Allelopathic Effects Of Compositae Plant Litters On Stipa Seeds In Loess Region

Litter is an important component in grassland ecosystem, which is the linkbetween plant and soil, playing a role in the process of energy flowing and nutrientcycling, has an impact on plants growth and community succession. Litteraccumulation and decomposition play an important role in controlling communitystructure and succession. Previous studies mainly focused on investigating litteraccumulation,decomposition rate and moisture dynamic, but the reports about effectof allelopathy which litter decomposed on seed germination and seedling growth isvery few.This research regarded the litter extract of three main species in NingxiaYunwushan nature reserve: Artemisia sacrorum Ledeb.,Artemisia annua L. and Artemisiagiraldii Pamp.. And the acceptor plants are Stipa bungeana, Stipa grandis, and Stipakrylovii Roshev.. Three plants litter were extracted by water and methanol. Theconcentration of litter is classified into4classes:0g/L,1g/L,10g/L and100g/L.Effects of different concentrations of litter extracts on seed germination and seedlinggrowth of Stipa bungeana, Stipa grandis, and Stipa krylovii Roshev. are studied bymeans of hydroponics. Index signs of allelopathy evaluation include: germinationrate,root length, seedling length, root weight and seedling weight.1. The allelopathy effects of litter extracts on Stipa krylovii Roshev. was thehighest sensitivity, and Artemisia giraldii Pamp. had the least allelopathic effect toStipa germination rate.2. Three litter extracts inhibited seedling length and root length, seedlingweight and root weight of three Stipa. The allelopathy of the extracts on seedling androot were not all the same at low concentration. As the concentration of extractsincreased, extracts inhibited to root is larger than to seedling.3. At low concentration, the allelopathic inhibitory effects of litter waterextracts were more effective compared with that of litter methanol extracts in fewtreatments. At high concentration, the allelopathic inhibitory effects of litter methanolextracts were more effective compared with that of litter water extracts in all thetreatments.4. The order of the allelopathic effects of three litter water extracts on Stipagrandis:1g/L, Artemisia annua L.> Artemisia sacrorum Ledeb.> Artemisiagiraldii Pamp.;10g/L and100g/L, Artemisia sacrorum Ledeb.> Artemisiaannua L.> Artemisia giraldii Pamp..The order of the allelopathic effects of three litter water extracts on Stipabungeana:1g/L and10g/L, Artemisia annua L.> Artemisia sacrorum Ledeb.>Artemisia giraldii Pamp.;100g/L, Artemisia sacrorum Ledeb.> Artemisia annuaL.> Artemisia giraldii Pamp.. The order of the allelopathic effects of three litter water extracts on Stipa kryloviiRoshev.:1g/L and10g/L, Artemisia sacrorum Ledeb.> Artemisia annua L.>Artemisia giraldii Pamp.;100g/L, Artemisia annua L.> Artemisia sacrorumLedeb.> Artemisia giraldii Pamp.