摘要
【目的】通过比较不同盐碱胁迫条件下松嫩草地灰绿型羊草和黄绿型羊草根际效应差异及其对光合生理活动和生长的影响,为适合于盐碱退化草地改良的羊草生态型的选择提供理论依据。【方法】采用盆栽控制试验方法,共设置对照、中度盐碱胁迫和重度盐碱胁迫3个处理,中度盐碱胁迫处理通过40 mmol·L^-1 NaCl溶液、40 mmol·L^-1 Na2CO3溶液、360 mmol·L^-1 Na2SO4溶液和360 mmol·L^-1 NaHCO3溶液,按1:1:1:1混合施加实现,重度盐碱胁迫处理通过200 mmol·L^-1的NaCl溶液、Na2SO4溶液、NaHCO3溶液和Na2CO3溶液按1:1:1:1混合施加实现,处理时间为30 d。测定分析不同处理间2种生态型羊草根际土与非根际土的pH、电导率、总有机碳、总氮、铵态氮、硝态氮和微生物碳、氮含量,植物叶片的净光合速率、脯氨酸含量、可溶性糖含量以及植物株高、地上生物量、地下生物量等指标。【结果】2种生态型羊草根际土壤和非根际土壤的铵态氮、硝态氮、有效氮及微生物碳和氮含量在中度盐碱胁迫处理下均显著高于重度盐碱胁迫处理,且均显著低于对照。2种生态型羊草在各盐碱处理条件下根际土壤pH均显著低于非根际土壤,根际土壤中有效氮和微生物碳、氮含量均显著高于非根际土壤。灰绿型羊草的pH根际效应在对照和中度盐碱胁迫处理下均显著大于黄绿型羊草。灰绿型羊草的有效氮根际效应和微生物碳根际效应在2个盐碱胁迫处理下均显著大于黄绿型羊草。2种生态型羊草的净光合速率在中度盐碱胁迫处理下均显著高于重度盐碱胁迫处理,且均显著低于对照。黄绿型羊草的净光合速率伤害率均显著高于灰绿型羊草。叶片脯氨酸含量和可溶性糖含量在中度盐碱胁迫处理下均显著低于重度盐碱胁迫处理,且均显著高于对照,灰绿型羊草的叶片脯氨酸敏感指数在重度盐碱胁迫处理下显著高于黄绿型羊草。灰绿型羊草的叶片可溶性糖含量敏感指数和渗透压在2个盐碱处理下均显著高于黄绿型羊草,且均显著高于对照。盐碱胁迫处理下,2种生态型羊草的地上生物量、地下生物量和总生物量均显著低于对照。在盐碱胁迫条件下,黄绿型羊草的株高和地下生物量的损失率显著高于灰绿型羊草。【结论】相对于黄绿型羊草,灰绿型羊草能通过根际效应有效地缓解盐碱胁迫对土壤理化性质造成的不利影响,并表现出更强的耐盐碱性。
【Objective】This study was designed to explore differences in rhizosphere effects and photosynthetic physiological activities between the grey green(GG)and yellow green(YG)ecotypes of Leymus chinensis(L.chinensis)in Songnen plains in response to saline-alkali stress,and to provide a theoretical basis for selecting the ecotype of L.chinensis suitable for the restoration of degraded saline-alkali grasslands.【Method】Using a pot experiment,the changes of soil and plant under the control,moderate salt-alkaline stress and severe salt-alkaline stress treatments for 30 days were studied,including pH,electrical conductivity,total organic carbon content,total nitrogen content,NH4+-N content,NO3--N content,microbial biomass carbon content and microbial biomass nitrogen content of rhizosphere soil and bulk soil,as well as leaf net photosynthetic rate,leaf proline content,leaf soluble sugar content and plant height,aboveground biomass and belowground biomass of the two ecotypes of L.chinensis.The moderate saline-alkali stress was achieved by mixing 40 mmol·L^-1 NaCl solution,40 mmol·L^-1 Na2CO3 solution,360 mmol·L^-1 Na2SO4 solution and 360 mmol·L^-1 NaHCO3 solution at 1﹕1﹕1﹕1.The severe saline-alkali stress treatment was reached by mixing 200 mmol·L^-1 NaCl solution,Na2SO4 solution,NaHCO3 solution and Na2CO3 solution at 1﹕1﹕1﹕1.【Result】The NH4+-N content,NO3--N content,available nitrogen content,microbial biomass carbon content and microbial biomass nitrogen content of rhizosphere and bulk soil under the moderate salt-alkaline stress treatment were significantly higher than those under the severe salt-alkaline stress treatment.For both ecotypes,the rhizosphere soil had a significantly lower pH value than that of the bulk soil.Moreover,the rhizosphere soil had greater available nitrogen content,microbial biomass carbon content and microbial biomass nitrogen content relative to the bulk soil.The rhizosphere effects of pH in the GG ecotype of L.chinensis were significantly higher than that of the YG ecotype under the control and moderate salt-alkaline stress treatment.The rhizosphere effects of available nitrogen content and microbial biomass carbon content in the GG ecotype of L.chinensis were significantly higher than those of the YG ecotype.For both ecotypes,the net photosynthetic rate,leaf soluble sugar content and leaf proline content under the moderate salt-alkaline stress treatment were significantly higher than those under the severe salt-alkaline stress treatment.The aboveground biomass,belowground biomass and total biomass under the salt-alkaline stress treatments were significantly lower than those under the control treatment.The loss rate of plant height and belowground biomass,and harm percentage of net photosynthetic rate in the YG ecotype of L.chinensis were significantly higher than them in the GG ecotype.Compared to the YG ecotype,the GG ecotype had significantly higher sensitive indexes of leaf proline content,leaf soluble sugar content and osmotic pressure.【Conclusion】The GG ecotype of L.chinensis could more effectively alleviate the adverse effects of saline-alkali stress on soil physical and chemical properties and showed stronger saline-alkali resistance than the YG ecotype.
作者
姚远
徐月乔
王贵
孙伟
YAO Yuan;XU YueQiao;WANG Gui;SUN Wei(Institute of Grassland Science,Northeast Normal University/Key Laboratory for Vegetation Ecology,Ministry of Education,Changchun 130024;College of Life Sciences,Changchun Normal University,Changchun 130032)
出处
《中国农业科学》
CAS
CSCD
北大核心
2020年第13期2584-2594,共11页
Scientia Agricultura Sinica
基金
国家重点研发项目(2016YFC0500602)
国家自然科学基金面上项目(31570470,31870456)。
关键词
盐碱胁迫
灰绿型羊草
黄绿型羊草
根际效应
光合生理
salt-alkaline stress
grey green ecotype of L.chinensis
yellow green ecotype of L.chinensis
rhizosphere effect
photosynthetic physiology
