摘要
为明确大气CO_2浓度升高对宁夏枸杞光合特性及生物量分配的影响,以宁夏枸杞苗木为试材,采用开顶气室(OTC)模拟自然环境大气CO_2浓度变化,设置3个CO_2浓度水平[CK(380±20μmol/mol)、TR1(570±20μmol/mol)、TR2(760±20μmol/mol)],分别于不同CO_2浓度处理90d、120d后,测定其净光合速率(P_n)、光响应曲线、CO_2响应曲线等相关指标及植株不同器官生物量。结果表明:(1)TR1及TR2下Pn于第一年处理至90d时均较CK显著升高(P<0.05),且TR1处理在120d时较CK显著降低;第二年处理90d时,TR1处理较CK下降了4.77%,处理120d时TR1、TR2均高于CK,但差异不显著。(2)随着CO_2浓度升高,两年中TR1、TR2处理的胞间CO_2浓度(C_i)较CK均显著升高,处理后120d时,气孔导度(G_s)较CK均显著下降;水分利用率(WUE)在第一年处理中均无显著变化,但在第二年处理120d时,TR1、TR2均较CK显著上升。(3)处理至90d和120d时,TR1、TR2组的宁夏枸杞苗木光饱和点、CO_2饱和点均高于CK,但TR2组初始羧化效率低于CK。(4)随着CO_2浓度升高,宁夏枸杞苗木地上部分生物量分配显著增加,地下部分生物量分配显著降低。研究发现,一定时间内适宜CO_2浓度升高可促进宁夏枸杞苗木光合作用,使得其地上部分生物量分配显著提高,地下部分生物量分配显著降低;但随着处理浓度升高及处理时间延长,其光合作用有下调趋势,表现为净光合速率、气孔导度、初始羧化效率等下降。
To explore the effects of elevated CO2 on photosynthesis characteristics and biomass allocation in Lycium barbarum.With L.barbarum seedlings as research materials,we applied open top chamber(OTC),a facility to control changed CO2 concentration to simulate natural environment in experiment.We conducted three gradients of CO2 concentration,the control group is(380±20)μmol/mol(CK),which is ambient CO2,and elevated was(570±20)μmol/mol(TR1),(760±20)μmol/mol(TR2).The effects of elevated CO2 on photosynthesis and biomass allocation of L.barbarumseedlings were assessed by net photosynthetic rate(Pn),light response curves,CO2 response curves and dry weight during seedlings exposed to all three treatments(CK,TR1,TR2)after 90 and 120 days in 2017 and 2018.Results showed:(1)when treated for 90 days in 2017,the TR1 and TR2 in Pnof L.barbarumseedlings were increased significantly than that of control(P<0.05).After 120 days,the Pnof TR1 was decreased significantly compared with CK(P<0.05).While Pn of TR1 was 4.77%lower than CK when we repeated the test after 90 days in2018(P>0.05).The treatment of TR1 and TR2 was higher in Pnthan CK after 120 days,but the difference between them was not significant(P>0.05).(2)With the rising of CO2 concentration,it is similar that the intercellular CO2 concentrations(Ci)of TR1 and TR2 treatment were soared respectively than ambient CO2 in 2017 and 2018(P<0.05).With the time prolonging until 120 days,the stomatal conductance(Gs)of TR1 and TR2 dropped conspicuously than that of CK(P<0.05).No difference in water use efficiency(WUE)in 2017,but it raised obviously than control after 120 days in 2018.(3)At 90 days,the light saturation point and CO2 saturation point of treatment TR1 and TR2 were all rising than control,which was maintained in 120 days,but the CO2 assimilation rate of TR2 was declined.(4)The biomass allocation of L.barbarumseedlings increased signally in its aboveground with CO2 rising,thus less allocated in underground organs(P<0.05).We concluded that slightly elevated CO2 could promote the photosynthesis of L.barbarumseedlings,as a result of photosynthesis,the biomass accumulation in L.barbarum seedlings was tend to its aboveground organs,while underground was reduced remarkably.With the concentration and incubation time extending,the photosynthesis in L.barbarumseedlings showed a downregulation trend,which revealed by its Pn,Gsand photosynthetic CO2 assimilation rate decreased.
作者
郭芳芸
哈蓉
马亚平
曹兵
GUO Fangyun;HA Rong;MA Yaping;CAO Bing(School of Agriculture,Ningxia University,Yinchuan 750021,China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2019年第2期302-309,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(31660199)
关键词
CO2浓度升高
宁夏枸杞
光合特性
生物量分配
elevated CO2 concentration
Lycium barbarum
photosynthesis characteristics
biomass allocation
