限食为啥能长寿

营养学家麦卡在试验中发现:在保证营养的前提下限制热量摄入,长期半饥半饱的人,寿命要比终日饱食的人长,这就是“麦卡效应”.为什么适当限食能长寿呢?美国著名免疫学家奥福尔说:限食可使机体免疫力在运动时仍保持旺盛,使免疫中枢器官——胸腺的定时紊乱得以推迟,从而延缓衰老过程. “麦卡效应”告诉我们:中老年人适当限食很重要.在保质的前提下适当减量,会使您长寿.     

SIRT1与衰老分子机理研究进展

指出了SIRT1(沉默信息调节因2相关酶1)是烟酰胺腺嘌呤二核苷酸(NAD)+依赖的组蛋白去乙酰化酶,可使多种蛋白的赖氨酸残基脱去乙酰基。SIRT1可作用于p53、FOXO、NF-κB、PPAR-γ等一系列底物,参与不同的信号途径,调控细胞的应激反应、凋亡和衰老。深入研究SIRT1对衰老的调控机理,有助于揭示衰老的复杂分子机制,并为以SIRT1为靶点延长人类寿命的新思路提供理论基础。对从SIRT1与衰老的分子机理最新研究进展进行了综述。     

衰老梨树更新复壮试验

<正>果树的自然衰老是果树生命中的必然阶段,但合理的综合管理,可以延缓衰老的进程,延长经济结果寿命。近年来,泊头市有相当一部分40a以上的梨树树势衰弱,结果很少,有的造成死亡,也有些盛果期树,树势衰弱,产量下降。究其衰老原因在以下几方面:①留枝过量,树体营养消耗过多,限制了根系生长。②)肥料单纯,造成了土壤中营养元素的比例失调,或施肥过于集中,造成根系灼伤,降低了根系的吸收功能。③水质较差,连年使用地下水,造成土壤pH值升高,土壤变碱,造成缺铁症,使树叶黄化,树势下降。④对老、弱枝过度修剪,由于树体衰弱,     

树多人长寿

健康长寿,人之同欲。树多人长寿的道理,目前得到越来越多人的普遍认同。渴望长寿是人类梦寐以求的永恒主题。从古至今,上至王侯将相,下至平民百姓,都希望自己能够健康长寿。人到底能活多少岁?一种说法认为,哺乳动物(包括人)的寿命是其生长期的5倍—7倍,人的生长发育期为20岁—25岁,则人类的自然寿命为100岁—175岁;另一种说法,生物的最高寿命约为性成熟期的8—10倍,而人类的性成熟期为14岁—15岁,按此推算,人类的最高寿命应是112岁—150岁;还有一种说法,根据细胞传代次数来推算,人体细胞体外分裂传代约50次左右,按平均每次分裂周期2年—4年…     

湿地松粉蚧蛹寄生蜂火炬松短索跳小蜂生物学特性

火炬松短索跳小蜂Acerophagus coccois Smith是湿地松粉蚧Oracella acuta(Lobdell)的原产地重要天敌。观察了火炬松短索跳小蜂羽化、交配、产卵、活动、成虫寿命和繁殖等生物学习性。结果表明,火炬松短索跳小蜂成虫寿命受温度和营养条件影响很大,雌雄蜂均需要补充营养,补充营养亦可显著延长成虫的寿命。以喂食5%蜜糖水、4~6℃保存的成虫寿命最长,雌虫平均寿命9.17d,雄虫平均寿命8.32 d;其次是供带寄主的松梢,雌雄虫平均寿命分别为5.50 d和5.43 d;平均寿命最短的是仅喂食5%蜜糖水的处理,雌雄虫平均寿命分别为4.12 d和3.98 d。室内繁殖试验表明,火炬松短索跳小蜂在广东省室内条件下能够寄生湿地松粉蚧,但子代蜂数量较少,寄生效能需进一步研究。     

板栗衰老树复壮技术要点

板栗衰老树复壮技术要点板栗树寿命很长，百年以上大树并不鲜见。这是因为板粟潜伏芽生命力极强，容易勇新景壮所致。因此，对衰老树采取相应的措施及时更新复壮是板栗生产上延长结果年限、提高板栗产量的重要内容之一。１衰老树的树相衰老树的树相，大体可分为三种类型，...     

限食—“长生不老”的灵丹妙药

最近,美国的科学家结束了一项历时15年、喂饲10万只白鼠的浩大试验,结果证明:限食可以延缓衰老、延长寿命,可能是现代最有效的“长生不老”之法。     

植物衰老机理研究进展探讨

指出了植物的衰老与自生基因和外界环境中光、温度、水分、营养等因素的影响有关，其调控机制公认的主要有自由基理论和细胞的程序死亡理论。分析了植物衰老时的生理生化变化，探讨了建立操纵植物衰老的方法，在农业生产以及园林花卉’、城市绿化、分子育种等众多实用方面具有潜在的价值。     

驻颜养生说少食·美食与美发

民谚云：“活到九十九，餐餐少一口。”　　祖国医学认为，人体是一个整体，“有储内者，必形诸外”，“视其外应，以知其内脏”。毛皮、皮肤、指甲的改变，必是脏腑功能失调或衰减所致。要想达到自然、持久的养颜长生，应依靠机体自身，而机体功能、能量的平衡，有赖于气血生化之源的脾胃健运，脾胃正常运转则依靠饮食有节、有度。把握好饮食的节与度，是养生驻颜的关键。　　日本专家的研究结果表明，少食不但可以减缓衰老，延长寿命，增强机体抵抗力、免疫力，还可以增强植物神经系统，内分泌系统的调节能力，防止骨质疏松。若机体经常处…     

防止衰老的新见解

衰老对每个人来说,在所难免。但只要加强自我保健,延缓衰老是完全可能的。最近,老年医学专家对防止衰老有益长寿提出了新的见解。维持标准体重。要求饮食定时定量,不要忽胀忽饥,凡是体重快速增减,都可以削弱皮下弹性纤维,使皮肤松弛,呈现早衰。专家们推测,45岁以上的人超过正常体重10％以上,每增加0.5公斤,寿命就可能减少29天。正常饮足水分。每天不论口渴与否,均应饮水8杯以上,天     

天然抗氧化剂的提取分离及功能研究

天然抗氧化剂是一类重要的生物活性物质,由于它可以清除人体代谢过程中产生的自由基而具有延缓机体衰老的功效.因此,研究抗氧化剂对于保障人体健康、抗老防衰、防止食品腐败等方面具有重大意义.本文在对枣中多酚物质提取和功能研究的基础上综述了天然抗氧化剂的种类、作用机理、提取分离、结构鉴别及其功能分析,旨在开发和利用天然抗氧化剂.     

日本植物香气对人体健康影响研究进展

我国城市化进程高速发展，高度城市化环境危害着城市居民的身心健康。另外，近年来随着我国老龄化进程急剧加快，保证老年人生活质量、延长健康寿命成为亟待解决的社会问题。日本曾经面临和中国国现状相似的境况，在极短的时期内经历了高速城镇化和人口老龄化的社会变迁。文中介绍了日本植物香气对人体健康影响的研究进展以及近年来的研究方向和研究内容。近年来，日本有关植物香气和健康的研究活跃，研究内容愈发细化，对受益人群的针对性更强，应用性进一步增强。同时，日本研究者也尝试拓展草药和具有传统文化意义的植物等新材料研究。通过梳理日本相关研究进展，归纳日本的研究内容和研究方法对我国相关研究的启示。     

Physiological and ecological implications of adaptive reiteration as a mechanism for crown maintenance and longevity

Reiteration is the process whereby architectural units are replicated within a tree. Both immediate (from apical buds) and delayed (from suppressed or adventitious buds) reiteration can be seen in many tree species where architectural units ranging from clusters of shoots to entire branches and stems are replicated. In large old trees and suppressed trees, delayed reiteration occurs without an obvious external stimulus such as defoliation or traumatic loss of the branch apex. This suggests that, in trees that are growth-limited, reiteration is an adaptive mechanism for crown maintenance. We discuss theories about the aging process and how delayed adaptive reiteration may help maintain crown productivity and increase longevity. These include: (1) reducing the respiration/photosynthesis ratio; (2) increasing hydraulic conductance to newly developing foliage; (3) reducing nutrient loss from the tree; and (4) rejuvenating the apical meristem. The ability to reiterate various architectural units may contribute to increasing lifetime reproductive output by prolonging tree longevity. Further studies on the physiological and ecological implications of reiteration are needed to understand its adaptive significance in the life history of trees.     

浅谈广西富硒茶的发展前景

介绍了富硒茶的功能，根据广西富硒茶的现状提出了广西茶叶应在生态资源，地理区位占优势的条件下开发富硒荼，探讨了广西富硒茶的发展前景。     

竹醋液对延长鲜切花观赏期效应的研究

用不同浓度的竹醋液对不同鲜切花进行试验,结果表明,不同浓度的竹醋液对延长玫瑰、康乃馨、非洲菊以及菊花切花观赏期效应不同,500～800倍竹醋液效果较好,每隔5 d将1～2mL原竹醋液直接施入1 L水体中,可显著改善鲜切花在离体后水分含量的减少;可使玫瑰、康乃馨、非洲菊以及菊花切花瓶插保鲜时间延长,花茎增大;延缓切花花瓣中过氧化氢酶活性的下降.试验证明:竹醋液对切花有延缓衰老、延长观赏期的作用.     

Quantifying plant response to ozone: a unifying theory

Published information about the effects of ozone on plants and ecosystems is synthesized into a conceptual model to explain the response of evergreen conifers, deciduous hardwoods and agricultural crops to ambient levels of ozone pollution. The effects of ozone on carbon balance and growth of individual plants can be quantified on the basis of concentration, external dose (concentration x duration of exposure), or uptake. For an equivalent dose within a single growing season, agricultural crops are the most sensitive to ozone, with hardwoods intermediate and conifers least sensitive. In contrast, all species display a similar decline in photosynthesis and growth in response to equivalent total uptake or uptake per leaf life span, with trees somewhat less sensitive than agricultural crops on a calendar time scale, but slightly more sensitive on a relative (leaf life span) time scale. Among species, differences in ozone uptake and response can be predicted from differences in the inherent leaf diffusive conductance.     

Modelling of bending creep of low- and high-temperature-dried spruce timber

In the current project, a finite element model is developed to analyse the long-term behaviour of timber beams. The time-dependent response of wood subjected to bending and moisture changes is investigated in terms of strains and stresses. A rheological model is implemented to capture the effects of creep, mechano-sorption and hygroexpansion. The model is validated against test results from Bengtsson and Kliger (Holzforschung 57:95–100, 2003). The results of the analysis showed that the mechano-sorptive creep of low- (LT) and high-temperature-dried (HT) timber beams can be sufficiently modelled with a spring and a single Kelvin body. The different mechano-sorptive behaviour of LT- and HT-dried specimens is considered with different mechano-sorptive and shrinkage–swelling parameters. The presented model could be used to derive general mechano-sorptive parameters: (1) for better prediction of creep over the service life and (2) to provide a basis of time-dependent probabilistic calculations for structural-sized timber in serviceability limit state.     

戒台寺和潭柘寺古树衰老的几个生理特征研究

通过对戒台寺和潭柘寺的卧龙松、自在松、抱塔松、活动松等油松及九龙松 (白皮松 )、娑罗树 (七叶树东西 2棵 )等古树的树体温度、叶绿素含量、叶及土壤矿物质含量等生理参数进行测定 ,与 40a生的油松、白皮松、七叶树进行对比 ,得出如下结论 :1 )树木的衰弱程度与其树体温度有一定相关性 ,即越衰老的树木树体温度越高 ;2 )老树的叶绿素含量一般均比对照低 ;3)衰老古树呈现明显的缺素症状。     

Use the insiders: could insect facultative symbionts control vector-borne plant diseases?

Insect vector-borne plant diseases, particularly those whose causative agents are viral, or phloem- and xylem-restricted bacteria, greatly impact crop losses. Since plants are immobile, the epidemiology of vector-borne diseases greatly depends on insect vectors, which are the only means of dissemination for many pathogens. The effectiveness of a vector-borne pathogen relies upon the vectorial capacity, which is affected by vector density, feeding activity on hosts, longevity before and after pathogen ingestion, duration of the incubation period, and vector competence. During the last decade, research on human vector-borne epidemics has stimulated interest in novel control strategies targeting different parts of the vector cycle, and our purpose here is to draw parallels between this field of research and agronomy. We review the literature on insect vectors of crop diseases and their symbiotic microorganisms with the aim of suggesting future integrated management techniques based on current research on insect-vectored human diseases. Vector transmission is a complex process and different modes of transmission are encountered irrespective of the pathogen. Facultative symbionts have varied effects on life history traits that could be used for vector population control. Symbiont selection, transformation, and their manner of dissemination are important when developing an integrated vector management system based on symbiont manipulation. In the short term, progress on our knowledge of the microflora of insect vectors of plant diseases must be made. In the long term, symbiont manipulation, which has been successfully demonstrated against human insect-vectored diseases, could be adapted to insect-borne plant diseases to increase sustainable crop production.     

Variations in leaf functional traits among plant species grouped by growth and leaf types in Zhenjiang,China

Leaf functional traits are adaptations that enable plants to live under various environmental conditions. This study aims to determine the differences in leaf functional traits among plants grouped by growth habit, leaf life span, leaf lifestyle, leaf form, and origin. Specific leaf area (SLA) of perennial or evergreen species was lower than that of annual or deciduous species because longer-lived leaves of perennial or evergreen species require more investment in structural integrity and/or defense against disturbances, especially with any resource constraint. SLA of large individuals was lower than that of small individuals. The low SLA in large individuals can improve their response to changing light and water conditions because increasing plant height is advantageous for light competition, but it can also impose a cost in terms of structural support and water transport. Petioles of plants with compound leaves were significantly longer than those of simple leaves because branching is expensive in terms of gaining height. SLA of plants increased with increasing invasiveness accordingly, and SLA of invasive plants was higher than that of their native congeners because invasive plants should invest more biomass on leaf growth rather than leaf structures per unit area to achieve a higher growth rate. Overall, variation in leaf functional traits among different groups may play an adaptive role in the successful survival of plants under diverse environments because leaf functional traits can lead to pronounced effects on leaf function, especially the acquisition and use of light. Plant species with different growth and leaf traits balance resource acquisition and leaf construction to minimize trade-offs and achieve fitness advantages in their natural habitat.