缺磷强光下脐橙的过剩能量耗散机制

Dissipation mechanism of excessive energy in umbilical orange under phosphorus deficiency and strong light stress.

采用营养液培养的方法,对缺磷强光下脐橙的过剩能量耗散机制进行了研究.结果表明,在强光下,用缺磷营养液处理脐橙后,光合色素含量、净光合速率Pn、光呼吸速率Pr、最大荧光Fm、光化学效率Fv/Fm和电子传递速率ETR下降,初始荧光Fo和光呼吸/光合比Pr/Pn升高.叶绿素荧光的非光化学猝灭的快相qNf下降,中间相qNm和慢相qNs升高.用DTT处理后Fo升高,qNm和qNs下降,qNf无明显变化.缺磷强光胁迫加剧了脐橙光合作用的光抑制,进而启动了多种能量耗散机制.

The dissipation mechanism of excessive energy of umbilical orange under phosphorus deficiency and strong light stress was studied with solution culture method.The results showed that under phosphorus deficiency and strong light stress,the photosynthetic pigment content,net photosynthetic rate (P_n),photorespiration rate (P_r),maximum fluorescence (F_m),photochemical efficiency (F_v/F_m) and electron transmit rate (ETR) of umbilical orange were all declined,while original fluorescence (F_o) and P_r/P_n ratio were raised.The fast-phase (qNf) of non-photochemical quenching of chlorophyll fluorescence was decreased,while the middle-phase (qNm) and slow-phase (qNs) were increased.After treated with DTT,F_o turned higher,but qNm and qNs were much lower than the control (H_2O),while qNf did not have any significant change.Phosphorus deficiency and strong light stress aggravated photoinhibition of photosynthesis,which in turn started up several dissipation mechanisms in umbilical orange leaf.