Culture on sugar medium enhances photosynthetic capacity and high light resistance of plantlets grown in vitro

Abstract

The significance of photosynthetic photon flux (PPF) and sugar feeding for the production of plants in vitro is only poorly understood. Nicotiana tabacum L. plantlets were grown photoautotrophically and photomixotrophically (3% sucrose) at two different PPFs (60 µmol m−2 s−1 and 200 µmol m−2 s−1) to investigate the effect of these culture parameters on photosynthetic performance and growth. Photomixotrophically‐grown plantlets showed an increase in carbohydrate content, mainly in glucose and fructose. Plant growth, dry matter accumulation and total leaf area were higher under photomixotrophic than photoautotrophic conditions. Not only biomass formation but also photosynthesis was positively affected by exogenous sucrose; the chlorophyll (Chl) content and the light‐saturated rate of photosynthetic oxygen evolution were higher in photomixotrophic plantlets. Photoinhibition occurred in plantlets that were grown photoautotrophically at the higher PPF. It became apparent as a loss in Chl content and photochemical efficiency. Photoinhibited plantlets showed a decrease in the D2/LHCII and CP47/LHCII ratios, suggesting a preferential loss of proteins from the photosystem II (PSII) core. The increased content of xanthophyll cycle pigments in photoinhibited plantlets indicated that also protective mechanisms were activated. Photomixotrophic growth of the plantlets prevented the occurrence of photoinhibitory symptoms. Therefore, we conclude that culture on sugar medium increases not only the photosynthetic potential but also the high light resistance of plantlets grown in vitro.

Acclimatization of 'VR043-43' (Vitis vinifera x Vitis rotundifolia) grapevine rootstock

“…For the PFD levels tested (18 and 43 μmol m -2 s -1 ), no difference between dry matter averages (11.9 mg per plant and 13.6 mg per plant, respectively) was obtained. However, Tichá et al (1998) observed a positive effect in biomass and leaf area of Nicotiana tabacum plants with addition of 30 g L -1 sucrose in the culture medium and Galzy and Compan (1992) obtained similar results with Vitis rupestris. The smallest dry matter of the aerial part (5.0 mg per plant) was obtained when sucrose was absent from the culture medium, probably due the necessity of increasing not only the PFD but in vitro CO 2 enrichment and humidity in the culture tubes environment in order to promote photosynthesis, transpiration and accumulation of dry matter (Kozai and Nguyen, 2003).…”

In vitro storage of plum germplasm by slow growth

“…Pruski et al (2000) found also yellow basal leaves in Prunus virginiana L. under cold storage both in dark and light conditions ascribing it to the presence of sucrose in the storage media. The presence of exogenous sugars is thought to limit the photosynthesis by several works in many species (Hdider, Desjardins 1994;Van Huylenbroech, Debergh 1996;Tichá et al 1998;Rybczynski et al 2007;Yuanyuan et al 2009) according to Koch's theory (Koch 1996) on the inhibitory influence of sugars on photosynthesis. We detected that the presence of PGRs seems to improve the quality of leaves.…”

Photosynthetic performance of two maize genotypes as affected by chilling stress

“…Fluorescence parameters characterising either dark-adapted state or light-adapted state were calculated according to the following formulae: maximum quantum yield of PSII, ΦPSII = Fv/Fm = (Fm -Fo)/Fm; actual rate of photochemical reduction of RC PSII, Qr/Qt = (Fs -Fo)/(Fm' -Fo) and Stern-Volmer definition of non-photochemical quenching, NPQ = (Fm -Fm')/ Fm' according to Roháček (2002). For more details see, e.g., Tichá et al (1998).…”