Responses Of Populus Simonii×Populus Pyramidalis 'Opera 8277' Cuttings To Wounding And Airborne Defensive Signals

A systematic study of the responses of Populus simonii×Populus pyramidalis'Opera 8277'cuttings to wounding and airborne defense signals is important to find a new way to control woody plant diseases and insect pests, to reveal the mechanism of inducible resistance.P.simonii×P.pyramidalis'Opera 8277'cuttings were used during experiments. Three treaments including Clostera anachoreta feeding, exposure to airborne defense signals and mechanical wounding were applied to poplar. Using thermo-desorption cold trap transfer-gas chromatography-mass spectrometry (TCT-GC-MS) device, CIRS-2 photosynthesis analyzer, Chlorophyll fluorometer(Imaging-PAM) and PAM-2100, H₂O₂ Histochemical localization, Affymetrix Genechip microarray,the relationship between the emissions of pentanal, hexanal, heptanal, octanal, nonanal, decanal and photosynthesis has been examied. The systimic influence of wounding on photosynthesis has been investigated. The contents of H₂O₂,JA and ABA in leaves and their way of transference were checked. The impact of herbivory by caterpillars (Clostera anachoreta) on defence gene expression profiles of popular was analyzed. Based on the experiment, we com to the following conclusons:1.The release rates of pentanal,hexanal,heptanal,octanal,nonanal and decanal from P.simonii×P.pyramidalis'Opera 8277'Cuttings increased significantly with the elevation of light intensity and O2 contents. The emission of hexanal,heptanal,octanal and nonanal is closely related with lipoxygenase/hydroperoxide lyase pathway,but has no relation with pentanal and decanal . The C5-C10 aldehydes might be formed in oxidation processes caused by reactive oxygen species produced in photosynthesis during insects attack., This is a protection mechanism for the plant to turn reactive oxygen species injury away to the PSI reaction center.2.Treatment of poplar trees with gaseous methyl jasmonate (MeJA),herbivore injure effectively reduced the net photosynthetic rate of poplar cuttings due to the non- stomatic limitation. The stomatic limitation was involved in the net photosynthetic rate decrese in response to the mechanical damage. All the above treatments can reduce the maximum efficiency of PSII. The coefficient of photochemical quenching (qP ) and RuBisco activity...