To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic r...To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic resin,Chinese fir was impregnated with a shellac solution.Since the shellac solution was difficult to penetrate into fast-growing Chinese fir,so microwave pretreatment was used to irradiate the wood to improve the permeability.This study investigated the effects of four factors,including the content of moisture in the wood before it was microwaved,the chamber pressure of microwave,the time of microwaving and the vacuum impregnation on the mechanical properties of Chinese fir wood.When the moisture content of wood before microwave was approximately 50%–60%,after microwaving and impregnation,the ultimate strength in static bending(modulus of rupture[MOR])and strength in compression perpendicular to the grain(SCPG)of the wood increased significantly.A microwave time of 100 seconds was more effective at improving the MOR and SCPG of the wood.If the wood was microwaved for too short or long period of time,the microwave pretreatment was not effective.When the samples were immersed in shellac for a longer period,the MOR and SCPG of Chinese fir gradually increased,but when the wood was impregnated for more than 12 hours,the increases were not significant.After the shellac penetrated the Chinese fir wood,it spread on the inner wall surface of tracheid to form a shellac film and easily formed plug-like deposits in microcapillaries.The use of Fourier-transform infrared spectroscopy,scanning electron microscopy and scanning electron microscopy-energy dispersion x-ray indicated that the microwave pretreatment can destroy the pit membranes on tracheids and facilitate the ability of shellac to penetrate the channel.展开更多
Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an Americ...Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura＇ and an European celery variety ‘Princer＇ were assayed by reversed-phase high-perfor mance liquid chromatography （RP-HPLC）.The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30％,10％,30％,20％,30％ and 20％,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura＇ and ‘Princer＇.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.展开更多
A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage ( B. chinensis L., cv. Zao\|Shu 5), winter greens ( B.var.rosularis Tsen et Lee, cv. Shang\|Hai\|Qing) and cele...A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage ( B. chinensis L., cv. Zao\|Shu 5), winter greens ( B.var.rosularis Tsen et Lee, cv. Shang\|Hai\|Qing) and celery ( A.graveolens L. var. dulce DC., cv. Qing\|Qin) were conducted, respectively. The initial soil and four incubated soils with different extractable Cd (0.15, 0.89, 1.38, 1.84 and 2.30 mg Cd/kg soil) were used for the pot experiment. Five treatments were designed (0, 0.0625, 0.125, 0.250 and 0.500 mg Cd/L) in nutrient solution in the sandy culture experiment. Each treatment in pot and sandy culture experiments was trireplicated. The objectives of the study were to examine Cd accumulation in edible parts of selected vegetable crops, its correlation with Cd concentrations in vegetable garden soil or in nutrient solution, and evaluate the criteria of Cd pollution in vegetable garden soil and in nutrient solution based on the hygienic limit of Cd in vegetables. Cadmium concentrations in edible parts of the three selected vegetable crops were as follows: 0.01—0.15 mg/kg fresh weight for Chinese cabbage, 0.02—0.17 mg/kg fresh weight for winter greens, and 0.02—0.24 mg/kg fresh weight for celery in the pot experiment, and 0.1—0.4 mg/kg fresh weight for Chinese cabbage, 0.1—1.4 mg/kg fresh weight for winter greens, and 0.05—0.5 mg/kg fresh weight for celery in the pot experiment(except no\|Cd treatment). The order of the three test vegetable crops for cadmium accumulation in the edible parts was celery>winter greens>Chinese cabbage in both the pot experiment and the sandy culture experiment. Cadmium accumulation in edible parts or roots of the vegetable crops increased with increasing of cadmium concentration in the medium(soil or nutrient solution). And cadmium concentrations in edible parts of the test vegetable crops were significantly linearly related to the Cd levels in the growth media (soil and nutrient solution). Based on the regression equations established and the limit of cadmium concentration in vegetable products, the thresholds of Cd concentration in the growth medium evaluated was as follows: 0.5 mg/kg soil of extractable Cd for soil and 0.02 mg /L for nutrient solution. The high capacity for cadmium accumulation in the edible parts of different vegetable crops together with the absence of visual symptoms implies a potential danger for humans.展开更多
基金the 2018 Forestry Science and Technology Research Project by Forestry Department of Fujian Province(No.2018-26)Science and Technology Innovation Special Fund Project of Fujian Agriculture and Forestry University(CXZX2019111S)+1 种基金National Natural Science Foundation of China(31971593,32071688)the Natural Science Foundation of Fujian Province Department of Science and Technology(2019J01386).
文摘To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic resin,Chinese fir was impregnated with a shellac solution.Since the shellac solution was difficult to penetrate into fast-growing Chinese fir,so microwave pretreatment was used to irradiate the wood to improve the permeability.This study investigated the effects of four factors,including the content of moisture in the wood before it was microwaved,the chamber pressure of microwave,the time of microwaving and the vacuum impregnation on the mechanical properties of Chinese fir wood.When the moisture content of wood before microwave was approximately 50%–60%,after microwaving and impregnation,the ultimate strength in static bending(modulus of rupture[MOR])and strength in compression perpendicular to the grain(SCPG)of the wood increased significantly.A microwave time of 100 seconds was more effective at improving the MOR and SCPG of the wood.If the wood was microwaved for too short or long period of time,the microwave pretreatment was not effective.When the samples were immersed in shellac for a longer period,the MOR and SCPG of Chinese fir gradually increased,but when the wood was impregnated for more than 12 hours,the increases were not significant.After the shellac penetrated the Chinese fir wood,it spread on the inner wall surface of tracheid to form a shellac film and easily formed plug-like deposits in microcapillaries.The use of Fourier-transform infrared spectroscopy,scanning electron microscopy and scanning electron microscopy-energy dispersion x-ray indicated that the microwave pretreatment can destroy the pit membranes on tracheids and facilitate the ability of shellac to penetrate the channel.
基金Supported by Shanghai Green Vegetable Industrial Technology SystemKey Scienceand Technology Research Program of Science and Technology Commission of Shanghai Municipality(12391900900)+1 种基金Innovation Project of Science and Technology Foundation of Pudong New District(PKQ2012-03)Special Fund for Agro-scientific Research in the Public Interest(201403032)~~
文摘Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura＇ and an European celery variety ‘Princer＇ were assayed by reversed-phase high-perfor mance liquid chromatography （RP-HPLC）.The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30％,10％,30％,20％,30％ and 20％,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura＇ and ‘Princer＇.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.
文摘A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage ( B. chinensis L., cv. Zao\|Shu 5), winter greens ( B.var.rosularis Tsen et Lee, cv. Shang\|Hai\|Qing) and celery ( A.graveolens L. var. dulce DC., cv. Qing\|Qin) were conducted, respectively. The initial soil and four incubated soils with different extractable Cd (0.15, 0.89, 1.38, 1.84 and 2.30 mg Cd/kg soil) were used for the pot experiment. Five treatments were designed (0, 0.0625, 0.125, 0.250 and 0.500 mg Cd/L) in nutrient solution in the sandy culture experiment. Each treatment in pot and sandy culture experiments was trireplicated. The objectives of the study were to examine Cd accumulation in edible parts of selected vegetable crops, its correlation with Cd concentrations in vegetable garden soil or in nutrient solution, and evaluate the criteria of Cd pollution in vegetable garden soil and in nutrient solution based on the hygienic limit of Cd in vegetables. Cadmium concentrations in edible parts of the three selected vegetable crops were as follows: 0.01—0.15 mg/kg fresh weight for Chinese cabbage, 0.02—0.17 mg/kg fresh weight for winter greens, and 0.02—0.24 mg/kg fresh weight for celery in the pot experiment, and 0.1—0.4 mg/kg fresh weight for Chinese cabbage, 0.1—1.4 mg/kg fresh weight for winter greens, and 0.05—0.5 mg/kg fresh weight for celery in the pot experiment(except no\|Cd treatment). The order of the three test vegetable crops for cadmium accumulation in the edible parts was celery>winter greens>Chinese cabbage in both the pot experiment and the sandy culture experiment. Cadmium accumulation in edible parts or roots of the vegetable crops increased with increasing of cadmium concentration in the medium(soil or nutrient solution). And cadmium concentrations in edible parts of the test vegetable crops were significantly linearly related to the Cd levels in the growth media (soil and nutrient solution). Based on the regression equations established and the limit of cadmium concentration in vegetable products, the thresholds of Cd concentration in the growth medium evaluated was as follows: 0.5 mg/kg soil of extractable Cd for soil and 0.02 mg /L for nutrient solution. The high capacity for cadmium accumulation in the edible parts of different vegetable crops together with the absence of visual symptoms implies a potential danger for humans.
