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1.
影响香菇中甲醛含量的因素分析 总被引：2，自引：0，他引：2
本文分析了香菇在不同生产阶段甲醛产生的原因,探讨了不同加工处理方式对鲜香菇和干香菇中甲醛含量的影响,讨论了外源因素对香菇中甲醛含量检出效果的作用,以期为进一步优化香菇加工处理以及改进检测方法提供参考。 相似文献
2.
土壤缓效钾是土壤有效钾的一部分,通过对NY/T 889-2004《土壤速效钾和缓效钾含量的测定》测定缓效钾含量的前处理方法进行改进,用标准COD消解器消解替代了油浴（或磷酸浴）,改进后的方法在精密度方面平行测定最大相对相差均≤8%,在准确度方面标准物质测定的单次结果均在标准值范围之内。实际样品测定方面,改进前和改进后的方法相对相差均≤8%。改进后的方法有较好的精密度和正确度,操作更加安全,消解效率高。 相似文献
3.
用硝酸提取方法测定石灰性土壤缓效钾含量过程中,在浸提溶液中加入一滴植物油作为消泡剂,可防止浸提液沸腾时溢出管口;用硬质大试管取代三角瓶,并用油浴取代电热板,每次浸提样品数量增加到60个左右,工作效率提高3～4倍.结果表明,浸提方法改进后,同一批样品浸提液开始沸腾时间前后相差5 s左右,浸提液温度基本稳定在103.8℃,平行样检测结果的变异系数在1.2%～2.4%之间,重复样检测结果的变异系数在1.2%～3.3%之间.用改进方法测定不同含量的石灰性土壤缓效钾时,与常规方法有85%的符合率.改进方法测定值与参比土样定值平均值的相对误差在0.4%～3.8%之间. 相似文献
4.
为强化香菇中维生素D2含量,并研究中波紫外线(UV-B)对香菇营养品质、活性氧代谢相关酶活性以及超微结构的影响,本研究将鲜香菇置于0.203 mW·cm-2的UV-B紫外灯下,正反面分别照射0.5、1、2、3 和4 h,考察香菇营养品质、表观形态、抗氧化相关酶活及其超微结构结。结果表明,与对照组相比,UV-B处理2 h后维生素D2含量从0升至104.87 μg·g-1,持续延长处理时间,维生素D2含量未出现显著增加,维生素C含量整体呈先上升后下降趋势,在UV-B处理2 h时最高为46.1 μg·g-1。有机酸、可溶性糖含量、酶等对UV-B处理不敏感,均保持稳定状态;但长时间照射使香菇色泽显著加深,细胞受损,膜透性增加;UV-B处理2 h时相对电导率较对照组提高了20.61%,处理3 h时相对电导率提高了63.25%。香菇经UV-B处理2 h后,在后期贮藏过程中表现出较好的品质稳定性。本研究结果表明,2 h的UV-B照射处理有助于提高香菇维生素D2、维生素C的含量和抗氧化系统的强化,并且对于其他营养品质无显著负面影响,对提高香菇的商品价值有较好的参考价值。 相似文献
5.
氢化物发生-原子荧光法测定植物样品中的硒含量 总被引：1，自引：0，他引：1
《农业研究与应用》2018,(6)
建立了氢化物发生-原子荧光法测定植物性样品中微量硒含量的方法。样品经微波消解完全后,先赶酸至1 mL,再用HCl在100℃还原10 min,然后以10 g/L的硼氢化钾(KBH4)为还原剂,5%HCl为载流,采用氢化物发生-原子荧光光谱仪进行测定。方法检测限为0.023μg/L,加标回收率为87.5%～105.0%,RSD小于1.0%,且标准物质测定结果均在推荐值范围内。该方法灵敏度和准确度高、稳定性好,适用于大量植物性样品中微量硒元素的测定。 相似文献
6.
土壤中总铬测定方法的比较研究 总被引：5，自引：0，他引：5
采用国标GB/T 17137-1997和GB/T 17141-1997中规定的两种方法即H2SO4-HNO3-HF、HNO3-HF-HClO4法对土壤样品进行消解处理,筛选了HNO3-HF-HClO4消化体系并进行改进,再运用火焰原子吸收分光光度法测定样品中总铬（Cr）的含量。结果表明：土壤总Cr测定中的3种预处理方法的测定结果存在明显差异,改进后的HNO3-HF-HClO4法优于原国标方法,该方法消解速度快（3 ~ 4 h）且完全,大大缩短了实验时间;该方法灵敏度高（最低检出限0.04 mg/L）、准确度高（相对误差在1.3% ~ 5.0%）、加标回收率高（94.6% ~ 108.7%）,精密度好（相对标准偏差小于5.7%）,是值得推广的土壤Cr消解方法,可应用于农业环境土壤质量样品的检测。 相似文献
7.
红枣挥发性物质在烘干过程中的变化研究 总被引：9，自引：1，他引：9
新鲜成熟的团枣在25～75℃逐渐烘干，当温度在4 h升高到50℃后，控制升温速率为每4 h升高5℃，直到75℃。取鲜枣100 g及从50℃开始每隔5℃取样100 g，去核、切碎，分别用95%乙醇浸泡，蒸去乙醇得膏，然后用除去过氧化物的乙醚萃取，醚液用无水硫酸钠干燥，低温下蒸发除去乙醚后得到挥发性物质，再用气相色谱—质谱联用仪测定了上述样品的挥发性化学成分。结果表明，新鲜成熟的团枣的挥发性成分主要为13种酯类，以棕榈烯酸乙酯、肉豆蔻烯酸乙酯、亚油酸乙酯、棕榈酸乙酯、油酸乙酯、月桂酸乙酯、肉豆蔻酸乙酯等的含量较高,且其含量随着温度的升高和时间的延长而逐渐略有减少；5-羟甲基-2-呋喃甲醛和5-羟基-5，6-二氢-麦芽酚在55℃以上检出，2-呋喃甲醛在65℃以上检出，随着烘干温度逐步升高和时间增长其残留含量逐渐增高；65℃时干枣的品质最好，烘干红枣的最高温度不宜超过70℃。 相似文献
8.
《水土保持研究》2020,(6)
为了探究宁南山区柠条枝作为香菇代料栽培基质的可行性,以78%苹果木为对照,柠条枝39%、苹果木39%进行柠条枝代料栽培香菇的初步探究,对于不同处理的香菇菌丝生长、子实体发育以及营养成分状况进行了测定与分析。结果表明:加入39%的柠条枝后菌丝生长速率降低0.88 mm/d,转色天数延长12 d,生育期延长35 d,基本实现全年生产;单棒产量与生物学效率不存在显著差异,表明所选柠条枝配方对于香菇子实体发育无显著影响;营养成分中,干物质、粗纤维、必需氨基酸以及部分矿物质元素含量降低,其中粗纤维含量与陕西传统栽培基质所产香菇不存在显著差异,脂肪、氨基酸总量以及鲜味氨基酸含量增加,重金属含量均低于国家相关标准,其他营养成分差异均不显著。该研究表明,宁南山区可进行香菇反季节栽培,柠条作为香菇产业的替代性资源具有可行性。由于香菇部分养分含量降低,适宜添加比例还需进一步探究。 相似文献
9.
淹水与风干过程中土壤有效磷含量变化研究 总被引：1，自引：0，他引：1
新鲜土壤在风干过程中,随着水分含量的减少,土壤中磷的有效性产生显著变化。本文选取了4种水稻土(沙溪庙组、遂宁组、黄壤、自流井组),分别测定鲜样和风干后的样品有效磷含量。结果表明:鲜样有效磷含量高于风干样品,风干后样品的有效磷含量减少程度与土壤的基本性质(水分状况、pH值、有机质)有关,比较发现:与鲜样的水分系数呈负相关、与pH值和有机质含量呈正相关,在各影响因素中水分含量>pH>有机质。 相似文献
10.
[目的]探究不同改良剂对融雪剂盐害土壤的修复效果及其对矮牵牛生长的影响,为改良剂的大田推广提供理论依据。[方法]采用香菇菌糠、平菇菌糠和脱硫石膏3种改良剂,通过土柱室内模拟试验,对改良后土壤的pH值,土壤电导率(EC),K+,Na+,Cl-、容重和孔隙度进行测定。[结果]改良处理后,pH值均有不同程度的降低;香菇菌糠施用量为24g/kg时,降低土壤EC值效果最显著;平菇菌糠改良可以有效提高土壤中K+离子含量;对于降低土壤中Na+离子含量而言,表现为:平菇菌糠香菇菌糠脱硫石膏;香菇菌糠处理(24g/kg)对于降低土壤中Cl-离子含量、土壤容重和提高孔隙度等方面效果最显著,土壤容重比CK减少了57.3%,孔隙度增加了24.6%,使矮牵牛单株鲜重较CK增加了244.64%。[结论]当香菇菌糠施用量达到24g/kg时,改良融雪剂盐害土壤的效果最显著。 相似文献
11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options. 相似文献
14.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate. 相似文献
15.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
16.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
17.
Yoav Bashan Bernardo Salazar Ma. Esther Puente Macario Bacilio Robert Linderman 《Biology and Fertility of Soils》2009,45(6):585-594
To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse
trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus
were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB;
the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons
reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened
later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons
growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants,
no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi,
enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant.
In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after
30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination
only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity
to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as
compost or PGPB can either amplify the effect or else attenuate it. 相似文献
18.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
19.
Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value. 相似文献
20.
Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation. 相似文献