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

Abstract

In tobacco leaves inoculated with tobacco mosaic virus (TMV), changes in chlorophyll (Chl) and carotenoid contents, parameters of slow Chl fluorescence kinetics, i.e. the maximum quantum yield of photosystem (PS2) photochemistry F v /F m , the effective quantum yield of photochemical energy conversion in PS2 Φ 2 , ratio of quantum yields of photochemical and concurrent non-photochemical processes in PS2 F v /F 0 , non-photochemical quenching (NPQ), and photochemical activities of isolated chloroplasts from systemically infected tobacco leaves were investigated. We compared two successive stages of infection, the first in the stage of vein clearing at 9 th day post inoculation (dpi) and the second at 22 nd dpi when two different regions, i.e. light-(LGI) or dark-green (DGI) islands in the infected leaf were apparent and symptoms were fully developed. These two different regions were measured separately. The Chl and carotenoid contents in infected leaves decreased with a progression of infection and were lowest in LGI in the second stage. Also the ratio of Chl a/b declined in similar manner. The maximum quantum yield of PS2 photochemistry F v /F m , was decreased in the following order: first stage, DGI, and LGI. The same is true for the ratio F v /F 0 . The decrease of Φ 2 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 the whole electron transport chain in isolated chloroplasts dramatically declined with the progression of symptoms, the lowest value was in LGI. Similarly, but to a lesser extent, the activity of PS2 in isolated chloroplasts decreased in infected leaves. Generally, the most marked impairment of the photosynthetic apparatus was manifested in the LGI of infected leaves.

Effect of fusaric acid on biomass and photosynthesis of watermelon seedlings leaves

“…The chlorophyll and carotenoid contents in infected leaves decreased with the progression of infection of tobacco mosaic virus (WILHELMOVA et al 2005). Cucumber cotyledons are highly sensitive to the toxin (produced by Alternaria tenuis Nees.…”

The effect of risk elements in soil to nitric oxide metabolism in tobacco plants

“…Pigment contents were established by HPLC (ECOM, Prague, Czech Republic) from acetone extracts using a reversed phase column Sepharon SGX C18 (Tessek, Praha, Czech Republic), data were captured and calculated by PC-software Clarity (DataApex, Prague, Czech Republic) (Procházková et al 2008). Chlorophyll fluorescence parameters from slow kinetics were measured after a 15 min dark period with the PAM Chl fluorometer (Walz, Effeltrich, Germany) on adaxial side of fresh leaves, using the DA 100 data acquisition system (Walz, Effeltrich, Germany) for sampling and calculation (Wilhelmová et al 2005).…”

Antioxidant protection during ageing and senescence in transgenic tobacco with enhanced activity of cytokinin oxidase/dehydrogenase

“…Measuring irradiance was 0.35 μmol m -2 s -1 , actinic irradiance 200 μmol m -2 s -1 , 700 ms saturated flash of 2 500 μmol m -2 s -1 (for detail see Wilhelmová et al 2005). The DA 100 data acquisition system (Walz, Effeltrich, Germany) was used for sampling and calculation.…”