Tag Archives: brassinosteroids

Photosystems functioning, the content of chemical elements, flavonoids and brassinosteroids in leaves of chimera Cornus controversa

16.10.2024   Uncategorized   No comments

A. F. Likhanov1, V. V. Schwartau2, N. V. Zaimenko3, N. P. Didyk3*,
O. V. Grygorieva3, I. P. Kharytonova3, O. I. Dziuba3,
O. V. Zakrasov3, M. Yu. Zhurba3, N. A. Pavliuchenko3

1National University of Life and Environmental Sciences of Ukraine, Kyiv;
2Institute of Plant Physiology and Genetics, National Academy of Sciences of Ukraine, Kyiv;
3M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: nataliya_didyk@ukr.net

Received: 28 May 2024; Revised: 06 July 2024;
Accepted: 07 October 2024; Available on-line:28 October 2024

The formation of chimera is a well-known phenomenon in variegated ornamental and wild plants, but the biochemical peculiarities of this phenomenon are not well studied. The purpose of this work was to conduct a comparative study of the photosynthetic apparatus functioning, the content of macro-, microelements, flavonoids and brassinosteroids in the variegated and green leaves of the periclinal chimera Cornus controversa plant grown in the collection of M. M. Gryshko National Botanical Garden of the NAS of Ukraine. Sampling was made during the period from June to October 2022. The content of photosynthetic pigments and brassinosteroids was measured spectrophotometrically, autofluorescence of leaf tissues was studied using an inverted microscope with a multi-channel fluorescence imaging system, Normalized difference vegetation index (NDVI) – using GreenSeeker devices and fluorimeter, the level of macro- and microelements – using plasma emission spectrometer. Phenolic secondary metabolites were separated by HPTLC. To assess the protective capacity of flavonoids, a bioassay on the germination of radish seeds Raphanus in the presence of AlCl3 was used. It was shown that green leaves of C. controversa chimera, compared to variegated ones, had a twice as high NDVI index, maintained photosynthetic function longer in autumn, and had higher content of macronutrients (Mg, Ca and S) but lower concentration of toxic metals (Al, Cu, Fe, Zn, Ti). Instead, variegated leaves accumulated more brassinosteroids and phenolic metabolites, which were found not only to reduce the toxic effect of aluminum but also to have a growth-stimulating effect on the roots of radish seedlings. Such specialization of green and variegated leaves may contribute to better plant chimeras adaptation to environmental pollution.

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Role of Ca ions in the induction of heat-resistance of wheat coleoptiles by brassinosteroids

21.05.2015   Uncategorized   No comments

Yu. E. Kolupaev1, A. A. Vayner1, T. O. Yastreb1, A. I. Oboznyi1, V. A. Khripach2

1V. V. Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@mail.ru;
2Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus;
e-mail: khripach@iboch.bas-net.by

The involvement of Ca2+ into the signal transduction of exogenous brassinosteroids (BS) (24-epibrassinolide – 24-EBL and 24-epicastasterone – 24 ECS) causing the increase of heat resistance of the cells of wheat (Triticum aestivum L.) coleoptiles was investigated using calcium chelator EGTA and inhibitor of phosphatidylinositol-specific phospholipase C – neomycin. Twenty-four-hour treatment of coleoptile segments with 10 nM solutions of 24-EBL and 24-ECS led to a transient increase in the generation of superoxide anion radical by cell surface and the subsequent activation of superoxide dismutase and catalase. Pretreatment of coleoptiles with EGTA and neomycin depressed to a considerable extent these effects and leveled the increase in heat resistance of wheat coleoptiles that were caused by BS. Possible mechanisms of involvement of calcium signaling into the formation of reactive oxygen species in plant cells and induction of heat resistance of plant cells by the action of exogenous BS have been discussed.

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