红叶石楠不同叶龄叶片的光合特性研究

Photosynthetic Characteristics of Photinia fraseri Leaves at Different Ages

以红叶石楠不同叶龄的叶片为研究对象,测定其净光合速率日变化(Pn)、光响应曲线、比叶重(LMA)、叶绿素含量等光合生理指标,估算不同叶龄叶片的最大净光合速率(P max)、光饱和点(LSP)、光补偿点(LCP)、暗呼吸速率(Rd)和表观光量子效率(AQY),揭示其不同叶龄叶片光合生理特性。结果表明,(1)不同叶龄叶片的净光合速率日变化都呈双峰曲线;(2)叶龄较小的叶片Pn受蒸腾作用(Tr)和光照强度(PAR)影响较大,叶龄较大的叶片Pn受气孔导度(Cond)和相对湿度(RH)影响较大;(3)随着叶龄增加,叶片光合能力不断增强;20d生叶片光饱和点显著小于10d生叶片,对光照更加敏感;叶片的光补偿点和叶绿素a/b变化不显著,各叶龄叶片对弱光的利用能力变化不明显。本研究阐明了红叶石楠不同叶龄叶片净光合速率的影响因素,为红叶石楠的栽培和日常管理提供科学依据。

In order to reveal leaf photosynthetic physiological characteristics of Photinia fraseri,different foliar age leaves were investigated.By measuring the photosynthetic physiological indexes such as the daily variation of net photosynthetic rate(Pn),light response curves,specific leaf weight(LMA),chlorophyll content et al,photosynthetic physiological parameters of the maximum net photosynthetic rate(P max),light saturation point(LSP),light compensation point(LCP),dark respiration rate(Rd)and apparent quantum yield(AQY)were estimated.The results showed that:(1)The diurnal variation of net photosynthetic rate of different foliar ages presented as a bimodal curve.(2)The net photosynthetic rate(Pn)of younger leaves are greatly affected by transpiration(Tr)and light intensity(PAR),while those older leaves are greatly affected by stomatal conductance(Cond)and relative humidity(RH).(3)With the increase of leaf age,the photosynthetic capacity of leaves increased continuously;The light saturation point of 20 days leaves was significantly lower than that of 10 days leaves,and it was more sensitive to light.The light compensation point and chlorophyll a/b of leaves did not change significantly,and the utilization ability of different age leaves to weak light did not change significantly.This study elucidated the factors influencing the net photosynthetic rate of leaves of Photinia fraseri at different leaf ages and provided scientific basis for the cultivation and daily management of Photinia fraseri.