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将塔里木荒漠优势种——胡杨(Populus euphraticu)和灰胡杨(Populus pruinosa)的种子置于8种浓度的NaCl(单盐)和土盐(复合盐)溶液中进行发芽实验,探讨两树种种子对不同盐类的耐受限度和适应萌发生境,采用隶属函数法综合评价其耐盐性。结果表明:两树种种子发芽率、相对发芽率、发芽势、发芽指数和子叶展平率均随NaCl浓度的增加而下降,相对盐害率升高。二者种子相对发芽率在浓度<0.4%的NaCl溶液中均超过75%,NaCl胁迫下2种种子发芽率无显著差异(p>0.05)。单盐处理下胡杨种子的各项发芽指标均优于灰胡杨,表明胡杨的耐盐(NaCl)能力强于灰胡杨。低浓度土盐溶液对二者种子萌发均具有促进作用,发芽率和发芽指数明显升高,而高浓度土盐溶液则抑制种子萌发。二者种子相对发芽率在浓度<0.8%的土盐溶液中均超过80%,且1.6%盐浓度下仍高于20%,此值远高于NaCl胁迫。土盐处理下两树种种子发芽率差异达极显著水平(p<0.01)。土盐处理下灰胡杨种子的各项发芽指标均优于胡杨,表明灰胡杨对土盐具有较强的适应性和耐盐能力。NaCl胁迫对二者种子萌发的抑制作用大于土盐。胡杨、灰胡杨均具有较强的耐盐性,但早期低盐条件是两树种幼苗建立的关键。
The seeds of Populus euphraticu and Populus pruinosa were germinated in 8 concentrations of NaCl (single salt) and saline (composite salt) solution, and the seeds of two tree species Salt tolerance and adapt to the germination habitat, membership function method to evaluate its salt tolerance. The results showed that the germination rate, relative germination rate, germination potential, germination index and cotyledon spreading rate decreased with the increase of NaCl concentration and the relative salt damage rate increased. The relative germination rate of both seeds was over 75% in NaCl solution with concentration <0.4%. There was no significant difference (p> 0.05) in germination rate of two seeds under NaCl stress. Populus euphratica seed germination indicators under single salt treatment are superior to gray poplar, indicating that Populus salina salt tolerance (NaCl) ability is stronger than gray poplar. Low concentrations of soil salt solution on both seed germination have a promoting effect, germination rate and germination index increased significantly, while the high concentrations of soil salt solution inhibited seed germination. The relative germination rate of the two seeds was more than 80% in soil salt solution with concentration <0.8% and still higher than 20% at 1.6% salt concentration, which was much higher than NaCl stress. The difference of seed germination rate of two tree seeds under soil salt treatment reached extremely significant level (p <0.01). The results showed that all the germination indexes of Populus euphratica seeds were better than that of Populus euphratica under the treatment of soil salt, indicating that Populus euphratica has strong adaptability to salt and salt tolerance. NaCl stress inhibited the seed germination more than soil salt. Populus euphratica and Populus euphratica have strong salt tolerance, but the early low salt conditions are the key to establish two seedlings.