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101.
Osorio-Córdoba J LL Rodriguez-Verástegui F Díaz de León-Sánchez E Bosquez-Molina JR Verde-Calvo HB Escalona-Buendía LJ Pérez-F lores C Pelayo-Zaldívar 《Phyton》2015,84(2):375-384
Cactus stems, the cladodes of Opuntia spp. cacti, are consumed in Mexico and other countries due to their fresh and herbaceous flavor, and because of their widely known nutraceutical benefits. In order to extend the postharvest life of this vegetable, the effect of a modified atmosphere packaging (MAP) was studied in cactus stems of the cultivar Atlixco stored at 4 ± 1 °C for 20 days under three types of atmospheres: (1) air (passive atmosphere), (2) 5 kPa O2 + 4 kPa CO2, and (3) N2. During storage, the titratable acidity decreased and the color of cladodes became darker and less green; however, the 5 kPa O2 + 4 kPa CO2 atmosphere was able to preserve both quality characteristics. All modified atmospheres reduced weight loss (from 8 to <2%) and the symptoms of chilling injury, and this physiological disorder appeared earlier in controls than in MAP-stored cladodes. The levels of fermentation metabolites were low in all three evaluated atmospheres. Because of this, only cladodes stored under the N2 atmosphere were selected for furthersensory analysis of the MAP effect on odor perception as evaluated by a trained panel. Results indicated that there was no detrimental effect (atypical odors) of MAP on this sensory characteristic. We conclude that cultivar Atlixco is suitable for preservation using MAP technology. 相似文献
102.
低氧气调包装对去壳雷笋褐变和木质化的影响 总被引:9,自引:0,他引:9
研究了在厚度为0.04 mm的聚乙烯(PE)袋内充气成分为2%O2、5%CO2和93%N2于10℃下贮藏时气调袋装去壳雷笋褐变和木质化进程.与对照相比,低氧气调包装(MAP)抑制了去壳雷笋贮藏前期丙二醛(MDA)的生成,显著抑制了过氧化物酶(POD)(P<0.05)和苯丙氨酸解氨酶(PAL)活性(P<0.01),最终显著抑制了笋肉的褐变(P<0.01),显著抑制了木质素(P<0.05)和纤维素的合成,从而延长了保鲜期.去壳雷笋的褐变可能由POD和PAL活性作用引起.POD和PAL活性的增加也可能诱导了木质素的合成. 相似文献
103.
A New Approach to Distinguishing Photosynthetic Types of Plants. A Case Study in Northeast China Transect (NECT) Platform 总被引:4,自引:0,他引:4
Discriminant analysis is an important method in multivariable statistic analysis to show what type an individual should belong
to. Based on actual field photosynthetic value set obtained from our research platform, North East China Transect (NECT),
a new approach, developed from the concept and principle of discriminant analysts, was proposed to distinguish C3 and C4 plants. Indices related to plant photosynthetic capacity measured by an LCA4 photosynthesis system were selected to build the discriminant model which is based on four related parameters: net photosynthetic
rate, transpiration rate, stomatal conductance, and difference in temperature between leaf surface and atmosphere. Compared
with other approaches, the present one is fast, straightforward, and efficient.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
104.
新疆荒漠盐碱生境柽柳盐分分泌特点及其影响因子 总被引:6,自引:0,他引:6
通过对生长于新疆盐碱生境下泌盐植物柽柳的泌盐效率,水分盐分含量和蒸腾强度等生理指标的测定,研究内外因子对柽柳盐分分泌作用的影响。结果显示:柽柳蒸腾作用的日变化呈双峰曲线,蒸腾峰谷出现在光照最强、温度最高的中午。柽柳体内含水量和含盐量在日间变化不明显。但盐腺对盐分的分泌效率却显示出明显的变化,表现为:与8:00—10:00对较高的泌盐率相比,在光照较强和温度较高的10:00—20:00其分泌作用有所降低,在20:00—22:00光照和温度降低时泌盐率却有回升的趋势。通过对泌盐量与诸影响因子的关系进行分析发现,柽柳在日间对钠、钾、钙、镁,硫,氯离子的分泌量与大气湿度呈现出很好的正相关性。盐腺在白天对各离子的分泌作用强于夜间。柽柳泌盐量与叶片含盐量的关系则表现出尽管柽柳叶片钠、硫元素的含量高于钙、钾、镁、氯元素,但对钠、氯离子的分泌作用却强于其它离子。与叶含盐量相比,盐腺对氯离子的相对分泌作用最强,对钠离子其次,对钾,硫离子的相对分泌作用较弱,对钙,镁离子的分泌最低。因此,柽柳对盐分的分泌作用受到植物体盐分含量及外界环境条件共同影响,其盐腺对不同离子的分泌作用具有很强的选择性。 相似文献
105.
Campylobacter jejuni in fresh chilled chicken meat is known to be a major risk factor for human gastrointestinal disease. In the present study, the survival under chilled conditions of different C. jejuni strains exposed to different gas mixtures usually used for gas packaging of food was examined. Bolton broth and fresh, skinless chicken fillets were inoculated with six and four strains, respectively, and exposed to the gas mixtures 70/30% O(2)/CO(2), 70/30% N(2)/CO(2), and 100% N(2) (the latter only investigated in broth) at refrigeration temperature (4-5 degrees C). In broth culture, the strains survived significantly longer when exposed to 100% N(2) and 70/30% N(2)/CO(2) than in the oxygen-containing gas mixture, 70/30% O(2)/CO(2) (P<0.0001). For the two anaerobic gas mixtures, the reductions only reached 0.3-0.8 log(10) CFU mL(-1) within the same period. In the presence of oxygen, the numbers of C. jejuni were reduced by a minimum of 4.6 log(10) CFU mL(-1) over 21 days. When inoculated onto chicken fillets, the C. jejuni strains also died significantly faster in the oxygen-containing gas mixture, 70/30% O(2)/CO(2) (P<0.0001), reaching reductions of 2.0-2.6 log(10) CFU g(-1) after 8 days. In the gas mixture without oxygen (70/30% N(2)/CO(2)), no reductions were observed. 相似文献
106.
Preparations and protein chemical characterizations performed with cytochromec oxidase (E.C. 1.9.3.1) from the purple bacteriumParacoccus denitrificans are reviewed. The simplest catalytically competent complex of the enzyme consists of two subunits of 62012 and 27999 Da. The theoretical hemea/protein ratio of the purified enzyme is 22.0 nmol/mg. The amino acid sequences of both proteins are compared with examples of subunits I and II of mitochondrial terminal oxidases from the main kingdoms of eukaryotes. The significance of the emerging conserved features such as membrane penetration patterns, invariant residues, stoichiometry, and sites of prosthetic groups are discussed. TheParacoccus enzyme represents the only prokaryotic oxidase detailed so far, which is directly related to the mitochondrial oxidases by common ancestry in the growing O2 atmosphere. 相似文献
107.
108.
黄海大气中的孢粉及其对海底沉积物中孢粉组合的影响 总被引:4,自引:0,他引:4
徐家声 《Acta Botanica Sinica》1994,36(9):720-726
1978—1979 年在黄海上空共收集到孢粉321 粒,属23 个属种。春季大气中所含孢粉数量最多,秋季次之,夏季和冬季较少。大气中木本花粉含量达74% ,草本花粉23% ,孢子3% 。通过大气中孢粉与1990 年黄海表层沉积物中孢粉组合的对比,反映出大气中孢粉与海洋沉积物中孢粉属种具有明显的对应关系。海洋沉积物中的孢粉分布显现近岸草本花粉含量高,远海木本花粉含量高的规律 相似文献
109.
110.
Abstract One population of Liposcelis bostrychophila Badonnel (CA selected) was exposed to a controlled atmosphere (CA) (35% CO2 + 1% O2 , balance N2 ) for 30 generations. Another population (control) was reared under natural atmospheric conditions. Reserves of triacylglycerol, polysaccharides and free amino acids were evaluated in adults of the CA selected and the control populations in generations F15 and F30 . The utilization rate of triacylglycerol and polysaccharides in the CA exposure were also determined in generation F30 . The results indicate that the reserves of triacylglycerol and polysaccharides increased significantly during selection for CA tolerance; the higher the tolerance level, the greater the reserves. A total of 15 free amino acids constituents were detected in both populations. The total amino acid content in the CA selected population was obviously higher than that in the control population. Exposure of this population to a controlled atmosphere was associated with a steady utilization of reserves. In contrast, the unselected population responded to the controlled atmosphere by accelerated utilization of triacylglycerol and polysachharides. Comparison of utilization rates during CA exposure showed that triacylglycerol is the main energy source, and polysaccharides contribute only a small extent to the metabolic energy supply. 相似文献