摘要
【目的】探讨不同磷效率紫花苜蓿(Medicago sativa L.)叶片光合性能对低磷胁迫的响应,从光能转化和利用的差异来揭示品种适应磷胁迫的机理。【方法】试验采用砂培法,供试材料为2个磷高效紫花苜蓿品种甘农6号(G6)、极光(JG)和2个磷低效品种Bara 310SC(B310)、甘农4号(G4)。以1/4霍格兰营养液为基础,设置磷浓度为0.5 mmol/L(正常对照)和0.05 mmol/L(低磷)两个处理水平,紫花苜蓿幼苗处理30天后,测定苜蓿幼苗叶片叶绿素荧光参数,将样品烘干后,测定生物量和磷含量。【结果】与对照相比,低磷胁迫下4个苜蓿品种的生物量和磷利用效率均降低,相对可变荧光诱导曲线J点和I点的荧光强度上升,初级醌受体(Q_(A))被还原的最大速率(M_(o))显著增加,受体库容量(S_(m))等参数下降,PSⅡ受体侧受损;活性反应中心数目(RC/CS_(o))降低,光能的吸收(ABS/RC、ABS/CS_(o))、捕获(TR_(o)/RC、TR_(o)/CS_(o))、传递(ET_(o)/RC)和耗散(DI_(o)/RC、DI_(o)/CS_(o))显著增加,性能指数(PI_(abs)和PI_(total))降低,光合电子传递受阻,PSⅠ和PSⅡ的整体性能降低。从品种间差异来看,磷高效利用型品种G6和JG这些参数的变化幅度均小于磷低效利用型品种B310和G4,且在相同磷处理下具有较高的生物量和磷利用效率。【结论】低磷胁迫主要抑制苜蓿叶片受体侧及反应中心电子传递链性能,使PSⅠ和PSⅡ性能下降,光合电子传递受阻,最终导致生物量和磷利用效率降低。与磷低效利用型品种相比,磷高效利用型品种具有较高的光合电子传递活性,能较好的维持光合系统的稳定性;与其他荧光参数相比,PI_(abs)对低磷胁迫最为敏感,且与磷利用效率显著正相关,能有效的反映PSⅡ光能转化效率、活性反应中心和受体侧的状况,是评估低磷胁迫下苜蓿光合活性的有效指标。
【Objective】This study was aimed to identify the effects of P deficiency on photosynthetic performance of alfalfa(Medicago sativa L.)and reveal the differences in light energy conversion and utilization among different varieties.【Methods】Sand culture method was used,two high-P-efficient varieties,Gannon 6(G6),and Aurora(JG);and two low-P-efficient alfalfa varieties,Bara 310SC(B310)and Gannon 4(G4)were selected as test materials.On the basis of 1/4 Hoagland solution,normal P control(0.5 mmol/L)and low P stress(0.05 mmol/L)solution were prepared.At the 30 days of culture,the chlorophyll fluorescence parameters of alfalfa leaves were measured,then the whole seedlings were harvested for the determination of biomass and P content.【Results】Compared with the control group,P deficiency decreased the biomass and P utilization efficiency of four alfalfa varieties,increased fluorescence intensity at points J and I of the relative variable fluorescence induction curve,increased the maximum rate of Q_(A) reduction(M_(o))significantly,parameters such as receptor pool capacity(S_(m))decreased and impaired the PSII receptor side;the number of active reaction centers(RC/CS_(o))decreased,light energy absorption(ABS/RC,ABS/CS_(o)),capture(TR_(o)/RC,TR_(o)/CS_(o)),transfer(ET_(o)/RC)and dissipation(DI_(o)/RC,DI_(o)/CS_(o))increased significantly,performance index(PI_(abs)and PI_(total))decreased,photosynthetic electron transfer was hindered,and the overall performance of PSⅠand PSⅡdecreased.In terms of the differences among varieties,the high-P-efficient varieties G6 and JG showed less variation in these parameters than the low-P-efficient varieties B310 and G4,and had higher biomass and P utilization efficiency under the same P treatment.【Conclusion】P deficiency mainly inhibits the performance of the electron transport chain on the acceptor side and reaction center of alfalfa leaves,which decreases the activity of PSⅠand PSⅡand hinders photosynthetic electron transport.These responses result in a reduction of
作者
卫先伟
潘新雅
王鹏飞
刘佳茜
李军保
王智
WEI Xian-wei;PAN Xin-ya;WANG Peng-fei;LIU Jia-xi;LI Jun-bao;WANG Zhi(College of Grassland Agriculture,Northwest A&F University,Yangling,Shaanxi 712100,China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;Shaanxi Academy of Forestry,Xi'an,Shaanxi 710000,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling,Shaanxi 712100,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2023年第4期690-703,共14页
Journal of Plant Nutrition and Fertilizers
基金
陕西省自然科学基础研究计划青年项目(2020JQ-264)
陕西林业科技创新重点专项(SXLK2022-02-12)
陕西省重点研发计划项目(2022SF-398)
国家自然科学基金(31700335)。
