Efficiency of photosynthetic apparatus of sweet pepper (Capsicum annuum L.) F1 hybrids and their parental components in high temperature conditions

Valentina Petkova, Velichka Todorova, Nasya Tomlekova

Abstract: The effect of high temperatures on the condition and functional activity of photosynthetic apparatus (PSA) in 12 sweet pepper (Capsicum annuum L.) genotypes – four F1 hybrids and their parental forms, through the chlorophyll fluorescence parameters of photosystem II (PS II) and plastid pigments content in leaves was evaluated. The study was conducted in 2010 – 2011 under field conditions. Measurements have been performed during the reproductive period of the plants, in the morning hours of the day at 21 – 23 ºC (used as controls) and in the afternoon at high temperature (33 – 35 ºC). In the dark-adapted leaves, an increase of the initial (Fo) fluorescence and a decline of the maximum (Fm) and variable fluorescence (Fo), as well as the potential quantum efficiency of PS II (Fv/Fm) were observed in all genotypes at high temperature conditions.
In conclusion, it was considered that (I) photosynthetic apparatus of the F1 hybrids possesses higher level of tolerance to moderate high temperature stress compared to that of the parental genotypes; (II) genotypes with orange fruits are more sensitive to high temperature than those with red-coloured fruits.

Keywords: chlorophyll fluorescence; high temperature; pepper; photosynthetic apparatus; pigments; tolerance

Date published: 2017-07-26