Evaluation of biological activity of new synthetic brassinolide analogs

Abstract

The responses of plants to exogenous treatment with new synthetic brassinosteroids (BRs) were assessed and compared with the activity of natural 24-epibrassinolide (24-EPI). Morphological experiments on plants of pea and flax showed that the boundary between stimulatory and inhibitory concentrations of individual BRs and 24-EPI used is very narrow and differs also with the plant species. Moreover brassinosteroids can exhibit effects similar to various other plant hormones. This was proven also in our experiments, where auxin, anti-auxin and cytokinin like effects were achieved by BRs application. One of the explanations of the different morphological effects could be the influence of brassinosteroid application on the level of endogenous hormones. There are changes in the levels of indole-3-acetic acid, 6-benzylaminopurine, trans-zeatin and dihydrozeatin in rape and wheat plants caused by BR 4 and 24-EPI application, but there is no general trend explaining unequivocally their influence. The fact that all tested BRs significantly increased the dry weight accumulation in comparison with non-treated reference rape plants can be accounted for the known BRs characteristics to avoid biotic stresses.

The effect of brassinosteroids on the morphology, development and yield of field-grown maize

“…On the other hand, Ö zdemir et al (2004) observed a slight decrease in the elongation of rice shoot after soaking of seeds in 3 9 10 -6 M 24-epibrassinolide solution, whereas the soaking of rice seeds in low concentrations of 28-homobrassinolide or 24-epibrassinolide promoted the growth of rice plants under low-temperature (Takematsu and Takeuchi 1989) or water stress conditions (Farooq et al 2009). Vlašánková et al (2009), who used the same type of BRs as those used in our study, also observed an inhibition of the epicotyl growth in pea and flax seedlings after soaking of seeds in BRs solutions ranging from 10 -7 to 10 -9 M concentrations. However, all these studies are somehow disadvantageous in the fact that they were usually made in strictly controlled environment conditions and that the plant height was measured in very young seedlings (7-to 35-days old), i.e.…”

“…The time of BRs application (in relation to the developmental stage of plant) has been shown to have an important effect on plant response to BRs treatment (Amzallag 2002;Khripach et al 2000;Núñez et al 2003;Ramraj et al 1997;Sasse 2003). The length of plant exposure to BRs, the frequency of application, the application mode and the type and dose of BRs can also substantially affect the growth/yield promoting activity of these compounds (Fariduddin et al 2003(Fariduddin et al , 2008Khripach et al 2003;Núñez et al 2003;Ramraj et al 1997;Sasse 2003;Vlašánková et al 2009). The degree of BRs influence on plants depends also on plant species and genotype (Ali et al 2008b;Hnilička et al 2007; Kang et al 2007;Khripach et al 2003;Núñez et al 2003;Ramraj et al 1997;Sairam 1994b;Shahbaz et al 2008;Torres-Ruiz et al 2007;Vardhini and Rao 2003;Vlašánková et al 2009;Zhao and Chen 2003).…”

The influence of pre-sowing seed treatment by biologically active compounds on soybean seed quality and yield

“…Substance No. 4154 (brassinosteroid), synthetic analogue of natural 24 -epibrassinolide ((2α,3α,17β-trihydroxy-5α-androstan-6-on, Vlašánková et al 2009), was used in the experiment.…”

Quality and Selected Metals Content of Spring Wheat (Triticum aestivum L.) Grain and Biomass After the Treatment with Brassinosteroids During Cultivation

“…Applied brassinosteroids (Fig. 1) Compounds KR1 -KR5 are synthetic permanently studied brassinolide analogues, which do not occur naturally in plants and will be published after finishing the synthesis of similar structures and protecting of these compounds by a patent (Vlašánková et al, 2009). In pot experiment plants were treated with three brassinosteroids (24-epibrassinolide, 24-epicasterone, and 4154) in two different growth stages in four parallel replicates in each brassinosteroid.…”