HYDROGEL AND WATER REGIMES IN THE CHLOROPHYLL- A FLUORESCENCE AND GROWTH OF Campomanesia xanthocarpa SEEDLINGS

Abstract

Water availability is one of the most important factors for the growth of tree seedlings in forestry-related regions. We hypothesized that under different water regimes, a waterretaining polymer (hydrogel) can positively contribute to chlorophyll-a fluorescence and growth in Campomanesia xanthocarpa (Mart.) O. Berg. Four water retention capacities (WRC) were evaluated: 25%, 50%, 75%, and 100%, depending on the presence or absence of hydrogel at the substrate. The lowest WRCs, particularly those under 25% without hydrogel, reduced chlorophyll index and negatively affected the photochemical activities of photosystem II. However, under low water availability the hydrogel mitigated the damage inflicted on the reaction centers and chlorophyll synthesis. The greatest growth effects occurred at 100% WRC in the presence of the hydrogel. Physiological indices were higher under 100% WRC without hydrogel and 50% with hydrogel. The increase in biomass and Dickson quality were more pronounced in the seedlings produced under 50% WRC and hydrogel, and the addition of these parameters to the substrate contributed to more viable morphophysiological indicators for the production of C. xanthocarpa seedlings.

Salicylic acid alleviates the water stress on photochemical apparatus and quality of Schinus terebinthifolia seedlings

“…In case of water deficit, similar findings of decreased chlorophyll content under lower water availability have been reported in seedlings of several tree species (Santos et al, 2021;Zuazo et al, 2021). SA application, Ribeiro et al (2020) observed increase in chlorophyll content with exogenous application of SA, which favored higher photochemical yields, results similar to those observed in this study with S. terebinthifolia.…”

“…Since these pigments are responsible for light interception and electron transfer excitation processes, their degradation decreased the photochemical activity of PSII (F v /F m ). The decreased PSII activity leads to increased excitation energy, resulting in excessive energy, ROS production, and lipid peroxidation (Santos et al, 2021;Zhao et al, 2021), thus inhibiting NADPH oxidation and electron transfer to the reaction centers (Xiong et al, 2021).…”

“…Overall, prolonged exposure of the seedlings to water deficit, characterized by 12 DWR, compromised the photochemical activities in PSII. When plants are subjected to water restriction conditions, energy loss occurs because the absorbed light energy is dissipated rather than used in photochemical reactions (Lawlor & Tereza, 2009;Santos et al, 2021).…”

“…In the context of the global climate change, water deficit stress is a major problem, as it adversely affects plant productivity and silvicultural activities. Under stress conditions, the intercellular CO 2 concentration in the substomatal chamber increases (Beltramin et al, 2020;Zandi & Schung, 2022), causing oxidative damage to chloroplasts and reducing photosynthetic pigment synthesis, thereby impairing the activities of photosystem II (PSII) and plant growth (Santos et al, 2021;Xia et al, 2022).…”

Does silicon help to alleviate water deficit stress and in the recovery of Dipteryx alata seedlings?

“…The same responses for LA were observed in seedlings of Schinus terebinthifolia Raddi (Beltramin et al, 2020), Cedrela odorata L. (Silva et al, 2021), and Campomanesia xanthocarpa O. Berg. (Santos et al, 2021), where these species had reduction in LA under low water availability.…”