S.M. Turaeva2, R.P. Zakirova2, V.V. Nikalaichuk3, K.S. Hileuskaya3 1 V.F. Kuprevich Institute of Experimental Botany, National Academy of Sciences of Belarus, 27 Academicheskaya str., Minsk, 220072, Belarus 2 S.Yu. Yunusov Institute of the Chemistry of Plant Substances AS RUz 3 Institute of Chemistry of New Materials, National Academy of Sciences of Belarus, 36 F. Skoriny Minsk, 220141 Belarus Phenolic compounds play an important role in the regulation of seed germination, plant
growth and development, and sustainability plants. Hydroxylated and methylated
derivatives of cinnamic acid can have a significant effect on plant metabolism. Caffeic
acid is an early intermediate in phenylpropanoid metabolism and a precursor of
polyphenols and many secondary compounds regulated the protective responses plants.
The potential applied of hydroxycinnamic acids (HCA) is significantly limited by their
low solubility in aqueous solutions. Overcoming poor bioavailability of HCA can be the
creation of their conjugates with biopolymers, such as chitosan. Chitosan is a non-toxic,
biodegradable material and is extracted from natural raw materials. Chitosan has
biological activity (elicitory, antibacterial, fungicidal, etc.), therefore, the use of caffeic
acid in the form of a conjugate with it can provide multiple effects – protective properties
when coating seeds with a film (film-forming properties of the polymer), stimulation of
growth plants, fungistatic effect, induction of sustainability plants.
It has been established the chitosan-caffeic acid conjugate is unstable when stored in
liquid form. Its lyophilized form was obtained. Additives were used as a stabilizer and
filler of lyophilizate. Kaolin and sepiolite have been shown to stabilize chitosan-caffeic
acid conjugate more effectively than the organic cryoprotectant mannitol. Lyophilized
conjugates are easy to transport, store and restore to the active form before seed treatment,
which avoids the loss of chemical and biological activity during storage. The lyophilized
form of the chitosan-caffeic acid conjugate accelerated seed vigor under normal growing
conditions. There were no significant changes in the growth and development parameters
of seedlings in normal and unfavorable growing conditions (prolonged salt stress - 200
mM NaCl). At the same time, seedlings under normal growing conditions showed a
decrease of oxidative processes in the roots treated with chitosan-caffeic acid conjugate
and antioxidant activity in seedlings (total antioxidant activity, total phenolic compounds
content and proline content) relative to control seedlings of winter wheat.
Proline content was increase and intensity of oxidative processes declined in seedlings
from treated chitosan-caffeic acid conjugate seeds under the salt stress. This may indicate
the viability preservation of seedlings under longer-term stress conditions or its greater
intensity.
The research work was carried out within the framework of the BRFFR-SCST grant
B21UZBG-019.