EFFECT OF SEVERAL PLANT SECONDARY CHEMICALS ON THE TRICHOGRAMMA OSTRANIA PANG ET CHEN
R esearch achievements and progress are summarized including categories of plant secondary chemicals,their extraction methods,features of their defense against pests(e.g.an tifeedant,growth inhibiting and poisoning effects)and their a pplications in botanical insecticides.
and the retained β-phase decomposes to cause the precipitation of secondary a-phase and the growth of original secondary a-phase, and the existence of type 1 and 2 of the secondary a-phase is confirmed.
The additinal stabilizing heat treatment was employed in order to remove the interference which there still exist precipitation of secondary phase that cause volume of the piston unstable during the piston working. The thermal expansion coefficient of eutectic Al-Si alloy piston was measured by laser-interfereatial expander from room temperature to 400C Investigation of the influence of rare earth metals on the thermal exponsion coefficient was also carried.
The results show that there is no obviously effect of boron content on the liquidus and the precipitation of secondary γ′ phase of IC6 alloys, but the addition of boron will lower the solidus significantly ( thus widen the range between solidus and liquidus ) and will promote the formation of low melting point phase M 3B 2. Moreover, B addition would make liquidus of interdendrite zones inter linked each other in a very wide range of temperature.
However, because of differences in seasonal cycles, circadian rhythms and secondary chemicals, many species may use the same primary attractant, without much interspecific attraction.
It is presumed that the high diversity of secondary chemicals, paralleling that of the plant species, makes a generalist strategy impractical.
However, the concentrations of secondary chemicals vary with season, environmental conditions, and geographical location.
The hypothesis that plant secondary chemicals were responsible for creating such barriers to herbivory was tested using heliconiine species as bioassays, in which reduced growth rates indicated presence of chemical barriers to feeding.
Quantitative variation in leaf nutrients, moisture, and secondary chemicals all appear to contribute to ant preferences for individuals and tissues of highly palatable plants.