24-Epibrassinolide Improves Root Anatomy and Antioxidant Enzymes in Soybean Plants Subjected to Zinc Stress

Abstract

The aim of this research was to determine whether 24-epibrassinolide can mitigate oxidative stress in soybean plants subjected to different zinc levels; to examine this, we evaluated the possible repercussions on anatomical, nutritional, biochemical, physiological and morphological behaviours. The experiment followed a completely randomized factorial design with two concentrations of 24-epibrassinolide (0 and 100 nM EBR, described as-EBR and + EBR, respectively) and three zinc supplies (0.2, 20 and 2000 μM Zn, described as low, control and a high supply of Zn). In general, low and high zinc supplies produced deleterious effects. However, plants exposed to high zinc +100 nM EBR presented increases of 25%, 7%, 9% 29% and 69% for root epidermis, root endodermis, root cortex, vascular cylinder and metaxylem, respectively, when compared to the same treatment without the steroid. The steroid spray alleviated the impact produced by zinc stress on nutritional status, and these results were intrinsically linked to incremental changes in root structure, mainly vascular cylinder and metaxylem. Antioxidant enzymes play crucial roles in the photosynthetic machinery of plants treated with 24-epibrassinolide and stressed by high and low zinc supply, modulating reactive oxygen species scavenging and protecting the chloroplast membranes, with clear positive repercussions on photosystem II efficiency and photosynthetic pigments. The stimulation induced by this steroid on gas exchange can be explained by the favourable conditions detected in stomatal performance and leaf anatomy, thus enhancing the diffusion of carbon dioxide.

Foliar Application of Zn Phosphite and Zn EDTA in Soybean (Glycine max (L.) Merrill): In Vivo Investigations of Transport, Chemical Speciation, and Leaf Surface Changes

“…In order to overcome the limits of detection imposed by the in vivo XRF measurements, it was necessary to increase the dose to 23 g Zn L −1 . High concentrations of Zn may however negatively influence the uptake and transport of other nutrients such as K, P, Mg, Fe, Cu, and Mo (Santos et al 2020). In the present study, interference of Zn supply on the concentration of K, Ca, Mn, and Fe in plant petiolule was not observed, which suggests that even in higher concentrations, Zn was not interfering badly the metabolism of other nutrients.…”

Salinity Effects on Morpho-Physiological and Yield Traits of Soybean (Glycine max L.) as Mediated by Foliar Spray with Brassinolide

“…This consistent salt-induced decrease was a result of stomatal closure due to the direct effect of the stress on photosynthetic capacity, such as diffusion of carbon dioxide (CO 2 ) into the leaves [ 51 ]. Stomatal conductance was greatly improved when BL was applied at the BL 4 and BL 5 growth stages, suggesting that the BL enabled CO 2 diffusion to improve stomatal variables and leaf anatomy [ 52 , 53 ], thereby minimizing the negative effects of salinity.…”

Interactive Application of Zinc and Herbicides Affects Broad-leaved Weeds, Nutrient Uptake, and Yield in Rice

“…The effectiveness of foliar application of Zn in enhancing grain Zn concentration may be due to Zn mobility in phloem (Zhang et al 2010;Hussain et al 2012). Unlike, Santos et al (2020) reported that high concentrations of Zn may negatively influence the uptake and transport of other nutrients such as K, P, Mg, Fe, Cu, and Mo. Concerning the tolerance of crop to applied herbicides, sulfonylurea herbicides such as pyrazosoulfuron-ethyl, azimsulfuron, and halosulfuron-methyl are among the most widely used compounds for the control of broadleaf weeds and sedges in rice (Takeda et al 1986).…”