环境胁迫对岷江干旱河谷豆科灌木幼苗根系生长及其结瘤的影响  

Effects of environmental stress on seedlings root growth and nodulation of leguminous shrubs in the dry valley of Minjiang River

作　　者：李芳兰[1] 朱林海[1,2] 包维楷[1] 

机构地区：[1]中国科学院成都生物研究所,成都640041 [2]西南大学,重庆400715

出　　处：《应用生态学报》2009年第8期1825-1831,共7页Chinese Journal of Applied Ecology

基　　金：中国科学院"西部之光"项目(08C2041100);中国科学院知识创新工程项目(KZCX2-XB2-02)资助

摘　　要：通过野外调查,分析了岷江干旱河谷海拔梯度上相同年龄段的白刺花、岷谷木蓝和小雀花幼苗根系结瘤、生物量积累、生物量百分比的变化及其相互关系;人为控制土壤水分(田间持水量(WHC)的80%、60%、40%和20%4个水平)研究了干旱对2月龄的白刺花与小雀花幼苗结瘤能力的影响.结果表明:1)干旱河谷低海拔地段(1600～1950m)幼苗的结瘤能力都很低,白刺花、岷谷木蓝和小雀花的平均结瘤数分别为每株(0.1±0.1)、(0.9±0.5)和(5.7±1.9)个,未结瘤的个体分别占65.1%、12.3%和17.6%;总体上随着海拔的升高,3种幼苗的根瘤数均呈增加趋势,且与细根百分比及根长正相关.2)土壤水分低于60%WHC时,白刺花与小雀花的根瘤数及生物量均明显减小;在20%WHC条件下,白刺花根瘤数为0,小雀花根瘤数为每株(9.8±3.6)个.综合分析发现,干旱河谷地区豆科灌木的结瘤固氮能力很低,土壤水分在40%WHC以上时其生物固氮才能有效发挥,与白刺花相比,小雀花结瘤能力较高,干旱忍受性较强.A field investigation was made to understand the seedlings root nodulation, biomass accumulation, root length, and fine root percentage of Sophora davidii, Indigofera lenticellata and Campylotropis polyantha along an altitudinal gradient on two contrasting sloped hills （ north Zongqu and south Jingzhoushan） in the dry valley of Minjiang River. In the meantime, a greenhouse experiment was conducted to study the adaptation responses of 2 month-old S. davidii and C. polyantha seedlings root nodulation to different soil moisture regimes （80%, 60%, 40%, and 20% WHC）. For the three test shrub species, fewer nodules were observed at lower altitude （1600-1950 m） areas, the nodule number per plant of S. davidii, I. lenticellata, and C. polyantha being 0. 1 ± 0. 1, 0. 9 ±0. 5, and 5.7± 1.9, and the non-nodulation plant accounting for 65. 1%, 12. 3% and 17.6%, respectively. The nodule number of the three species increased with increasing altitude, and correlated positively with root length and fine root percentage. However, there were no significant differences in the plant growth and biomass at different altitudes. When the soil moisture con- tent was lower than 60% WHC, the nodule number and the fresh and dry mass of both S. davidii and C. polyantha decreased markedly, and at 20% WHC, no nodule and only 9.8 ± 3.6 nodules were observed for S. davidii and C. polyantha, respectively, indicating that in this dry valley, the root nodulation capability of endemic leguminous shrubs was very low. Comparing with S. davidii, C. polyantha had higher root nodulation capability and drought-resistance. Prior to introducing these shrub species in forestation practices, to keep the soil moisture content higher than 40% WHC was recommended for relatively efficient biological nitrogen fixation.

关 键 词：环境因子 干旱河谷 海拔梯度 生物固氮 水分胁迫 

分 类 号：Q948.1[生物学—植物学]