[Effects of cucumber leaf's PS II activity and electron transfer on its PS I activity in recovery process after chilling-induced photoinhibition].
Taking Cucumis sativus L. (Jinchun No. 4) as test material, through the determination of chlorophyll-a fluorescence transient and light absorbance at 820 nm, and in combining with chlorophyll quenching, this paper studied the recovery of cucumber leaf' s PS I and PS I activities and the interactions between PS I and PS II in the recovery process at room temperature (25 degrees C) and under different light intensities (0, 15, and 200 micromol x m(-2) x s(-1)) after six hours of low temperature (4 degrees C) and strong light (200 micromol x m(-2) x s(-1)) stress. Different extent of photoinhibition of the PS II and PS I occurred after the stress. During the recovery process at room temperature, the PS II activity recovered quickly and was insensitive to light intensity, while the PS I activity recovered quickly under weak light intensity (15 micromol x m(-2) x s(-1)) but slowly under strong light intensity (200 micromol x m(-2) x s(-1)), suggesting that after the chilling-induced photoinhibition, the reduced electron transfer from PS II to PS I protected the PS I from further inhibition, accelerating the recovery of PS I activity. In the breeding of chilling-resistant species of cucumber, it should not only pursue the higher chilling-resistance of PS II and faster recovery of PS II after chilling-induced photoinhibition, but also pay more attention to the coordinating of PS I and PS II during and after the chilling-induced photoinhibition. In the culture of cucumber, after chilling happened, a practical method to reduce light intensity would help the recovery of cucumber leaf PS I activity to protect the photosynthetic apparatus against photoinhibition.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, Shandong, China. zhangzishantaian@163.com
Zi-Shan
ZS
Zhang
Cheng
C
Yang
Hui-Yuan
HY
Gao
Wei-Wei
WW
Wang
Xue-Juan
XJ
Sun
Xiang-Long
XL
Meng
Qing-Wei
QW
Meng
D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003080:Cold Temperature; D018553:Cucumis sativus / Q000378:metabolism / Q000502:physiology*; D004579:Electron Transport; D008027:Light; D055668:Photochemical Processes; D010788:Photosynthesis; 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; D000077194:Chlorophyll A