TITLE:
Effect of Photon Flux Density and Exogenous Sucrose on the Photosynthetic Performance during In Vitro Culture of Castanea sativa
AUTHORS:
Patricia L. Sáez, León A. Bravo, Manuel Sánchez-Olate, Paulina B. Bravo, Darcy G. Ríos
KEYWORDS:
Sucrose, PFD, Micropropagation, Photosynthesis, Chlorophyll Fluorescence
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.14,
October
27,
2016
ABSTRACT: The low photon flux density (PFD) under in vitro conditions and sucrose added to the culture medium negatively limits the photochemical
activity and photoprotective mechanisms of microshoots. In this work we hypothesize
that decreasing sucrose in the culture medium in combination with increasing irradiance,
could improve the photosynthesis and consequently the in vitro growth. We evaluated
the effect of exogenous sucrose (30 and 5 g·L-1, HS and LS,
respectively), under different PFD (50 and 150 μmol photons m-2·s-1,
LL and HL, respectively) on the photosynthetic performance and growth of Castanea sativa microshoots. Decreasing sucrose negatively affected the physiological
attributes evaluated. Only chloroplast ultrastructure was improved by LS; however
this did not lead to an improved in photosynthesis or growth. HL HS produced an
increase in photosynthetic activity and chlorophyll contents, reaching under these
conditions a higher proliferation rate and biomass production. Additionally, the
photochemical activity (electron transport rate and non-photochemical quenching)
was improved by HL. Thus, our results suggest that, at least for C. sativa HL is beneficial during the in vitro culture, improving photosynthetic performance
as well as growth, but this is only possible in the presence of moderate concentrations
of sucrose added to the culture medium.