Substances in dead plant tissue that stimulate infection of French bean leaves by Botrytis cinerea

Spreading lesions were found in primary leaves of French bean after inoculation with pieces of dead bean tissue on which a droplet of a suspension ofBotrytis cinerea conidia was placed, and after inoculation with conidia suspended in a diffusate from dead tissue. After fractionation of aqueous extracts from dead bean leaves, the infection-stimulating activity was confined to the fractions containing sugars and phosphate esters.The infection-stimulating activity and the concentrations of carbohydrates and orthophosphate in extracts of liquid N₂-killed bean leaves varied slightly with the manner and degree of senescence. No consistent correlation, however, was observed between infection-stimulating activity and concentration of particular components. This was also true for extracts from other dead bean tissues. The stimulation of infection exhibited by extracts from dead flowers of different plant species, however, was closely correlated with the orthophosphate concentration.Inocula containing only orthophosphate and sugars in the same concentrations as found in the extracts, did not stimulate the infection to the same extent as the extracts did. It is concluded that, in addition to simple carbohydrates and orthophosphate, one or more other compounds in the extracts are involved in the stimulation of infection.Samenvatting In primaire bonebladeren onstonden zich uitbreidende lesies na inoculatie met stukjes dood boneweefsel waarop een druppeltje van een suspensie van conidiën vanBotrytis cinerea was aangebracht, maar ook na inoculatie met condiën in een diffussat van dood weefsel. Na fractionering van waterige extracten van dode bonebladeren bleek de infectiestimulerende activiteit gebonden te zijn aan de suiker- en fosfaatesterfracties.De infectiestimulerende activiteit en de concentraties van koolhydraten en orthofosfaat in extracten van met vloeibare N₂ gedode bonebladeren varieerden enigszins met wijze en mate van veroudering. Er werd echter geen vaste correlative waargenomen tussen infectiestimulerende activiteit en concentratie van bepaalde stoffen. Dit gold ook voor extracten van andere dode boneweefsels. De infectiestimulatie teweeggebracht door extracten van dode bloemen van verschillende plantesoorten was evenwel nauw gecorreleerd met de orthofosfaatconcentratie.Inoculatie met sporensuspensies waaraan orthofosfaat en suikers waren toegevoegd tot de concentraties gelijk waren aan die in de extracten, gaf veel minder infectie dan die met sporen gesuspendeerd in de extracten zelf. Daarom wordt geconcludeerd dat naast eenvoudige koolhydraten en orthofosfaat een of meer andere stoffen in de extracten betrokken zijn bij de stimulatie van de infectie.     

施硅对硅细胞的发育及不同光照时间处理海滨雀稗可溶性糖含量的影响

探讨施硅后海滨雀稗硅细胞的变化及其对光照严重不足时可溶性糖含量的影响。试验设对照(不施硅,CK)和施硅( Si,K2SiO32 mmol/L)及光照1 h和自然光照(约12 h)处理,观察海滨雀稗叶片硅细胞的发育,测定植株可溶性总糖、蔗糖和还原性糖含量。显微观察结果表明:不施硅时叶尖硅细胞发育不良,叶基硅细胞发育较好;施硅后硅细胞发育完全,数目增多,体积增大,哑铃型突出;表明施硅促进了硅在叶片的沉积。不施硅时,植株可溶性总糖、蔗糖和还原糖含量均为光反映极显著小于12 h光照处理;1 h光照条件下,植株可溶性总糖、蔗糖和还原糖含量均为施硅处理极显著高于不施硅处理;表明光照时间不足时硅有提高可溶性糖含量的作用。施硅后硅在叶片的沉积提高了植株对有限光能的利用,弥补了光照不足引起的光合作物产物可溶性糖含量的降低,提高了草坪草对短日照光强不足的耐性。     

Optimization of the Fermentation Conditions of Sweet Oats by Response Surface Methodology

[目的]研究蒸料时间、接种前水分含量、接种量、发酵温度和发酵时间这5个因素对甜胚子甜度的影响,得到最佳发酵条件。[方法]用Plackett-Burman（PB）实验设计对影响甜胚子甜度的5个因素进行效应评价,筛选显著因素;选取最陡爬坡法选取逼近最佳响应面区域;Box-Behnken实验设计及响应面分析,确定最优发酵条件。[结果]PB设计筛选出3个对还原糖含量有显著影响的因素：接种前含水量、接种量、发酵温度,用最陡爬坡法确定中心水平后,中心组合实验法分析出其接种前含水量为45.26%,接种量为0.014%（g/g）,发酵温度为28℃,预测还原糖含量的最大值为13.16%。[结论]用优化后的条件制作甜胚子,还原糖的含量为12.91 mg/g,这一结果和预测值一致。     

国内外不同卷烟中水溶性糖·总氮·总植物碱含量的差异分析

[目的]探索国内外卷烟中水溶性总糖、还原糖、总氮、总植物碱含量的差异。[方法]采用连续流动法测定了国内外112个卷烟样品中水溶性总糖、还原糖、总氮、总植物碱含量,并对检测结果进行差异性研究。[结果]国内卷烟中的水溶性总糖、还原糖、总植物碱含量显著高于国外卷烟,而总氮含量明显低于国外卷烟。水溶性总糖、还原糖含量在国内烤烟型卷烟中最高,国外混合型最低,不同类型卷烟中的大小顺序为：国内烤烟型〉国内混合型〉国外烤烟型〉国外混合型卷烟;国内烤烟型卷烟中总氮、水溶性总糖、还原糖含量最低;国内烤烟型和混合型卷烟总植物碱含量均显著高于国外烤烟型和混合型卷烟,但国内烤烟型和混合型之间以及国外烤烟型和混合型之间均无显著性差异。国内烤烟型中的1类烟水溶性总糖、还原糖含量最高,总氮含量最低;在不同价位卷烟中水溶性总糖、还原糖含量的大小顺序为：1类〉2类〉3类〉4类。[结论]为研究国内外不同卷烟特点和烟叶原料在工业中的合理使用提供参考。     

不同色泽无花果果皮色素变化特征及其与果实糖分累积的关系

以5个不同果皮颜色的普通型无花果品种的秋果为试材,研究果实发育过程中果皮色素的变化,以及果皮色素含量与果实糖分累积的关系。结果表明:无花果果皮中叶绿素含量先升后降,类胡萝卜素含量先降后升,花色苷含量在成熟期呈持续上升的趋势。无花果果皮颜色是叶绿素、类胡萝卜素、花色苷等共同作用的结果,果实成熟期不同色素的含量因品种而异,红色和紫色品种果皮中的花色苷含量远高于黄色和黄绿色品种。紫色品种M121成熟期不仅花色苷和类胡萝卜素含量最高,而且叶绿素含量在5个品种中名列第二,一方面揭示了决定无花果色泽的色素多样性,另一方面表明了M121品种在抗氧化活性等方面具有的潜在的优势。无花果成熟过程中果实中的葡萄糖、果糖和蔗糖含量持续上升,可溶性糖的大量积累早于花色苷的大量积累。各品种叶绿素含量与可溶性糖含量均呈负相关,类胡萝卜素和花色苷与可溶性糖含量呈正相关。     

Biochemical Characterization of Mycoplasma bovirhinis,Mycoplasma dispar and Recent Bovine Isolates of Mycoplasma canis

The pattern and kinetics of substrate utilization by the type strains of Mycoplasma canis, M. bovirhinis and M. dispar and ten recent M. canis isolates from cattle were determined. Metabolism of a range of sugars and organic acids by M. dispar was detectable by measurement of oxygen uptake. Organic acids were not utilized by M. bovirhinis or M. canis, and there was no oxygen uptake during metabolism of glucose or other sugars, as monitored by a pH-change method. The M. canis strains varied in their ability to metabolize sugars; seven of the isolates from cattle had the distinctive ability to metabolize sucrose, and one isolate, plus the type strain (from a dog), metabolized N-acetylglucosamine. The M. bovirhinis strain metabolized maltose. However, all the test strains oxidized glycerol at high rates and with a high affinity. Oxidation of glycerol has been reported for other mycoplasmas from the bovine respiratory tract and leads to the production of hydrogen peroxide, a potential virulence factor.     

节水栽培对小麦生育期及生理生化的影响

研究了节水栽培对小麦全生育进程及叶片可溶性糖、脯氨酸和叶绿素含量的影响。结果表明 :轻度、中度和重度水分胁迫 ,小麦生育期平均分别比对照提前 3、4和 6d。可溶性糖含量在不同的生育时期随水分胁迫程度有不同的变化规律 ;脯氨酸含量随水分胁迫程度的增加而增加 ,其中以孕穗期的含量最大 ;有利于提高小麦叶绿素含量的节水模式为 :抽穗期、灌浆期、乳熟期土壤水分分别控制在田间最大持水量的 60 %～ 65 %、75 %～ 80 %、60 %～ 65 %。     

Determination of neutral sugars in soil by capillary gas chromatography after derivatization to aldononitrile acetates

We have quantified ribose, rhamnose, arabinose, xylose, fucose, mannose, glucose, and galactose in soil by gas chromatography (GC) simultaneously after converting to aldononitrile acetate derivatives. A recommended single-hydrolytic step by 4 M trifluoroacetic acid (TFA) at 105 °C for 4 h was more effective for releasing soil neutral sugars from non-cellulosic carbohydrates and better suited to our purification procedure compared with the sulphuric acid hydrolysis. Linearity of the GC detection for each neutral sugar was in the range of 10-640 μg ml⁻¹ and the recovery of neutral sugars from the spiked soil samples ranged from 76% to 109.7%. The coefficients of variation of the neutral sugars in four soils were lower than 2.0% for the instrument and 4.6-7.6% for the whole determination procedures. Compared with the trimethylsilyl (TMS) derivatization, the recovery of our newly modified method was more satisfactory and the reproducibility of ribose was improved significantly. Moreover, the aldononitrile acetate derivative was more stable than TMS derivative. Therefore, it is a promising approach suitable for a routine use in the quantitative analysis of soil neutral sugars, since it is fast, sensitive, and reproducible.     

Elevated CO2 does not favor a fungal decomposition pathway

We examined the effect of prolonged elevated CO₂ on the concentration of fungal- and bacterial-derived compounds by quantifying the soil contents of the amino sugars glucosamine, galactosamine and muramic acid. Soil samples were collected from three different terrestrial ecosystems (grassland, an aspen forest and a soybean/corn agroecosystem) that were exposed to elevated CO₂ under FACE conditions for 3-10 years. Amino sugars were extracted from bulk soil and analyzed by gas chromatography. Elevated CO₂ did not affect the size or composition of the amino sugar pool in any of the systems. However, high rates of fertilizer N applications decreased the amount of fungal-derived residues in the grassland system. We suggest that these results are caused by a decrease in saprophytic fungi following high N additions. Furthermore, our findings imply that the contribution of saprophytic fungi and bacteria to SOM in the studied ecosystems is largely unaffected by elevated CO₂.