GRAMINEAE PLANTS GROWTH STIMULATION BY SURFACE-ACTIVE RHAMNOLIPIDS
The effect of biogenic surfactants which were synthesized by the culture Pseudomonas sp. PS-17, particularly rhamnolipid biocomplex, on the growth of cereal plants — wheat and barley in the early stages of vegetation, as well as its effect on the activity of indole-3-acetic acid was studied. The effect of rhamnolipid biocomplex on the growth activity of winter wheat and spring barley was studied in vegetation (sand culture) and field experiments with pre-sowing treatment of seeds with rhamnolipid biocomplex solutions of different concentrations. To investigate the action of surface-active rhamnolipid biocomplex on the extension growth of plant cells the specific biotest on sections of wheat coleoptiles was used. The stimulating effect of rhamnolipid biocomplex on the growth of cereal plants, as well as the optimal concentration for its use in pre-sowing treatment of seeds was established: for winter wheat — 10 mg/l, for spring barley — 50 mg/l ( Р ≤ 0,05). The application of rhamnolipid biocomplex contributed to the increase of aboveground dry weight of wheat on 16%, of barley — on 18% compared to the control ( Р ≤ 0,05). Rhamnolipid biocomplex effectiveness was also confirmed in the field experiment — after the treatment of spring barley seeds the vegetative mass was averagely 34% ( Р ≤ 0,05) higher than in the control. The obtained results indicate the prospects of practical use of rhamnolipid surfactants as environmentally friendly growth stimulants for cereal plants for modern technologies in agriculture. They can be effective in creating complex preparations with indole-3-acetic acid and, possibly also with other phytohormones, that will allow the enhancement of their activity.