This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identif...This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. malaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. malaccensis leaves.The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1:10(g·ml-1), and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography–mass spectroscopy(GC/MS), which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components,Pentadecanal(32.082%), 9-Octadecenal,(Z)(15.894%), and Tetradecanal(6.927%) were the major compounds.Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.展开更多
Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus （P） concentration ranges in t...Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus （P） concentration ranges in the foliage of P-stressed and healthy plants, and to define cri- tical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca（H2PO4）2.H2O, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency （0.17 %） and toxicity （0.41%） to be determined at 90 % maximum yield from linear re- gressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.展开更多
文摘This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. malaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. malaccensis leaves.The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1:10(g·ml-1), and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography–mass spectroscopy(GC/MS), which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components,Pentadecanal(32.082%), 9-Octadecenal,(Z)(15.894%), and Tetradecanal(6.927%) were the major compounds.Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.
文摘Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus （P） concentration ranges in the foliage of P-stressed and healthy plants, and to define cri- tical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca（H2PO4）2.H2O, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency （0.17 %） and toxicity （0.41%） to be determined at 90 % maximum yield from linear re- gressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.
