Chemical Compositions And Antifungi Actions Of Pyroligneous Acids From Walnut Shell Of 2 Species

To achieve the comprehensive utilization of walnut shell, and to find a potential way to exploit walnut shell, pyroligneous acids from walnut shell of 2 species were prepared by pyrolyzing, and collected at 90~550°C. Pyroligneous acids from walnut shell of Juglans regia L.(H) and Juglans sigillata Dode(T) were obtained after refinement. The basic properties of the pyroligneous acids were measured, and the chemical compositions were analyzed by Gas Chromatography-Mass Spectrometry. Moreover, antifungi activities of each pyroligneous acid were tested by mycelium growth rate method, pathogen spore germination on concave slide, detached leaves test, fruit method and potted plant test. The results showed:(1) The test of basic properties showed that the pH values, total acids, specific gravities of the 2 pyroligneous acids were close to other pyroligneous acids. The basic properties of the 2 kinds of pyroligneous acids were similar. 62 compounds belonging to 9 groups were identified by GC-MS analysis, mainly organic acids, phenols, ketones, furan and pyran derivatives, benzene and derivatives, alcohols, esters and anhydrides. The content of organic acids was the highest, the relative contents in H and T were 37.43% and 38.55%, respectively. The followed was phenol compounds, the relative contents in H and T were 24.71% and 22.73%, respectively.(2) 53 compounds were identified in H, while 57 compounds were identified in T. The chemical compositions of 2 pyroligneous acids were similar, 48 common compounds were obtained in the 2 pyroligneous acids, 5 and 9 special compounds were obtained in H and T, respectively. The contents of each compounds in the 2 pyroligneous acids were different.(3) The 2 pyroligneous acids showed antifungi activities in different degrees, the antifungi activities were increasing with the concentrations. They all showed the strongest inhibition on Rhizoctonia cerealis, the values of EC50 of H and T on Rhizoctonia cerealis were 15.65 mg/mL and 15.23 mg/mL, respectively.(4) The results of pathogen spore germination indicated that pyroligneous acids showed high antifungi activities, and the antimicrobial activities on Colletotrichum gloeosporioides were higher than that on Botrytis cinerea. The activities of pyroligneous acids of inhibite pathogen spore germination were higher than that of inhibition mycelium growth.(5) The results of detached leaves test and fruit method indicated that pyroligneous acids showed control effects on tomato early blight, tomato gray mold and walnut anthracnose to some extent, and the highest control effects were 62.16%, 29.67% and 30.13%, respectively. The control effects were increasing with the concentrations. The protect control effects were higher than cure control effects. The differences between the 2 pyroligneous acids were not significant. However, the antifungi activities of pyroligneous acids tested by this method were lower than that by mycelium growth rate method and pathogen spore germination method.(6) The results of potted plant test indicated that pyroligneou acids showed well control effects on wheat powdery mildew, and the highest control effect was 78.05%, control effects of protection were higher than control effects of cure. The test of physiological and chemical responses on wheat showed that pyrolligneous acids from walnut shell could increase the activities of SOD and POD of wheat, and enhance the disease resistance of plant.