外源精胺对离体铁皮石斛花芽分化过程中游离多胺含量的影响

以铁皮石斛去根苗为试材,研究了外源精胺(Spm)对离体铁皮石斛花芽分化过程中内源游离多胺含量的影响.在添加14.5mg/L Spm的MS培养基上培养铁皮石斛去根苗的花芽分化率为15.0%,未添加激素的对照组的为0.在花芽分化过程中去根苗内源游离亚精胺(Spd)、Spm的含量及Spm/Put(腐胺)、Spd/Put的值均高于对照组,说明高水平的内源游离Spm、Spd含量及Spm/Put、Spd/Put有利于去根苗花芽的分化.在花芽分化过程中游离Put含量低于对照组,说明外源Spm促进了Put转化为Spd和Spm.实验揭示外源Spm可引起铁皮石斛内源游离多胺代谢及比值的变化,促进花芽分化.     

活性氧与植物多胺

活性氧是一类氧化性很强的物质,植物在逆境胁迫下,活性氧水平升高,造成氧化胁迫.活性氧造成细胞膜的伤害主 要是对磷脂膜和蛋白膜的破坏.近年来的研究证明多胺是参与植物逆境反应的一类小分子物质.     

多胺的作用机理研究进展

对多胺的作用机理进行了全面综述,提出了今后的研究方向,展望了多胺的应用前景.     

多胺在植物生长发育中的作用

多胺被认为是一类新的植物激素或第二信使而受关注。本文主要介绍多胺在植物根系、叶片、花芽分化、座果和衰老中的作用。     

番木瓜综合利用的研究

介绍热带名果番木瓜的历史、现状、营养及综合利用.阐述了番木瓜蛋白酶、果脯、果酱等制品的工艺流程.     

多胺与逆境胁迫关系综述

多胺是广泛分布于植物体内并具有调控作用的生理活性物质,与植物对逆境胁迫得响应密切相关.本文综述了国内外在渗透胁迫、盐胁迫、低氧胁迫、温度胁迫等逆境条件下植物体内多胺合成的变化及功能的研究进展.     

多胺在植物生长发育过程中的生理作用

多胺被认为是存在于植物中的一类生长调节物质。本文介绍了多胺在植物种子萌发、生长和分化、花的发育、果实形成和衰老等过程中的生理作用及在提高植物抗逆性中的作用。     

高等植物体内多胺的生理功能及其分子生物学研究进展

多胺作为新一类植物生理活动物质与植物生理活动关系密切,如参与各种生理胁迫反应、参与植物衰老进程的调控、花芽分化、胚胎发育等。本文概述了高等植物体内多胺的分子生物学代谢途径,重点综述了多胺在高等植物中生理学功能和分子生物学方面的研究进展,并对有关问题进行了讨论和展望。     

生物技术在番木瓜上的应用

综述生物技术在番木瓜上应用,包括番木瓜离体快繁、胚培养、体细胞胚诱导、制作鼢人工种子、分子标记与基因工程等方面的内容.     

荔枝花芽分化过程中内源激素含量的动态变化

分析了荔枝花芽分化过程中植物内源激素的动态变化，结果发现，在花芽分化临界期，IAA、ZRs和GA等3类内源激素含量较高，其相应的叶片也具有同样的变化趋势；同时，ABA的含量也升高，抑制了茎尖的营养生长，使其免发“冬梢”，从而与IAA、GA和CTK相互作用，使茎尖由营养生长锥转入生殖生长．在花器官分化期，3类促进植物生长发育的内源激素再度升高，而ABA则消失．提出调节荔枝花芽、花器官的分化不是某一种激素单独作用的结果，而是各种激素在时间、空间上的相互作用产生的综合效果．     

药用植物金银花病虫害种类及综合防治

金银花是重要的药用植物,在中医临床上应用具有悠久的历史.本文就金银花病虫害的种类、危害特点及其防治技术进行了研究和总结,旨在为人工种植金银花的病虫害防治提供参考.     

B细胞产生抗体的年龄相关性变化

衰老动物的B细胞无论是对胸腺依赖性抗原,还是对非胸腺依赖性抗原的免疫应答能力都下降。这不仅表现在抗体的数量上,而且还表现在抗体的质量(对抗原的亲和力)上。     

Changes in unpunished responding during response-contingent punishment

In two experiments, gerbils that were punished for eating exhibited an increase in only the most probable of several ongoing alternative responses (running) during sessions when eating was suppressed. These results support previously suggested punishment and implicit avoidance rules for predicting the effects of response-contingent punishment in multiple-response baseline procedures. Most subjects also exhibited a decline in unpunished digging responses during punishment sessions. Neither this decline in the digging behavior nor the amount of increase in running behavior supported a quantitative constant proportion rule which predicts that each of the unpunished responses will increase to occupy a constant proportion of the time available to it.     

陶行知研究范型的嬗变(上)

从知识社会学的视角,陶行知研究大致可以分为三种类型:史观学派的、史料学派的、融和贯通的陶行知研究。潘开沛的《陶行知思想的批判》是史观学派陶行知研究的典型,它表现了陶行知研究中存在强烈的意图伦理色彩和政治建构特征;以胡晓风为代表的《陶行知全集》整理工作是史料学派陶行知研究的典范,它为20世纪90年代多元化的陶行知研究提供了统一的文献基础,大大推进了陶行知研究的深度。章开沅、唐文权的《平凡的神圣》,胡晓风、金成林的《陶行知与中国现代化》是融和贯通的陶行知研究的代表性著作。它们尝试在中西文化教育史观和现代化模式之下,重新解读陶行知思想与实践,还历史的本真面目。陶行知研究范型的嬗变是学术发展的内在继承与突破、政治社会的现实制约、研究共同体的学识、情感复杂互动的结果。     

转型时期意大利婚姻形态的变化

在近代化转型时期的意大利,传统的婚姻伦理观念受到冲击,性道德观念发生变化,人们私生活混乱,导致严重的社会问题;14、15世纪之前意大利妇女普遍早婚,夫妇年差较大;随着精英妇女参与宗教、政治、文化活动,中下层妇女参加社会化生产,男女尤其妇女初婚年龄上升,夫妇年差缩小,到17、18世纪,晚婚晚育成为近代婚姻模式的主流.     

Developmental Changes in Imitation from Television during Infancy

Infants' (N = 276) ability to learn from television under seminaturalistic conditions was examined in five experiments with 12-, 15-, and 18-month-olds. In all experiments, an adult performed a series of specific actions with novel stimuli. Some infants watched the demonstration live, and some infants watched the same demonstration on television from prerecorded videotape. Infants' ability to reproduce the target actions was then assessed either immediately or after a 24-hour delay. Infants of all ages exhibited imitation when the actions were modeled live. There were age-related and task-related differences, however, in infants' ability to imitate the same actions modeled on television. The role of perceptual, attentional, and cognitive development in the ability to learn from television is discussed.     

Conjunctive differentiation of gape during food-reinforced keypecking in the pigeon

The pigeon’s keypecking response includes both a head-transport (peck) and a jaw-movement (gape) component. Because the two components are mediated by different effector systems, they may potentially be viewed as orthogonal responses. A response differentiation procedure was used to bring gape amplitude under operant control. The procedure employed a conjunctive response requirement in which reinforcement was contingent upon both gaping and key contact. The key-contact requirement was held constant, while the gape contingency was systematically varied to reinforce either decreases or increases in gape amplitude with respect to baseline. The procedure was effective in shifting the gape distributions in both the upward and downward directions and in inducing new gape values that deviated from the baseline in the reinforced direction. These observations indicate that gape may be brought under operant control. However, subjects showed a bias in the differentiation of the gape response, such that larger gapes were more readily differentiated than smaller gapes. The results are discussed in relation to the methodological utility of the paradigm, the problem of biological constraints on learning, and the heuristic utility of a response components analysis.