不同覆盖栽培年限雷竹林光合生理研究

Photosynthetic Physiology of Phyllostachys praecoxcv.prevernalis in Different Mulching Cultivation Periods

为揭示覆盖栽培竹林生理生态变化机制,给竹林生态修复技术研究提供依据,分别对覆盖0、3、6、9a和12a雷竹林光合性状和光响应特征等进行研究。结果表明:竹林净光合速率(Pn)随覆盖年限增长,逐渐减小,在覆盖6a时显著减小;气孔导度(Gs)随覆盖年限增长,逐渐减小,覆盖9a时显著减小;覆盖6a后竹林胞间CO2浓度(Ci)均高于覆盖0、3a竹林;蒸腾速率(Tr)总体随竹林覆盖年限增长,逐渐减小,在覆盖3a时即显著减小;竹林水分利用效率(WUE)以覆盖3a竹林最高,覆盖12a竹林最低;Pn与Gs呈极显著正相关,与Tr呈显著正相关,与Ci呈负相关,但相关不显著;竹林光响应过程中,光合有效辐射(PAR)达20μmol·m-2·s-1后,覆盖3a竹林Pn均高于其他竹林,PAR升高至400μmol·m-2·s-1后,各竹林Pn以覆盖12a竹林最低;覆盖3a竹林潜在最大净光合速率(Pmax)最大,覆盖12a竹林最小;覆盖0a竹林光补偿点(LCP)最低,覆盖6a后竹林LCP均在10.000μmol·m-2·s-1以上;覆盖6a竹林光饱和点(LSP)最高,达737.703μmol·m-2·s-1。结论认为:覆盖对竹林光合作用起到制约作用,覆盖时间越长,竹林越难以形成可持续生产力;竹林覆盖至第6年,光合生理发生显著减弱,竹林种群受覆盖胁迫越来越严重,此时,需要及时养竹以更新竹林和采取有效的竹林恢复措施,同时,要重点开展竹林土壤生态修复技术研究,以促进实现竹林可持续经营。

To reveal the eco-physiological responses mechanism of mulching cultivation bamboo forest,and provide evidence for ecological rehabilitation of bamboo forest,photosynthetic traits and photoresponse of mulching 0year,3years,6years,9years,12 years Phyllostachys praecox cv.Prevernalis forests were studied.Results showed that with increased of mulching cultivation periods,net photosynthetic rate(Pn)of bamboo forest decreased gradually,it declined significantly when mulching 6years.Stomatal conductance(Gs)decreased gradually with increased of mulching cultivation periods,it reduced significantly while mulching 9years.After mulching 6years,intercellular CO2concentration(Ci)of bamboo forest was higher than mulching 0year,3years forest.Mulching periods increased,transpiration rate(Tr)of bamboo forest decreased gradually on the whole,and decreased significantly while mulching 3years.Water use efficiency(WUE)was highest in mulching 3years bamboo forest,and lowest in mulching 12 years bamboo forest.Pnexhibited a very significant positive correlation with Gs,significant positive correlation with Tr,and showed negative correlation with Ci,but had no significance.After photosynthetically available radiation(PAR)reached 20μmol·m-2·s-1 in the process of photoresponse of bamboo forest,the Pnof mulching 3years bamboo forest was highest,after PARreached 400μmol·m-2·s-1,the Pnof mulching 12 years bamboo forest was lowest.MaximumPn(Pmax)was highest in mulching 3years bamboo forest,lowest in mulching12 years bamboo forest.The light compensation point(LCP)was lowest in mulching 0year bamboo forest,and it beyond 10.000μmol·m-2·s-1 after mulching 6years.The light saturation point(LSP)was highest in mulching 6years bamboo forest,it reached 737.703μmol·m-2·s-1.The results suggested that mulching cultivation restricted the photosynthesis of bamboo forest,mulching longer,it was more difficult to form sustainable productivity.While mulching 6years,photosynthesis of bamboo forest decreased significantly,bamboo population suffered further stress,in this case,it was necessary to pause mulching cultivation to keep standing bamboo,and to use effective measures for bamboo forest recovery,meanwhile,it was more important to study ecological restoration technology of degraded soil of bamboo forest,and to realize the sustainable management of bamboo forest.