Exogenous calcium alleviates low night temperature stress on the photosynthetic apparatus of tomato leaves.
The effect of exogenous CaCl2 on photosystem I and II (PSI and PSII) activities, cyclic electron flow (CEF), and proton motive force of tomato leaves under low night temperature (LNT) was investigated. LNT stress decreased the net photosynthetic rate (Pn), effective quantum yield of PSII [Y(II)], and photochemical quenching (qP), whereas CaCl2 pretreatment improved Pn, Y(II), and qP under LNT stress. LNT stress significantly increased the non-regulatory quantum yield of energy dissipation [Y(NO)], whereas CaCl2 alleviated this increase. Exogenous Ca2+ enhanced stimulation of CEF by LNT stress. Inhibition of oxidized PQ pools caused by LNT stress was alleviated by CaCl2 pretreatment. LNT stress reduced zeaxanthin formation and ATPase activity, but CaCl2 pretreatment reversed both of these effects. LNT stress caused excess formation of a proton gradient across the thylakoid membrane, whereas CaCl2 pretreatment decreased the said factor under LNT. Thus, our results showed that photoinhibition of LNT-stressed plants could be alleviated by CaCl2 pretreatment. Our findings further revealed that this alleviation was mediated in part by improvements in carbon fixation capacity, PQ pools, linear and cyclic electron transports, xanthophyll cycles, and ATPase activity.
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Guoxian
G
Zhang
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Yufeng
Y
Liu
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Yang
Y
Ni
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Zhaojuan
Z
Meng
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Tao
T
Lu
Horticulture Department, Shenyang Agricultural University, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, Liaoning Province, China; Key Laboratory of Protected Horticulture of Liaoning Province, Shenyang, Liaoning Province, China.
Tianlai
T
Li
D000251:Adenosine Triphosphatases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000378:metabolism; D057486:Carbon Cycle / Q000502:physiology; D002734:Chlorophyll / Q000378:metabolism; D003080:Cold Temperature; D004579:Electron Transport / Q000502:physiology; D018551:Solanum lycopersicum / Q000378:metabolism* / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology*; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism* / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D000251:Adenosine Triphosphatases; D002122:Calcium Chloride; D002118:Calcium