Effect of brassinolide application on antioxidant characteristics and endogenous hormones of Leymus chinensis (Trin.) Tzvelev under different light intensity regimes

Abstract

Different light and shade intensities are the main constraints to achieve potential biomass accumulation in Leymus chinensis (Trin.) Tzvelev. An experiment was conducted to explain the physiochemical and morphological adversity triggered by various light intensities. Adverse impacts were lessened with exogenous brassinolide (BR). Treatments consisted of 100% natural light (T0), 100% natural light + 0.1 mg L-1 BR (BT0), light shade (70% natural light) (T1), light shade + BR (70% natural light + 0.1 mg L-1 BR) (BT1), moderate shade (50% natural light) (T2), and moderate shade + BR (50% natural light + 0.1 mg L-1 BR) (BT2). These were completely randomized design treatments with five replicates. Results showed that dry biomass production and endogenous hormone levels (abscisic acid [ABA], zeatin riboside [ZR], gibberellic acid [GA], and indole acetic acid [IAA]) increased, while osmolyte accumulation (soluble sugars and proteins, free amino acids, and proline), antioxidant activity (peroxidase [POD], superoxide dismutase [SOD], and catalase [CAT]), and lipid peroxidation decreased under shade at T0. Treatment T1 depicted the most promising results for these attributes. However, biomass accumulation (33%-56%), osmotic substances (soluble sugars,13%-38%; soluble proteins, 9%-41%; free amino acids, 8%-16%; proline, 11%-41%), and antioxidant enzyme activities (POD, 11%-14%; SOD, 3%-33%; CAT, 4%-23%) increased. On the other hand, lipid peroxidation was reduced by BR application, as indicated by decreased malondialdehyde (MDA) content (7%-31%) and relative conductivity (7%-19%) under both natural and shade conditions. Likewise, the biosynthesis of ABA (2%-22%), ZR (11%-24%), and GA (30%-50%) improved under exogenous BR compared with the control. The IAA contents (22%-28%) decreased under foliar-applied BR compared with the control. Results suggested that light to moderate shade improved the biomass production and physiological performance of L. chinensis, while BR application exhibited further improvement.

Light Deficiency Inhibits Growth by Affecting Photosynthesis Efficiency as well as JA and Ethylene Signaling in Endangered Plant Magnolia sinostellata

“…Given that low light intensity can impact stress tolerance in various plants, such as Calamus viminalis, Anoectochilus roxburghii, and Leymus chinensis [50][51][52], and light deficiency also weakened the resistance of M. sinostellata [53], stress response TFs were identified and analyzed in a genome wide range. TIFY and mitochondrial transcription termination factors (mTERFs) are related to stress response and have important roles in stress tolerance in plants [72,73].…”

“…JA interacts with ethylene signaling pathways to regulate abiotic stress tolerance and may act as a core signal in such an intertwined network [49]. Various studies found that light deficiency can alter stress tolerance and disease resistance in plants [50][51][52][53][54][55][56]. However, its molecular mechanisms in plants are complex and unclear.…”

Alteration in morpho-physiological attributes of Leymus chinensis (Trin.) Tzvelev by exogenous application of brassinolide under varying levels of drought stress

“…Under drought and other stress conditions, plants accumulate large amounts of various osmo-protectants such as glycine betaine, proline, soluble sugars, and free amino acids that ultimately maintained the tissue water status and protect the cellular organelles as well as organic molecules from ROS by acting as physical barrier (Farooq et al, 2009;Kumar et al, 2012;Zong et al, 2018). Increased accumulation of osmo-protectants under drought stress might have aggravated stress severity.…”

“…Leaf electrical conductance (EC) was measured by adopting Jin-huan et al (2015) method. Soluble sugars content was assayed by anthronecolorimetric method (Zong et al, 2018). The material was put into a centrifuge tube, where 80% ethanol was added.…”

“…Furthermore, plant growth regulators mediated accumulation of osmo-protectants help the plant to maintain the cellular water potential by depressing osmotic potential. Increased activities of antioxidant enzymes escalate the detoxification of ROS and therefore lessen the lipid peroxidation (Zong et al, 2018). Maintenance of permeability of biological membranes and water potential are of prime importance for plant cells to exhibit growth (Anjum et al, 2012), whereas higher water potential activates hydrolases and thus lessens apoplast for cell expansion under growth.…”