三峡库区多年高水位运行对消落带狗牙根生长恢复的影响

为深入了解三峡库区多年高水位运行对消落带优势植物生长恢复的影响,分别于2008年和2017年定量调研了库区长寿段消落带狗牙根(Cynodon dactylon)种群的变化,探讨了库区高水位运行对消落带狗牙根萌发、生长和物质分配的影响。结果表明,多年的高水位运行导致不定芽形成和萌发显著被促进,形成更多的分株;高水位运行导致狗牙根分株的株高、茎宽和叶片数被显著抑制,而叶长和种群的总叶片数被显著促进,且随着消落带水位的降低叶长呈降低趋势,而叶宽和总叶片数呈增加趋势;高水位运行导致狗牙根种群匍匐茎和地下茎的茎长、茎节数和总茎长均被显著促进,且随着消落带水位降低匍匐茎茎长和茎节数呈显著的降低趋势,而地下茎茎长和茎节数呈增加趋势;高水位运行导致狗牙根地下茎储存的干质量呈增加趋势,而分株和匍匐茎的干质量呈降低趋势,而且在种群物质分配中地下茎所占的比例呈增大趋势,低水位狗牙根种群的分株和高水位种群的匍匐茎所占的比例也呈增加趋势。因此,狗牙根不仅具有很强的耐淹和生长恢复能力,也具有很强的拓殖能力,可以作为库区中低位消落带恢复和重建的主要原生物种。

Influence of multi-year high water level running on growth recovery of Cynodon dactylon population in water-level-fluctuating zone of the Three Gorges Reservoir

To clarify influence of multi-year high water level running on growth recovery of dominant plants in water-level-fluctuating zone of the Three Gorges Reservoir, the quantitative changes of Cynodon dactylon population in Changshou area were investigated in 2008 and 2017. We also discussed the influences of high water level on the germination, growth, and material allocation of C. dactylon. The results showed that multi-year high water level running significantly promoted the formation and germination of adventitious buds which made more ramets to be formed. Multi-year high water level running significantly restrained plant height, stem width, and leaf number of the ramets, while leaf length and total leaf number of the population were significantly promoted. Furthermore, the leaf length was decreased with water level decreasing. However, the leaf width and total leaf number showed the opposite increasing trend. Simultaneously, multi-year high water level running led to the significant promotion of stem length, stem nodes number and total stem length of stolons and rhizomes. The stem length and stem nodes number of the stolons were decreased with the water level decreasing. On the contrary, stem length and stem nodes number of the rhizomes were increased with water level decreasing. As a result of high-water-level operation for many years, dry mass of the rhizomes showed an increasing trend, while dry mass of the ramets and the stolons showed an opposite decreasing trend. In addition, the proportion of the rhizomes, ramets in low water level, and stolons in high water level also showed an increasing trend in material distribution of the population. Therefore, C. dactylon not only have strong flood resistance and growth recovery ability, but also have strong colonization ability, which can be used as one of the primary native species for vegetation recovery and reconstruction of in low or middle water-level-fluctuating zone of the Three Gorges Reservoir.