Study Of Allelopathic Effect Of Achnatherum Inebrians On Seed Germination Of Several Plants

Studying the allelopathy of plant was one of the main areas of activity in chemical ecology. Achnatherum inebrians was a perennial herb of gramineae Achnatherum, and a poisonous weed mainly in northern of China, and threatened the safety of ecology and production in natural grassland. This study revealed the law of Achnatherum inebrians’ allelopathy from the effects of its aqueous extracts of strains and rhizosphere soil on seed germination of 6 species of plants, and provided a theoretical basis for the prevention and control of Achnatherum inebrians. The main results were as follows:1. After the 6 species of plant seed were treated by the aqueous extracts of different concentration of Achnatherum inebrians, mostly showed that the low concentrations could promote and the higher concentrations could inhibit, and the more higher concentrations had more obvious inhibition on seed germination of receptor plants; The inhibiting strengths of aqueous extracts in different parts were “leaves>stem>roots”; The effects of aqueous extracts on the germination of plant seeds had some differences among species, indexes, and the integrate allelopathy showed a inhibition on overall.2. The effects of aqueous extracts of Achnatherum inebrians in different periods, parts and layers of soil on sowing forages showed a inhibition on overall.The extents of inhibition of strains’ aqueous extracts were “Bromus inermis > Medicago sativa > Onobrychis viciaefolia”, and the limited extent of periods of seed germination were “flowering > regreening period > ripening stage” and indexes of seed germination “germination index> germination rate > germination potential”; The limited degree of aqueous extracts of soil was “Medicago sativa > Bromus inermis > Onobrychis viciaefolia” and periods of seed germination was “spring soil >autumn soil > bare soil”; Overall, the aqueous extracts of soil was promoting for germination index and potential, while had the effects of inhibition on germination rate, The limited degree showed “germination rate > germination index > germination potential”; Aqueous extracts of had the effects of promoting in soil layers of 0-15 cm, while had the effects of inhibition in soil layers of 15-20 cm and sensitivity was “15-20 cm>10-15 cm>5-10 cm>0-5 cm” from strong effects to weak in order; The limits of tolerance in Onobrychis viciaefolia was higher than Bromus inermis, Medicago sativa for the aqueous extracts of plant and rhizosphere soils of Achnatherum inebrians; Thus, as well tolerated as Onobrychis viciaefolia should be considered firstly when the degraded grassland of Achnatherum inebrians was restored.3. The effects of aqueous extracts of Achnatherum inebrians in different periods, parts and layers of soil on accompanying species showed a inhibition overall. The aqueous extract’s extent of inhibition of plant was “Seriphidium transiliense > Stipa capillata” and periods of seed germination was “ripening period >regreening period> flowering” and seed germination was “germination potential > germination index > germination rate”; The limited degree for the aqueous extracts of soil was “Seriphidium transiliense > Stipa capillata” and period of seed germination was “autumn soil >bare soil > spring soil”, and the degrees of average sensitivity on germination rate and potential showed effects of promoting, while germination index showed effects of inhibition, and seed germination was “germination index> germination potential>germination rate”, and different layers of soil was “0-5 cm>10-15 cm>5-10 cm>15-20 cm”; Thus, aqueous extracts of plants and soils of Achnatherum inebrians affected the seed germination and seedling growth of companion species in a certain extent, which was one of the reasons that could cause its degradation from the community.4. The degrees of sensitivity of autotoxinic allelopathy was different in different periods, parts and soil of Achnatherum inebrians. The limited degree of seed germination period was “regreening period>flowering>ripening period” and seed germination was “germination potential > germination index >germination rate”; The limited degree of seed germination period from the aqueous extracts of soil was “autumn soil > spring soil > bare soil” and seeds germination was “germination index > germination rate>germination potential”, and the inhibition of different soil was “0-5 cm>5-10 cm>10-15 cm>15-20 cm”. Effects of Achnatherum inebrians on itself was lower; Although the overall performance was a inhibition, it had not effects on many indicators or promoted in the low concentration, which was probably the important factors that Achnatherum inebrians spread rapidly and became the dominant species in the community.