• Volume 36,Issue 2,2015 Table of Contents
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    • Screening and comprehensive evaluation of drought resistance indices of rice at germination stage

      2015, 36(2):1-5. DOI: 10.7671/j.issn.1001-411X.2015.02.001

      Abstract (3453) HTML (514) PDF 1.03 M (1735) Comment (0) Favorites

      Abstract:【Objective】To study the effect of drought stress on rice growth at germination stage and screen rice drought resistance indicators quickly and efficiently. 【Method】Sixty-two rice varieties (lines),including indicia and japonica rice and space-induced mutants, were studied under drought artificially created by PEG-6000. Eight indicators such as shoot length,maximum root length,coleoptile length, root number and shoot dry mass etc. were tested under stressed and control conditions. 【Result and conclusion】Rice germination, especially the root length, was seriously affected by drought stress, and the impact of drought stress on root dry matter accumulation was much greater than that of shoot dry matter accumulation. Two indicators of maximum root length and coleoptile length significantly correlated with the comprehensive drought capability which were suitable for drought resistance screening at rice germination stage. Fourteen out of 62 materials have been identified to be highly drought resistant through dynamic clustering statistics, which will be promising for rice drought resistance breeding.

    • Effects of salt stress on photosynthetic characteristics and some physiological traits of rice varieties at different nitrogen levels

      2015, 36(2):6-12. DOI: 10.7671/j.issn.1001-411X.2015.02.002

      Abstract (1886) HTML (554) PDF 988.51 K (2054) Comment (0) Favorites

      Abstract:【Objective】To understand the response to salt stress on rice varieties cultured at different nitrogen levels. 【Method】Two north japonica rice varieties were cultured at five nitrogen levels of nutrient solution until booting stage, the changes of biomass, photosynthetic characteristics and some physiological characteristics of two rice varieties were measured in three salt concentrations. 【Result and conclusion】The biomass of rice varieties which were cultured at different nitrogen levels of nutrient solution decreased under salt stress; there were significant decrease in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and apparent mesophyll conductance (AMC) of rice leaves under salt stress. The Pn reduction was due to non-stomatal restriction factors in low-nitrogen-level nutrient solution, however, the stomatal and non-stomatal limitation factors resulted in the Pn reduction in high-nitrogen-level nutrient solution. Under salt stress, the activity of antioxidant enzymes such as SOD, POD and CAT, the contents of proline and soluble sugar of leaves in 1/2N-level nutrient solution were significantly higher than those at other nitrogen-levels, the membrane permeability and the content of MDA in 1/2N-level were lower than those at other nitrogen-levels. The results show that rice varieties cultured in 1/2N-level nutrient solution can improve the capacity of osmotic regulation, enhancing the salt-tolerance ability of rice varieties at booting stage. The capacity of salt-tolerance of Jiudao13 is higher than that of Jijing88.

    • Drought resistant characters during germination of different wheat germplasm in Yunnan Province and their correlations with the index and coefficient of drought resistance

      2015, 36(2):13-18. DOI: 10.7671/j.issn.1001-411X.2015.02.003

      Abstract (1529) HTML (412) PDF 765.66 K (1584) Comment (0) Favorites

      Abstract:【Objective】To explore indicative characters for predicting drought resistance in the whole growing period of different wheat germplasm in Yunnan Province at seed germination stage by simulating drought stress. 【Method】Six germination characters associated with drought resistance, including germination energy, germination rate, number of radicels, length of maximal radicels, length of coleoptiles and length of embryos among 70 accession wheat materials of Yunnan with 5 subspecies in 2 species, were studied under water and hypertonic solution of polyethylene glycol (PEG-6000) described by GB/T21127-2007 treatment conditions. Moreover, the correlations between observed average values and relative values of six germination characters and indexes and coefficients of drought resistance were analyzed. 【Result and conclusion】Among 5 subspecies, most of the observed average values and relative values of six germination characters did not show consistently significance in the whole growing period between varieties of drought resistance and highly drought resistance and the control of Yunxuan 11-12 of highly weak resistance, between varieties of drought resistance and highly drought resistance and varieties of middle resistance or between drought resistance and highly drought resistance and weak and highly weak resistance. Accordingly, most of the observed average values and relative values did not indicate conformable significance to their relative indexes and coefficients of drought resistance in the whole growing period. These results show that it is impossible to filter out the varieties of drought resistance and highly drought resistance in the whole growing period among all subspecies just depending on a single associated germination character of drought resistance. Thus, the breeding materials of different subspecies with drought resistance and highly drought resistance should be screened out by a combination of some germination characters (relative number of radicels, relative length of maximal radicels, relative length of coleoptiles and relative length of embryos, and ratios of length of radicels-embryos) associated with drought resistance and indexes and coefficients of drought resistance.

    • Studies on the optimization of maize haploid induced rates

      2015, 36(2):19-24. DOI: 10.7671/j.issn.1001-411X.2015.02.004

      Abstract (1532) HTML (491) PDF 741.41 K (1497) Comment (0) Favorites

      Abstract:【Objective】To optimize the technical measures to improve maize haploid induced rates. 【Method】Effects of five factors, including parent genotypes, selection of germplasm and generations, environments, pollination period, parts of maize ear on the rates of maize haploid were conducted in the field from 2011 to 2012.【Result and conclusion】The haploid induced rates were different among different materials with the same factor and different among different factors with the same materials. The haploid induced rates in female parent genotypes were significantly different. There was no significant correlation between the crossing pattern and the induced rate. The optimal induced haploid generation of five germplasms was S1. Compared to Changchun, Sanya was more conducive to improve the induced rate of haploid. The haploid induced rate of early pollination maize was higher than that of the late ones. The haploid induced rate at the top of the maize ear was higher than that at the bottom.

    • Effects of metal resistant plant growth promoting bacteria on corn growth and Zn accumulation

      2015, 36(2):25-30. DOI: 10.7671/j.issn.1001-411X.2015.02.005

      Abstract (1792) HTML (500) PDF 804.35 K (1500) Comment (0) Favorites

      Abstract:【Objective】Effects of metal resistant plant growth promoting bacteria(PGPB) on corn growth and Zn accumulation were studied to provide a fundamental groundwork for mitigating the stress of heavy metal on crop growth and decreasing heavy metal uptake. 【Method】A pot experiment was carried out to study the effects of inoculation with two Zn resistant PGPB, Ⅱ2R3 and Ⅳ8R3 on corn plant growth and Zn uptake from Zn contaminated soils (0, 200, 400 and 800 mg·kg-1 Zn addition). 【Result and conclusion】The strains Ⅱ2R3 and Ⅳ8R3 not only grew well with different concentrations of Zn, but also absorbed or accumulated much higher Zn from the growing medium. Individual inoculation of strain Ⅳ8R3 to the soil with 200 or 400 mg·kg-1 Zn addition both promoted the corn growth. For the soils with 800 mg·kg-1 Zn addition, simultaneous inoculation with strains Ⅱ2R3 and Ⅳ8R3 promoted the corn growth . Individual or simultaneous inoculation with strains Ⅱ2R3 and Ⅳ8R3 to the soils at three Zn pollution levels (200, 400 and 800 mg·kg-1 Zn addition) decreased the soil bioavailable Zn concentration. For the soil with a high Zn pollution level (800 mg·kg-1 Zn addition), the inoculation of strains Ⅱ2R3 or Ⅱ2R3+Ⅳ8R3 decreased Zn uptake and transportation in corn. However, all of three inoculation treatments had no significant effects on Zn uptake of corn when strains Ⅱ2R3, Ⅳ8R3, Ⅱ2R3+Ⅳ8R3 were inoculated to the soils with 200 or 400 mg·kg-1 Zn addition. The results indicate that inoculation with metal resistant PGPB to high Zn-contaminated soil can promote the corn growth and inhibite the uptake and transportation of Zn in corn. Inoculation with strains Ⅱ2R3 or Ⅳ8R3 to high Zn-contaminated soils can inhibite the uptake and transportation of Zn in corn. The effects of inoculation with strains Ⅱ2R3 or Ⅳ8R3 on corn growth are related to the different levels of Zn pollution and characterization of the strains.

    • Effects of nitrogen, phosphorus and potassium levels on the growth of Neyraudia reynaudiana of soil and water conservation plant

      2015, 36(2):31-35. DOI: 10.7671/j.issn.1001-411X.2015.02.006

      Abstract (1413) HTML (342) PDF 783.57 K (1598) Comment (0) Favorites

      Abstract:【Objective】To explore the effects of nitrogen, phosphorus and potassium levels on the growth of burmareed, Neyraudia reynaudiana .【Method】Nutrient solution-sand culture experiment was applied to study the response of burmareed which was a very excellent soil and water conservation plant at different nitrogen, phosphorus and potassium levels.【Result and conclusion】The results indicated that 0.750 mmol·L-1 N and 0.030 mmol·L-1 K significantly affected the burmareed growth and reduced the aboveground and underground biomass of burmareed. The concentration of 0.005 mmol·L-1 P did not affect the aboveground biomass, but significantly reduced the underground biomass. The effect of 0.750 mmol·L-1 N on the growth of burmareed was significantly stronger than that of 0.030 mmol·L-1 P and 0.030 mmol·L-1 K. In low P and K condition, burmareed could increase root length and surface area, which displayed its strong capacity of adapting and self-adjusting for low P and K stress. Supplement of nitrogen is very important for revegetation with burmareed.

    • Effects of biological organic fertilizer on wax gourd wilt disease, microorganism and enzyme activities in soil

      2015, 36(2):36-42. DOI: 10.7671/j.issn.1001-411X.2015.02.007

      Abstract (2664) HTML (272) PDF 971.56 K (1987) Comment (0) Favorites

      Abstract:【Objective】To research the effects of the biological organic fertilizer(BOF) on controlling wax gourd wilt disease, microorganism and enzyme activities in soil.【Method】The biological organic fertilizer(BOF) was made by mixing the mature compost with functional bacteria in proportion to identify the effects in pot experiment.【Result and conclusion】The occurrence of wax gourd wilt disease decreased by applying BOF, and along with the increasing amount of fertilizer application, the efficacy was more significant. When the disease-control effect of CPC treatment was assigned as 0, the disease-control effects of the treatments of BOF1,BOF2 and BOF3 were 42.27%,52.92% and 70.15%, respectively, which were higher than that of disease-control effect(31.91%)of organic fertilizer treatment; With the same amount of effective nutrients, the height, stem diameter, leaf width, and fresh mass of plant in BOF2 treatment were significantly higher than that of OF treatment, which indicated that the BOF could promote the growth of wax gourd. The number of bacteria and actinomycets in soil increased significantly by BOF, while the amount of fungi and Fusarium oxysporum in soil decreased. Urease, acid phosphatase, catalase and invertase activities in soil of BOF were higher than those of CK and CPC treatment. The results showed that BOF could improve soil enzyme activities, adjust soil microbial community structure, improve the soil quality and fertility conditions, hence decrease the occurrence of the wax gourd wilt disease.

    • Determination of the amide herbicides in milk using dispersive liquid-liquid microextraction prior to GC-MS

      2015, 36(2):43-48. DOI: 10.7671/j.issn.1001-411X.2015.02.008

      Abstract (1693) HTML (828) PDF 1.01 M (1766) Comment (0) Favorites

      Abstract:【Objective】To supervise the food safety problem in milk and achieve a rapid and accurate determination of pesticide residues in milk. 【Method】In this paper, a simple, sensitive and environment friendly dispersive liquid-liquid microextraction (DLLME) technique coupled with gas chromatography-mass spectrometry (GC-MS) was established for the extraction and determination of four amide herbicides (alachlor, acetochlor, pretilachlor, and metolachlor ) in milk samples. 【Result and conclusion】The factors that affected extraction efficiency were studied and optimized. Eventually, 40 μL carbon tetrachloride was used as the extractant, 1 000 μL methanol was chosen as the dispersant and the extraction time was set to 1.0 min. Under the optimum conditions, the good linearity was exhibited from 0.05 to 5.00 mg·L-1 herbicide, with the correlation coefficient being more than 0.997 8. The method had a high sensitivity, and the limits of detection (S/N=3) of the four amide herbicides ranged from 0.8 to 1.4 μg·L-1. The recoveries of the target analytes from milk samples were found between 67.0% and 105.7%, and the relative standard deviations (RSD) varied from 1.6% to 8.3%. The method can be successfully applied for the analysis of amide herbicides in real milk samples.

    • Characterization of long chain 3-ketoacyl-ACP synthase in Xanthomonas campestris

      2015, 36(2):49-54. DOI: 10.7671/j.issn.1001-411X.2015.02.009

      Abstract (1862) HTML (410) PDF 1.88 M (1611) Comment (0) Favorites

      Abstract:【Objective】The functions of the three genes XcfabF1,XcfabF2 and XcfabB, which were annotated as encodes putative 3-ketoacyl-ACP synthase in fatty acid synthesis in Xanthomonas campestris 8004 genome, were studied. 【Method】Three genes coloned into expression plasmid pBAD24M separately were transformed into the fabB and fabF temperature sensitive mutant CY242 and CY244 of Escherichia coli. The activity of XcFabF1, XcFabF2 and XcFabB in vitro was assayed by cell-free extracts. 【Result and conclusion】The genetic complementary revealed that XcfabB and XcfabF1 genes could restore the growth of mutant CY242 and CY244 respectively, but XcfabF2 could not restore the growth of mutant CY242 or CY244. The cell-free extracts of XcFabF1 and XcFabB could elongate octanoyl-ACP to longer acyl-ACP, while XcFabF2 could not catalyse the elongation in vitro assay. The above results demonstrate that XcfabB and XcfabF1 encode 3-ketoacyl-ACP sysnthase I and 3-ketoacyl-ACP sysnthase II respectively, but XcfabF2 is not involved in long chain fatty acid synthesis in X. Campestris.

    • A comparative study of photosynthetic characteristics between Pennisetum purpureum × P. americanum cv. Reyan No.4 and Miscanthus floridulus

      2015, 36(2):55-60. DOI: 10.7671/j.issn.1001-411X.2015.02.010

      Abstract (1735) HTML (342) PDF 841.41 K (1530) Comment (0) Favorites

      Abstract:【Objective】 The purpose of this study was to obtain high quality raw materials for producing biofuels. 【Method】 Diurnal variation of photosynthetic characteristics of Pennisetum purpureum × P. americanum cv. Reyan No.4 and Miscanthus floridulus was studied and the correlation between net photosynthetic rate and major impact factors was analyzed using the LI-6400 portable photosynthesis analyzer in the field. 【Result and conclusion】 The results showed that diurnal variation of the net photosynthetic rate (Pn) of ‘Reyan No4’ and M. floridulus showed a “single peak”, with no “midday depression” phenomenon. Pn of ‘Reyan No4’ (25.45 μmol·m-2·s-1) was slightly higher than that of M. floridulus (25.08 μmol·m-2·s-1). Transpiration rate (Tr), water use efficiency (WUE), light use efficiency (LUE) and stomatal conductance (Gs) were similar to Pn and reached the maximum at about 13:00. Tr, LUE and Gs of ‘Reyan No4’ were slightly higher than those of M. floridulus. Diurnal variation of stomatal limitation value (Ls) for both grasses was bell-shaped, reaching the highest value (0.86 μmol·m-2·s-1) at about 11:00 and the lowest in the early morning and late afternoon, but diurnal variation of intercellular CO2 mole fraction (xi) was the opposite. Pn of two grasses was negatively correlated with atmospheric CO2 mole fraction (xa) (P<0.05), and positively correlated with relative air humidity (RH) and Gs (P<0.05), respectively. These results indicate ‘Reyan No4’ has a stronger photosynthetic capacity than M. floridulus.

    • Drought resistance evaluation based on leaf anatomical structures of 25 shrubs on the Tibetan Plateau

      2015, 36(2):61-68. DOI: 10.7671/j.issn.1001-411X.2015.02.011

      Abstract (2156) HTML (445) PDF 1.11 M (1649) Comment (0) Favorites

      Abstract:【Objective】This study reported the leaf anatomical structure, stomatal characteristics, and the response mechanism of water adaptability of 25 shrubs on Tibetan Plateau, with an aim to provide a reference beneficial to afforestation and selection of drought-resistant plants on the Tibetan Plateau and an attempt to outline how to screen excellent drought-resistant plants. 【Method】Conventional paraffin section technique was used to make comparison with 12 indexes such as the thickness of leaf cuticle, upper epidermis, lower epidermis, palisade tissue, spongy tissue, and leaf thickness. The principal component analysis and subordinate function were used to develop a system to analyze and evaluate the plant drought resistance. 【Result and conclusion】The result showed that the leaves of all the 25 shrubs had typical xeromorphic structures, and the maximum leaf thickness was up to 323.00 μm, 186.25 μm on average, and the maximum epidermal layer thickness was up to 4.83 μm, with an average of 1.71 μm, which presented that upper epidermis was 30.00% thicker than lower epidermis averagely, proving that the leaf stomata were small and dense as the result of long-term adaptive evolution in a drought plateau environment. Moreover,12 indicator species differed from each other significantly.The five representative drought resistance indexes, including stomatal density, leaf thickness, palisade tissue thickness, spongy tissue thickness and stratum corneum thickness had been screened through a principal component analysis combined with the variation coefficient of each index. By using the method of subordinate function values, this study provides a sketch of content on sorting drought performance into different levels, including highly drought-resistant species, drought-tolerant species, drought-resistant in general species, and drought-sensitive species.

    • A study on the understory species diversity in various urban forests

      2015, 36(2):69-73. DOI: 10.7671/j.issn.1001-411X.2015.02.012

      Abstract (1806) HTML (553) PDF 710.04 K (1586) Comment (0) Favorites

      Abstract:【Objective】Species richness and diversity of understory plants of different types in urban forests of Guangzhou were studied, with an aim to provide the scientific basis for close-to-nature management of plantation and biodiversity conservation.【Method】Plots were set up to survey the stand structure in different types of urban forests of Guangzhou from September to October in 2012. Understory species richness, diversity and evenness index were used to study the species diversity of different types of urban forests.【Result and conclusion】The results showed that the understory species were the richest in natural forests(71 species), which belonged to 46 families and 60 genera, followed by those of plantation (31 species), which belonged to 25 families and 31 genera. The understory species of plantation in rehabilitation were relatively few (31 species), which belonged to 17 families and 30 genera. Diversity comparisons among different types of urban forests showed that the species diversity of natural forests was higher than that of the plantation. The community and the forest landscape were better as well. Therefore construction of plantation of urban forests in Guangzhou with close-to-nature forestry management ideas is of significant implication.

    • Density and medium effect on teak stump growth

      2015, 36(2):74-78. DOI: 10.7671/j.issn.1001-411X.2015.02.013

      Abstract (2389) HTML (233) PDF 669.48 K (1508) Comment (0) Favorites

      Abstract:【Objective】The purpose of this study was to analyze the density and medium effect on teak,Tectona grandis, stump quality and to find out the best density and medium for teak stump production.【Method】Six types of density and four media were used by orthogonal trial in teak stump cultivation.【Result and conclusion】The result showed that ground diameter,root diameter, underground fresh mass and other indexes of seedlings without fertilization had significant or highly significant differences among treatments when 6 and 12 months old, and all treatments could produce stumps which meet the degree of taproot enlargement (DTE) criterion(DTE>1.57). The stump quality became higher when 12 months old and V(loess)∶V(sand)=2∶1,150 plants·m-2,V(loess)∶V(sand)=2∶2,200 plants·m-2 and V(loess)∶V(sand)=3∶2,150 plants·m-2 meet the afforestation standard(DTE>1.57, 0.8 cm<ground diameter<1.6 cm). There were significant or highly significant differences in ground diameter, root diameter and underground fresh mass among different density levels and different medium compositions. The effect on teak stump quality is density>medium. Loess mixed with sand at ratio 2∶1-2∶2 as medium and density 150-200 plants·m-2 are suitable for teak stump productions when cultivated in 12 months.

    • In vitro propagation of Acacia mangium × A. auriculiformis

      2015, 36(2):79-84. DOI: 10.7671/j.issn.1001-411X.2015.02.014

      Abstract (2069) HTML (555) PDF 1.25 M (1587) Comment (0) Favorites

      Abstract:【Objective】To improve the propagation efficiency and extend the planting of Acacia mangium × A. auriculiformis.【Method】This study was carried out to explore the techniques of in vitro propagation of Acacia mangium × A. auriculiformis using stem segments with buds collected from 16-year plants as the explant. 【Result and conclusion】Current season stem segments carrying 3-5 axillary buds were sterilized with w=0.1% mercuric chloride and φ=75% alcoho1 for 15 min and 30 s respectively before they were inoculated onto MS medium. Buds could be induced successfully on MS with a shooting rate of 95.68%. The bud proliferation index was 3.97 after being transferred onto MS+6-BA 1.5 mg·L-1+NAA 0.1 mg·L-1+ sucrose 30-40 g·L-1 for 35 d. The buds all rooted on the 15th day from inoculation onto 1/2 MS medium after pre-cultured on MS supplemented with IBA 600 mg·L-1 for 4-8 h. Inoculating the proliferated buds onto 1/2 MS+IBA 1.0 mg·L-1+NAA 0.5 mg·L-1+sucrose 30 g·L-1 also generated a high rooting rate of 99.43%. The survival rate reach 94.67% after the rooted plantlet are transplanted to the yellow soil medium.

    • Effect of heat-moisture treatment on the physicochemical properties of waxy wheat starch

      2015, 36(2):85-89. DOI: 10.7671/j.issn.1001-411X.2015.02.015

      Abstract (1990) HTML (371) PDF 1.44 M (2881) Comment (0) Favorites

      Abstract:【Objective】The effect of heat-moisture treatment (HMT) including time,temperature and water content, on the physicochemical properties of waxy wheat starch was investigated. 【Method】The pasting properties such as clarity, solubility, swelling power, freeze-thaw stability, morphology, and X-ray crystallinity of the starch were evaluated. 【Result and conclusion】HMT reduced the transparency, solubility and freeze-thaw stability of waxy wheat starch. However, the swelling power of waxy wheat starch decreased and then increased. HMT did not obviously change the particle shape and size of starch granules, but the surface of starch granules became uneven, and the central of the granules became blurred; some crack and indentation appeared. HMT reduced the birefringence intensity of starch granules. The X-ray diffractometry result revealed that HMT promoted a reduction in the starch relative crystallinity,but the native and HMT starch maintained the A diffraction pattern.

    • Studies on optinmization preparation of granular activated carbon from agricultural wastes

      2015, 36(2):90-94. DOI: 10.7671/j.issn.1001-411X.2015.02.016

      Abstract (1740) HTML (298) PDF 780.47 K (2091) Comment (0) Favorites

      Abstract:【Objective】The technology conditions for preparation of granular activated carbon from agricultural wastes were optimized and the factors influencing the activation were investigated in order to find an efficient way to produce granular activated carbon.【Method】 The effects of raw materials including corn stalk, peanut shell and pine-nut shell, the content of binder and the activation time on the adsorptive performance were analyzed.【Result and conclusion】Under the designed conditions, the factor of raw material had the most significant influence, which was followed by the content of binder and the activation time.The optimum result was achieved when the raw material was corn straw, the activation time was 45 min, and the content of binder was 35%. The maximum adsorptive ability of granular activated carbon has the iodine value of 828.60 mg·g-1, the methylene cyaine adsorption value of 143.22 mg·g-1, the surface area value of 604.98 m2·g-1. The results have certain influences on improving the economic and environmental benefits of granular activated carbon.

    • Design and test of multi-dot temperature and humidity wireless data acquisition system in granary based on μC/OS-II

      2015, 36(2):95-99. DOI: 10.7671/j.issn.1001-411X.2015.02.017

      Abstract (1692) HTML (263) PDF 1.51 M (2472) Comment (0) Favorites

      Abstract:【Objective】To construct the real-time embedded multi-dot temperature and humidity wireless data acquisition system based on the granary environment control for temperature and humidity requirements and wireless data transfer characteristics. 【Method】This design applied multi-dot single bus digital temperature sensor DS18B20 and humidity sensor HIH3605 to detect granary environment, transplanted a typical real-time embedded operating system μC/OS-II to LPC2103 high performance processor platform, and chose JZ877 for wireless data transmission. 【Result and conclusion】 Practical tests proved that multi-dot temperature and humidity effective collection and monitoring (alarm) system was established. The real-time operating system has wireless data transmission, data storage and processing functions. It also has advantages of simple human-machine interface and easy of network extensibility.

    • A nonlinear rheological model of castor pressing based on stress-relaxation tests

      2015, 36(2):100-105. DOI: 10.7671/j.issn.1001-411X.2015.02.018

      Abstract (1624) HTML (405) PDF 741.70 K (1501) Comment (0) Favorites

      Abstract:【Objective】To reveal rheological characteristics in the process of castor seed press. 【Method】The stress-time relationship of stress-relaxation process was obtained by stress-relaxation tests with the uniaxial compression equipment. Based on the results and the semi-theoretical and semi-empirical method, a nonlinear rheological model was established using the improved generalized Maxwell model. The parameters of the model were achieved by nonlinear regression method.The calculated values of model were compared with the experimental results. 【Result and conclusion】The results show that the model calculated values matching well with the experimental results, which means the model can simulate nonlinear rheological properties of castor seeds when the strain is over 0.65.

    • Agricultural high temperature disaster monitoring based on meteorological data mining in Guangdong Province

      2015, 36(2):106-112. DOI: 10.7671/j.issn.1001-411X.2015.02.019

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      Abstract:【Objective】To forecast agrometeorological disasters and their levels as an example of high temperature disaster in Guangdong Province. 【Method】 Due to lack of disaster decision rule and historical disaster level data, high temperature disaster level rules were built using fuzzy clustering algorithm (FCM) based on the meteorological data in the long term. Those rules were concluded from the cluster centers of the key attribute and membership degree matrix according to the maximum membership degree principle. Based on these rules, possible disasters and their levels were predicted by dynamic meteorological data. The back propagation network algorithm (BP) in the absence of disa-ster decision rules was applied to study historical meteorological observation data and synchronous disaster level released by the meteorological bureau. The trained BP network models were accurate to discover the inner rules of disasters, so the BP network models were fit for predicting the possible disasters and their level through dynamic observation of data at many meteorological stations. 【Result and conclusion】 Comparing the results of the two methods of data mining, the neural network is found slightly better than the fuzzy clustering to predict the meteorological disaster level.

    • An analysis of volatile components in ‘Guanyinlü’ litchi by headspace solid-phase microextraction with GC-MS

      2015, 36(2):113-116. DOI: 10.7671/j.issn.1001-411X.2015.02.020

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      Abstract:【Objective】The volatile components from ‘Guanyinlü’ litchi fruit were detected .【Method】Qualitative and quantitative analyses were carried out using headspace solid-phase microextraction (HS SPME) and gas chromatography-mass spectrometry(GC-MS). 【Result and conclusion】A total of 66 volatile components were detected in ripe ‘Guanyinlü’ litchi fruits, including 20 alkenes, 11 esters, 11 alcohols, 3 ketones, 6 alkanes, 4 aldehydes, 2 aromatic compounds and 10 others, among which the major components were D-limonene; 2-buten-1-ol, 3-methyl; cyclohexene, 1-methyl-4-(1-methyle thylidene); β-myrcene; ethyl acetate; 2-buten-1-ol, 3-methyl-, acetate; 2,6-octadien-1-ol,3,7-dimethyl-,(Z); 3-methyl-3-buten-1-ol; 1-octen-3-ol; azulene, 1,2,3,5,6,7,8,8a-octahydro-1, 4-dimethyl-7-(1-methylethenyl)-,[1S-(1α,7α,8aβ)]-. The quality of ‘Guanyinlü’ litchi might be related to the presence and relative content of the alkene of aroma components.

    • Improved methods to recover and reamplify trace DNA fragments from the polymorphic PAGE band

      2015, 36(2):117-120. DOI: 10.7671/j.issn.1001-411X.2015.02.021

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      Abstract:【Objective】To optimize the methods of recovery and reamplification of trace DNA fragments from polymorphic polyacrylamide gel electrophoresis (PAGE) bands. 【Method】 Effects of four methods of dissolving polyacrylamide gel and recovery efficiencies of trace nucleic acids were obtained. 【Result and conclusion】 Dissolving/Bing buffer from Bioteke kit showed high recovery rates of DNA fragments from PAGE gels with only 1.0-7.5 ng nucleotide. Effects of amplification positively correlated with recovery efficiencies. The separation of liquid mixture and impurities was the key to successful amplification. This research forms a fast, efficient DNA recycling and amplification method from polymorphism PAGE, which provides a new approach to analyze the causes of genetic diversity.