芝麻叶中总黄酮的最佳提取工艺研究

该文测定了芝麻叶中总黄酮的含量，并对芝麻叶黄酮的提取工艺进行了研究。重点探讨了采用乙醇提取法和微波处理与乙醇提取相结合的方法提取芝麻叶黄酮类化合物的最佳工艺条件。试验结果表明：芝麻叶中总黄酮的含量为0.98%；乙醇提取法的最适工艺参数是浸提剂乙醇浓度为80%、浸提温度为80℃、料液比为1∶25、浸提时间为2.5 h，如此条件可使黄酮提取率达95.6%；微波处理与乙醇提取相结合的方法的最适工艺参数是微波功率200 W、微波处理时间70s，乙醇浓度为80%、浸提温度为80℃、料液比为1∶25、浸提时间为30 min，这种工艺可使黄酮提取率达95.8%。     

双频超声协同强化提取黑米黑色素的试验研究

为进一步提高超声辅助提取黑米黑色素的效果,研究探讨了双频超声协同强化提取的方法。通过对pH值、提取时间、提取温度、液料比、乙醇浓度进行单因素试验,考察各因素对黑色素提取效果的影响,利用正交试验,优化其工艺条件。试验结果表明：各因素对黑米黑色素提取的影响大小依次为：pH＞乙醇浓度＞液料比＞温度＞时间。优化后的提取工艺条件为：pH值为2、超声时间为30?min、提取温度为50℃、液料比为30?mL/g、乙醇浓度为70%。在此条件下,得出平均提取率为6.85%。对比浸渍法、加热回流提取法,超声法提取黑米黑色素具有工艺简单、节省提取时间、溶剂用量少、提取效率高、减少黑色素损失的优点。     

微波辅助提取多穗柯嫩叶黄酮工艺研究

该研究比较了微波辅助水提(MW)、微波辅助氢氧化钙溶液提取(MCW)、水提(W)、氢氧化钙溶液提取(CW)、乙醇回流(E)和甲醇回流(Me)等工艺提取多穗柯黄酮的效果，用正交设计筛选MCW工艺条件，并对材料预煮与微波处理时间的关系、氢氧化钙溶液浓度对提取效果的影响进行了探讨。结果表明，MCW提取效果明显优于W、CW、MW和E或Me；材料预煮和适当的氢氧化钙浓度可以明显提高MCW黄酮提取效果；研究得出的最佳工艺条件为：1.2%氢氧化钙水溶液，固液比1∶12，预煮时间5 min，高档功率微波处理25 min。此工艺提取率达到96%，提取物黄酮含量达到37%，是一种高效、无污染的提取多穗柯黄酮工艺。     

马兰水溶性粗多糖提取工艺的研究

该文首次报导了马兰水溶性多糖的水提醇沉工艺。采用单因子试验和L₉(3⁴)正交试验设计，研究了料水比、提取时间、提取温度和乙醇浓度对马兰水溶性多糖提取的影响。结果表明，影响多糖得率的主次因素为乙醇浓度、料水比、提取时间及提取温度；马兰水溶性多糖最佳提取工艺条件为：料水比1∶30，提取时间2 h，提取温度100℃，95%乙醇醇析。在此最佳工艺条件下，马兰水溶性多糖的得率为4.12%。     

超声波辅助提取北五味子黄酮类化合物的研究

探讨北五味子黄酮类化合物的提取方法。以北五味子为原料,研究不同溶剂结合超声波辅助提取北五味子中黄酮类化合物的工艺条件,通过单因素试验及正交试验,结果表明,最佳提取条件为:提取剂乙醇浓度60%、温度60℃、时间30min、料液比1:40。     

超声波辅助提取北五味子黄酮类化合物的研究

探讨北五味子黄酮类化合物的提取方法。以北五味子为原料,研究不同溶剂结合超声波辅助提取北五味子中黄酮类化合物的工艺条件,通过单因素试验及正交试验,结果表明,最佳提取条件为：提取剂乙醇浓度60%、温度60℃、时间30min、料液比1：40。     

勐库大叶茶中总黄酮最佳提取工艺的研究

黄酮类化合物具有多种药理作用,勐库大叶茶中含有丰富的黄酮类物质。本试验采用乙醇恒温浸提的方法提取勐库大叶茶中的总黄酮,并结合正交试验选择出最佳的提取工艺条件。结果表明4因素对勐库大叶茶中总黄酮提取得率影响的主次顺序为乙醇浓度>固液比>提取温度>提取时间,最佳提取工艺条件为乙醇浓度70%、料液比1g:30 mL、提取温度85℃、提取时间2.0 h,在此条件下总黄酮的提取率为2.096%。     

雪莲果水溶性粗多糖提取分离工艺优化

为了考察雪莲果中粗多糖的较优提取分离工艺,采用水提取法提取雪莲果中多糖,以提取温度、料液比、提取时间、乙醇终浓度为影响因素,在单因素试验的基础上进行四因素三水平的正交试验。正交试验以粗多糖得率为考察指标,优化粗多糖的提取分离工艺。四因素中提取温度对试验结果影响最大,其次是乙醇终浓度和料液比,最后是提取时间。雪莲果粗多糖较优提取分离工艺为提取温度90℃,乙醇终体积分数为80%,料液比1∶20g/L,提取时间2 h。在此条件下粗多糖得率为5.11%,粗多糖的总糖质量分数为46.2%。     

超声波辅助提取山豆根氧化苦参碱研究(简报)

为了优化山豆根氧化苦参碱的超声波辅助提取工艺,该文采用单因子试验和L9(34)正交试验设计,研究了超声波功率、超声波提取时间、超声波提取温度、乙醇浓度、液料比、浸置时间和提取液pH值对山豆根氧化苦参碱提取的影响.结果表明,影响氧化苦参碱得率的主次因素为超声波提取时间、超声波提取温度、超声波功率及浸置时间;经正交试验确定山豆根氧化苦参碱最佳提取工艺条件为:超声波提取时间150min,超声波提取温度90℃,超声波功率300W,浸置时间20 min.在此最佳工艺条件下,山豆根氧化苦参碱的得率为1.253%.与对照试验相比,得率提高了73%,纯度提高了17%.     

微波辅助提取仙人掌多糖的工艺研究

该文采用微波辅助法提取米邦塔仙人掌多糖，并与热回流提取方法进行比较。通过设计正交试验，得出优化的工艺条件：以水为提取剂，料液比1∶10(w/v)，提取2次，每次提取3 min，微波炉功率700 W，选用70%乙醇沉淀。微波提取粗多糖的得率和含量分别为6.8%和8.5%，高于热回流提取粗多糖的得率4.7%和含量8.3%。微波提取不仅缩短了提取时间，降低提取剂用量，而且提高了仙人掌多糖得率。     

Characterization of the missing diploid progenitors of the common oat

Summary The genomic formula ACD of the hexaploid oat,Avena saliva, AC for the tetraploid speciesA. magna andA. murphyi, and the hypothesis that the A genome was contributed byA. strigosa group and C genome byA. ventricosa—A. eriantha group, have derived from karyotype studies. Cytogenetic evidence, however, does not support any of the known diploid oats as possible progenitors of the hexaploid oats.A. magna, and to a lesser extent,A. murphyi, are closer to the hexaploids than other tetraploids. Morphologically, these tetraploids resemble thesterilis type, which is apparently the genuine form of the hexaploid oats, with a few important differences. Spikelet morphology of these three wild oats indicates some features that must also occur in one or more of their diploid progenitors: 1. Ventricose diaspore containing the entire spikelet, 2. Long and broad callus with blunt tip, 3. Awn insertion at the lower one quarter of the lemma, 4. Close proximity of lemma tips of the two lower florets.A. magna andA. murphyi have narrow ecological ranges and are restricted to heavy alluvial soils which are now mostly under cultivation. It is likely that on similar soil type the diploid progenitors would grow as well and a search for them should be attempted there. Morocco is the most promising area for finding the missing diploids. Not onlyA. magna andA. murphyi grow there, but except one, all other annual oat species as well.     

Litter decomposition of Acacia auriculiformis Cunn. Ex Benth. and Acacia mangium Willd. under coconut trees on quaternary sandy soils in Ivory Coast

Litter decomposition of Acacia auriculiformis and Acacia mangium on sandy soil under coconut trees was studied in a field trial using the litterbag technique. The study was conducted during 2001 and 2002 in Ivory Coast. Litterbags containing 450 g of dried leaves and 450 g of dried small stems were set up in two coconut plantations of different ages, 3 and 20 years old. Dry matter weight and concentrations of total nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and C/N ratio were determined at 90, 180, 270, and 360 days. The decomposition rate constant (k) and the half-life time decomposition of dry matter (T ¹/₂) were calculated. The study showed that A. auriculiformis and A. mangium have the same rate of decomposition on each coconut plantation. The k value varied from −1.592 day⁻¹ to −1.492 day⁻¹. The half-life time decomposition value of dry matter (T ¹/₂) ranged from 283 to 301 days. Nitrogen was released between 0 and 180 days with an N concentration for A. auriculiformis and A. mangium varying from 2.03 to 1.80% and 1.97 to 1.79%, respectively. After 180 days, the litters immobilized N. Phosphorus and Mg were released faster from A. mangium than from A. auriculiformis. A positive correlation was found between the N concentration of each Acacia species and the litter dry weight at 90 and 180 days. Likewise, C/N ratio was positively correlated with litter dry weight at 90 days.     

About the origin of the French grey shallot

The results of the isozyme analysis suggest a closer genetical connection of the French grey shallot to Allium oschaninii and A. vavilovii than to A. cepa.Abbreviations GPI glucose-6-phosphate isomerase - IDH isocitrate dehydrogenase - PDG phosphogluconate dehydrogenase - PGM phosphoglucomutase - TPI triosephosphate isomerase     

Influence of light and pH on growth and nitrogenase activity on temperate-grown Azolla

Summary We investigated the influence of light intensity and pH on growth and acetylene reduction in three strains of Azolla filiculoides and one strain of A. pinnata cultivated under ambient conditions in Naples, Italy. A. pinnata showed maximum growth and acetylene reduction activity at 65% of natural light intensity (82 Klux) and at pH 5–7. In contrast, three A. filiculoides strains showed maximum values in a wider range of light intensity (50–100%) and pH (5–9). All optimal growth conditions of light intensity and pH were obtained from the determination of doubling time for dry and fresh weight increases. The lowest doubling time for all strains was in the range 2.7–3.3 days. Under these optimal conditions, the acetylene reduction activity rates were 46 nmol ethylene h^–1 mg^–1 dry weight for two strains of A. filiculoides from California, and 90 nmol for A. filiculoides from Naples and A. pinnata from Tancheng, Peoples Republic of China. These values correspond to those reported for strains of A. filiculoides and A. pinnata cultivated in areas outside Italy where the use of Azolla as biofertilizer has resulted in increased crop production. Therefore, the strains studied here may have a similar potential in Southern Italy as a source of biomass, dry matter and nitrogenous compounds.Research work supported by CNR, Italy. Special grant I. P. R. A. Sub-project 1. Paper No. 814     

利用牧草与沼渣栽培毛木耳及其残渣改良土壤效果

以不同比例牧草与沼渣替代木屑栽培毛木耳对其产量、品质及氨基酸含量影响各异。30%草粉 +30%沼渣替代木屑效果较好,生物效率为107.5%,产量比对照高82.2%,粗蛋白、氨基酸、粗脂肪、可溶性糖含量分别比对照高3.7%、1.75%、0.13%、0.37%;以50%草粉或沼渣替代木屑其毛木耳产量分别比对照高55.1%和61.0%。山地果园连续3年施用5t/hm²沼渣、5t/hm²菌渣和5t/hm²鲜草处理区与对照相比,其红壤中腐殖酸碳含量分 别提高22.9%、26.5%和16.5%;红壤中团粒结构依次提高78.5%、79.9%和69.3%,改良土壤效果较好。     

Grain yield response of Zea mays (hybrid AE 703) to Azotobacter chroococcum H23

Summary Field experiments were conducted during 1985 and 1986 to examine the effect of Azotobacter chroococcum on the grain yield of maize. Application of 40 kg N ha^–1 plus A. chroococcum caused a significant increase in maize yield. Azotobacter inoculation was more efficient at lower doses (40 kg N ha^–1) than at high doses (80 kg N ha^–1) of urea.     

The genome donors of the groundnut/peanut (Arachis hypogaea L.) revisited

Arachis hypogaea, the cultivated groundnut is a tetraploid with an AABB genomic constitution. The available literature on the origin of groundnut reveals that there is general agreement that the cultivated groundnut has evolved from the wild tetraploid species A. monticola, with which it crosses freely to produce fertile hybrids. However, the issue of actual diploid ancestors of A. monticola is still unresolved. Both cytogenetic and molecular evidences support A. duranensis being the most probable progenitor and donor of the A genome to A. hypogaea. For the B genome, the cytogenetic evidence suggests A. batizocoi to be the most probable progenitor, but the RFLP banding pattern indicates that A. batizocoi is more distantly related to A. hypogaea than other species of section Arachis. RFLP banding pattern indicates A. ipaensis to be one of the closest species to A. hypogaea and the possible donor of the B genome. The present article critically analyzes the available data, which suggests that until an amphidiploid is produced synthetically between A. duranensis × A. ipaensis and crossed successfully with A. hypogaea to produce a fertile hybrid, this issue would remain unresolved. A. batizocoi would remain the most probable donor of the B genome because of its directly demonstrable cytogenetic affinity.     

Structural parameters and functional patterns of simulated earthworm burrow systems

Summary Earthworm burrow systems have been simulated by modelling, from field observations, five main characteristics of burrow units: density (number of burrows per unit volume), mean length, angular orientation, middle coordinates and diameter. The functional properties of the burrow systems have been analysed using structural parameters, i. e. number of full perforations, mean available burrow surface and minimal burrow spacing, and by estimating the shortest pathway through the burrow system. The simulations are used to study the effects of each of the main characteristics on structural parameters and the shortest pathway. This work reveals that the specific role of density is to lead to a threshold by determining an optimal horizontal distance, and that the mean length governs the vertical critical dimension of the system. These simulations may be applied to explain the nature of field burrow systems.     

Influence of clipping and soil water status on vesicular-arbuscular mycorrhizae of two semi-arid tussock grasses

Summary Using two tussock grasses, Agropyron desertorum, a grazing-tolerant species, and A. spicatum, a grazing-sensitive species, we measured the responses of vesicular-arbuscular mycorhizae (VAM) to clipping and soil moisture status. The clipping was carried out over a 4-year period (1982–1985). For the soil moisture × clipping studies, a rainout shelter was used to create drought stress, and irrigation was used to create high moisture conditions over a 2-year period (1984 – 1985). No consistent patterns in VAM infection frequency and VAM fungal spore counts were observed, either between species or among treatments. Increased moisture tended to increase total root and total VAM length, but there were no consistent moisture × clipping effects. Nor did the phenology of the fungus follow consistent patterns: there were similar lengths of root containing vesicles and arbuscules in 1984, and predominantly vesicles in 1985. The greatest effect was a large difference in VAM activity between years regardless of treatment, despite our attempts to use extreme environmental conditions and a rigorous sampling design. The VAM of both plant species were highly correlated. We postulate that VAM are highly plastic and that they respond to environmental pressures that we do not yet understand.     

Powdery Mildew Resistance in a Collection of Chinese Barley Varieties

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.