水分胁迫和复水对石灰岩地区柏木幼苗根系生长的影响  

Influence of water stress and re-watering on the root growth of Cupressus funebris Endl. seedlings in the limestone area

作　　者：刘锦春[1,2,3] 钟章成[1,2,3] 

机构地区：[1]西南大学三峡库区生态环境教育部重点实验室,重庆400715 [2]重庆市三峡库区植物生态与资源重点实验室,重庆400715 [3]西南大学生命科学学院,重庆400715

出　　处：《生态学报》2009年第12期6439-6445,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30370279);西南大学博士基金资助项目(SWU109009)

摘　　要：利用适生植物自身的抗旱能力来进行石灰岩地区植被的恢复和重建是石灰岩生态研究中的重要问题。为了解石灰岩山地适生物种柏木对水分胁迫的适应机制,以柏木实生苗为材料,通过盆栽水分受控实验,研究了其根系生长特性及复水后的修复能力。结果表明:在水分胁迫程度不大、历时不长的情况下,水分胁迫有诱导根系下扎的趋势,复水后,根长在原有的基础上进一步伸长。随着胁迫的加剧和胁迫时间的延长,柏木幼苗的根长、根平均直径、根表面积和根体积等根系大小参数均呈降低趋势,以采取小根系来增强竞争力。复水后,除重度干旱外,其余处理组根系大小参数都能恢复到对照水平,补偿作用与胁迫程度有关。一定程度的水分胁迫对柏木幼苗的茎叶生长没有产生影响,而对根的抑制作用明显,根冠比降低,但胁迫程度加剧和历时延长后,柏木幼苗的根冠比有增大的趋势。柏木幼苗在水分胁迫较轻时把较多的碳水化合物分配到茎叶中,而胁迫严重时把较多的碳水化合物分配到根部。复水促进根、冠干物质的积累,但不同的胁迫程度和胁迫时间促进作用不同。The Karst landscape,one of the three vulnerable ecotones,is very widespread in the world,but especially in the large limestone region of southwest China. It often features water limitation to plants due to low water retention capacity and high exposure of rocks. Therefore,it is a very important issue to find some drought-resistant plants for vegetation restoration and reconstruction in the limestone area. In order to assess the suitability of trees in the limestone area,we studied the resistance of root growth characteristics of Cupressus funebris Endl. seedlings to water stress and their recovery after re-watering. Our controlled experiment included four water levels：control （CK）,light water stress （LS）,medium water stress （MS） and severe water stress （SS）. The results are as follows：The length of Cupressus funebris Endl. seedlings had a trend of increase when the water stress was only moderate,and after re-watering,it increased more. However,with the aggravation of stress,the seedlings decreased the surface area,average diameter and volume of roots. After re-watering,all these indices could recover to the level of CK but they could not when suffering SS. Light water stress had no effect on the shoot growth,but obviously restrained the root growth,so that the root-to-shoot ratio of Cupressus funebris Endl. seedlings showed a trend of decrease at the beginning of stress,but a trend of increase at the end. Cupressus funebris Endl. seedlings had a strategy of allocating more carbohydrate to stems and leaves under light stress while allocating more carbohydrate to roots under severe stress. Re-watering promoted the increase of shoot and root biomass,nevertheless,different extents and periods of stress had different influences on the growth of shoot and root.

关 键 词：石灰岩 水分胁迫 复水 柏木(Cupressus funebris Endl.) 根系生长 

分 类 号：Q945[生物学—植物学]