Salicylic acid on gas exchange and growth of Hymenaea courbaril L. seedlings under flooding

Abstract

Flooding is a stressful condition that causes damage to the photosynthetic apparatus, negatively affecting the growth of seedlings of fruit species, including Hymenaea courbaril L. Studies on physiological management, such as exogenous application of phytohormones, to alleviate abiotic stress have increased. The objective of this study was to evaluate the effect of foliar application of salicylic acid (SA) on H. courbaril seedlings subjected to flooding. The seedlings received foliar application of four concentrations of SA (0, 100, 200, and 400 mg L-1) and were subjected to two water regimes: a) control - non-flooded and irrigated daily and b) flooded - seedlings were placed in a plastic pool, keeping the water depth at ± 5.0 cm above the substrate level. After 35 days, we evaluated the gas exchange, initial growth, quality, and potential ecological resilience of the seedlings. All flooded seedlings survived, but had reduced photosynthesis, carboxylation of Rubisco efficiency, and water-use and stomatal conductance when they received 100-300 mg L-1 SA. The seedlings that received between 100 and 300 mg L-1 SA had greater growth, quality, and phenotypic plasticity. Foliar application of SA did not mitigated the effect of flooding on gas exchange but contributed to the growth of H. courbaril seedlings.

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

“…However, adaptive responses to flooding vary with the species. For example, Santos et al (2023) observed that Hymenaea courbaril L. seedlings did not have morphological adaptations and reduced gas exchange, but tolerated 30 days flooding.…”

“…A stability after 15 days of flooding indicates physiological plasticity of this species to short periods of stress through morphological adjustments such as the appearance of hypertrophied lenticels that favored metabolic adjustments. 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.…”

“…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).…”

“…mitigate the harmful effects of reactive oxygen species (ROS) (Silva et al, 2019b;Santos et al, 2023). Moreover, it delays the degradation of protein D 1 and the functional damage on photosystem II (PSII), promoting electron transfer stability in reaction centers (Hou et al, 2019;Poór et al, 2019;Santos et al, 2022a).…”

“…The seedlings were transplant with height 10 cm for plastic pots with a capacity of 2 kg filled (Figure 1c) with Dystrophic riparian forests or floodplains, are subject to water stress due to soil flooding from an increase in the water table depth because to climate change or anthropogenic actions (Rosa et al, 2015;Santos et al, 2023); this can cause stress for the species inserted in these localities. The reduction in O 2 concentration (anoxia) in the soil becomes limiting to photosynthetic metabolism and plant growth, especially because the plants under study present high metabolic demands (Gonçalves et al, 2013).…”