Effect of foliar application of brassinolide on photosynthesis and chlorophyll fluorescence traits of Leymus chinensis under varying levels of shade

Abstract

The present study was conducted to determine the effect of exogenous application of brassinolide (BR) on Leymus chinensis grown under shade, i.e., control (100% natural light), mild shade (70% natural light), and moderate shade (50% natural light). Shade substantially enhanced the plant growth, synthesis of photosynthetic pigments, photosynthetic efficiency, and chlorophyll (Chl) fluorescence attributes of L. chinensis as compared with control. The order of increase was mild shade > moderate shade > natural light except Chl content, where the order of increase was moderate shade > mild shade > natural light. Likewise, application of BR resulted in further exacerbation of plant height, plant fresh and dry mass, but less in case of Chl and carotenoids contents, gas-exchange characteristics, and Chl fluorescence attributes. The results conclude that shade significantly enhanced plant growth through alterations in physiological attributes of L. chinensis, while, application of BR may not further improve the plant growth under shade.

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

“…Hu et al (2013) indicated that a combination of ABA and BR can enhance L. chinensis growth and the net photosynthetic rate. Yang et al (2018) point out that foliar application of BR increased photosynthesis of L. chinensis under different light intensity levels. Further antioxidant enzymes, namely, POD, SOD, and CAT were higher under excessive light conditions (100% natural light), decreased at 70% natural light, and were enhanced once again at 50% natural light; however, BR application on L. chinensis plants enhanced the antioxidant activity at each shade level (Table 7).…”

“…In this perspective, light shade enhanced biomass production, which was boosted by BR spraying ( Table 2). The increase in biomass production under shade and BR application might be due to improved photosynthetic activity due to better synthesis (Yang et al, 2018) and osmotic mediated adjustments to ng g -1 ng g -1 protect photosynthetic pigments (Chaves et al, 2008;Hayat et al, 2011). Similarly, Perrin and Mitchell (2013) reported that increased shade levels improved biomass production and growth of the European yew.…”

“…Leymus chinensis is highly adaptable to various environmental conditions and can survive under different abiotic stresses (Ma and Liang, 2007;Wang et al, 2008). However, the scarce availability of information regarding different light intensity mediated adversity (Yang et al, 2018) and associated perturbations in the L. chinensis metabolism needs extensive exploration. Moreover, adverse impacts of different light intensities might also influence biomass and other morphological traits and can thus decrease potential benefits to be had by growing L. chinensis (Chen et al, 2013).…”

“…Sensitivity to photoinhibition declines because of improved accumulation of osmotic substances and antioxidants (Niu et al, 2016). The BR could regulate the photosynthesis of L. chinensis at varying light intensities (Yang et al, 2018). Information regarding high light intensity mediated adversity in the metabolic process of L. chinensis is indispensable to improve tolerance.…”

Characterization of LcGAPC and its transcriptional response to salt and alkali stress in two ecotypes of Leymus chinensis (Trin.) Tzvelev

“…According to intraspecific differentiation of L. chinensis for eco-geographic regions, leaf color and genetic distance [3], L. chinensis could be classified into two ecotypes as gray-green type and yellow-green type [4]. Many studies have demonstrated physiological, ecological and genetic variability, including drought resistance, salt-alkali stress and photosynthesis in the two ecotypes [5][6][7][8]. Zhou et al [5,6] reported that the physiological characteristics of drought [5] and salt-alkali resistance [6] in the gray-green type were significantly increased compared with the yellow-green type.…”