The volatile compounds from ash-leaf maple (Acer negundo L.) were examined by adsorption-thermodesorption and GC-MS. Thirty-two compounds, including alcohols, ketones, aldehydes, esters, terpenoids, carboxylic acids, ...The volatile compounds from ash-leaf maple (Acer negundo L.) were examined by adsorption-thermodesorption and GC-MS. Thirty-two compounds, including alcohols, ketones, aldehydes, esters, terpenoids, carboxylic acids, etc. were identified. The analysis revealed that the diurnal rhythm of release of volatile compounds from maple differed in July and in August. In July, the releasing of most volatile compounds reached the peak at 14 o'clock, when in August, the emission of volatile compounds reached the peak at 10 o'clock. Besides diurnal rhythm, there also existed other differences in the releasing of volatiles and their relative contents in July and in August. A possible explanation for this phenomenon is the maturation of leaves, since the sampling conditions were the same both in July and August. At the same time, the response of Anoplophora glabrpennis Motschulsky to volatiles was examined with field bioassay with traps. cis-3-hexen-1-ol was found to be more effective to attract A. glabrpennis than other volatiles released by ash-leaf maple tree in field trapping test. A mixture of 1-butanol, 1-pentanol and 2-pentanol was tested to be the most attractive to A. glabripennis among all tested volatiles. More field trapping tests should be conducted.展开更多
Six types of termites＇ baits （cartoon, rough tissues, soft toilet tissues, acacia wood, saw dust of building wood and sackcloth） were elicited variable degree of attraction toward Anacanthotermes ochaceus, where th...Six types of termites＇ baits （cartoon, rough tissues, soft toilet tissues, acacia wood, saw dust of building wood and sackcloth） were elicited variable degree of attraction toward Anacanthotermes ochaceus, where the best one was cardboard, followed by soft and rough toilet tissue at mono-choice and multiple-choice tests. Chemical analysis showed that there were variations in the chemical constituents （lignin, cellulose, N, H and C） of the six baits studied. On the other hand, olfactory reactions of harvester termites toward eight volatile oils （four natural medical plants and four commercial terpines） were repellent, but the most repellent one was cineol and the least one was clove oil. The most tested oils were caused inhibition in feeding, except cedar wood. The most toxic oils were cineol followed by thymol.展开更多
Colletotrichum gloeosporioides is the causal agent of anthracnose disease in fruits and vegetables, representing a global problem. The use of biocontrol agents has proved effective against fungal diseases in a wide va...Colletotrichum gloeosporioides is the causal agent of anthracnose disease in fruits and vegetables, representing a global problem. The use of biocontrol agents has proved effective against fungal diseases in a wide variety of products. In this work, the antifungal activity of Wickerhamomyces anomalus against C. gloeosporioides isolated from contaminated avocados was evaluated. The antagonism and volatile compound inhibition were measured on Petri dishes. In the mixed cultures, the mycelia damage was observed by scanning electron microscope （SEM）. Chitinase and glucanase production by the antagonism was quantified by the reducing sugars method, and biofilm formation was evaluated with 1% crystal violet. The yeast W. anomalus could reduce the growth of C. gloeosporioides up to 65% by direct antagonism and 10% by volatile compounds. The antagonist did not allow the conidia germination and mycelia growth in any of the tested formulations. SEM showed mycelial damage caused by W. anomalus. The antagonist showed adhesion to the mycelium by a polysaccharide biofilm. The presence of mycelium stimulated the hydrolytic enzyme production with the maximal activity of 21.4 U/mg for chitinases at 24 h and 10 U/mg for glucanases at 60 h. These results showed that W. anomalus used together different mechanisms to express its antifungal activity against C. gloeosporioides. This study might be the first report for this phytopathogen isolated from avocado fruits, which could represent an opportunity to establish biocontrol of diseases for this agricultural product.展开更多
文摘The volatile compounds from ash-leaf maple (Acer negundo L.) were examined by adsorption-thermodesorption and GC-MS. Thirty-two compounds, including alcohols, ketones, aldehydes, esters, terpenoids, carboxylic acids, etc. were identified. The analysis revealed that the diurnal rhythm of release of volatile compounds from maple differed in July and in August. In July, the releasing of most volatile compounds reached the peak at 14 o'clock, when in August, the emission of volatile compounds reached the peak at 10 o'clock. Besides diurnal rhythm, there also existed other differences in the releasing of volatiles and their relative contents in July and in August. A possible explanation for this phenomenon is the maturation of leaves, since the sampling conditions were the same both in July and August. At the same time, the response of Anoplophora glabrpennis Motschulsky to volatiles was examined with field bioassay with traps. cis-3-hexen-1-ol was found to be more effective to attract A. glabrpennis than other volatiles released by ash-leaf maple tree in field trapping test. A mixture of 1-butanol, 1-pentanol and 2-pentanol was tested to be the most attractive to A. glabripennis among all tested volatiles. More field trapping tests should be conducted.
文摘Six types of termites＇ baits （cartoon, rough tissues, soft toilet tissues, acacia wood, saw dust of building wood and sackcloth） were elicited variable degree of attraction toward Anacanthotermes ochaceus, where the best one was cardboard, followed by soft and rough toilet tissue at mono-choice and multiple-choice tests. Chemical analysis showed that there were variations in the chemical constituents （lignin, cellulose, N, H and C） of the six baits studied. On the other hand, olfactory reactions of harvester termites toward eight volatile oils （four natural medical plants and four commercial terpines） were repellent, but the most repellent one was cineol and the least one was clove oil. The most tested oils were caused inhibition in feeding, except cedar wood. The most toxic oils were cineol followed by thymol.
文摘Colletotrichum gloeosporioides is the causal agent of anthracnose disease in fruits and vegetables, representing a global problem. The use of biocontrol agents has proved effective against fungal diseases in a wide variety of products. In this work, the antifungal activity of Wickerhamomyces anomalus against C. gloeosporioides isolated from contaminated avocados was evaluated. The antagonism and volatile compound inhibition were measured on Petri dishes. In the mixed cultures, the mycelia damage was observed by scanning electron microscope （SEM）. Chitinase and glucanase production by the antagonism was quantified by the reducing sugars method, and biofilm formation was evaluated with 1% crystal violet. The yeast W. anomalus could reduce the growth of C. gloeosporioides up to 65% by direct antagonism and 10% by volatile compounds. The antagonist did not allow the conidia germination and mycelia growth in any of the tested formulations. SEM showed mycelial damage caused by W. anomalus. The antagonist showed adhesion to the mycelium by a polysaccharide biofilm. The presence of mycelium stimulated the hydrolytic enzyme production with the maximal activity of 21.4 U/mg for chitinases at 24 h and 10 U/mg for glucanases at 60 h. These results showed that W. anomalus used together different mechanisms to express its antifungal activity against C. gloeosporioides. This study might be the first report for this phytopathogen isolated from avocado fruits, which could represent an opportunity to establish biocontrol of diseases for this agricultural product.
