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以新疆筛选的5个种源胡杨(Populus euphratica)种子为材料,置于不同NaCl浓度梯度(25、50、150、250、300mmol·L~(-1))下进行种子萌发试验,并测量分析不同种源地气候与土壤生态因子,探讨盐胁迫下不同种源胡杨种子的发芽特征及其与生态因子之间的关系,同时讨论不同种源胡杨比叶面积(SLA)与环境适应性之间的关系。结果表明,在NaCl胁迫下,5个种源胡杨种子的平均发芽率、发芽指数及发芽势间有显著差异(P<0.05),其中种源D(甘家湖种源)种子在盐胁迫下的平均发芽率(19.19%)、发芽指数(4.14)及发芽势(15.57%)显著>其他4个种源种子(发芽率12%~15%,发芽指数2~2.7,发芽势8%~11%,P<0.05);在25mmol·L~(-1)浓度的NaCl胁迫下,除种源E外,其他4个种源种子的发芽率相比对照处理(0mmol·L~(-1))增大11%~35%,相对盐害率均显示负值(P<0.05),而在盐浓度为50 mmol·L~(-1)时,其种子萌发开始受到明显抑制(P<0.05);种源E的SLA值最低而种源D的最高,其中间有显著性差异(P<0.05)。不同种源胡杨种子的发芽率与采样地年平均降水量、土壤40cm的pH值间有显著正相关关系(P<0.05)。以上结果表明,低浓度盐对胡杨种子萌发有一定的促进作用,而高盐浓度下,种子萌发受到明显抑制;145~192mmol·L~(-1)浓度为胡杨种子萌发的耐盐临界浓度。研究结果为自然界现有的变异中筛选具较耐盐的胡杨种子和选育耐盐种质材料提供一定的科学依据。
Populus euphratica seed from 5 provenances screened in Xinjiang was used for seed germination test under different NaCl concentration gradients (25, 50, 150, 250, 300 mmol·L -1) The climate and soil ecological factors in different provenances, the germination characteristics of Populus euphratica from different provenances under salt stress and its relationship with ecological factors, and the relationship between the specific leaf area (SLA) of different provenances and environmental adaptability Relationship. The results showed that under NaCl stress, the average germination rate, germination index and germination potential of Populus euphratica seedlings from five provenances were significantly different (P <0.05). The seeds of provenance D (Ganjiahu provenance) under salt stress The average germination rate (19.19%), germination index (4.14) and germination potential (15.57%) were significantly higher than those of other four provenances (germination rate 12% ~ 15%, germination index 2 ~ 2.7, germination potential 8% ~ 11 %, P <0.05). Under the NaCl stress of 25 mmol·L -1, the seed germination rate of the other four provenances was higher than that of the control (0 mmol·L -1) ) Increased by 11% ~ 35%, while the relative salt damage rates showed negative values (P <0.05). However, the seed germination began to be significantly inhibited at the salt concentration of 50 mmol·L ~ (-1) (P <0.05 ). Source E had the lowest SLA and highest source D, with significant differences (P <0.05). The germination rate of Populus euphratica seeds from different provenances was positively correlated with the annual average precipitation of sampling sites and the pH value of soil 40 cm (P <0.05). The above results showed that the low salt concentration promoted the seed germination of Populus euphratica while the seed germination was significantly inhibited under the high salt concentration. The critical salt concentration of 145-192 mmol·L -1 was the salt tolerance of Populus euphratica seed germination. The results provide some scientific evidences for the selection of the more tolerant Populus euphratica seeds and the breeding of salt-tolerant germplasm materials in the existing variation in nature.