Alfalfa Phytoestrogen Content: Impact of Plant Maturity and Herbage Components

Legumes contain a range of non‐nutritional phytochemicals that may have health‐promoting effects in humans. In this study, we determined the concentrations of four phytoestrogens (coumestrol, apigenin, luteolin and quercetin) in field‐grown alfalfa (Medicago sativa L.). Differences between plants of different stages of maturity, between plant parts, and different canopy segments were assessed. The concentration of individual phytoestrogen in whole herbage varied between 15 and 225 μg g^?1 dry matter (DM) and was strongly affected by stage of maturity. Coumestrol and apigenin concentrations were highest at early vegetative stages, luteolin and quercetin at early vegetative and late flowering stages. All phytoestrogens were found in lowest concentrations at the early flowering stage (average 68 μg g^?1 DM); stage at which alfalfa is usually harvested when used as a forage source for animals. At vegetative stages, apigenin was the predominant phytoestrogen in herbage followed by coumestrol, the reverse being observed upon initiation of flowering; luteolin and quercetin were found at all stages in similarly lower concentrations. Concentrations of luteolin, quercetin and apigenin were 225, 410 and 690 % greater, respectively, in flowers than in leaves or stems; coumestrol concentration was similar between plant parts. In flowers and stems the predominant phytoestrogens were apigenin and quercetin, followed by coumestrol and luteolin. Similar concentrations (average 26 μg g^?1 DM) of each of the four phytoestrogens were found in leaves. Concentrations through the herbage canopy varied and were greatest at >60 cm from the soil surface for apigenin and coumestrol, but greatest at >60 and 0–20 cm for quercetin and at 0–20 cm for luteolin. The results suggest that if alfalfa is to be used as a source of phytoestrogens and is harvested for the production of herbal supplements or nutraceuticals, management will need to be adapted.     

槟榔红色素的抗氧化活性

测定槟榔红色素(areca red pigment,AP)对 DPPH·和·OH的清除能力、对脂质体过氧化的抑制能力、对Fe2+的络合能力,并测定其还原能力.结果表明:槟榔色素对DPPH·、·OH的清除能力较强:对脂质体过氧化的抑制能力很强,抑制率高达79.84%;与VE、没食子酸(gallic acid,GA)、BHT相比,槟榔色素的还原力、对Fe2+的络合能力较弱.说明槟榔红色素是较好的抗氧化剂.     

不同稀释液对藏獒精液保存效果的影响

比较了8种稀释液在藏獒精液冷冻保存和低、常温保存(5 ℃,10 ℃,15 ℃,20 ℃)的效果.结果表明:2号和8号稀释液在冷冻保存时效果最好,精子活力和顶体完整率分别达到0.40和49%,与对照组相比差异显著(P<0.05).在藏獒的低温、常温保存试验中,所有稀释液在15 ℃时保存时间最长,综合考虑,7号液保存效果最好;在15℃时精子平均存活时间为103 h,显著高于对照组和其它稀释液(P<0.05).     

新的信息资源环境下图书馆员角色转变的思考

本文分析了信息时代图书馆员角色转变的几个重要因素及特点,揭示了新时代图书馆员应承担的几种重要角色,对信息时代图书馆员的发展进行了探讨.     

3种农药的微核效应研究

运用蚕豆根尖微核技术研究3种农药(甲胺磷、甲基硫菌灵和盐酸吗啉胍)在不同浓度下的诱变效应。结果表明,3种农药诱发蚕豆根尖细胞微核率与对照组相比均有不同程度的上升(P<0.05或P<0.01),农药浓度与微核率呈剂量-效应关系,盐酸吗啉胍的诱变效应大于其他2种农药。     

β-葡聚糖对啤酒易滤性影响的研究

通过对啤酒中β-葡聚糖的定性定量分析和啤酒易滤性的测定,发现溶解状态的β-葡聚糖对啤酒的过滤没有明显的影响,而β-葡聚糖凝胶对啤酒过滤有严重影响.啤酒中β-葡聚糖凝胶的分子量在300 000以上,当含量达到20 mg/1时,就会使啤酒膜过滤困难.啤酒的易滤性与β-葡聚糖含量之间里r=-0.222的不显著负相关,而与β-葡聚糖凝胶的含量之间呈r=-0.841~(***)的极显著负相关.     

对农业推广的信息服务

本文论述了农业信息服务与农业推广的相互关系，分析了图书馆在农业推广的农业信息服务工作中的作用和功能，并提出了相关的一些构想。     

Landscape and habitat factors affecting cabot's tragopan Tragopan caboti occurrence in habitat fragments.

Cabot's tragopan Tragopan caboti is an endemic and endangered pheasant of the lower montane forests of southeastern China. The typical habitats of the tragopan have been seriously fragmented because of forest management for timber production and farmland reclamation in recent years. The effects of the fragment size and isolation on the distribution of the cabot's tragopan were studied in Wuyanling Natural Reserve. Thirty one habitat fragments (2.5-48.5 ha) surrounded by non-habitat sapling coniferous forests, in an intensively managed forested landscape, were surveyed over four seasons for the occurrence of cabot's tragopan. Five of the 31 fragments were occupied in all four seasons and nine were not occupied. Both landscape and habitat factors affected the occurrence of cabot's tragopan, with landscape factors having the greatest effect. Large and less isolated habitat fragments containing a larger amount of the tree Daphniphyllum macropodum were occupied significantly more often than small, isolated fragments. The appearance of cabot's tragopan in the habitat fragments was best explained by the size of the fragments, the distance to the nearest suitable habitat and the amount of macropdous daphniphyllum trees. Our results could be used to improve the management of the forests where Cabot's tragopan occurs in southeastern China.     

能源甘蔗的开发利用

本文介绍国内外能源甘蔗育种现状，慨述能源甘蔗在能源、糖料、饲料等方面的利用及其副产品的综合开发利用，说明能源甘蔗作为一种新型的生物能源，具有广阔的发展前景。     

番茄早疫病抗病性鉴定方法

 早疫病是番茄的主要病害,在我国南北方发生较严重,常给生产造成很大损失。进行抗病育种是解决早疫病的有效途径,此工作在国内已受重视,而抗病性鉴定方法,却是抗病育种的重要环节。