摘要
地瓜藤(Ficus tikoua)、荻(Triarrhena sacchariflora)、牛鞭草(Hemarthria altissima)和狗牙根(Cynodon dactylon)是三峡库区常见的岸生植物,自然分布于河岸带不同垂直高程的地段。为了明确它们在成库后"三峡库区消落区"长期完全水淹条件下的存活和生长情况,实验设置对照(不进行水淹,常规供水管理)和完全水淹两个处理,30、60、90、120、150和180d6个水淹时间水平,研究了4种植物在完全水淹条件下的存活、生物量变化和恢复生长。结果发现:1)4种植物在完全水淹条件下的存活率与其在河岸带上的垂直分布高程密切相关。分布于距江面高程较高的河岸段的地瓜藤植株,在全淹30d后就全部死亡;分布在中高程河岸段的荻在全淹150和180d后全部死亡;可以分布于低高程河岸段的牛鞭草和狗牙根,淹没180d后存活率分别为90%和100%。2)全淹抑制了荻、牛鞭草和狗牙根的生长,总生物量增量显著低于对照植株。与水淹0d相比,全淹处理植株的地上部分生物量显著降低,荻在全淹60和120d后,地下部分生物量显著降低,但牛鞭草和狗牙根的地下部分生物量与水淹0d水平相比无显著差异。3)水淹处理结束后,存活的荻、牛鞭草和狗牙根植株都能很好地恢复生长。在恢复生长过程中,全淹30、60和90d后,荻、牛鞭草和狗牙根植株的总分枝长相对生长速率与对照植株无显著差异,全淹120、150和180d后,牛鞭草和狗牙根植株的总分枝长相对生长速率显著高于对照植株。全淹处理的荻、牛鞭草和狗牙根植株的总叶片数相对生长速率始终显著高于对照植株。遭受长期完全水淹后,植株在有限的营养储备条件下,快速产生叶片以迅速积聚光合产物可能是植物更为优化的恢复生长方式。
Aims Ficus tikoua, Triarrhena sacchariflora, Hemarthria altissima and Cynodon dactylon are four riparian plants in Three Gorges Reservoir Region that are naturally distributed on riverbanks of different elevations. Our objective was to determine their survival and growth after long-term submergence in the water-fluctuation zone in Three Gorges Reservoir Region.
Methods We studied survival and biomass increase of plants subjected to 30, 60, 90, 120, 150 and 180 d submergence and in a control (no submergence). We measured total shoot length, total shoot number and total leaf number during the post-submergence recovery period.
Important findings Survival of the plants after long-term submergence was associated with their distribution pattern on riverbanks. Ficus tikoua, mainly occurring on high-elevation sites, died after 30 d submergence. Triarrhena sacchariflora, from intermediate-elevation sites, died after 150 and 180 d submergence. 90% and 100% of submerged plants of H. altissima and C. dactylon, respectively, survived after 180 d submergence. Submergence inhibited the growth of all plants, and the total biomass increase of each species was significantly lower than that of control plants. The aboveground biomass of all submerged plants decreased significantly. After 60 and 120 d submergence, the belowground biomass of T. sacchariflora decreased significantly, but that of H. altissima and C. dactylon did not change during submergence. All surviving plants grew. After 30, 60 and 90 d submergence, the relative grown rate (RGR) in total shoot length of all submerged plants was not significantly different with that of con- trol plants, but after 120, 150 and 180 d submergence, the RGR in total shoot length of submerged H. altissima and C. dactylon was higher than that of control plants. The RGR in total leaf number was always higher than that of control plants after all submergence durations. After long-term submergence, this might be an effective way for plants to generate more new leaves and accelerate photosynthesis.
出处
《植物生态学报》
CAS
CSCD
北大核心
2008年第5期977-984,共8页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(30440035
30500041和30770406)
教育部新世纪优秀人才支持计划项目(NCET-06-0773)
国家科技支撑计划(2006BAC10B01)
重庆市科技攻关项目(CSTC2007AB049)
中国科学院西部行动计划(KZCX2-XB2-07)
关键词
地瓜藤
荻
牛鞭草
狗牙根
三峡库区
存活
恢复生长
Ficus tikoua, Triarrhena sacchariflora, Hemarthria altissima, Cynodon dactylon, Three Gorges Reservoir Region, survival, recovery growth