Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest du...Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.展开更多
The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The re...The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The results showed that the total FAA content ranged from 48.71 to 62.05 mg/g among the 7 test ma- terials. Among the 16 kinds of FAAs, Ala, Arg, Glu and Asp, four kinds of flavor amino acids, showed the highest contents, and their total content ranged from 36.05 to 53.96 mg/g, accounting for 69.11%-86.47% of the total FAA content. The total contents of flavor amino acids and FAAs all reached the peaks in all the test ma- terials, except the control cultivar, at middle harvest period. The essential amino acid content was trended to be increased in all the test materials with the extended harvest period, and it reached the peak at the late harvest period. Sutong showed the highest flavor amino acid content and FAAs content, followed by Y-H002, Suyan and Sulian, while the control cultivar showed the lowest contents.展开更多
The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical...The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.展开更多
[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla...[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.展开更多
To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,w...To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,were investigated.The harvest period ranged from August 22nd to October 6th,samples were collected every 5 d(totally 10 plucking days,indicated as H1-H10).The results indicated that changes in pectin content were the main causes of softening in fragrant pears.The scavenging of free radicals mainly occurred because of the collaborative effects of superoxide dismutase(SOD)and catalase(CAT).In the harvest periods H1-H3,the hardness,titratable acid(TA),chlorophyll content,density,and diameter of the stone cells,as well as the cellulose and hemicellulose content of the Korla fragrant pears were at their highest.During the periods H7-H10,the single-fruit weight,fruit horizontal and vertical diameter,color coordinates L,a*,b*,soluble-solids content(SSC),SOD activity,CAT activity,and water-soluble pectin were higher than in the other plucking periods.The highest vitamin C(VC)content and moderate values for a variety of indicators were observed during H3-H7.Variations in the Korla fragrant pears during H1-H3 mainly manifested through changes in softening-related parameters.During H3-H10,changes in the softening-related,aging-related,color-related,and quality indices had a dominant role.On this basis,some suggestions for the post-harvest processing of fragrant pears have been proposed.Fruit,during H1-H3,are suitable for transportation and storage;during H7-H10 are suitable for fresh-eating and further processing;and during H3-H7,exhibited moderate values for a variety of indicators and had the highest commercial value.This research provides a systematic evaluation of the characteristics of mature Korla fragrant pears during the harvest period and can form the basis for fruit quality control and processing of Korla fragrant pears.展开更多
This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions fo...This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions for the existence of at least two positive periodic solutions of this model is established.展开更多
A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigate...A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.展开更多
In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, ...In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, by constructing appropriate Lyapunov function and using comparison theorem with an impulsive differential equation, we study that a positive periodic solution exists. Thirdly, we prove that system is globally attractive. Finally, numerical simulations are presented to show the feasibility of the obtained results.展开更多
文摘Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.
基金Supported by National High-tech R&D Program of China(2012AA10A406-5)National Natural Science Foundation of China(31272664)+2 种基金Natural Science Foundation of Jiangsu Province(BK20140439)Jiangsu Province Science and Technology Support Program,China(BE2012420)Independent Innovation Foundation of Agricultural Science and Technology of Jiangsu Province(CX(14)2081)~~
文摘The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The results showed that the total FAA content ranged from 48.71 to 62.05 mg/g among the 7 test ma- terials. Among the 16 kinds of FAAs, Ala, Arg, Glu and Asp, four kinds of flavor amino acids, showed the highest contents, and their total content ranged from 36.05 to 53.96 mg/g, accounting for 69.11%-86.47% of the total FAA content. The total contents of flavor amino acids and FAAs all reached the peaks in all the test ma- terials, except the control cultivar, at middle harvest period. The essential amino acid content was trended to be increased in all the test materials with the extended harvest period, and it reached the peak at the late harvest period. Sutong showed the highest flavor amino acid content and FAAs content, followed by Y-H002, Suyan and Sulian, while the control cultivar showed the lowest contents.
基金This work was supported by the Natural Science Foundation of Liaoning Province(No.20180551065).
文摘The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.
基金Supported by the Fundamental Research Funds for Environment and Plant Protection Institute,Chinese Academy of Tropical Agricultural Sciences(16300420170291630042017008)
文摘[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.
基金The authors acknowledge that this work was financially supported by the Xinjiang Production and Construction Corps Strong Youth Science and Technology Innovation Key Talents Project(Grant No.2021CB039)the Tarim University President Fund Project(Grant No.TDZKCQ201902)+4 种基金National Natural Science Foundation of China(Grant No.31660475)the Young and Middle-aged Scientific and Technological Innovation Leading Talents Project of Xinjiang Production Construction Corps(Grant No.2018CB014)the Innovation and Entrepreneurship Project of Xinjiang Production Construction Corps Special Commissioner for Science and Technology(Grant No.2019CB037)the Production Construction Group Key Laboratory of Special Agricultural Products Further Processing in Southern Xinjiang(Grant No.AP1905)the National Youth Fund Project(Grant No.31201364).
文摘To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,were investigated.The harvest period ranged from August 22nd to October 6th,samples were collected every 5 d(totally 10 plucking days,indicated as H1-H10).The results indicated that changes in pectin content were the main causes of softening in fragrant pears.The scavenging of free radicals mainly occurred because of the collaborative effects of superoxide dismutase(SOD)and catalase(CAT).In the harvest periods H1-H3,the hardness,titratable acid(TA),chlorophyll content,density,and diameter of the stone cells,as well as the cellulose and hemicellulose content of the Korla fragrant pears were at their highest.During the periods H7-H10,the single-fruit weight,fruit horizontal and vertical diameter,color coordinates L,a*,b*,soluble-solids content(SSC),SOD activity,CAT activity,and water-soluble pectin were higher than in the other plucking periods.The highest vitamin C(VC)content and moderate values for a variety of indicators were observed during H3-H7.Variations in the Korla fragrant pears during H1-H3 mainly manifested through changes in softening-related parameters.During H3-H10,changes in the softening-related,aging-related,color-related,and quality indices had a dominant role.On this basis,some suggestions for the post-harvest processing of fragrant pears have been proposed.Fruit,during H1-H3,are suitable for transportation and storage;during H7-H10 are suitable for fresh-eating and further processing;and during H3-H7,exhibited moderate values for a variety of indicators and had the highest commercial value.This research provides a systematic evaluation of the characteristics of mature Korla fragrant pears during the harvest period and can form the basis for fruit quality control and processing of Korla fragrant pears.
文摘This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions for the existence of at least two positive periodic solutions of this model is established.
文摘A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.
文摘In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, by constructing appropriate Lyapunov function and using comparison theorem with an impulsive differential equation, we study that a positive periodic solution exists. Thirdly, we prove that system is globally attractive. Finally, numerical simulations are presented to show the feasibility of the obtained results.
