significant changes. Under moderate salt stress (100-150 mmol/L NaCl), the levels of chlorophyll (Chl) and soluble protein (SP) decreased slightly, while the levels of relative conductivity (REC), malondialdehyde (MDA) or H₂O₂ began to increase, and the levels of GSH and SOD, POD and CAT reached a high point, respectively, and the salt tolerance reached the highest at these treatment. However, at high salt stress (200-250 mmol/L NaCl), the contents of Chl, SP and GSH decreased sharply and reached the lowest point, while the levels of REC, MDA reached the highest point, respectively, and the levels of GSH and SOD, POD and CAT activities decreased significantly, indicating that ‘J172’ plantlets were subjected to severe oxidative stress. Salt stress also led to the significant enhancement of isoenzyme bands such as CuZnSOD in chloroplasts and cytoplasm, MnSOD in mitochondria as well as POD2, POD3 and POD4.【Conclusion】The ‘J172’ clones had certain salt-resistant ability and could be cultivated in salt-bearing areas lower than 150 mmol/L.