水淹对三峡库区岸生植物秋华柳(Salix variegata Franch.)存活和恢复生长的影响

The effects of flooding on survival and recovery growth of the riparian plant Salix variegata Franch.in Three Gorges reservoir region

植物在水淹后的存活和恢复生长状况可以衡量其对水淹的耐受能力,为了解三峡库区岸生植物秋华柳(Salix variegata Franch.)的水淹耐受能力,研究了长期水淹条件下秋华柳植株的存活和恢复生长状况。实验设置了3个水淹深度:对照,水淹根部(植株置于水中,仅地下部分被淹没)和水淹2m(植株置于水中,顶部距水面2m),6个水淹时间:20d,40d,60d,90d,120d和180d。研究结果表明:(1)水淹对秋华柳植株存活率的影响较小。水淹根部处理的植株在水淹180d后,存活率仍为100%,水淹2m处理的植株在水淹120d后,存活率也为100%,直到180d后,存活率才下降为0。(2)水淹后,秋华柳植株仍然可以进行恢复生长,表现出很强的恢复生长能力,但因水淹处理的不同,其恢复生长存在差异。随着水淹时间的延长,秋华柳植株出水后到开始恢复生长之前所需的时间增加,但所有水淹处理的植株在水淹结束后一周内都可以开始恢复生长。在相同水淹时间处理下,水淹处理的秋华柳植株在恢复生长期间的相对生长速率都高于对照植株,水淹40d,60d,90d后,水淹2m的秋华柳植株分别比对照植株高57.8%,143.4%,130.4%。水淹结束时,秋华柳地上部分生物量随水淹深度的不同而不同,水淹根部处理的植株几乎与对照植株无显著差异,水淹2m处理的植株都低于对照植株。水淹结束后,不同处理的秋华柳植株生长2个月后的地上部分生物量与其在水淹结束时不同处理植株地上部分生物量的变化趋势相似。本研究表明,秋华柳在长时间的水淹后具有很高的存活率,并可以进行很好的恢复生长,表现出较强的水淹耐受能力,可以考虑将其应用于三峡库区消落区的植被构建。

Species＇ flooding tolerance can be characterized by its survival during submergence and by its recovery growth after deubmergence, to evaluate the tolerance of the riparian plant Salix variegata Franch. in Three Gorges reservoir region to flooding, a long-term flooding experiment was conducted and the survival and recovery growth of S. variegata were analyzed. Three flooding-depth levels and six flooding durations were set in the experiment. Three flooding-depth levels included control, belowground submergence（ belowground of plants submerged in water） and complete submergence with 2m water depth（top of plants 2m below water surface）. Six flooding durations included 20 days, 40 days, 60 days, 90 days, 120 days and 180 days. It was found in the experiment that： （ 1 ） The flooding had less effects on the survival of S. variegata. The survival percentage of the plants subjected to the belowground submergence was still 100% after 180d inundation, but it decreased to 0 after 180d submergence with 2m water depth. （2） The S. variegata plants were still able to start recovery growth after flooding, and showed strong recovery capability even though the recovery growth was different due to the different intensities of water submergence. With the increase in duration of flooding, the time S. variegata needed to start recovery growth increased. However, all flooded plants could recover in one week when flooding was ended. Under the condition of the same flooding duration, the plants subjected to belowground submergence and 2m water depth submergence had higher RGR than the control plants. After 40d, 60d and 90d inundation, The RGR of the plants submerged with 2m water depth were 57.8%, 143.4% , 130.4% higher than that of the control plants, respectively. In the experiment, it was shown that the growth of S. variegata varied with flooding intensity. The aboveground biomass of the plants subjected to belowground submergence was not significantly different from that of the control plants, but the plants submerged with 2m water depth had lower aboveground biomass than the control plants. Mter 2 months growth following flooding termination, the variation pattern in aboveground biomass among plants subjected to treatments of different flooding depths was similar to that of plants when flooding was just ended. The research demonstrates that S. variegata has high survival and good recovery growth after long-term flooding. It shows good tolerance to flooding and could be taken as a candidate species in the revegetation of water-level-fluctuation zone in Three Gorge reservoir region.