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模拟三峡库区消落带水淹对3类土壤中桑树和水桦生长的影响
袁贵琼1, 刘 芸1, 邬静淳,等1
西南大学 资源环境学院
摘要:
【目的】筛选出能适应长时间水淹的植物并明确其耐淹机理。【方法】以三峡库区2年生乡土树种桑树(Morus alba)和引进树种水桦(Betula nigra)为研究对象,结合库区水位运行规律和紫色土、水稻土、黄壤3种主要的土壤类型,通过盆栽模拟水淹试验,设置常规供水组和水淹组2个处理组,研究库区秋冬季长时间(时长90 d)水淹对桑树与水桦生长特性和光合生理的影响。【结果】水淹胁迫显著影响了桑树和水桦的生长及生物量积累(P<0.05),在90 d水淹试验结束后,桑树与水桦茎基部均产生了一定数量的不定根,且在紫色土和水稻土上的存活率均达到100%,在黄壤上的存活率分别为85%和80%;其地上部与地下部生物量积累总体受到显著抑制,两树种的根冠比也显著降低(P<0.05);桑树与水桦的总根长、根总表面积、根系活力等形态指标在水淹胁迫下均有不同程度下降,而根平均直径呈增大趋势。3种土壤上桑树和水桦的光合作用在水淹胁迫下发生显著变化,Pn显著降低,Gs、Ci、Tr较对照组均有不同程度下降,但Ls高于对照组。3种土壤上桑树和水桦的叶绿素a和叶绿素b含量显著下降,但叶绿素a/b值较对照组有一定程度增大,更接近于3∶1。水淹结束后,3种土壤上水淹组桑树和水桦的Fv/Fm与对照相比虽有一定程度下降,但仍保持在较高水平,其qP、ETR、ΦPSⅡ变化趋势与Fv/Fm相同,均呈现下降趋势,而其qN呈现升高趋势。【结论】在长达90 d水淹的情况下,紫色土、水稻土、黄壤3种土壤上,桑树和水桦各生长指标及光合指标均保持在较高水平,表明桑树和水桦对长期水淹具有良好的适应性,可以作为三峡库区消落带植被恢复重建的适生树种。
关键词:  三峡库区  水淹  桑树  水桦  光合生理  生长特性
DOI:
分类号:
基金项目:国家自然科学基金项目“木本植物对三峡库区消落带异质生境的响应及其适应性”(31370602)
Response of growth of mulberry and birch under three soil types to simulated flooding in the Three Gorges Reservoir Region
YUAN Guiqiong,LIU Yun,WU Jingchun,et al
Abstract:
【Objective】The objective of this study was to screen out plants that can adapt to prolonged flooding and clarify the mechanism of flooding resistance.【Method】Two-year-old local mulberry trees (Morus alba L.) and introduced water birch (Betula nigra) were planted in the main soil types of purple soil,paddy soil and yellow soil in reservoir area.Conventional water supply group and flooding group (F) were used to study the growth characteristics and photosynthetic physiology of M.alba and B.nigra in autumn and winter under 90 d flooding.【Result】Waterlogging significantly affected the growth and biomass accumulation of M.alba and B.nigra (P<0.05).After 90 days of flooding,a certain number of adventitious roots were formed on the stem base of both M.alba and B.nigra.The survival rates on purple soil and paddy soil were both 100%,and that on yellow soil were 85% and 80%,respectively.The biomass accumulations above and below ground were significantly inhibited,and the root to shoot ratio was also significantly decreased (P<0.05).Morphological indexes such as total root length,root total surface area and root vigor of M.alba and B.nigra decreased under flooding stress,while the average root diameter increased.The photosynthesis of M.alba and B.nigrachanged significantly under flooding stress,Pn decreased significantly,Gs, Ci and Tr decreased to some extent,while Ls was higher compared to the control group.The contents of chlorophyll a and b in M.alba and B.nigra decreased significantly,but the chlorophyll a/b ratio increased to more close to 3∶1.After flooding,the Fv/Fm of M.alba and B. nigra in flooding group decreased compared with the control,but remained at a high level.The changes of qP,ETR and ΦPSⅡ were same as Fv/Fm,while qN was opposite.【Conclusion】The growth and photosynthesis of M.alba and B.nigrawere maintained at high level after 90 days of flooding,indicating that they have good adaptability to flood and can be used for restoration and reconstruction of fluctuation zone vegetation in the Three Gorges Reservoir Region.
Key words:  Three Gorges Reservoir Region  flooding  Morus alba  Betula nigra  photosynthetic physiology  growth characteristic