Allelopathic effects of exogenous phenolic acids composted by wheat straw on seed germination and seedling growth of rice
This experiment aimed to investigate allelopathic effects of phenolic acids composted by wheat straw at different concentrations on seed germination and seedling growth of rice by means of plate culture and sand culture.The results showed that the seed germination indexes in all phenolic acids treatments were promoted at lower acid concentrations and were inhibited at higher concentrations.Most of the phenolic acids played a promotive role at lower concentrations and an inhibitory role at higher concentrations in biomass accumulation,chlorophyll contents and root activity of rice as well.However on malondialdehyde content of rice,the phenolic acids presented opposite effect.The allelopathic effect of phenolic acid solution on rice was related to the kinds and concentrations of phenolic acid,and its threshold depended on the kinds.
Flexible wing surfaces can be observed in many natural flyers and their use in small engineered flying vehicles has translated too many beneficial properties. These benefits have manifested themselves in the aerodynamic forces as well as flight stability which are an effect of how the flow and the membranes interact both statically and dynamically. In this work, time dependent particle image velocimetry and digital image correlation are used to study the fluid structure interaction for flow over a membrane wing. The wings examined here are multi-cell silicon rubber membrane wings which have a scalloped free trailing edge with different levels of pretension. The pretension effects the natural frequencies of the membranes and is shown to affect the extension magnitude and membrane motion frequency which are both also affected by aerodynamic loading. Examinations of the membranes through time based and frequency domain analysis motions shows they are highly correlated with the flow. The velocity measurements...