Physiological effects and transport of 24-epibrassinolide in heat-stressed barley

Abstract

This paper presents a study of the metabolic response (dark respiration intensity, photosystem II efficiency, metabolic activity) and the yield of barley treated with 24-epibrassinolide and subjected to high-temperature stress. Transport of exogenously applied 24-epibrassinolide in barley and changes in the profile of brassinosteroids that may occur in tissues after 24-epibrassinolide application were also studied. The water solution of 24-epibrassinolide (0.005 and 0.25 mg dm -3 ) was applied via infiltration of the first and second leaves of 12-day-old seedlings. Control plants were treated with water solution of hormone solvent (ethanol). Fifteen-day-old plants were subjected to hightemperature stress (42°C for 3 h). The influence of hormone treatment and stress conditions was investigated in the first and second leaves based on measurements of PSII efficiency. The aftereffect of plant treatment was investigated in the seventh leaf (measurements of PS II efficiency, dark respiration intensity, metabolic activity). The transport efficiency of 24-epibrassinolide exogenously applied to the first and second leaves, as well as the profile of other brassinosteroids, was also measured on the seventh leaf. Finally, yield formation was estimated. 24-epibrassinolide showed protective action, which manifested itself in the improved functioning of PSII, but this was observed in case of higher hormone concentration and only for the first, older leaf. The PSII efficiency of the seventh leaf was similar in plants treated with brassinosteroid and in the control plants, whereas the respiration intensity and metabolic activity decreased in plants previously treated with higher concentration of 24-epibrassinolide. The use of a higher hormone concentration at the seedling phase ultimately resulted also in lower crop yield. Brassinosteroids-brassinolide and castasterone-were detected in barley leaves. 24-epibrassinolide was found only in trace amounts in control plants. Its exogenous application directly to the apoplast of the first and second leaves resulted in an increase in the 24-epibrassinolide content in the seventh leaf, but did not depend on whether a high or low concentration had been applied to the plants.

Brassinosteroids increase winter survival of winter rye (Secale cereale L.) by affecting photosynthetic capacity and carbohydrate metabolism during the cold acclimation process

“…Brassinosteroids are steroidal plant growth promoting regulators, which control complex metabolic pathways in the plants development and vegetative growth (Fridman and SavaldiGoldstain 2013;Holá et al 2010). Brassinosteroids are also very important in the plant's protection against heat stresses, oxidative stress, drought and salinity (Bajguz and Hayat 2009;Janeczko et al 2011;Fahad et al 2015) and may be involved in increasing resistance to biotic stresses by inducing the systemic resistance process (Nakashita et al 2003). At high temperatures, brassinosteroids also affect the plant's carbohydrate metabolism and photosynthesis.…”

Effects of 24-epibrassinolide Pre-treatment on UV-B-Induced Changes in the Pigment Content of Pea Leaves

“…It has been shown that the EBR application exerts a direct role in the regulation of plant photosynthesis [ 2 ]. Several studies have also reported the role of EBR in the protection of photosynthetic apparatus against environmental stresses by enhancing plant tolerance to abiotic stresses [ 1,[3][4][5] ]. Brassinosteroid-enhanced stress tolerance was proposed to relate to increased activity of the reactive oxygen species scavenging system -antioxidant enzymes (via accumulation of abscisic acid) and with increased content of ascorbic acid and carotenoids [ 1,3,5 ].…”

Occurrence of brassinosteroids and influence of 24-epibrassinolide with brassinazole on their content in the leaves and roots of Hordeum vulgare L. cv. Golden Promise

“…In plants of the Poaceae family, BRs have been found so far in rice (Oryza sativa) (Abe et al 1984(Abe et al , 1995Park et al 1994;Suzuki et al 1995;Wu et al 2008;Asahina et al 2014), maize (Zea mays) (Gamoh et al 1990;Suzuki et al 1986;Kim et al 2005), wheat (Triticum aestivum) (Yokota et al 1994;Janeczko and Swaczynova 2010), rye (Secale cereale) (Schmidt et al 1995;Antonchick et al 2003Antonchick et al , 2005, barley (Janeczko et al 2011;Dockter et al 2014) as well as in canary grass (Phalaris canariensis) (Shimada et al 1996) and perennial ryegrass (Lolium perenne) (Taylor et al 1993).…”

“…BL, CS in cv. Sezam (Janeczko et al 2011); CS, EBL and 28-homocastasterone (HCS) in cv. Bowman (Dockter et al 2014;Gruszka et al 2016a); CS in cv.…”