生态学报2018，Vol.38Issue(8)：2722-2731,10.DOI:10.5846/stxb201704150673
三峡库区消落带不同水淹强度下池杉与落羽杉的光合生理特性
Photosynthetic characteristics of Taxodium ascendens and Taxodium distichum under different submergence in the hydro-fluctuation belt of the Three Gorges Reservoir
摘要
Abstract
After the completion of the Three Gorges Dam Project,the water level of the Three Gorges Reservoir Area (TGRA) fluctuated between 145m a.s.l.in summer and 175m a.s.l.in winter.These extreme water fluctuations along with an annual 30m water-level drawdown have led to the formation of the hydro-fluctuation zone around the reservoir,turning the terrestrial ecosystem into a wetland experiencing winter flooding every year.Under these water fluctuation conditions,the richness and diversity of the vegetation decreased and soil erosion was exacerbated,which further damaged the ecological structure and function of the riparian ecosystem of the reservoir area.The effective way to solve this problem is to restore the riparian vegetation artificially.Understanding the photosynthetic adaptation mechanism of water-tolerant species in the hydro-fluctuation zone is of great importance to undertake vegetation restoration in the TGRA.In order to research the adaptation mechanism of the species suitable to the hydro-fluctuation belt of the TGRA,we designed the following three water regimes:periodic shallow submergence (SS,175m),moderate submergence (MS,170m),and deep submergence (DS,165m).Li-6400 portable photosynthetic measurement system was used to test the light response curves of photosynthesis of Taxodium ascendens and Taxodium distichum after four cycles of submergence,in situ,in the TGRA.The light response curves were fitted and analyzed using the rectangular hyperbola model,the non-rectangular hyperbola model,the rectangular hyperbola modified model,and the exponential equation model.The optimal model was screened out from the four models by analyzing proximity between the simulated and measured values of photosynthetic parameters,and then it was used to analyze the photosynthetic characteristics of the two species under different submergence conditions.Results showed that:(1) The fit of different models was significantly different.The exponential equation model was the best model for the light response curve in accordance with the physiology of the two species;(2) The light response curves of the two species showed similar trends in variation,and along with an increase in the intensity of submergence,the photosynthetic rate of the two species also increased;(3) The maximum photosynthetic rate,apparent quantum yield,and light saturation point of the two species growing under both deep and moderate submergence conditions were higher than that in shallow submergence,while the light compensation point of the two species decreased significantly in deep submergence conditions.These results suggest that the utilization capacity of both low light and high light of the two spccies were improved after submergence.Submergence also stimulated the photosynthetic potential of the two species,which may be related to the positive self-adjustment ability and the photosynthetic compensation of the two species after submergence stress.This also indicates that when the habitat is stressed,plants often adapt themselves to maximize photosynthesis.Thus,it is appropriate to use these two species for reconstructing the vegetation in the hydro-fluctuation belt of the TGRA.关键词
三峡库区/消落带/水淹/池杉/落羽杉/光合特性/光响应曲线Key words
Three Gorges Reservoir Area/hydro-fluctuation belt/submergence/Taxodium ascendens/Taxodium distichum/photosynthesis/light response curves引用本文复制引用
贺燕燕,王朝英,袁中勋,李晓雪,杨文航,宋虹,李昌晓..三峡库区消落带不同水淹强度下池杉与落羽杉的光合生理特性[J].生态学报,2018,38(8):2722-2731,10.基金项目
重庆市林业重点科技攻关项目(渝林科研2016-8) （渝林科研2016-8）
中央财政林业科技推广示范项目(渝林科推[2017-12]) （渝林科推[2017-12]）
国家林业局天然林保护工程管理中心项目(2016-01) （2016-01）
国际科技合作专项(2015DFA90900) （2015DFA90900）
重庆市研究生科研创新项目(CYB16066) （CYB16066）
