刨花板生产系统的PLC设计

通过对刨花板生产系统中的送板过程、翻板过程、锯边切割、堆垛并送出等生产工艺及生产流程的研究,以及对刨花板生产系统中电气控制系统的剖析,设计出基于PLC刨花板生产系统的电气控制系统.     

榕树与榕小蜂共生体系维持机制的研究进展

榕树与传粉榕小蜂是传粉互利共生和协同进化的经典范例之一，分子钟和化石记录显示榕树与榕小蜂共生体系的起源大约在8700万年前。共生体系是如何维持如此漫长的年代？围绕这一问题国内外学者已经展开了较为丰富的研究，本文综述了国内外关于共生体系的起源与维持的主要研究成果，旨在讨论该热点领域研究进展。促进该领域的研究深入开展。     

聚果榕小蜂群落在中国西双版纳和缅甸曼德勒之间的地理变异

榕树及其传粉榕小蜂之间的相互作用是互惠共生的经典例子，每种雌雄同株的榕树还庇护着多样的非传粉小蜂，并共生形成多营养级的榕小蜂群落，是研究群落生态学的有趣模型。区域的物种库、物种的生物地理特征及种间相互作用可能影响榕小蜂群落，但研究很少。本研究选择分布于中国西双版纳和缅甸曼德勒的雌雄同株聚果榕小蜂群落作为研究对象，比较地理分布差异对榕小蜂个体大小及共存网络的影响。结果显示：聚果榕小蜂群落在两地由相同的6个种组成，但分布于西双版纳的6种榕小蜂的个体均显著大于分布在曼德勒的同种榕小蜂。在两个分布地传粉榕小蜂均为优势种，然而在西双版纳传粉榕小蜂种群较大，而在曼德勒非传粉小蜂更丰富。在两地聚果榕有不同的榕小蜂群落结构和物种丰富度，且榕小蜂共存的网络也存在变异，在两地共存网络有相同的节点、边、连接度和全局聚类系数，但是在西双版纳的共存网络有较大的直径和较高的群落矩阵温度，这表明分布于西双版纳的聚果榕小蜂群落种间互作不太紧密，群落受到的干扰较大。由此，阐明了由地理分布所驱动的榕小蜂群落变异。     

榕树传粉生物学的特性

榕树传粉生物学是当今植物生殖生物学研究的一个热点 .榕树为榕小蜂提供具生态保护作用的栖息场所和生长发育必须的营养物质 ,榕小蜂为榕树传粉 ,二者是植物和昆虫间高度专一化的互惠共生伙伴 .榕树和榕小蜂各具独特的生物学特性 ,共生双方在形态结构、生理生态和生物学行为上高度特化和互适 ,在物候生活史链上环环衔接 ,构成一个十分复杂而精确的传粉生态系统 .     

Population biology of figs: Applications for conservation

Summary The flowering phenology typical of at least monoecious figs-intra-tree synchrony and inter-tree asynchrony-poses problems for persistence of the pollinator population, and hence of the fig population itself, when fig population size is small. Establishment and maintenance of a population of the short-lived, species-specific wasp pollinator require that the fig population include a critical minimum number of trees (critical population size: CPS). Below CPS, temporal gaps between flowering trees occur that are unbridgeable by the pollinator, leading to its local extinction. This has implications for conservation in two contexts: human-aided invasions of introduced fig/wasp pairs, in which initial populations of figs and/or wasps may be small, and the persistence of figs and wasps in fragmented forest, in which initially large populations may be drastically reduced. Long-distance range extension by fig/wasp pairs is problematical for two reasons: 1) the fig species must first attain CPS, most likely through repeated seed dispersal events, before the wasp can establish; and 2) long-distance transit should be difficult for the tiny, short-lived wasp pollinators. I review the biology of natural and human-aided range extension by figs and fig wasps, and show that in human-aided range extensions these two difficult steps are circumvented. Once introduced into an area where hosts are abundant, fig wasps should readily establish from a small number of initial colonists, since they mate before dispersal and are highly tolerant of inbreeding. They are thus less subject than many insects to the genetic and demographic hazards of small population size. Of 5–6 fig/wasp pairs that have performed human-aided long-distance range extensions, one Asian pair,Ficus microcarpa and its pollinatorParapristina verticillata, is established in numerous areas in the northern neotropics, and the plant may become a serious weed. In tropical forests, figs may provide keystone resources for frugivores, providing fruit during seasons when other resources are scarce. Figs pose difficult problems for conservation biology, since minimum viable populations appear to be large, and since many species of tropical rainforests occur at low densities. This means that minimum areas required for persistence of a fig population- and for those of other species that would be affected were figs to be removed from the system-may often be large.     

木瓜榕隐头果传粉前后挥发性化合物构成及其变化规律

 榕树与其传粉榕小蜂通常以隐头果挥发物作为交流媒介.采用顶空动态法提取木瓜榕隐头果传粉前后的挥发物,用GC-MS联用仪鉴定各化合物,峰面积归一法和内标法测定各成分含量.结果表明:木瓜榕传粉前 (雌花期)和传粉后的顶空样品中分离出53种化合物,多数为单萜类和倍半萜类化合物,(E)-β-ocimene、linalool 、limonene、5-epiprezizaene、khusimene、cis-β-Cedrene、cis-α-bergamotene、α-farnesene 和bicyclogermacrene是其重要的挥发物成分.雌花期隐头果挥发物释放量明显高于传粉后挥发物释放量,且雌雄隐头果挥发物种类、构成及释放量上高度类似,存在着明显的模拟现象.同时,雌雄个体挥发物释放量存在明显的空间变异.     

福建省6种榕树及其传粉小蜂共生体系的比较

榕树(Ficus spp.)和榕小蜂共生体系是由宿主和共生者之间的生殖配合维系的.采用隐头花序解剖、对比观察的方法研究了福建省东北部6种榕树及其共生昆虫传粉体系的种间差异.结果表明：6种榕树花的性别分离成雌花、瘿花、雄花和两性花，植株的性表达有雌雄同株和雌性两性异株的区别，雌、瘿花有或无花柄（子房柄）单层或双层排列，雄花有散生、半集中和集中着生的分布方式，花序大小、花的数量、苞片数目、孔道苞片功能分区、出飞孔形成方式均有差异并与榕小蜂的行为相对应，每种榕树通常仅有1种传粉昆虫，6种榕树及其共生小蜂分别形成各自独立的传粉体系.显然，这种传粉体系存在丰富的种间差异性，各共生体系对传粉生物学的性状有不同的进化选择，体现了共生双方进化适合度和共生对策，维护了共生体系的稳定性和独立性.     

Ecological and evolutionary dynamics of fig communities

Summary I review the status of five topics in fig research: pollen-vector versus seed production, flowering phenology and wasp population dynamics, monoecy versus dioecy, parasite pressure, and fig wasp behavior. I raise several new questions based on recent research on two components of fig reproduction: pollen-donation (male) and seed-production (female) success. I focus on how these two components of reproductive success depend on the flowering phenology of the figs and the population dynamics of the pollinator wasps.