插条粗度和萌芽度对降香黄檀扦插成活率的影响

在江门市林科所苗圃选择不同粗细度、不同萌芽度的降香黄檀插条进行扦插繁殖试验,每10 d进行1次成活率调查。结果表明:插条的萌芽度和粗细度均极显著影响扦插的成活率,萌芽度和粗细度的交互作用对扦插的成活率也有极显著影响;未萌芽插条扦插成活率明极显高于已萌芽插条的扦插成活率;3种粗细度的枝条中以粗细度为0.7~1.2 cm的插条扦插成活率最高;在枝条萌芽度及粗细度交互作用下,粗细度为0.7~1.2 cm的未萌芽插条扦插成活率最高,粗细度小于0.7 cm的已萌芽插条扦插成活率最低。     

C语言在线评价与测试系统的开发与探讨

随着网络教育的发展,接受网络教育和考试认证的人越来越多,在线考试正在得以迅速发展.本文简要介绍在线系统工作原理和系统配置.     

油草混播种类对油菜生产和草地生产性能的影响

为筛选与门源油菜混播效益最高的牧草种类,解决油菜连作障碍问题,提高青藏高原高海拔区土地的生产能力,本研究采用油菜混播箭筈豌豆、青稞和燕麦的方式,分时段取样,探究了油菜混播不同牧草对在不同时段牧草自身生产能力的影响,并通过土地当量比判断各混播组合的优劣。研究表明油菜-燕麦混播处理在7月6日时表现干重最高,单位面积达174.48 g；在7月21日表现为鲜重和鲜干比最高,在8月15日时表现为株高显著高于单作油菜(p＜0.05),较单作油菜高97.02%；鲜重最高,达2817.00 g。在9月11日,油菜-青稞和油菜-燕麦混播处理的株高显著高于单作油菜(p＜0.05),分别较单作油菜高64.33%和99.68%,以油菜-青稞混播处理的干重最高,达589.00 g,较单作油菜处理高147.51%。油菜-箭筈豌豆混播和油菜-燕麦混播有产量优势,油菜-燕麦混播的土地当量比最高,为1.11,土地利用效果最好。     

基于UPLC-QTOF/MS的小麦发芽代谢组学分析方法

为探究不同提取方法对发芽小麦代谢物提取效果的影响,本研究建立了基于超高效液相色谱-四级杆飞行时间质谱(UPLC-QTOF/MS)的发芽小麦非靶向代谢组学样品前处理方法和分析方法,以发芽2 d周麦26籽粒为材料,设计提取溶剂、提取方式、提取时间3个因素在3个水平上L9(34)正交试验,并通过主成分分析和聚类分析确定提取效果最佳的组合。以80%乙腈(0.1%甲酸)震摇提取30 min可检测出1609个代谢峰,说明提取溶剂对代谢物提取效果起主要作用。共鉴定出92种小麦代谢物。     

β-carotene attenuates weaning-induced apoptosis via inhibition of PERK-CHOP and IRE1-JNK/p38 MAPK signalling pathways in piglet jejunum

Weaning may cause oxidative injury, immune response impairment, apoptosis and other injuries in piglets. Oxidative and endoplasmic reticulum stress (ERS) can elicit inflammatory responses, and persistent oxidative and ERS also may lead to apoptotic cascades, which is associated with the pathogenesis of multiple diseases. β-carotene, a natural carotenoid, has potential anti-inflammatory and antioxidant functions. However, the effect of β-carotene on apoptosis in weaned piglets and the detailed molecular mechanism remain unclear. In this study, we found that β-carotene decreased malondialdehyde (MDA) levels and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in piglet serum. β-carotene could inhibit the mRNA levels of caspase-3 significantly, but had no significant inhibitory effect of the mRNA levels of caspase-9 and caspase-12 in the piglet jejunum. In addition, β-carotene decreased the activation of GRP78, CHOP, and JNK/p38 MAPK and the ratio of Bax/Bcl-2. Furthermore, β-carotene had a significant influence on the activation of ERS and apoptosis-related signals in TG-induced IPEC-J2. In the present study, β-carotene pre-treatment attenuated the ratio of Bax/Bcl-2 and prevented TG-induced increases in the level of PERK-CHOP and IRE1-JNK/p38 MAPK pathway activation in a dose-dependent manner. Overall, these findings indicate that β-carotene may protect weaning-induced apoptosis through inhibiting ERS.     

Optimisation of fertiliser rates in crop production against energy use indicators

Optimising mineral nitrogen (N) use in crop production is inevitable target as mineral fertilisers reflect one of the highest inputs both in terms of economy and energy. The aim of the study was to compare the relationship between the rate of N fertiliser application and different measures of energy parameters exemplary data for spring-wheat in boreal climate condition in Estonia in 2006–2010. The effect of mineral N with rates 0, 40, 80, 120 and 160 kg N ha⁻¹ was studied on the background of composted cow manure and without organic fertilisers. Univalent parameters, energy gain (EG) (energy output − energy input) and energy ratio (ER) (energy output/energy input) were calculated. To aggregate parameters with different units (ER and EG) we proposed two standardisation approaches for combined indices. ER maximisation gave both organic fertilisation background optimum N norms significantly lower than EG (p < 0.05) optimisation. Both the new combined indices gave optimum N norms in between the rate of ER an EG. Composted cow manure background did not affect mineral N optimisation significantly. We suggest optimisation of mineral N according to bi-dimensional parameters as they capture important features of production efficiency and are more objective using as advisory tool for sustainable production systems.     

基于B/S的农业气象自动化观测系统国家级平台设计与应用

农业气象自动化观测系统国家级平台是依托中国气象局组织的农业气象自动化观测试点工作而设计开发,平台的搭建采用B/S架构实现多级用户、跨平台登录,采用XML及JSON等数据传输格式实现国家级、省级、台站级用户信息交互,实现农业气象观测XML数据传输状态的监控、台站端设备状态的评估以及数据内容的实时查询。     

SPME/GC-MS法分析不同龙眼品种果实中的香气成分

采用 SPME/GC-MS法对4个龙眼品种果实香气成分进行了分析鉴定。结果表明，4个龙眼品种共检测出44种芳香物质，其中烷类11种，烯类18种，酯类10种，醇类3种，酮类1种，炔类1种，它们构成4种龙眼主要的香气成分。4个龙眼品种在香气组成和含量上有所差异，储良、东良、东丰、石硖中分别含有25种、24种、26种、21 种香气成分。其中，4种龙眼共有的香气成分有7种：分别是十七烷、罗勒烯(顺式)、罗勒烯(反式)、别罗勒烯、1,3,8-对-薄荷三烯、α-石竹烯、(E)-β-金合欢烯，但其相对含量都有所差异；此外，各品种也具有自己独特的香气成分，如储良特有的香气成分有9种：包括十六烷、2-甲基-4-亚甲基-5 -(2,2-二甲基环丙基)-1-戊烯、5-环丙基戊酸乙酯、二十酸乙酯、棕榈酸乙酯、9-十六碳烯酸乙酯、香叶基芳樟醇、芳樟醇、2,7-二甲基-3-辛烯-5-炔；东丰特有的3种：包括1-碘十一烷、反式，反式-法尼基酸甲酯、2-羟基十二烷酸甲酯；石硖特有的4种：包括十一烷、(-)-异丁香烯、1,3,3-三甲基-2-乙基环己烯、喇叭茶醇；东良没有特有的香气成分。     

Detection of cigarettes and other tobacco products by giant African pouched rats (Cricetomys gambianus)

If the illicit tobacco trade were eliminated, governments could gain at least $31.3 billion a year, and more than 164,000 premature deaths a year could be avoided after 2030 (Joossens, Merriman, Ross, and Raw, 2009). Dogs have been used successfully in tobacco control programs, and there is a good chance that rats could also play an important role. In the present experiment, giant African pouched rats were trained to respond to filters that had been stored together with cigarettes (i.e., soaked) and to not respond to filters that had been soaked with noncigarette items. Generalization to untrained types of tobacco was then tested. The sensitivity of 4 rats trained on filters soaked with 1 of 7 types of cigarettes ranged from 86% to 100% (mean, 95%). There was very little evidence of generalization when the rats were tested on tobacco leaves and snuff but good evidence of generalization when the rats were tested on cigarettes that had been soaked with strong-smelling additives. These findings suggest that rats may be a valuable asset in the global effort to control illicit cigarette trade.