摘要
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。
An experiment was conducted to compare salt tolerance of Populus euphratica and Populus pru- inosa under eight different NaCl and mixed salt treatments and evaluated by the fuzzy subordination methods. Our objective was to elucidate the threshold salinity for the two species under different salt treatments and suitable germination habitat. The results showed that germination percentage, relative germination percentage, germination energy, germination index and cotyledon outspread rate of the two species declined and relative salt harm rate ascended with increasing NaCl stress. The relative germination percentage of two species exceeded 75 % under d0.4 % solution, and the value came near to zero under 1.4 %. The germination percentage of the two species were not significantly different under NaCl stress（ p〈0. 05）. The average germination percentage, subordinate function values, threshold salinity of P. euphratica was higher than that of P. pruinosa, which indicated that P. euphratica had a higher salt tolerance than P. pruinosa under NaCl stress. However, the germination percentage and index of the two species were higher than that of CK under low concentration of mixed salt, whereas high concentration of mixed salt could inhibit seed germination. The relative germination percentage of the two species exceeded 80% under d0. 8% solution, and the value also exceeded 20 % under 1.6 %. The germination percentage of the two species were significantly different under mixed stress（p〈0.01）. The average germination percentage, subordinate function values, threshold salinity of P. pruinosa were higher than that of P. euphratica, indicating that P. pruinosa was more salt tolerant and well ecologically adaptive than P. euphratica under natural condition. NaCl had greater harmfulness on seed germination than mixed salt. The experiment revealed that P. euphratica and P. pruinosa were higher salt tolerant, the low salinity was the important factor for seeds germination and seedlings establishment of desert dominant species.
出处
《中国沙漠》
CSCD
北大核心
2013年第3期743-750,共8页
Journal of Desert Research
基金
国家自然科学基金项目(31060066
30960033)
中国科学院"西部之光"人才培养计划项目(RCPY200807)
国家重点基础研究发展计划前期研究专项(2011CB411909
2012CB426507)资助
