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

Abstract

In the present work, the effects of 24-epibrassinolide (EBR) on the UV-Binduced changes in the pigment content of pea leaves were studied. Control (non-EBR-treated) and EBR-treated plants were irradiated with UV-B for 3 h and pigment analysis was performed after 24 and 48 h. The results show that EBR spraying of plants 48 h prior to UV-B exposure alleviates its detrimental effect on chlorophyll a and b (Chl a and Chl b) content in comparison with control pea leaves. An increase in carotenoids (Car) and UV-B absorbing compounds was also observed at low dose of UV-B radiation. For the first time, it is shown that UV-B damage effect on control leaves is accompanied by a significant (more than 50%) increase in their pheophytin a (Pheo a) content 48 h after the UV-B exposure and that the EBR pre-treatment prevents the increase of Pheo a content in UV-B irradiated leaves. In addition, it is demonstrated that EBR application modifies UV-B-induced alterations of energy distribution between the main pigment-protein complexes in pea thylakoid membranes.

Effect of exogenously applied 20-hydroxyecdysone on the efficiency of primary photosynthetic processes substantially differs across plant species

“…Only a few plant species (Arabidopsis, pea, barley, rape) have been yet examined in more detail regarding the effect of plant sterols on the individual components of the PETC and only BRs have been assessed in this respect. The experimental evidence available thus far for BRs seems to suggest that the PSI complex should be more sensitive to the imbalances in BR content than PSII (Krumova et al 2011(Krumova et al , 2013Dobrikova et al 2013Dobrikova et al , 2014. Besides our previous study (Rothová et al 2014), we now found that PSI-associated parts of the PETC were affected by 20HE also in pea, canola, and wheat.…”