不同苗龄台湾牛樟光合特性研究

Study on Photosynthetic Characteristics of Different Age’s Cinnamomumkanehirae

对1~3年生台湾牛樟(Cinnamomum kanehirae)幼苗日变化及光响应进行测定,研究不同苗龄台湾牛樟幼苗光合生物学特性,为台湾牛樟引种后的高效栽培和管理提供依据。结果表明,1天内不同苗龄台湾牛樟净光合速率(Pn)最高均发生在12:00,其中2年生台湾牛樟日平均Pn最高(6.64μmol·m^-2·s^-1),1年生台湾牛樟日平均Pn最低(0.40μmol·m^-2·s^-1)。光响应结果表明,随着光照强度的降低,1~3年生台湾牛樟Pn均出现先增加后减小的趋势,变化范围分别在-0.78~2.75μmol·m^-2·s^-1,-1.67~7.44μmol·m^-2·s^-1和-2.00~8.50μmol·m^-2·s^-1之间。随着苗龄的增加,台湾牛樟光补偿点(LCP)和表观量子效率(AQY)均不断增加,总体变化范围分别为5.8~21.0μmol·m^-2·s^-1和1.2%~3.0%之间。叶片Pn与气孔导度(Gs)、胞间CO2浓度(Ci)、和蒸腾速率(Tr)之间均具有极显著的相关关系(P<0.01),Pn与光合有效辐射(PAR)之间无显著相关关系。

1-year-old to 3-year-old Cinnamomum kanehirae were selected as experimental materials to dis?cuss diurnal change and photoresponse and photosynthetic characteristics were analyzed.Results showed that the highest net photosynthetic rate(Pn)was at 12 o'clock for all C.kanehirae.The highest average Pn was 6.64μmol·m^-2·s^-1 for 2-year-old C.kanehirae,and the lowest average of Pn was 0.40μmol·m^-2·s^-1 for 1-year-old C.kanehirae.Photoresponse showed that with decrease of light intensity,Pn of 1-year-old to 3-year-oldC.kanehirae appeared increased first and then decreased,with ranges of-0.78 to 2.75μmol·m^-2·s^-1,-1.67 to 7.44μmol·m^-2·s^-1 and-2.00 to 8.50μmol·m^-2·s^-1,respectively.With increase of seedling ages,light compensation point(LCP)and apparent quantum efficiency(AQY)increased continuously with ranges of 5.8 to 21.0μmol·m^-2·s^-1 and 1.2%to 3.0%,respectively.There were extremely significant correlations be?tween Pn and stomatal conductance(Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr).There was no significant correlation between Pn and photosynthetically active radiation(PAR).