Effects of Salinity Stress on Chloroplast Structure and Function

Abstract

Salinity is a growing problem affecting soils and agriculture in many parts of the world. The presence of salt in plant cells disrupts many basic metabolic processes, contributing to severe negative effects on plant development and growth. This review focuses on the effects of salinity on chloroplasts, including the structures and function of these organelles. Chloroplasts house various important biochemical reactions, including photosynthesis, most of which are considered essential for plant survival. Salinity can affect these reactions in a number of ways, for example, by changing the chloroplast size, number, lamellar organization, lipid and starch accumulation, and interfering with cross-membrane transportation. Research has shown that maintenance of the normal chloroplast physiology is necessary for the survival of the entire plant. Many plant species have evolved different mechanisms to withstand the harmful effects of salt-induced toxicity on their chloroplasts and its machinery. The differences depend on the plant species and growth stage and can be quite different between salt-sensitive (glycophyte) and salt-tolerant (halophyte) plants. Salt stress tolerance is a complex trait, and many aspects of salt tolerance in plants are not entirely clear yet. In this review, we discuss the different mechanisms of salt stress tolerance in plants with a special focus on chloroplast structure and its functions, including the underlying differences between glycophytes and halophytes.

Foliar Application of Potassium Mitigates Salinity Stress Conditions in Spinach (Spinacia oleracea L.) through Reducing NaCl Toxicity and Enhancing the Activity of Antioxidant Enzymes

“…In an investigation, it was found that both ionic and osmotic elements were responsible for K + efflux [12]. The K + equilibrium is upset via reduced influx, elevated efflux, and declined cytosolic K + collections under high Na + concentrations [55]. The results of Chow et al [59] also supported the present results.…”

“…In glycophytic plants, a declined K + : Na + proportion is the utmost frequently detected concern of Na + -stress. The major reason for decline of K concentration in cells may be due to the reason that Na + hinders K + influx into the cell [55,56]. Yet, Na + leading to the stimulation of K + efflux may be another potential cause.…”

Comparative Analysis and Phylogenetic Relationships of Ceriops Species (Rhizophoraceae) and Avicennia lanata (Acanthaceae): Insight into the Chloroplast Genome Evolution between Middle and Seaward Zones of Mangrove Forests

“…This finding suggests that the size of mangrove chloroplast genomes in the seaward zone may be compact compared with mangrove species in the middle zone, which is caused by adaptation under coastal stress conditions, especially salt stress. Salinity can affect plants in several ways, such as by changing the chloroplast size, number, lamellar organization, and lipid and starch accumulation and interfering with cross-membrane transportation [71].…”

Influence of silver nitrate and copper sulphate on somatic embryogenesis, shoot morphogenesis, multiplication and associated physiological biochemical changes in Gladiolus hybridus L.

“…3F-G). Exposure to high concentration of the metals may inhibit electron transport chain by blocking photosynthetic electron transport in PS II oxidizing or reducing sites of the photosystem, which may result in ROS generation and oxidative stress to plants (Fernandes and Henrique 1991;Dudev and Lim 2008;Huang et al 2020;Pontes et al 2020) with overall effect on plant physiological parameters associated with photosynthetic quantum and other adjustment responses in metabolic processes (Souza et al 2019;Hameed et al 2021). In the present study, Chla content of the shoot cultures was highest in 7.5 µM treatment with CuSO 4 .5H 2 O where 0.1981 ± 0.12 mg g −1 FW were accumulated over the control and other concentrations tested.…”

“…3F 4 ). This suggests that supplementing Cu in the culture medium at moderate levels enhanced leaves Chl content, while higher inhibited its biosynthesis due to possible effect on photosynthetic machinery of thyllakoids where it forms an integral functional unit of PS II (Hameed et al 2021). Maximum shoot morphogenesis, elongation, leaves expansion and Chl content was achieved with shoot tip explants of Musa acuminata when cultivated on medium supplemented with AgNO 3 (up to 10 mg L −1 ) over control cultures and other ethylene inhibitors tested (Tamimi 2015).…”