期 刊 ：生态学报 2008年 28卷 6期 页码：2571~2571～2580
关键词：香根草；菖蒲；空心莲子草；三峡库区；长期水淹；生长；存活；
Keywords:Vetiveria zizanioides, Acorus calamus, Alternanthera philoxeroides, Three Gorges Reservoir Region, long-term submergence, growth, survival,
摘 要 ：人工构建三峡库区消落区植被是控制消落区水土流失、保护消落区生态环境的重要措施，选择能够耐受长时间完全水淹的植物物种是该措施实施的关键。为了验证香根草、菖蒲、空心莲子草能否用于消落区植被的构建，实验模拟消落区的长期完全水淹条件，设置30d、60d、90d、120d、150d和180d等6个完全水淹时间水平，研究了3种植物在完全水淹条件下生长、生物量积累及存活状况。结果发现：(1)3种植物在经受长时间的完全水淹后有较高的存活率，180d全淹处理后，香根草、菖蒲和空心莲子草的存活率分别为87.5%、100%和50%。(2)这3种植物有不同的水下生长能力。全淹条件下，香根草生长缓慢，几乎没有产生新的叶片，总叶长也没有显著变化；菖蒲能够持续产生较对照植株更为细长的叶片，空心莲子草只在水淹初期(30d内)能够快速伸长地上部分的枝条，并迅速产生新叶片，但随水淹时间的延长，总枝条长及总叶片数没有再显著增加。(3)与对照植株相比，全淹处理抑制了3种植物总生物量的增加，但对3种植物的地上、地下部分生物量抑制程度不同。全淹条件下，香根草的地上部分和地下部分生物量与水淹0d水平(水淹处理开始前一天，下同)相比无显著变化，根冠比高于对照植株；菖蒲的地上部分生物量随水淹时间延长而降低，但却高于对照植株，地下部分生物量始终低于水淹0d水平，根冠比低于对照植株；空心莲子草的地上部分生物量与水淹0d水平相比无显著差异，但地下部分生物量与水淹0d水平相比大幅降低，根冠比低于对照植株。结果表明，这3种植物都有很强的水淹耐受能力，可应用于三峡库区消落区植被的构建。同时，发现植物对长期完全水淹的耐受能力很大程度上与植株在水下的生长情况及植株的营养储备水平相关，剧烈的水下生长会消耗大量的营养储备，进而造成植株存活率降低。植株在全淹条件下有限的生长能力及丰富的营养储备可能是耐淹物种的重要特征。
Abstract:In order to control soil erosion and maintain the eco-environmental quality in the water-level-fluctuation-zone in Three Gorges Reservoir, riparian vegetating is an important measure among all possibilities. For riparian vegetating, selection of appropriate plant species adapted to long-term submergence is crucial. To confirm whether Vetiveria zizanioides, Acorus calamus, and Alternanthera philoxeroides are suitable plant species for riparian vegetating, a flooding simulation experiment was conducted and the growth, biomass accumulation and survival of the three species subjected to 30d, 60d, 90d, 120d, 150d, and 180d full submergence were investigated. It was found that: (1) The three plant species showed high tolerance to full submergence, 87.5%, 100% and 50% of all submerged plants of V. zizanioides, A. calamus and A. philoxeroides after 180d submergence survived, respectively. (2) The three plant species possessed different underwater growth ability. V. zizanioides grew slowly, the length and number of total leaves did not change significantly. A. calamus kept producing narrower and longer leaf blades as compared with those of control plants. A. philoxeroides grew vigorously, shoots elongated notably and new leaves formed quickly in less than 30d, however, the length of total shoots and the number of total leaves did not increase significantly after any longer duration. (3) Submergence inhibited the biomass accumulation of three plant species significantly, but the change of aboveground biomass and belowground biomass differed among the three plant species. The aboveground biomass and belowground biomass of V. zizanioides did not change significantly during its submergence duration, but the root/shoot ratio was slightly higher than that of control plants. The aboveground biomass of submerged A. calamus plants decreased with the duration of submergence, but it was higher than that of control plants, the belowground biomass of A. calamus decreased significantly with the duration of submergence, and their root/shoot ratio was lower than that of control plants. The aboveground biomass of A. philoxeroides did not change significantly when it was submerged in water, but the belowground biomass decreased greatly with the duration of submergence, and the root/shoot ratio was lower than that of control plants. The results demonstrated that these three plant species were submergence-tolerant and could be applied in riparian vegetating of water-level-fluctuation zone in Three Gorge Reservoir. Meanwhile, our results also suggested that the survival and thus tolerance of these three species to submergence was associated with their performance of underwater growth. Intensive underwater growth may have consumed more nutrient storage and decreased the availability of energy for maintenance, which is crucial for survival. Limited underwater growth ability and sufficient carbohydrate reserve may be important factors for selecting long-term submergence-tolerant species.
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