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1.
饲料添加剂用黄芩甙提取工艺条件的优化 总被引：2，自引：1，他引：2
为了优化饲料添加剂用黄芩甙提取工艺，采用L9(34)正交试验设计方法，对浸提和酸沉工艺进行了优化试验研究，采用紫外分光光度法对提取物黄芩甙进行含量测定。结果表明：浸提较优工艺为A3 B3 C2，即浸提时间1.5 h，浸提温度100℃，浸提pH 7.0；酸沉较优工艺为A′2 B′3 C′1 D′3，即保温时间1.0 h，保温温度80℃，保温pH 1.0，静置时间12 h。经两次正交试验设计所得优化提取工艺可行，提取率为91.56％，含量为94.12％。 相似文献
2.
旱作春玉米冠层及叶片瞬态气体交换及水分利用效率日变化特征 总被引：3，自引：0，他引：3
旱作作物不同尺度瞬态气体交换和水分利用效率同步观测的研究，对于节水高效农业理论研究和生产实践均具有及其重要的意义。该文采用涡度相关技术和LI-COR6400便携式光合作用测定仪测定旱作春玉米灌浆期冠层、叶片瞬时CO2和H2O汽交换速率，并分析其瞬态水分利用效率日变化特征。结果表明，旱作春玉米灌浆期0～100 cm根层土壤相对湿度为40%时，日变化过程中晴日中上部位叶片的光合速率高峰值为1.3 mg·m-2·s-1(29.82 μmol·m-2·s-1)，与同纬度地区灌溉玉米的光合速率高峰值相近；而群体下光合速率高峰值为0.9 mg·m-2·s-1(20.65 μmol·m-2·s-1)，只及同纬度地区灌溉玉米灌浆期光合速率高峰值的54.5%；群体和叶片水分利用效率高峰值分别为0.16 g(CO2)/g(H2O)和0.06 g(CO2)/g(H2O)，正午前后分别维持在0.0055～0.0123 g(CO2)/g(H2O)和0.0113～0.0197 g(CO2)/g(H2O)，叶片尺度的光合速率和水分利用效率在10∶00以后的时段内明显高于群体水平。 相似文献
3.
显热通量（sensible heat flux，H）是反映地表湍流运动的重要参数，准确获取该参数对于区域内热量交换规律的认识和农业生产及水资源的有效管理具有重要意义。涡动相关仪（eddy covariance system，EC）和大孔径闪烁仪（large aperture scintillometer，LAS）是目前生态系统水热通量的主要测量手段，但两者观测范围的空间尺度存在差异。该研究以呼伦贝尔草甸草原生态系统为对象，通过对比分析两种方法观测的显热通量（HLAS和HEC）变化特征，对两者之间的差异（ΔH）及产生原因进行探究，并且定量研究了不同因子对ΔH的影响程度。结果表明，在不同时间尺度内，HLAS和HEC的变化趋势基本一致，显热通量主要受到净辐射的驱动作用，同时ΔH与净辐射存在正相关性；对应时刻HLAS和HEC之间线性回归方程斜率为1.13，拟合优度R2为0.81，说明大孔径闪烁仪在草甸草原区有着很好的适用性；EC能量平衡闭合程度会影响HLAS和HEC之间差异，剔除能量平衡闭合率（energy balance ratio，EBR）小于0.8的数据后，HLAS和HEC之间线性回归方程斜率减小至1.05，说明能量平衡闭合程度越高ΔH越小；净辐射（net radiation，Rn）、风速（wind speed，WS）、波文比（Bowen ratio，Bowen）和饱和水汽压差（saturated water vapor pressure difference，VPD）与ΔH之间相关性显著，是ΔH的主要气象环境因子；ΔH单个影响因子的解释能力从高到低依次为净辐射、风速、EC能量平衡闭合率、饱和水汽压差、波文比，任意两个不同影响因子之间均呈现双因子增强作用，解释能力较高的交互影响因子为净辐射/风速和风速/波文比。研究结果有利于准确理解LAS与EC显热通量观测过程中的空间尺度效应，同时可为区域尺度扩展和遥感地面验证过程中通量数据的质量控制提供科学参考依据。 相似文献
4.
低温胁迫对圆叶决明的伤害及施用Ca肥防护效果的研究 总被引：2，自引：0，他引：2
圆叶决明在0℃低温下分别胁迫6、12、18、24 h后,叶片叶绿素总量较对照(25℃)下降21.89%、26.04%、28.16%、29.31%,可溶性蛋白质含量、H2O2含量和·O-2净产生速率随胁迫时间增加,活性氧清除酶SOD的活性随胁迫时间先上升后下降。施Ca2+处理可明显降低圆叶决明叶片·O-2净产生速率、H2O2含量和细胞质膜的电解质渗透率,同时提高了叶绿素含量和抑制活性氧的产生,其中以0.5 mmol/L浓度的CaCl2处理效果为最佳,说明Ca2+对低温胁迫下圆叶决明的膜结构起有效的保护作用。 相似文献
5.
针对5HM-1型脉动流化干燥机存在的脉动效果不理想、物料输送不够流畅等问题，研制了脉动振动流化干燥机，重点解决了气流分配器的设计与布置、以及气流分配的均匀性问题，增设了振动输送装置和导料装置，解决了物料的输送与“反流”问题。利用该设备对玉米和啤酒糟这两种物料进行干燥时，加热温度分别以70～75℃和65～70℃为宜，最佳脉动频率分别为3.0 Hz和2.0 Hz左右，最佳床层倾角分别为2.5°～3.8°和3.5°～4.8°，最佳气流速度分别为0.8～1.0 m/s和0.9～1.1 m/s，在设定的床层倾角和气流速度条件下，最佳振动频率均为32 Hz左右。干燥上述两种物料时，其干燥强度分别为20.87 kg(H2O)/m2·h和21.76 kg(H2O)/m2·h，单位热耗分别为5.86 MJ/kg(H2O)和4.91 MJ/kg(H2O)，单位能耗分别为7.38 MJ/kg(H2O)和6.47 MJ/kg(H2O)。 相似文献
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猪粪堆肥过程中NH3和H2S的释放及除臭微生物的筛选研究 总被引：1，自引：1，他引：1
为了治理粪便臭气污染，测定了猪粪好氧堆肥过程中NH3和H2S的释放量以及堆肥温度、pH值、含水率、水溶性铵态氮等指标。结果表明，NH3在前20天释放量占总释放量的84.6%、H2S在前13天释放量占总释放量的100%。因此，在堆肥初期的前20天是控制臭气的最佳时期。并从畜禽粪便、垃圾、土壤和堆肥中分离、纯化了一些微生物，经过初筛得到能利用NH3的微生物41株，经过复筛得到脱除H2S较好的细菌一株，与对照相比其去除率达85.7%，经鉴定该菌是松鼠葡萄球菌。 相似文献
8.
La(NO3)3 对盐胁迫下黑麦草幼苗生长及抗逆生理特性的影响 总被引：2，自引：0，他引：2
为探讨稀土元素镧(La)对牧草盐胁迫伤害的缓解作用, 采用水培法研究了叶面喷施20 mg·L-1La(NO3)3 对NaCl 胁迫下黑麦草幼苗生长及其抗逆生理特性的影响。结果表明: 盐胁迫显著抑制黑麦草幼苗的生长, 提高叶片电解质渗漏率及丙二醛(MDA)、O2- 和H2O2 含量, 其作用随盐浓度的增大而增强。超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(AsA)、谷胱甘肽(GSH)、可溶性蛋白质、脯氨酸含量随盐浓度增大呈先升后降趋势, 可溶性糖和Na+/K+比逐渐增大, 质膜H+-ATP 酶活性逐渐降低, 过氧化物酶(POD)活性及POD 同功酶数量表达增强。喷施La(NO3)3 处理可降低盐胁迫下黑麦草幼苗叶片的O2- 和H2O2 含量, 提高SOD、CAT、POD、APX 和质膜H+-ATP 酶的活性及POD 同功酶的表达, 使AsA、GSH、可溶性蛋白质、可溶性糖和游离脯氨酸含量及幼苗生物量增加, Na+/K+比降低。表明La(NO3)3 可通过提高抗氧化系统的活性和积累渗透溶质减轻盐胁迫伤害, 从而提高黑麦草的耐盐性。 相似文献
9.
为了明确类芽孢杆菌(Paenibacillus sp.)Bg1的主要抗真菌物质及其特性,本文利用抑菌圈法测定了Bg1抗菌蛋白在各种处理条件下抑菌活性的稳定性;通过60%硫酸铵沉淀、DEAE-Sephadex A50离子交换层析及Sephadex G100凝胶过滤层析进行了抗菌蛋白的分离纯化,以SDS-PAGE进行了其纯度检测。结果表明,28~100℃处理30 min、4℃存放55 d及在pH值3~7范围内菌株Bg1抗菌蛋白抑菌活性均无显著性变化,但pH值!8显著影响其抑菌活性,蛋白酶处理则使其抑菌活性完全丧失;纯化后所得抗菌蛋白分子量约10 KD。据此可知,类芽孢杆菌Bg1主要抗菌活性物质为低分子量蛋白,其对热和酸性条件及贮存时间稳定性好,具有进一步开发应用的潜能。 相似文献
10.
宰后冷却工艺对冷却猪肉肉色、质量分类的影响 总被引：6，自引：3，他引：6
研究了宰后猪胴体分别采用常规冷却工艺(宰后45 min起，(3±0.5)℃、0.4 m/s冷风冷却24 h)和二阶段急速冷却工艺(宰后35 min起，-20℃、2 m/s冷风冷却1.5 h；(3±0.5)℃、0.4 m/s 冷风冷却22.5 h)对冷却猪肉肉色、质量分类的影响。通过测定冷却猪肉pH值 和T(温度)及肉色仪器测定参数值(L*、a*、b*)和肉色分值， 确定了它们之间的相关性，并进行猪肉质量分类判断。结果表明， 常规冷却工艺冷却猪肉的T45min与pH45min、L*、肉色分值呈极显著性相关(p＜0.01)，相关系数分别为-0.37，0.45，-0.39；L*与肉色分值呈最大的负相关，相关系数达-0.80；PSE猪肉占18.6%,RFN(正常)猪肉占80.4%,而DFD猪肉仅占1.0%。二阶段急速冷却工艺在宰后初期比常规冷却工艺不仅有效降低冷却猪肉温度，而且同时使其pH值下降缓慢；其PSE猪肉降至12.0%，RFN(正常)猪肉升至87.0%，DFD猪肉仍为1.0%。提示二阶段急速冷却工艺可改善冷却猪肉肉色、进而提高其质量。 相似文献
11.
In order to identify key adaptive traits which affect productivity in Mediterranean grain and forage legumes and simultaneously determine the agricultural potential of a wide range of Vicia species, germplasm collected from the wild throughout the eastern Mediterranean was grown under semi-arid conditions in Tel Hadya, Syria (313 mm growing season rainfall). These included species currently in use in Mediterranean agriculture, such as V. sativa L., as well as those more widely used in the past-such as V. ervilia L., but also a broad selection from Section Narbonensis (B. Fedtsch. ex Radzhi) Maxted, including V. narbonensis L, V. johannis Tamamsch., V. hyaeniscyamus Mout., V. serratifolia Jacq., and V. kalakhensis Khattab et al. V. faba, a near relative of the taxa in Section Narbonensis, was included as a domesticated control. Where applicable, a representative range of subspecies was used. Accessions were chosen from a wide range of habitats in terms of latitude (31.02–40.72 decimalo), longitude (27.1–43.17 decimalo), altitude (20–1510 m), rainfall (180–1700 mm/yr) and soil depth (5–50 cm) in order to maximise diversity within species. Agricultural potential was determined by measuring seed, hay and biological yield, as well as agronomic traits such as harvest index, standing crop height, and seed size. The comparative influence of phenology and key agronomic traits such as plant habit and seed size on productivity varied tremendously between species, depending on their reproductive strategies. In V. sativa and V. ervilia, the smaller seed species which rely on long vegetative phases and growing seasons to accumulate sufficient biomass to set seed, and in which there was comparatively little agronomic variation, phenology had a large impact on yield. In early emerging taxa such as V. ervilia and V. s. subsp. sativa, with built-in long vegetative phases and growing seasons, seed yield was negatively correlated with flower ing (r = –0.86 to –0.88), whereas the opposite was the case for later emerging taxa such as V. s. subsp. nigra (L.) Ehrh. (r = 0.95). Within V. narbonensis and relatives, the larger seeded Vicia species which rely on more conservative reproductive strategies where high seedling vigour associated with large seeds enables the species to enter reproductive phases relatively early, phenology had a much smaller impact on yield than did variation of key traits such as seed weight, plant habit and pod shattering. Among the undomesticated germplasm harvest indices ranged from 0.09–0.31, hay yields from 0.1–3.4 t/ha, seed yield from 0–2.0 t/ha, and dry matter at maturity from 1.6–6.5 t/ha. Sub-specific taxonomy was crucial in determining agronomic potential. V. narbonensis var. aegyptiaca Kornhuber ex Asch. et Schweinf. showed the most potential, combining an upright habit, large seeds (212 mg) and tendency to retain intact pods after maturity, with the highest yield, harvest index and crop height of all the wild Vicia species. V. sativa subsp. sativa, V. ervilia and V. narbonensis var. narbonensis were less productive, but still showed agricultural potential. The smaller seeded V. narbonensis, var. affinis, var. jordanica H. Schäf. and var. salmonea (Mout.) H. Schäf., and their close relatives V. johannis, V. hyaeniscyamus, V. serratifolia and V. kalakhensis have little to offer Mediterranean agriculture on the basis of poor agronomy. 相似文献
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Sofie E. De Meyer Koenraad Van Hoorde Bram Vekeman Tamara Braeckman Anne Willems 《Soil biology & biochemistry》2011,43(12):2384-2396
We investigated the diversity of rhizobia isolated from different indigenous legumes in Flanders (Belgium). A total of 3810 bacterial strains were analysed originating from 43 plant species. Based on rep-PCR clustering, 16S rRNA gene and recA gene sequence analysis, these isolates belonged to Bradyrhizobium, Ensifer (Sinorhizobium), Mesorhizobium and Rhizobium. Of the genera encountered, Rhizobium was the most abundant (62%) and especially the species Rhizobiumleguminosarum, followed by Ensifer (19%), Bradyrhizobium (14%) and finally Mesorhizobium (5%). For two rep-clusters only low similarity values with other genera were found for both the 16S rRNA and recA genes, suggesting that these may represent a new genus with close relationship to Rhodopseudomonas and Bradyrhizobium. Primers for the symbiotic genes nodC and nifH were optimized and a phylogenetic sequence analysis revealed the presence of different symbiovars including genistearum, glycinearum, loti, meliloti, officinalis, trifolii and viciae. Moreover, three new nodC types were assigned to strains originating from Ononis, Robinia and Wisteria, respectively. Discriminant and MANOVA analysis confirmed the correlation of symbiosis genes with certain bacterial genera and less with the host plant. Multiple symbiovars can be present within the same host plant, suggesting the promiscuity of these plants. Moreover, the ecoregion did not contribute to the separation of the bacterial endosymbionts. Our results reveal a large diversity of rhizobia associated with indigenous legumes in Flanders. Most of the legumes harboured more than one rhizobial endosymbiont in their root nodules indicating the importance of including sufficient isolates per plant in diversity studies. 相似文献
15.
J. K. Leary N. V. Hue P. W. Singleton D. Borthakur 《Biology and Fertility of Soils》2006,42(3):215-223
Gorse (Ulex europaeus) infestation occupies over 4,000 ha of agriculture and conservation lands on the southeastern slope of Mauna Kea on the Island
of Hawaii. The aim of this investigation is to identify ecological features associated with this weed invasion by comparing
the gorse-infested areas to the surrounding uninfested areas of this landscape. The soils within the gorse infestation are
more acidic, resulting in higher levels of KCl-extractable Al and lower levels of Mehlich III-extractable Ca, Mg, Mn, and
Zn. Yet, gorse accumulates higher concentrations of Ca, Zn and, Cu than the kikuyu grass (Pennesitum clandestinum), which is ubiquitous throughout the site. The Ca:Al and Mg:Al molar charge ratios of the soils are lowest within the epicenter
of the gorse infestation, while the molar ratios are highest in the gorse apical stem tissues. All gorse plants are nodulated
and have higher nitrogen contents than the surrounding kikuyu grass. Furthermore, the δ15N of the gorse stem tissues approaches 0‰, suggesting that nitrogen is being symbiotically fixed from the atmosphere. Characterization
of the Bradyrhizobium isolated from gorse nodules shows similarities and distinctions to Bradyrhizobium isolated from the endemic legume koa (Acacia koa) within the same location. Population densities of the indigenous Bradyrhizobium are higher within the gorse rhizosphere than the kikuyu grass. Soil acidification, nutrient depletion, and symbiotic nitrogen
fixation distinguish gorse-infested areas from the surrounding uninfested areas. These observations suggest that gorse has
a competitive advantage over kikuyu grass under conditions of soil nutrient deficiency. 相似文献
16.
I. V. Rodushkin T. I. Moiseenko L. P. Kudryavtseva 《Water, air, and soil pollution》1995,85(2):731-736
The powerful mass-flow of melt water during the brief period of spring thaw provides a surge of pollutants and causes extremely toxic short term conditions. Together with the increase in total metal concentrations during this period, a redistribution in metal speciation occurs that increases the proportion of more toxic forms. Concentrations of ion-exchangeable fractions of nickel (Ni), copper (Cu), aluminium (Al), and manganese (Mn) show strong negative correlations with pH. The sum of complex metal species shows a strong positive correlation with total organic carbon (TOC). A data analysis model based on relationships observed between key parameters and metal behaviour together with gidrological data allowed an assessmrnt of the metal impact on waterbodies from accumulated airborne pollution (Ni, Cu) as well as from accelerated leaching from watersheds (Al, Mn). 相似文献
17.
The difficulty and problems encountered in the study of cultivated plants, in general and sugarcane, in particular has been
indicated. In order to understand these problems, a brief review on the taxonomy of Saccharum and closely related taxa, namely, Erianthus, Sclerostachya, Narenga and Miscanthus (generally known as ‘Saccharum complex’) has been given. A short account on the important morphological features that are specific to sugarcane has also
been stated as classification is commonly based on such morphological characters. A note has been added on the chromosome
number, origin, and distribution of the species of ‘Saccharum complex’ members. Taxonomic keys have been devised for identification of the genera of Saccharinae and for the species of
Saccharum and Erianthus occurring in India. A new combination, Sclerostachya fallax (Balansa) Amalraj et Balasundaram, has also been proposed. 相似文献
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Ten leguminous trees, four exotic species (Australian Acacia) and six indigenous species (three Sahelian Acacia spp. and three Sesbania spp.), were grown for 4 months in a natural Sahelian soil inoculated with or without the endomycorrhizal fungus, Glomus intraradices. In control trials, the determinant factor structuring the soil nematode fauna was the plant species, related plants having a similar influence on the nematode community in the soil. Soil nematode abundance increased from exotic acacias (3.3 g-1 dry soil) to native acacias (11.5 g-1 dry soil) and Sesbania species (17.6 g-1 dry soil). Plant feeding nematodes (mainly Scutellonema and Tylenchorhynchus) were significantly less abundant under exotic acacias (1.4 g-1 dry soil) than under native acacias (7.2 g-1 dry soil) or Sesbania species (7.3 g-1 dry soil). Bacterial feeding nematode density increased from exotic acacias (1.2 g-1 dry soil) to native acacias (3.0 g-1 dry soil) and Sesbania species (7.7 g-1 dry soil) as total densities. However, the differences in the structure of the nematode communities between plant groups were suppressed in the presence of the mycorrhizal fungus. In fact, no difference in nematode densities remained between plant groups when G. intraradices developed in several dominant taxa belonging to different trophic groups, particularly: Tylenchorhynchus, Apelenchina, Cephalobus and Dorylaimoidea. This study clearly indicated that inoculation with the arbuscular mycorrhizal fungus G. intraradices diminished the plant-specific effect on the structure of the soil nematode community. 相似文献
19.
One hundred and forty-seven Chinese barley varieties maintained at the Gene Bank of the National Barley Improvement Centre,
Zhejiang, and 84 progenies from these varieties were tested at the seedling stage for their reaction to 32 selected pathotypes
of Blumeria graminis f. sp. hordei. Eighteen resistance spectra were identified comprising single or combined resistances from eight known (Ml(Bw), Ml(Ch), Mla7, Mla8, Mla9, Mla13, MlaRu4 and Mlg) and six unknown resistance genes. The most frequent gene was Ml(Bw), which was found in 69 varieties and previously detected in only a few European winter barley varieties. The genes Mla8 and Ml(Ch) were also often present, but other resistance genes were rare. After inoculation, considerably fewer pathogen colonies were
observed in ‘Aiganqi’ and one line of ‘Tong5’. Twenty varieties were composed of lines with different resistance genes. China
is likely to be a region of origin of the genes Ml(Bw), Mla7, as well as three unknown genes found in original landraces and perhaps another three unknown genes detected in cultivars
bred in China. The resistances of varieties from the Zhejiang province and those originating from 11 other Chinese provinces
were quite different. Unfortunately, none of the varieties are promising sources of resistance to powdery mildew and China
does not seem to be a region suitable for identifying such sources. 相似文献
20.
Summary Feeding by the isopod, Oniscus asellus, produced changes in the sulfur constituents of leaf litter substrates (Acer negundo, A. saccharum, Fagus grandifolia, Picea rubens, and Tsuga canadensis). Isopod consumption of leaf litter generally accelerated the mineralization of carbon-bonded S and increased the formation of ester sulfate in all substrates. After the isopod egestion of A. negundo leaves, fecal decomposition over 6 weeks increased total S concentration from 68 to 120 mol S/g due to the catabolism of organic carbon. During the same period sulfate decreased from 34 to 20 mol S/g and carbon-bonded S increased from 34 to 100 mol S/g. Thus the total S pool in aged feces became enriched with organic S (83% of total S). Macroinvertebrate consumption accelerated the transformation of S constituents and the carbon-bonded S concentration approached that of the Oa organic horizon of a northern hardwood forest.Dedicated to the late Prof. Dr. M.S. Ghilarov 相似文献