Fungistasis and general soil biostasis - A new synthesis

In most soils, fungal propagules are restricted to a certain extent in their ability to grow or germinate. This phenomenon, known as soil fungistasis, has received considerable attention for more than five decades, mostly due to its association with the general suppression of soil-borne fungal diseases. Here, we review major breakthroughs in understanding the mechanisms of fungistasis. Integration of older fungistasis research and more recent findings from different biological and chemical disciplines has lead to the consensus opinion that fungistasis is most likely caused by a combination of microbial activities, namely withdrawal of nutrients from fungal propagules and production of fungistatic compounds. In addition, recent findings indicate that there are mechanistic links between these activities leading towards an integrated theory of fungistasis. Among the potentially fungistatic compounds volatiles have received particular attention. Whereas it has long been assumed that fungistasis is the result of the metabolic activity of the total soil microbial biomass, more recent research points at the importance of activities of specific components of the microbial community. These insights into fungistasis have also formed the basis for strategies to increase general soil suppression. Besides these basic and practical aspects of fungistasis, its impact on fungal ecology, in particular on fungal exploration strategies, is discussed. Finally, we take a closer look at plant-soil feedback experiments to demonstrate the occurrence of fungistasis-like phenomena and to suggest that fungistasis may be part of a much wider phenomenon: general soil biostasis.     

重庆市三峡库区柑橘渣的营养物质和苦味物质研究

本文对重庆市三峡库区柑橘渣的营养物质和苦味物质含量进行了系统检测。结果表明,重庆市三峡库区的柑橘渣无氮浸出物、消化能和钙含量较高,氨基酸组成全面,但粗蛋白质和总磷含量低,水分、粗纤维和苦味物质含量高,作为潜在的饲料资源,经过适当处理可以大量开发作畜禽饲料。     

Effect of seawater concentration on the productivity and nutritional value of annual Salicornia and perennial Sarcocornia halophytes as leafy vegetable crops

The halophyte Salicornia was recently introduced as a fresh vegetable crop that thrives in extreme salt conditions. Two annual Salicornia and two perennial Sarcocornia ecotypes were investigated for yield production and nutritional value in response to different seawater concentrations in the irrigation solution. A harvest schedule based on a three-week cycle gave better productivity than a two-week or a four-week cycle. Total yield declined with increasing percentage of seawater above 50% in the irrigation water, however annual plants had always ca 2–3-fold higher fresh biomass in comparison to their perennial counterparts. Increased percentages of seawater in the irrigation solution had the following effects on ion concentrations in the shoots: no change in Ca²⁺ and Mg²⁺, a slight increase in K⁺, and marked elevations in Na⁺ and Cl⁻. Importantly, total polyphenol, β-carotene and ureides, all known for their antioxidant capacities, rose with increasing seawater percentage, findings that indicated improved nutritional values for Salicornia and Sarcocornia irrigated with high concentrations of seawater. Impressively, both the annual Salicornia and the perennial Sarcocornia ecotypes exhibited high total shoot lipid contents of up to 2.41 and 2.06 mg g⁻¹ fresh weight, respectively, which included an omega-3 fraction of 47.6 and 41.2% of the total fatty acid content. Moreover, the high fatty acid content of the annual Salicornia ecotype was not significantly affected by increasing seawater concentrations. In this study, we thus demonstrated the feasibility of cultivating Salicornia and Sarcocornia by applying a multiple harvest system and 100% percentages of seawater in the irrigation water generating economic yields with high nutritional value. The findings also showed that Salicornia and Sarcocornia leafy vegetables may attract additional interest as an alternative source of omega-3 polyunsaturated fatty acids for human consumption, even when the crop irrigated solely with seawater.     

琼胶寡糖诱导菜豆活性氧相关防御及机理初探

以琼胶寡糖作为激发子处理菜豆叶片,研究其诱导菜豆的抗性反应及作用机理.结果表明,100μg·mL-1的琼胶寡糖处理菜豆叶片下表皮,会促进菜豆叶片下表皮保卫细胞释放H2O2和气孔关闭.同时100μg·mL-1的琼胶寡糖喷施菜豆植株,能显著提高脂氧合酶(LOX)活性(P＜0.05),在3h达最高,并检测到具有抑菌作用的挥发性物质2,3-butanedione、2-methyl-butanoic acid、1-octen-3-ol和junipene含量增加.综上所述,100μ.g·mL-1的琼胶寡糖激发菜豆产生活性氧,并产生抗菌物质,进而增强其防御抗性.     

育苗移栽对麦套棉~（14）CO_2同化量及运转分配的影响

运用１４Ｃ示综技术，研究了营养钵育苗移栽对麦套棉１４Ｃ同化物生产、运转分配及其再分配的影响。试验结果表明，营养钵育苗移栽不仅使棉株在苗期、蕾期、花铃期的１４Ｃ同化量显著提高，而且对各期同化产物向子棉的再动员具有明显的促进作用。各期标记后３天的测定结果显示，育苗移栽增加棉苗同化物质向根系和茎中的分配，而减少向顶芽的分配，这有利于促根壮苗；蕾期同化物质向顶芽和边心的分配比例下降，这有利于控制棉花的营养生长，防止或减轻茎枝旺长，实现健壮稳长，促进花芽分化；育苗移栽在花铃期的效果表现为，促使更高比例的同化物质向生殖器官（特别是成铃）中分配，因而有利于蕾铃发育。上述影响的综合在现是单位面积上的铃数、单铃重、衣分和皮棉产量显著提高。     

The Nutritive Value of Ten Inbred Lines of Faba Beans (Vicia faba L.) in Relation to their Content of Antinutritional Constituents and Protein Quality

Ten inbred lines of fabe beans (Vicia faba L.) selected according to their quality characters have been investigated for carbohydrates, proteins, and antinutritional compounds. Digestible energy, N-balance trials with growing rats comprising determination of the protein digestibility and biological value were used as criteria in connection with comprehensive chemical-biochemical analysis. The chemical composition of the ten lines showed a considerable diversity as cad the results from the rat crisis. However, the content of vicine and convicine in all or the investigated lines were below the level previously found to have effects on the nutritive value, Starch, protein and fibre were the quantitatively dominating seed constituents, and all showed great variation among the lines. The starch content was not correlated to the quality or nutritive value of the seed, whereas the protein content was negatively correlated to the biological value and net protein utilization. These correlations followed the content of essential amino acids, lysine, threonine and methionine in the faba bean proteins. The content of the sulfur-containing ammo acids cysteine and methionine are especially dominant factors for protein quality. A simple method for total sulphur determination was found nut 10 be a sufficiently reliable technique for evaluating the content of methionine and cysteine in the faba beans. Tannin, insoluble- and total dietary fibre are phenolic aromatic compounds which were negatively correlated with the faba bean quality as expressed by digestible energy, the protein digestibility and the biological value of the faba beans. The results obtained have also revealed, that it is not sufficient to consider tannin as a group in relation to the faba bean quality. We need to separate and evaluate the different types, of phenolics in relation to the variations in quality of faba beans. Some of the low molecular weight (LMW) phenolics in the faba beans seem 10 be involved in inhibitory effects on hydrolase enzymes, chymotrypsin and trypsin. Trypsin and chymotrypsin from different animals were different in their sensitivity to faba bean inhibitors and additional experiments are required to reveal details about these effects. It has also been revealed that fructosans Lind LMW carbohydrates (oligosaccharides) are important in relation to the quality of faba beans.     

海拔对黄土高原地区赤霞珠果实酚类物质含量及抗氧化活性的影响

【目的】研究黄土高原地区2个不同海拔条件下赤霞珠果实酚类化合物含量及抗氧化活性的差异,为不同立地条件下酿酒葡萄的种植提供理论依据。【方法】以高海拔(1 280 m)坡地和低海拔(909 m)谷地种植的赤霞珠果实为研究对象,对其理化指标、酚类物质含量、抗氧化活性(DPPH自由基清除法、铜离子还原能力和超氧自由基清除能力)及10种单体酚(没食子酸、安息香酸、丁香酸、咖啡酸、阿魏酸、香豆酸、水杨酸、儿茶素、槲皮素、芦丁)含量进行分析,比较海拔对赤霞珠果实酚类物质含量及抗氧化活性的影响。【结果】坡地和谷地赤霞珠果实糖酸比分别为18.7和20.3,与坡地赤霞珠相比,谷地赤霞珠的成熟度较好;坡地和谷地赤霞珠果实总黄烷醇含量分别为330和348 mg/kg,花色苷含量分别为1 182和929 mg/kg,与坡地赤霞珠相比,谷地赤霞珠总黄烷醇含量较高,但花色苷含量较低;坡地和谷地赤霞珠果实抗氧化能力分别为9 715和9 824μmol/kg(DPPH自由基清除法),26 033和37 109μmol/kg(铜离子还原能力),71.6%和74.0%(超氧自由基清除能力),以上3种抗氧化方法的测定结果均表明,谷地赤霞珠果实抗氧化能力强于坡地,其中以铜离子还原能力测定结果差异最大;对坡地和谷地赤霞珠果实中所含的10种单体酚进行检测,除香豆酸外,其他9种单体酚含量均表现为谷地高于坡地,其中以安息香酸、咖啡酸、阿魏酸、儿茶素和槲皮素的差异较为明显。【结论】海拔对赤霞珠果实的品质有一定影响,但影响程度在不同品质指标间存在差异;在黄土高原地区,低海拔谷地赤霞珠果实的成熟度、酚类化合物含量及抗氧化能力均优于高海拔坡地赤霞珠果实。     

农药助壮素电极的研制

研制成以四间甲苯硼酸钾为活性载体的农药助壮素选择性电极。该电极在ｐＨ４．５￣９．５的１０＾－２ｍｏｌ／Ｌ氯化锂水溶液中，测定助壮素的线性响应范围为１．２×１０＾－２￣７．５×１０＾－６ｍｏｌ／Ｌ，斜率为５４．０，检测下限为１．４×１０＾－６ｍｏｌ／Ｌ。电极性能良好，适用于助壮素的快速分析。     

苹果加工品种果实中的酚类物质与褐变研究

【目的】研究加工苹果品种的酚类物质组成及其与果实褐变的关系,为选择加工品种和加工工艺提供依据。【方法】利用Folin-C法和高效液相色谱法等测定分析了10个苹果加工品种(4个酿酒品种、6个制汁品种)的果实酚类物质组成、果实褐变度及多酚氧化酶活性。【结果】果实中酚类物质的含量和比例因品种类型而异,苦涩酿酒苹果总酚含量高于甜或酸苹果。原花青素、绿原酸、表儿茶素及儿茶素是苹果果肉中含量较高的酚类物质,苹果特征酚类物质根皮苷在苦绯甘品种中大量存在。果实的褐变度与总酚、原花青素、儿茶素和根皮苷相关性较高,绿原酸与果实的褐变度相关性较低。【结论】酚类物质含量与苹果加工品种类型有关,酿酒品种的总酚含量高于制汁品种。果实中黄烷-3-醇含量对褐变度影响较大。     

应用单细胞凝胶电泳技术评价复合微生态制剂的遗传毒性

采用DNA损伤检测技术———单细胞凝胶电泳技术(SCGE,又名彗星试验)来检测复合微生态制剂对鱼类DNA的损伤,尝试利用鱼类的单细胞凝胶电泳技术来评价外来化学物质对水生生态环境的影响。试验结果表明,复合微生态制剂对鱼类的DNA没有明显的损伤作用,各试验浓度组与对照组相比没有显著性差异(P>0.05),复合微生态制剂对水体生态环境具有安全性。试验同时表明,鱼类肾细胞的DNA损伤可作为评价外来化学物质遗传毒性的生物标志物。