title: Differences in the responses of photosystem I and photosystem II of three tree species Cleistanthus sumatranus, Celtis philippensis and Pistacia weinmannifolia exposed to a prolonged drought in a tropical limestone forest.
abstract: Drought stress can induce closure of stomata, thus leading to photoinhibition. The effects of prolonged severe drought under natural growing conditions on photosystem I (PSI), photosystem II (PSII) and cyclic electron flow (CEF) in drought-tolerant tree species are unclear. In spring 2010, southwestern China confronted severe drought that lasted several months. Using three dominant evergreen species, Cleistanthus sumatranus (Miq.) Muell. Arg. (Euphorbiaceae), Celtis philippensis Bl. (Ulmaceae) and Pistacia weinmannifolia J. Poisson ex Franch. (Anacardiaceae) that are native to a tropical limestone forest, we investigated the influence of this stress on PSI and PSII activities as well as light energy distribution in the PSII and P700 redox state. By the end of the drought period, predawn leaf water potential (Ψ(pd)) largely declined in each species, especially in C. sumatranus. Photosystem I activity strongly decreased in the three species, especially in C. sumatranus which showed a decrease of 65%. The maximum quantum yield of PSII after dark adaptation remained stable in P. weinmannifolia and C. philippensis but significantly decreased in C. sumatranus. Light response curves indicated that both linear electron flow and non-photochemical quenching were severely inhibited in C. sumatranus along with disappearance of CEF, resulting in deleterious excess light energy in PSII. We conclude that PSI is more sensitive than PSII to prolonged severe drought in these three drought-tolerant species, and CEF is essential for photoprotection in them.
authors: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
authors: Wei
authors: W
authors: Huang
authors: Pei-Li
authors: PL
authors: Fu
authors: Yan-Juan
authors: YJ
authors: Jiang
authors: Jiao-Lin
authors: JL
authors: Zhang
authors: Shi-Bao
authors: SB
authors: Zhang
authors: Hong
authors: H
authors: Hu
authors: Kun-Fang
authors: KF
authors: Cao
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D002119:Calcium Carbonate; D002734:Chlorophyll / Q000378:metabolism; D003624:Darkness; D055864:Droughts; D004579:Electron Transport; D008027:Light; D019684:Magnoliopsida / Q000502:physiology* / Q000528:radiation effects; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000502:physiology / Q000528:radiation effects; D045331:Photosystem I Protein Complex / Q000502:physiology* / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000502:physiology* / Q000528:radiation effects; D027927:Pistacia / Q000502:physiology / Q000528:radiation effects; D018515:Plant Leaves / Q000502:physiology / Q000528:radiation effects; D054046:Plant Stomata / Q000502:physiology / Q000528:radiation effects; D018526:Plant Transpiration / Q000502:physiology; D012621:Seasons; D013312:Stress, Physiological / Q000502:physiology; D014197:Trees; D034401:Ulmaceae / Q000502:physiology / Q000528:radiation effects; D014867:Water / Q000502:physiology*
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D014867:Water; D002734:Chlorophyll; D002119:Calcium Carbonate