Photosynthetic activity of variegated leaves of Coleus × hybridus hort. cultivars characterised by chlorophyll fluorescence techniques

Abstract

Different pigments often occur together and affect photosynthetic characteristics of the respective leaf portions. In this study, photosynthetic activity in variegated leaves of five cultivars of the ornamental and medicinal plant, Coleus × hybridus hort., was estimated by image analysis and point data measurements of major chlorophyll (Chl) fluorescence parameters and related to the amount of photosynthetic pigments measured with a Chl meter or spectrophotometrically in leaf extracts. Significant differences in Chl and carotenoid (Car) contents were noticed among differentially pigmented sectors of a leaf and among the cultivars. Although the higher Chl concentration was noticed in purple parts compared to green parts of the leaves, the values of minimal and maximal fluorescence yield at the dark-and light-adapted state (F0, F m , F 0 ', F m ', respectively) were a little lower than those in the green sectors, indicating photoprotective effects provided by anthocyanins and Car, more abundant in the red parts. The lowest Chl and Car content was detected in creamy-yellow and pink sectors and this contributed to low F 0 , F m , and F m ', maximal quantum yield of PSII photochemistry, and nonphotochemical and photochemical quenching but high PSII maximum efficiency and effective quantum yield of PSII photochemistry. Both methods of Chl fluorescence analysis revealed heterogeneity in capture, transfer, and dissipation of excitation energy but Chl fluorescence imaging was more suitable in examining very narrow pigmented leaf areas.

Phenology, vegetative growth, and yield performance of fig in Southeastern Brazil

“…The variations in chlorophyll a/b ratio rise due to the differences between photosystems I and II (PSI / PSII), as well as to size and composition of the antenna complex of each photosystem that is responsible for light collection. These differences also can be attributed to growing and environmental conditions, as well as to the phenological stage (Cancellier et al, 2011;Borek et al, 2016). For Troyano, there was a reduction of the ratio of chlorophyll a/b, but that was not statistically different from 'Roxo de Valinhos' and PI-189.…”

Photosynthetic response of cabbage in cadmium-spiked soil

“…Iron substitutes magnesium and heme is produced instead of Chl (Zhou and Qiu 2005). Greenness index often inversely corresponds with F0, namely, higher greenness index and chemically assayed Chl content correlate with lower F0 values (Baker 2008, Borek et al 2016. The downward trend in SPAD readings for the late cultivar ceased over time, and the time course of changes in F0 was opposite to that of SPAD.…”

“…However, even distinct changes in Fv/Fm may be insufficient to accurately assess functioning of the photosynthetic apparatus. Therefore, it is necessary to take other values into account (Bączek-Kwinta et al 2011b, Borek et al 2016.…”

Chlorophyll biosynthesis and epidermal characteristics of the leaves of a variegated variety vs. all-green variety of Chlorophytum capense

“…According to the Chl fluorescence data, YS retained high Fv/Fm values, suggesting that high Car in YS might be responsible for harvesting light energy. Meanwhile, Borek et al (2016) showed that higher Car in purple parts of Coleus × hybridus hort. cultivars could provide photoprotective effects.…”

“…Similar results have been also observed in some other variegated leaves of Coleus × hybridus hort. cultivars, Hedera helix, Ardisia pusilla, and Scindapsus aureus (Khalekuzzaman et al 2015, Borek et al 2016. According to the Chl fluorescence data, YS retained high Fv/Fm values, suggesting that high Car in YS might be responsible for harvesting light energy.…”