沼液营养液对基质栽培草莓叶片气体交换日变化的影响

Effects of nutrient solution based on biogas slurry on diurnal change leaf gas exchange of strawberry in soilless cultivation

以基质栽培下‘红颜’草莓(Fragaria ananassa Duch cv.Benihoppe)为试材,以沼液与山崎配方不同浓度的混合液为营养液,研究其对草莓叶片气体交换参数日变化的影响及各参数与环境因子的关系,以期探索适宜草莓生长的最佳沼液营养液配比,为沼液在草莓基质栽培中的科学利用提供理论依据。结果表明:不同浓度沼液处理的草莓叶片净光合速率Pn、蒸腾速率Tr和气孔导度gs的日变化皆为双峰曲线,峰值分别出现在11:00和15:00时且上午峰值高于下午。胞间CO2浓度Ci和水分利用效率WUE日变化在首茬果实转红期均呈现先降后升的趋势,第3茬果实完熟期的Ci在15:00时之前趋于平缓、之后下降、至17:00时再次平缓,WUE则呈先降后升再降的趋势。气孔限制值Ls日变化为单峰曲线,第1茬果实转红期最高峰值出现在13:00时,第3茬果实完熟期最高峰值推移至17:00时。Pn、Tr、gs、Ci和WUE在首茬果实转红期的日均值均高于第3茬果实完熟期,而Ls的日均值则小于第3茬果实完熟期。沼液浓度影响了草莓气体交换参数的大小且不同生育期的影响程度不同,体积比1∶1为临界值,低于该浓度(2∶3)促进了两时期内草莓叶片Pn、gs、Tr和WUE的升高,而降低了Ci和Ls,高浓度的沼液处理(3∶2),两时期内叶片的Pn、gs、Tr和WUE明显降低,而Ci和Ls明显上升。各参数与环境因子相关性表明:gs、Ci、Ls和WUE分别与空气相对湿度RH、空气CO2浓度Ca显著相关,Ls、WUE分别与空气温度Ta显著相关,而Pn、Tr与4个环境因子(光合有效辐射PARo、Ta、RH、Ca)均无显著线性关系;gs、Ci与PARo和Ta无相关性;Ls和WUE均与PARo无显著线性关系。沼液浓度影响了草莓平均株产,沼液与山崎配方体积比为2∶3的平均株产最高,体积比为3∶2时最低,体积比1∶1与对照无显著差异。因此考虑经济成本和草莓产量,建议沼液应用于草莓基质栽培时,沼液与山崎配方比例不宜超过1∶1。

To determine the optimum mixed proportion of Yama Zaki nutrient solution(NS)and biogas slurry(BS)for strawberry(Fragaria ananassa Duch cv.Benihoppe)in soilless cultivation,diurnal changes of leaf gas exchange parameters and environmental factors under different mixture treatments were measured and analyzed.The results demonstrated that diurnal changes of leaf net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(gs)were double-peak curves with the highest 11:00 peak and the lowest 15:00 peak.Intercellular carbon dioxide concentration(Ci)and water use efficiency(WUE)decreased first and then increased in fruit expansion during first-cut period(FFE).In fruit harvesting during third-cut period(TFH),Ci was stable before 15:00,then decreased,and stabled again at 17:00,while WUE showed tendency of decreasing first,then increasing and decreasing again at last.Diurnal change of stomatal limitation value(Ls)was singlepeak curve and the peaks occurred at 13:00(FFE)and 17:00(TFH)respectively.Daily mean value of Pn,Tr,gs,Ci and WUE were higher but Ls was lower in FFE than in TFH.Pn,gs,Tr and WUE were enhanced while Ci and Ls were reduced in mixture of 2∶3(BS∶NS),while the opposite case happened in mixture of 3∶2(BS∶NS).gs,Ci,Ls and WUE were highly correlated with relative humidity(RH)and air CO2 concentration(Ca).There was a significant correlation between Ls,WUE and air temperature(Ta),but not between Pn,Tr and 4 environmental factors,which were photosynthetically active radiation(PARo),Ta,RH and Ca.There was no significant correlation between gs,Ci and PARo,Ta,and the same for the correlation between Ls,WUE and PARo.Yield per plant in mixture of 2∶3(BS∶NS)was the highest,while it was the lowest in mixture of 3∶2(BS∶NS),and there was no significant difference between 1∶1(BS∶NS)mixture and the control group.Therefore,1:1 was the threshold value for optimum mixed proportion of NS and BS,and it can be applied in strawberry production.