桑黄菌原生质体的高效分离探究

以桑黄菌丝体为材料,研究不同酶解条件对桑黄菌原生质体产量的影响,以期优化出高效分离桑黄原生质体的理想条件。采用四因素三水平正交试验方法,结果表明在使用1.5%溶壁酶的酶液、菌龄为10 d的菌丝体、0.6 mol·L-1甘露醇为酶解渗透压稳定剂时,酶解时间为3 h、酶解温度为30℃、酶解转速为100 r·min-1的处理条件下,桑黄菌原生质体分离产量最高,为4625万个·m L-1。通过正交试验筛选出了分离桑黄原生质体的最佳处理方式,对于高效分离桑黄原生质体具有指导意义,为选育桑黄各种生物活性物质的高产菌株及相关遗传研究奠定基础。     

红锥的天然分布与适生条件研究

红锥是南亚热带地区优良的珍贵乡土阔叶造林树种。在充分论述红锥天然林的分布区域、植被、土壤、生态习性和生长情况的基础上,分析红锥的适生生态条件与发展前景,为科学地发展红锥人工造林提供依据。     

河西走廊胡麻生育气候条件分析及适生种植区划

分析研究得出影响该地区胡麻生育状况及产量形成的关键气象因子是5-6月各旬的平均气温和7月下旬-8月下旬的旬平均气温；其次为降水，光照的影响最小。关键期是胡麻苗期和蒴果形成阶段。并以此为依据进行了河西地区胡麻生态气候适生种植分区。提出了合理利用气候资源的途径。     

高密度培养基因工程菌的条件优化

高密度发酵是发酵工业的发展趋势之一。然而，随着发酵规模的扩大，诸多因素影响着基因工程菌的表达和产物形成量的高低。本文分析和介绍了宿主、营养、PH、温度、溶氧、比生长速率等条件对重组蛋白产生的影响及有关的研究进展。     

云烟优质适产的气候条件分析

通过对云南主烟区与省外,国外主要区的气候条件对比分析,揭示烟优质适产的天气气候特点,为烤烟种植与区划提供科学的参考依据。     

春季柑橘幼树生长对红壤水分条件的响应

以第四纪红黏土发育的红壤、2年生宫川温州蜜柑(Citrus unshiu Marc.cv.Miyaga Ma Mase)盆栽幼树为材料,采用土壤水分探头(FDR)实时监测红壤水分含量,控制红壤水分设5个处理:SMC30、SMC45、SMC60S、MC75和SMC90(分别代表红壤相对含水量的30%、45%、60%、75%和90%),研究了红壤水分条件对柑橘幼树根、叶、春梢和横径的影响。结果表明,当红壤水分为SMC75时最适合柑橘幼树生长,且柑橘幼树根、春梢和横径及叶面积、周长、宽生长参数均在此处理时达最大值。幼树根生长指标(根体积、总根长、根上下扫描面积和根表面积)均与红壤水分间呈极显著抛物线相关,叶形态指标(叶面积、叶周长、叶宽、叶长、叶长/宽比值、叶形状因子)以SMC75为界,随着红壤水分的增加或减少,其生长量均受到了一定程度的影响。SMC≤45%,幼树春梢长和横径受到显著抑制。     

壳聚糖酶生产菌的产酶工艺条件研究

壳聚糖是自然界中唯一一种带阳离子的能生物降解的高分子材料，已广泛应用于农业、医药、食品等领域。其降解产物甲壳低聚糖具有比壳聚糖更好的溶解性和生理活性，采用酶法降解具有反应条件易于控制、产物安全性高和环境污染少等独特的优越性，因此，筛选壳聚糖降解酶的方法和条件有重要意义。对壳聚糖酶生产菌所产壳聚糖酶的培养条件进行了初步研究，并对测定壳聚糖酶酶活力的DNS法进行了研究。结果表明，DNS法的最大吸收波长在495 nm。该实验所用菌种产壳聚糖酶的培养条件以培养时间为60 h，初始pH值为5.0，装液量为50 mL     

最简易的菜篮子工程项目-芽苗菜

凡是利用植物种子或其他营养贮存器官,在黑暗或弱光条件下直接生长出可供食用的芽苗、芽球、嫩芽、幼茎、幼梢,均称为芽苗类蔬菜。     

安徽省棉花生长气候条件分析及产量预报模式研究

安徽省棉花产量逐年低而不稳，产量波动相当大，造成这种差异的原因除种植制度、栽培条件等人为因素不同外，还与气候差异密切相关。从农业气象角度分析了安徽省气候条件对棉花生长的影响，并建立该省棉花产量的预报模式。     

水平槽工程适宜条件初探

由于水平槽工程土方量大和需要二次回填土，具体实施时需考虑坡度、土层厚度、地面破碎度、土壤性质、植被类型等因素，防止因水平槽工程实施不当，加速水土流失的进程。在水平槽不适合的地区，可用保水保土性能较好的鱼鳞坑代替。     

Structural and biological study of carboxymethylated Phellinus linteus polysaccharides

Polysaccharides isolated from Phellinus linteus were chemically modified by carboxymethylation, and the structural and physiological properties of the derivative were investigated. 13C NMR spectroscopy showed that the polysaccharides extracted from P. linteus contained (1-3)-beta-glucans with a (1-6)-linkage. The carboxymetehylation of the P. linteus polysaccharides was confirmed by Fourier transform infrared spectroscopy, and the degree of substitution was obtained by the potentiometric titration, which was calculated to be 0.63. The bronchoalveolar lavage experiments showed that the carboxymethylated derivative raised the nitric oxide production. In addition, the carboxymethylation stimulated in vitro cytotoxic activity against the HT1080 cell line. Thus, the derivative exhibited the enhanced activity of immune systems, which would be explained by the improved water solubility and structural changes by carboxymethylation. However, a slight decrease in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the derivative was observed.     

外源营养物对菌丝体生物质材料的生长研究及其性能表征

为优化菌丝体生物质材料配方和成品性能,该研究以菌丝生长速率为评价指标,首先通过单因素试验筛选出较佳外源营养物.再利用Plackett-Burman试验确定了影响平菇菌丝生长的主要因素为葡萄糖、酵母粉和KH2PO4,通过最陡爬坡试验和Box-Behnken响应面分析对添加物进行分析,得到较佳外源营养物组合为:质量分数为4...     

Alkali-extractable soil organic matter: An important factor affecting the mycelial growth of ectomycorrhizal fungi

Significant effects of two fractions of alkali-extractable soil organic matter (AEOM) extracted from three different soils (agricultural soil, soil from deciduous forest, soil from spruce monoculture) on mycelial growth of 17 isolates of ectomycorrhizal fungi were observed. Growth of Lactarius deterrimus, Meliniomyces bicolor and one of the isolates of Leccinum aurantiacum was significantly stimulated by acid-insoluble fraction extracted from all three soils. The stimulatory effects were frequent but inhibition of mycelial growth of some isolates was also observed. The fungal response to the presence of the organic extract in the nutrient medium was isolate-specific rather than species-specific. Organic matter extracted from different source soils affected differently the mycelial growth, the largest number of stimulatory effects being observed in an experiment where the extract was richest in trace elements Zn and Cu. At the same time, the observed stimulatory effects were not attributable to increased concentrations of trace elements in the nutrient medium. The results indicate that soil may be used as a source of extractable organic fractions which, when used as a cultivation medium additive, may significantly improve the growth of responsive fungal isolates. Under natural conditions, AEOM (traditionally designated humic substances) represent a potential factor affecting the composition of cenosis of ectomycorrhizal fungi in soil.     

Effect of soybean lipoxygenase on volatile generation and inhibition of Aspergillus flavus mycelial growth

Volatiles generated from lipoxygenase (LOX) normal and LOX deficient soybean (Glycine max) varieties with and without added lipase inhibited Aspergillus flavus mycelial growth and aflatoxin production. Soybean volatiles were analyzed using a solid phase microextraction (SPME) method combined with gas chromatography-mass spectrometry (GC-MS). Twenty-one compounds, including 11 aldehydes, three alcohols, four ketones, one furan, one alkane, and one alkene were detected in the LOX normal soybean line. However, only nine volatile compounds were observed in the LOX deficient soybean variety. The antifungal aldehydes hexanal and (E)-2-hexenal were observed in both LOX normal and LOX deficient lines and were detected at significantly higher amounts in soybean homogenate with added lipase. These aldehydes may be formed through alternate pathways, other than the LOX pathway, and may account for the inhibition of A. flavus growth observed. Other volatiles detected, particularly the ketones and alcohols, may contribute to the antifungal activity observed in both LOX normal and LOX deficient soybean lines. These results suggest that other factors, other than LOX activity, may better explain why soybeans are generally not as severely affected by A. flavus and aflatoxin contamination as other oilseed crops.     

A comparison of two methods for the estimation of mycelial biomass in leaf litter

The agar-film technique (AF) and hexosamine assay (HA) were compared as methods for measuring the biomass of fungal mycelium in plant litter by application to the growth of Mycena galopus in sterilised leaves of Fraxinus and Betula. The data were statistically analysed and the precision, sources of variation, efficiency (man-hr), sensitivity and potential accuracy compared. Satisfactory precision (coefficient of variation < 10%) was obtainable by both methods, when the experimental design was optimum for minimum variance with an acceptable amount of labour. With procedures as described, HA was slower (× 2) and less sensitive, the minimum measurable biomass difference being 0.29 v. 0.14 mg g^?1 oven-dry weight, but the efficiency of both methods could be improved. The major sources of variation were the primary litter samples (flasks), the sampling error of AF (microscope fields) and the experimental error of HA (hydrolyses and cation-exchange columns). The biomass values were broadly realistic in terms of the yield efficiency of the fungus and nutrient immobilization (C, N, P, K), but were 2–3 times larger by HA than AF. The AF technique is recommended for mixed mycelia in plant litter, although it is likely to underestimate biomass; HA is probably more accurate, but is limited to monocultures. The accuracy of AF could be greatly increased by optimizing the maceration of litter. Particular importance is placed on the necessity of obtaining more accurate factors for converting the experimental data to biomass, i.e. moisture content (AF), relative density (AF) and hexosamine content (HA) of mycelium of varying age.     

LED光质配比对香菇菌丝生长及转色期生理活性的影响

为了探究不同光质和光质配比对香菇菌丝生长及转色期的影响,该研究采用9种LED光质处理,以香菇‘L808’为试材,测定了香菇菌丝生长及转色期的生长势、转色特点及5种胞外酶活性,并采用线性回归和主成分分析方法对各指标进行评价。结果表明：在菌丝生长期,与黑暗处理（CK₁）相比,红光处理下菌丝平均生长速率显著提高12.13%（P＜0.05）,羧甲基纤维素酶（carboxymethylcellulase,CMC酶）活性平均增加66.81%,而红蓝光比为3︰7时,菌丝平均生长速率显著降低2.62%（P＜0.05）,CMC酶活性平均降低10.46%。在菌丝转色期,与白光处理（CK₂）相比,红蓝光7︰3处理第54天时菌丝完成转色,漆酶活性平均增加19.21%,而此时红光和黄光处理下的菌丝未转色,漆酶活性平均降低9.50%。菌丝生长期CMC酶活性与木聚糖酶活性、淀粉酶活性与漆酶和多酚氧化酶活性均呈正相关。菌丝转色期CMC酶活性与木聚糖酶活性、淀粉酶活性、漆酶活性呈正相关,淀粉酶活性与漆酶活性、多酚氧化酶活性呈正相关。综上所述,红光和红蓝光7︰3分别是菌丝生长期和转色期的适宜光质。该研究结果可为香菇生长的LED光质选择以及香菇工厂化栽培下的光环境控制提供理论依据。     

担子菌菌丝体呼吸速率变化规律的研究

试验研究灵芝、猴头和金针菇 3种担子菌菌丝体阶段呼吸速率随菌丝生长的变化规律结果表明 ,3种担子菌呼吸速率随菌丝生长均呈单调上升趋势 ,其数值因菌种而异 ,菌丝呼吸速率在菌丝同一生长期变化较小。 3种担子菌菌丝平均生长速度随菌丝长度的增加均呈单峰变化趋势 ,菌丝呼吸速率最大值出现时间滞后于菌丝日生长速度最大值出现时间     

The penetration of soil by mycelial strands of ectomycorrhizal fungi

Soil factors affecting growth of mycelial strands from ectomycorrhizas into surrounding soil were studied experimentally. Treated soil cores were inserted into root boxes for 4–6 weeks, then infiltrated with gelatin, sectioned, and mycelial strands harvested. Very large differences in mycelial strand growth (measured by weight) occurred between different soils, some soils completely inhibiting growth of strands of the mycorrhizal fungus Rhizopogon luteolus. Compaction of soil reduced mycelial strand penetration greatly e.g. by 80 per cent in one experiment. Soil sterilization ameliorated compaction effects. High soil phosphorus tended to increase strand growth but nitrogen level and Pseudomonas fluorescens. a common soil bacterium, had small or inconsistent effects.     

Development of an immunological technique for estimating mycelial biomass of Mycena galopus in leaf litter

Antisera were produced in rabbits against cell wall and cytoplasmic components of the mycelium of a litter-decomposing basidiomycete, Mycena galopus (Pers. ex Fr.) Kummer. The antisera were conjugated with fluorescein isothiocyanate, and positive reactions were obtained in direct and indirect fluorescent antibody (FA) tests with homologous antigens and with heterologous antigens of M. galopus from pure cultures and field material. Cross reactions occurred with fungal associates of M. galopus on Quercus litter from a deciduous woodland, but these were mostly removed by absorption with a preparation of Cladosporium herbarum Link ex Fr. Membrane filtration combined with FA staining and rhodamine-gelatin counter-staining was found to be a feasible means of estimating the biomass of FA-reactive mycelium of M. galopus in leaf litter.     

The uptake and translocation of phosphate by mycelial strands of pine mycorrhizas

Uptake and rapid translocation of ³²P-orthophosphate to Pinus radiata mycorrhizas from soil by mycelial strands of Rhizopogon luteolus was demonstrated. In greenhouse material, translocation occurred from soil for at least 12 mm and some 30–80 per cent of phosphate absorbed from 5 × 10^?6M as KH₂PO₄ was translocated. In the field, translocation occurred for 12 cm. Uptake by excised mycelial strands was metabolically mediated. Translocation occurred more rapidly when the untreated ends of strands were placed in an osmoticum: polarity in translocation was also observed. It was concluded that uptake and translocation by mycelial strands (as distinct from individual hyphae) provide an effective method for mycorrhizal exploitation of large inter-root soil volumes and assist the plants in competition for nutrients.Large differences occurred between strains of the same species in mycelial strand growth in soil. Mycelial strands of R. luteolus grew through the test soil at 1.3-2.9 mm/day and along P. radiata roots at 1.7 mm/day at 25°C day and 16°C night temperatures.