The Effects of Cold Stress on Photosynthesis in Hibiscus Plants

Abstract

The present work studies the effects of cold on photosynthesis, as well as the involvement in the chilling stress of chlororespiratory enzymes and ferredoxin-mediated cyclic electron flow, in illuminated plants of Hibiscus rosa-sinensis. Plants were sensitive to cold stress, as indicated by a reduction in the photochemistry efficiency of PSII and in the capacity for electron transport. However, the susceptibility of leaves to cold may be modified by root temperature. When the stem, but not roots, was chilled, the quantum yield of PSII and the relative electron transport rates were much lower than when the whole plant, root and stem, was chilled at 10°C. Additionally, when the whole plant was cooled, both the activity of electron donation by NADPH and ferredoxin to plastoquinone and the amount of PGR5 polypeptide, an essential component of the cyclic electron flow around PSI, increased, suggesting that in these conditions cyclic electron flow helps protect photosystems. However, when the stem, but not the root, was cooled cyclic electron flow did not increase and PSII was damaged as a result of insufficient dissipation of the excess light energy. In contrast, the chlororespiratory enzymes (NDH complex and PTOX) remained similar to control when the whole plant was cooled, but increased when only the stem was cooled, suggesting the involvement of chlororespiration in the response to chilling stress when other pathways, such as cyclic electron flow around PSI, are insufficient to protect PSII.

The ameliorating effects of polyamine supplement on physiological and biochemical parameters of Stevia rebaudiana Bertoni under cold stress

“…Free radicals such as ROS are responsible for all of these damages. Under cold condition, PSII and photosynthetic linear electron transport inhibit and tend to a reduction in F V /F m value (Paredes & Quiles, 2015). Our investigation indicated that polyamines moderated F V /F m reduction in cold-treated plants .…”

Changes in Proteome and Protein Phosphorylation Reveal the Protective Roles of Exogenous Nitrogen in Alleviating Cadmium Toxicity in Poplar Plants

“…The data revealed that the expression of PGR5 was markedly up-regulated by the interaction of Cd + N. Previous studies have shown that PGR5 is closely related to the cyclic electron flow in PS I [48]. Paredes and Quiles [49] revealed that when Hibiscus plants are subjected to cold stress, the amount of PGR5 polypeptide increases, suggesting that under abiotic stress, up-expressed PGR5 could protect photosystems and enhance the resistance of plants to environmental stress. Therefore, the PGR5 protein (A0A2K2BVX5) was screened out as a candidate protein for further research.…”

In silico metabolic network analysis of Arabidopsis leaves

“…It is hypothesized that the observed flexibility might allow the modulation of the ATP: NADPH ratio to match the demand of metabolism under changing environmental conditions [66, 67], as non-cyclic electron flow allows for simultaneous NADPH and ATP synthesis, whereas cyclic electron flow solely generates ATP. It is prevalent in the literature that under environmental stress, such as cold, light or osmotic stress, certain metabolic changes arise, that modulate the cellular ATP: NADPH demand [91, 92]. In this regard, it has been acknowledged, that this modulation requires fine-tuned regulation of the contribution of cyclic electron flow to photosynthesis [93].…”