| 摘要 |
Disclosed are bioagent compositions for plant care which can be used for treatment of plants and seeds. Such treatment serves to inhibit the activity of plant pathogens against the treated plants, stimulate natural plant immunity against such pathogens and provides plant growth biostimulation. The compositions comprise a chitosan polymer which can either be in the form of particles of microcrystalline chitosan which are in a composition of pH greater than 6.9, or in the form of a chitosan salt gel which are in a composition of pH of from 5.0 to 6.9. In either form, the chitosan polymer has specified molecular weight, polydispersity degree and degree of deacetylation characteristics. Preferably the chitosan polymer has a bimodal molecular weight distribution and contains a fraction of water-soluble oligoaminocarbohydrates. The characteristics of the chitosan polymer used in the compositions are obtained by the step-wise neutralization of, and chitosan preciptation from, acid solutions of chitosan under controlled conditions. |
