The Relationship Between D Hordein and Malting Quality in Barley

The contribution of grain protein to the malting quality of barley (Hordeum vulgareL.) was investigated by comparing the hordein composition and the malting quality in barley produced under a range of field conditions. Two malting cultivars, Schooner and Arapiles, and one feed cultivar, Galleon, were grown under five nitrogen regimes in each of two years. Hordein composition of the grain was determined at maturity using a combination of sodium dodecyl sulphate-polacrylamide gel electrophoresis and laser densitometry. Malt extract was determined on all samples after micromalting. Variation in growth conditions resulted in a wide range of grain protein contents and malt extract values, as well as variation in the proportions of the individual B, C and D hordeins in the grain. D hordein in particular varied over a 10-fold range. High levels of all protein fractions were associated with low malt extract. Total protein, as expected, displayed a strong, negative correlation with malt extract. The relationship was cultivar specific and separate regression lines were generated for each cultivar. Of the individual hordein fractions, D hordein displayed the strongest negative correlation with malt extract and its relationship to malt extract was independent of cultivar. A consistent relationship between D hordein and malt extract was observed across seasons, treatments and cultivars that was indicative of a causal relationship between D hordein and malting quality. D hordein therefore offers an alternative measurement to total protein for the prediction of malting quality over a wide range of environmental conditions and cultivars.     

干旱胁迫下灰色链霉菌对桔梗幼苗根际土壤酶活性、养分及微生物的影响

以不同浓度的灰色链霉菌发酵液处理干旱胁迫的桔梗根际土壤为研究对象,将不同浓度的灰色链霉菌发酵液(原液,原液稀释10倍,原液稀释50倍,原液稀释100倍(菌数1×10~8cfu·mL~(-1)),原液稀释150倍)200m L分别与花盆0~20 cm的土搅拌,无菌水作为对照(CK),土壤的持水量控制在45%左右,待桔梗生长至四叶期时,分别于7、14、21、28、35 d取其根际土壤(0~20 cm)。采用比色法和高锰酸钾滴定法测定桔梗根际土壤蔗糖酶、脲酶、过氧化氢酶、纤维素酶和蛋白酶活性的变化,稀释平板计数法测定微生物数量。结果表明,随着灰色链霉菌发酵液稀释倍数增加,桔梗根际土壤蔗糖酶、脲酶、过氧化氢酶、纤维素酶和蛋白酶活性均逐渐升高,发酵液稀释到100倍时,土壤蔗糖酶、脲酶、过氧化氢酶、纤维素酶和蛋白酶活性均达到峰值,比CK的峰值分别提高了68%、12.63%、11.53%、128.24%、43.51%。在第35天时,用灰色链霉菌发酵液稀释100倍处理干旱胁迫的桔梗根际土壤有机质、全氮、有效磷、速效钾含量比CK分别升高了280.13%、99.15%、60%和60.12%;灰色链霉菌发酵液处理的土壤中细菌不断增加,在第35天时比CK增加了355.43%,而土壤中放线菌和真菌先增加后降低,但高于CK。土壤酶活性、土壤养分因子和土壤微生物数量的相关性分析表明,脲酶与有机质、全氮、有效磷、速效钾和细菌呈极显著正相关(P0.01),纤维素酶与有机质、全氮、有效磷、速效钾、细菌和放线菌呈极显著或显著正相关,蛋白酶与有效磷、速效钾、细菌、放线菌和真菌呈极显著或显著正相关,蔗糖酶和过氧化物酶与有机质、全氮、有效磷、速效钾和细菌呈负相关且不显著,与放线菌、真菌正相关且不显著。     

Two new isopimarane diterpenes from the feces of Trogopterus xanthipes

Chemical investigation of Trogopterus Feces has led to the isolation of two new isopimarane diterpenes, wulingzhic acid A (1) and wulingzhic acid B (2). Their structures were elucidated by chemical and extensive spectral analysis. Compounds 1 and 2 exhibited weak activity of antithrombin and moderate activity of antiplatelet aggregation in vitro.     

复合酶提取绿茶茶多酚工艺及其抑菌性

以绿茶为研究对象,采用复合酶(纤维素酶和果胶酶质量比1︰1)辅助提取绿茶中茶多酚,在单因素的基础上,选择酶添加量、酶解温度、pH、乙醇浓度为影响因子,运用响应面法进行四因素三水平试验设计,研究各因素对绿茶茶多酚得率的影响,以及绿茶茶多酚的抑菌性。结果表明:响应面试验绿茶茶多酚提取的最佳工艺参数为酶添加量2.0mL,酶解温度48℃,pH4.8,乙醇浓度50%,在该条件下绿茶茶多酚得率为24.59%,接近预测值24.68%。绿茶茶多酚浓度与抑菌效果成正相关,当绿茶茶多酚浓度为1×10^-2mg/mL时,绿茶茶多酚对枯草芽孢杆菌和大肠杆菌效果较显著,抑菌率分别为46.01%和45.77%,而对金黄色葡萄球菌抑制效果不显著。     

8份强筋小麦品种抗旱性评价

为给强筋冬小麦品种的抗旱性评价和抗旱指标筛选提供理论依据,以黄淮麦区种植的8个强筋小麦品种为材料,在水培条件下设置正常供水(对照)和20%聚乙二醇(PEG-6000)模拟干旱胁迫两个处理,测定了萌发期11个抗旱相关指标、幼苗期20个抗旱相关指标,计算各指标的抗旱系数,采用主成分分析法和隶属函数法求得综合抗旱能力评价值(D值),基于D值评价萌发期和幼苗期抗旱性;在旱棚池栽条件下,测定了2种水分处理下(适时一次灌溉、雨养)籽粒产量,基于产量抗旱系数评价全生育期抗旱性。结果表明：(1)干旱处理下,8个小麦品种萌发期发芽势、发芽率等10个抗旱指标显著低于对照,根冠比显著高于对照;幼苗期叶片净光合速率、气孔导度等13个抗旱指标不同程度地低于对照,胞间CO₂浓度、SOD活性等7个抗旱指标显著高于对照。(2)与适时一次灌溉相比,雨养条件下小麦籽粒产量显著降低,降幅18.70%～28.66%,产量抗旱系数为0.713～0.813。(3)8个强筋小麦品种在萌发期和幼苗期抗旱等级不尽相同。藁8901在2个生育时期均表现出抗旱性;科大1026、郑麦7698和丰德存麦5号在幼苗期表现出抗...