The role of silicon in the mitigation of water stress in Eugenia myrcianthes Nied. seedlings

Abstract

Silicon (Si) is a beneficial element that can mitigate effects of water stress on photosynthetic metabolism and plant growth. Thus, the aimed was to evaluate the effect of Si in mitigating the stressful effect of water deficit and flooding in Eugenia myrcianthes Nied. seedlings. The seedlings received three silicon doses (0, 2, and 4 mmol) and were subjected to two water regimes (I – continuous irrigation and S – water fluctuation, characterized as water stress obtained by two cycles of water regimes: irrigation suspension and flooding). Each cycle was ended when the seedlings had a photosynthetic rate close to zero (P0) when the stressful irrigation condition was normalized until the photosynthetic rate reached the values of the control seedlings (REC). The evaluations were carried out in five periods: T0 – initial seedling condition; 1st and 2nd P0; and 1st and 2nd REC. The E. myrcianthes seedlings reached P0 at 22 and 50 days under water deficit and flooding, respectively. Water stress caused damage to photochemical activities in photosystem II. E. myrcianthes is a species sensitive to water stress, but capable of adjusting to water fluctuation, and the application of 2 mmol Si contributed to the regulation of gas exchange, photochemical yields, and growth of this species at the deficit and flooding phases. We emphasize that E. myrcianthes seedlings have potential for resilience due to physiological plasticity, regardless of the silicon application.

Does silicon and salicylic acid contribute in the morphophysiology of Schinus terebinthifolia seedlings under flooding?

“…However, as the plant is exposed to stress, metabolic processes decrease or destabilize (Santos et al, 2023). The reduction in A can be attributed both to stomatal closure and to the decline in the photochemical phase of photosynthesis, increasing C i (Rosa et al, 2018;Santos et al, 2022bSantos et al, , 2023. With an increased exposure to flooding, ROS production can occur due to the activity of the alcohol dehydrogenase enzyme, largely increasing the activity of fermentative enzymes, obtaining of energy in this condition occurs mainly through alcoholic fermentation (Borella et al, 2019), reducing the photosynthetic capacity of plants.…”

“…Although we did not evaluate in this study, foliar application of Si possibly favored the activity of antioxidant enzymes that repair cell damage by detoxification of ROS, increasing the functionality of the chloroplast ultrastructure and the synthesis of photosynthetic pigments (Etesami and Jeong, 2018), therefore stabilizing metabolic processes. According to Santos et al (2022b) foliar application of Si mitigated the effect of flooding about photosynthetic metabolism in Eugenia myrcianthes Nied. seedlings.…”

“…In the literature, 2 mmol of Si alleviated effect of water stress in Eugenia myrcianthes Nied. seedlings (Santos et al, 2022b) and application of SA stimulated the growth of Hymenaea courbaril L. under flooding (Santos et al, 2023).…”

“…The use of Si, generally in the form of silicate, attenuates the effects of water stress in plants by increasing water use efficiency and improving metabolic pathways (Etesami and Jeong, 2018;Silva et al, 2019a;Santos et al, 2022b). In the plant, Si acts by providing greater tissue rigidity (Lima et al, 2019), increasing nutritional and photosynthetic efficiency and stomatal regulation due to hormonal signals (Santos et al, 2022b).…”

“…The use of Si, generally in the form of silicate, attenuates the effects of water stress in plants by increasing water use efficiency and improving metabolic pathways (Etesami and Jeong, 2018;Silva et al, 2019a;Santos et al, 2022b). In the plant, Si acts by providing greater tissue rigidity (Lima et al, 2019), increasing nutritional and photosynthetic efficiency and stomatal regulation due to hormonal signals (Santos et al, 2022b). Furthermore, this element correlates with phytohormone signaling, gene expression, and other benefits to the antioxidant system of plants (Manivannan and Ahn, 2017;Neves et al, 2019), as a protective mechanism against to stressed conditions.…”