Approach of allelopathy study with Arabidopsis thaliana (L.) Hevnh. and Neurospora crassa

Allelopathy in Arabidopsis seeds was investigated in the present study because there are few available reports of allelopathy studies regarding the early development stage of the plant life cycle, and because Arabidopsis is widely used as a model plant for molecular biology. When cockscomb ( Celosia cristata ) was incubated together with Arabidopsis seeds, the growth of cockscomb was promoted by Arabidopsis seeds. Exudate of Arabidopsis seeds showed a promotive activity on the growth of cockscomb and Arabidopsis itself. A new method for studying allelopathic mechanisms involving the interaction of the plant Arabidopsis thaliana (L.) Hevnh. and the fungus Neurospora crassa was suggested. Arabidopsis seed exudate and the water-soluble fraction of the exudate promoted Arabidopsis growth and reduced fungal germination, indicating that the seed exudate has a species-selective activity. Conversely, the ethylacetate-soluble fraction inhibited growth of all tested materials in the current study. These results demonstrate that the water-soluble substance(s) released from Arabidopsis seeds have species-selective activity on growth of both plants and microorganisms.     

2015―2020年国家西北内陆棉区棉花品种区域试验参试品种(系)枯黄萎病抗性评述

对2015-2020年参加西北内陆棉区区域试验的192个棉花品种(系)枯萎病、黄萎病的抗性分析,为棉花抗病育种及品种推广提供依据.结果表明,参试棉花品种(系)未出现对枯萎病和黄萎病免疫的品种;参试棉花品种(系)对枯萎病的抗性水平较高,除2018年高抗和抗病品种(系)占比为88.2％外,其他年份均在92％以上;参试的品种...     

Effect of Discontinuous Administration of β -glucan and Glycyrrhizin on the Growth and Immunity of Pacific White Shrimp Litopenaeus Vannamei

A six-week growth trial was conducted to compare the effects of different feeding strate- gies of dietary immunostimulants on the growth and immunity of white shrimp Litopenaeus vannamei （4.70 ±0.20g）. Shrimps were fed with diet containing glycyrrhizin continuously, containing β -glucan continuously, discontinuously （seven days with diet containing β -gluseven days with diet without -glucan; two days with diet containing β-glucan following five days with diet without -glucan）,     

不同蛋能比对凡纳滨对虾幼虾生长、饲料转化、血清指标和体组成的影响

导读：虾料配制时首先考虑的因子。 前言 凡纳滨对虾原产于美洲中南部的太平洋沿岸,我国于1988年引进,由于该虾生长快、适应性强、食性广、价格高、抗病力强等优点,迅速成为主要养殖品种。当前,饲料成本占总养殖成本的50～60％,而蛋白水平又是影响生长性能和饲料成本的主要因素。那么怎样才能降低饲料成本呢？通过优化蛋白能量和非蛋白能量在饲料中的比例,可以达到这一目的。如果蛋白相对于能量过量,那么,     

磷矿周围环境镉污染情况调查研究

为掌握磷矿区周围镉污染情况,确保畜禽养殖生产安全,采用电感耦合等离子体质谱法对矿区周围环境中的水源、土壤、饲草和畜禽体内的镉污染程度展开调查。结果：矿区环境中土壤、地表水镉含量均超标;畜禽中牛肾脏、牛肠、牛肺脏、羊脾脏、羊肌肉镉含量超标。结论：磷矿周围环境以及饲养的牲畜存在较严重的镉污染,从公共卫生学角度应给予高度关注。     

液氮冷媒介质对速冻饺子冻裂率的影响

研究饺子新型冻结技术,探索液氮速冻工艺对调理食品品质的作用规律。该文以饺子为研究对象,和面水面质量比、皮馅质量比、面粉品质、馅料配比、产品规格、冻结时间、冻结方式、冻结介质等诸多因素对饺子冻裂率都有重要影响。该试验以猪肉、香菇、大豆组织蛋白为饺子馅主要原料,研究了和面时的水面质量比、面团的静置时间、皮馅比、饺子在液氮池中的沉浸时间对饺子冻裂率的影响。结果表明:以上四因素对饺子的冻裂率都有不同程度的影响。和面水面质量比为56∶100、面团静置时间在10 min、皮馅质量比在1∶1.3、液氮池沉浸时间为40 s,制作好的饺子在立即速冻后的冻裂率为37%,感官评定得分为77.6。该研究为液氮沉浸速冻工艺在调理食品的应用提供了一定的理论参考。     

生姜群体光台特性的研究

利用田间同化箱对生姜的群体光合特性进行了研究。结果表明，生姜群体光合速率（ＣＰｎ）有明显的季节变化和日变化，随着季节的进展ＣＰｎ呈二次曲线型。ＣＰｎ的日变化呈单峰曲线，峰值出现在中午１２时左右。ＣＰｎ的峰值与旺盛生长季节相吻合。在本试验范围内单位土地面积的ＣＰｎ随ＬＡＩ的增加而增加，若以叶面积计算ＣＰｎ则随叶面积指数（ＬＡＩ）的增加而降低。在田间试验条件下ＣＰｎ随光强和ＣＯ２浓度的增加而增加，在自然光下未测到生姜ＣＰｎ的光饱和点。     

平欧杂种榛压条苗生根及生长情况调查研究

以科尔沁沙地栽培的辽榛3号(84-226)、辽榛7号(82-11)和达维(84-254)平欧杂种榛(Corylus heterophylla Fisch.×Corylus avellana L.)为研究对象,应用自根直立压条法进行苗木繁育,并对繁殖苗的生根情况进行统计分析,结果表明:辽榛7号的生根率最高且生根数量最多;达维的生根基径和压条苗地上部分最佳。综合分析表明,辽榛7号的压条苗生根情况最好;3个品种压条苗均达到一级苗标准,能满足生产需要。     

Somatic cell and innate immune responses in mammary glands of lactating cows to intramammary infusion of Bifidobacterium breve at pre-drying off period

Intramammary infusion of Bifidobacterium breve (B. breve)-induced somatic cell (SC) counts, chemiluminescent response (CL), lactoferrin (LF) concentrations and mastitis-causing pathogens from quarters with subclinical mastitis were measured to evaluate innate immune response of mammary glands in dairy cows at 3 to 4 weeks before drying off. SC counts in 7 quarters of 7 control cows and 5 quarters of 6 cows with mastitis increased markedly on day 1 and SC values in control cows were significantly (P<0.05) increased and returned to pre-infusion levels on day 5 after B. breve-infusion. CL values in both groups increased markedly on day 1 and then decreased after B. breve-infusion; however, CL values in cows with mastitis did not return to normal levels on day 5 and at postpartum. The CL values were highly correlated with their SC counts in milk from both groups. LF concentrations increased toward day 3 after B. breve-infusion and were higher in cows with mastitis. B. breve-infusion eliminated 16.6% (1/6) of pathogens from 6 quarters with chronic subclinical mastitis. B. breve-induced SC responses in quarters from 3 cows with mastitis showed characteristic patterns of recovery, persistent and new infections. B. breve-induced SC counts in quarters from the cows in the pre-drying off were lower (25.7–70.6%) than those of the cows in mid-lactation. The intrinsic innate immune response in cows on pre-drying off may be decreased and appears to be insufficient to eliminate pathogens from mammary gland in the pre-drying off.