Photosynthesis in leaves of Nicotiana tabacum L. infected with tobacco mosaic virus

Wilhelmová, Naděžda; Procházková, Dagmar; Šindelářová, Milada; Šindelář, Luděk
PHOTOSYNTHETICA 43 [4]: 597-602, 2005

Klíčová slova: carotenoids; chlorophyll; chlorophyll fluorescence
Abstrakt: In tobacco leaves inoculated with TMV, changes in chlorophyll and carotenoid contents, parameters of slow Chl fluorescence kinetics, i.e. the maximum quantum yield of photosystem 2 (PS2) photochemistry Fv/Fm, the effective quantum yield of photochemical energy conversion in PS2 Φ2, ratio of quantum yields of photochemical and concurrent non-photochemical processes in PS2 Fv/F0, non-photochemical quenching (NPQ), and photochemical activities of isolated chloroplasts were investigated. The Chl and carotenoid contents in infected leaves decreased with a progression of infection and were lowest in LGI. The ratio of Chl a/b declined similarly. The maximum quantum yield of PS2 photochemistry Fv/Fm, was decreased in the following order: first stage, DGI, and LGI. The same is true for the ratio Fv/F0. The decrease of Φ2 in infected leaves declined as compared to their controls. On the contrary, NPQ increased in infected leaves, the highest value was found in the first infection stage. Photochemical activities of whole electron transport chain in chloroplasts dramatically declined with progression of symptoms, the lowest value was in LGI. The activity of PS2 in chloroplasts decreased to a lesser extent in infected leaves. Generally, the most marked impairment of the photosynthetic apparatus was manifested in the LGI of infected leaves.
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