三种水库消落带草本植物对完全水淹的适应机制研究

Adaptation Mechanism of Three Herbs in the Water-level-fluctuation-zone of Reservoir to Complete Submergence

为了解虉草(Phalaris arundinacea)、牛鞭草(Hemarthria altissima)和狗牙根(Cynodon dactylon)3种水库消落带草本植物在完全水淹条件下的生理生态适应机制,对这3种植物的生态指标(枝条、叶和生物量)和生理指标(可溶性糖、淀粉和根系活力)的动态变化特征进行了研究。结果表明:在完全水淹条件下,虉草、牛鞭草和狗牙根都不产生新的枝条,它们通过减少总叶数、总叶长和生物量的方式来适应水淹环境。虉草和狗牙根通过减缓枝条生长速率来适应水淹环境,而牛鞭草则是通过先加快生长后抑制生长来保存活力。虉草、牛鞭草和狗牙根均以少量的碳水化合物(可溶性糖和淀粉)消耗,降低根系活力等方式来适应长期的水淹环境。3种草本植物的水淹耐受能力由大到小依次为狗牙根、虉草、牛鞭草。

In order to understand the adaptive mechanism of three plant species, including Phalaris arundinacea, Hemarthria altissima and Cynodon dactylon, in the water-level-fluctuation-zone （WLFZ）, dynamic changes in ecological and physiological indicators, such as branch, leaf, biomass, soluble sugar, starch and root vigor, were studied. The results showed that P. arundinacea, H. altissima and C. dactylon did not generate new branch, and reduced total leaf number, total leaves length and biomass for adapt to submergence environment. P. arundinacea and C. dactylon adapted to complete submergence by slow growth, while H. altissima accelerated growth at first and then inhibited growth to preserve vitality. P. arundinacea, H. altissima and C. dactylon consumed little carbohydrate, reduced root vigor to adapt complete submergence. The tolerance of prolonged submergence of the three herbs is as the following： C. dactvlon 〉 P. arundinacea 〉 H. altissima.