Releasing Variation And Effects On Pasture Seeds Germinating Of Volatile Organic Compounds From Artemisia Frigida Wild.

This paper do the primary study on the releasing variation of VOCs and aqueous extract of Artemisia frigida Willd. which is an important part of exploring the succession of the grassland vegetation. The techno-route of this reaserch is based on the theories of plant chemical-ecology and plant physiology, combined with Thermal-desorption Cold Trap/Gas Chromato graphy/Mass Spectrometry (TCT/GC/MS) to study the the releasing variation of VOCs from A. frigida,effects on pasture seeds germination and the seedings growth.The purpose is to provide the theoretical basis and scientific methods for controling degeneration and improving environment of grassland in northern plain area of China.This research mainly come to launch from three respects, fistly, uesd dynamic headspace collection, TCT/GC/MS to analyse the composition, concentration and the releasing variation of A. frigida in two states of normal, damaged for 2h, inorder to identify the components, concentration and the releasing variation of VOCs of A. frigida; compared the components of VOCs of A. frigida in different states. Secondly, used GC/MS to analyse the composition and concentration of aqueous extract of A. frigida, in order to identify the components of aqueous extract and to compare with the components of VOCs of A. frigida. Finally, used bioassay method to study the effects on the germination of four species pasture seeds, Melitotus suaveolens Ledeb., Sorghum sudanense, Elymus dahuricus Turcz. and Agropyron cristatum L. by three kinds of monomer-compounds of Eucalyptol,α-Terpineol andβ-Pinene of VOCs released from A. frigida Willd.. The results as follows:1. The components of VOCs of A. frigida are mostly terpene compounds and its ramifacation,which accounts for above 89% of the total, thereinto,Eucalyptol accounts for most content. The results of the dynamic variation of VOC released from normal A. frigida Wild. indicated that the release of Eucalyptol reached the peak in July, commonly others components of terpene reached the peak in June or Auguast.,which was due to the environment factors.2. The results of the variation of components and relative contents of VOCs from A. frigida which have damaged in different seasons showed that: compared with VOCs from undamaged A. frigida, the VOCs from A. frigida which damaged for 2h were added 2 kinds of Aldehydes, 2 kinds of Fatty ester; moreover the VOCs were added 2 kinds of Terpenoids and reduced 5 kinds of Terpenoids. The VOCs from A. frigida which damaged for 24h were added Alcohols, the Aldehydes and the Fatty ester had a little variation, the rest are mainly the same as the VOCs from A. frigida which damaged for 2h.3. The annual dynamic variation of VOCs from A. frigida which damaged for 2h is the same as the annual dynamic variation of VOCs from normal A. frigida.Compared with the VOCs from noraml A. frigida, the kinds and intensity of VOCs from A. frigida which damaged for 2h both increased.4. Analyzed by GC/MS, the result showed that the aqueous extract of A. frigida has the same 10 kinds of components as the VOCs of A. frigida, which accounts for 33% of total. Eucalyptol accounts for most content. This result is also the same as the VOCs of A. frigida.5. The results of bioassay method indicated that: every monomer-compounds on the concentration of 0.1ppm had the stimulative effect on the germination and growth of M. suaveolens and S. sudanense; with increasing of the concentration, the inhibitory effect was appeared, and the inhibitory effect enhanced with the concentration increasing. And the inhibitory effect to the young shoots and young roots was stronger than to the seed germination, the inhibitory effect to the young shoots was stronger than to the young roots.This study proved that, the releasing variation of VOCs released from A. frigida was obvious. The monomer-compounds of VOCs of A. frigida had obvious effects on the germination of pasture seeds. The VOCs of A. frigida had the allelopathy potencial. The results based on systemic reaserch showed the allelopathy potencial of VOCs of A. frigida, to provide theory basis for studying the herd-resisitance mechanism of A. frigida, aslo provided basic theory for protecting A. frigida and the plants of Artemisia,and preventing hungriness of grassland.