大花蕙兰茎尖组织培养及其形态建成的研究

以大花蕙兰(Cymbidium grandi,lorium)茎尖为外植体,在改良的Vacin和Went培养基上诱导形成了原球苹,并且在添加有1 mg/1BA的‘Vacin和Went培养基上获得了快速繁殖无性系,将原球茎转移到加有香蕉匀浆汁的Knudson c培养基上,很快长出叶片和根,形成完整的再生植株。较高浓度的BA(1.O mg/1)能促进原球茎的增殖;较低浓度的BA(O.4mg/1)能促进原球茎的分化。形态发生的显微观察表明原球茎来源于体细胞胚,它的发育过程与合子胚十分相似。     

植物向光性运动机理的新见解

向光性反应是植物器官适应环境,向有利方向生长的一种良好的生物学特性。1880年,Charles Darwin和Francis Darwin首先发现这个现象,并认为是某些物质引起的。1928年,Went证明燕麦芽鞘经单侧光照后,背光一侧芽鞘顶部扩散到琼脂的生长刺激活性是向光一侧的一倍。1924年,     

植物生长素的发现历史

生长素(auxins)是最早被发现的植物激素。这一名称是由荷兰人郭葛(F.Kogl)提出来的。“汁液”是生长素等植物激素的最早、最原始的观念。导致发现生长素的启发性工作要算达尔文(Charles Darwin)的金丝虉草和燕麦试验(1880)。达尔文得出的结论是:胚芽鞘受到单侧光照射时,某种影响从胚芽鞘的顶尖传递到下面的部分并使之弯曲。后来,这一结论被罗扎特(W.Rothert,1894)、波伊逊-詹逊(Boysen-Jensen,1913)、帕尔(Paal,1918)、索丁(H.Soding,1925)、休伯特(E.Seubert,1925)进一步证实和发展。1928年溫特(F.W,Went)发明生长素的定量测定方法——燕麦弯曲试法。1934年郭葛及其同事分离出纯粹的激素,经鉴定为吲(口朶)乙酸(indoleacetic acid)。     

日本血吸虫形态的若干观察

自从桂田(1904)首先发现日本血吸虫之后,继之对该虫形态的研究颇不乏人,其中主要有藤浪(1904)、宫川(1916)、Faust和Meleney(1924)、Severinghaus(1928)和多田(1928)等氏。近年来作者在进行各种药物对虫体作用的研究工作中,有机会系统地观察和研究了正常虫体的形态和组织构造,发现过去研究者们的描述不够完善,并有若干的形态构造尚未加以叙述。为了补充或提供其他方面的参考,故将观察的结果介绍于后。     

植物生长物质的过去、现在和将来

自从西欧一些实验室的少数工作者把生长素的概念置于可靠的实验基础上以来,大约有三十多年了。1930年引起我对这问题的兴趣多半是由于这一件事,那就是Herman Dolk和我差不多同时进入加利福尼亚理工学院。Went的学位论文在1928年发表,而大约在发表前三年已完成了这方面的工作。这篇论文清楚地证明了假定的“生长物质”的真实性,并且指出如何抽提及测量生长素。Cholodny有名的     

关于鳞喙白蛉(Phlebotomus squamirostris Newstead, 1923)雌蛉色板形态学的探讨

1923年Newstead氏鉴定了松山等氏 1916年 6—7月间从日本所捕到的白蛉;发现其中有一新种,定名为鳞喙白蛉 Phlebotomus squamirostris,并对其雌雄蛉做了形态描述。1928年Sinton氏(1928)研究了Newstead氏的鳞喙白蛉模式和副模式标本,进一步明确了 De Meijere 氏(1909)在爪哇岛所发现的搅扰白蛉 Phlebotomus perturbans;     

中国植物生理学的五十年——新长征的序曲

1956年 F.W.Went教授在“美国植物学杂志”(American Journal of Botany)的五十周年纪念集中,曾经撰写过一篇题为“植物生理学在美国的五十年”的论文。二十三年后,今天我荣幸地在你们的面前讲     

植物调节物质的生物测定法—(Ⅰ)黄瓜幼苗形态法

生物测定在植物激素的研究中起着极其重要的作用。尤其在合成生长物质的筛选及其化学结构与生物活性的关系的研究方面。早在1938年Koepfli等就借豌豆试法(Went和Thimann 1937)对50余种物质的测定提出了具有生物活性的生长物质的五点基本化学结构要求(Koepfli等1938)。接着很多植物激素学家     

植物对生长物质的敏感性在发育调节中的重要作用

自从50多年前Went和Kogl发现生长素——吲哚乙酸以来,迄今已从植物体内发现了五大类生长物质。这就是生长素、赤霉素、细胞分裂素、脱落酸等抑制剂和乙烯。除乙烯外每一类当中都有很多结构相似、功能相近的化合物,例如赤霉素类中已发现约70种化合物了。最初用植物激素这个词来表述现在称为生长素的一些物质,是从1937年Went     

石斛兰茎段培养和植株再生

石斛兰杂交种幼茎上部切成长约5 mm的茎段,接种在添加15%(体积比)椰乳的固体Vacin和Went培养基上,6至8周后,茎段上的侧芽长成带叶的幼茎,以后幼茎分化出根,形成完整的植株。茎段培养可大大提高石斛兰幼茎上部侧芽的成活率。     

Role of cytokinins in stress resistance of plants

The facts of both positive and negative influences of cytokinins on stress resistance of plants are known today. Without pretending to a final choice between these points of view, we have made an attempt to analyze the details of the experiments that gave rise to conclusions about the nature of the effect of cytokinins on the resistance to stress-causing influences with a focus on their intensity and duration. The review deals with the data concerning the influence of different adverse factors on the content of endogenous cytokinins and transduction of cytokinin signals, examines the influence on plant resistance of treatment with exogenous hormone, and the effects of genetic modifications causing changes in cytokinin content and signaling. Resistance is considered not only as a mean of plant survival under severe stress but also as an instrument of maintaining growth rate in plants exposed to moderate stress. Literature data and our own results make it possible to conclude that cytokinins play an important role in formation of plant resistance to adverse influences; however, the effect of these hormones depends on stress intensity. Under moderate stress, cytokinins ensure maintenance of plant growth, whereas a drop in cytokinins hampers growth under a strong influence of adverse factors, which is a prerequisite for mobilization of limited resources characteristic of severe stress and ensures preservation of plant viability.     

The impact of cytokinin on jasmonate-salicylate antagonism in Arabidopsis immunity against infection with Pst DC3000

Cytokinin has long been shown to be an essential modulator of growth and development in plants. However, its implications in plant immunity have only recently been realized. The interaction between jasmonate and salicylate pathways is regarded as a central backbone of plant immune defense. However, the effect of cytokinin on the jasmonate and salicylate mediated balance in plant immunity is still not known. Here, we analyze the impact of cytokinin on the jasmonate-salicylate antagonism in Arabidopsis immunity regarding infection with hemibiotrophic pathogen Pseudomonas syringae pv tomato DC3000 (Pst DC3000). Systems biology analysis of a refined hormone immune pathway model provides insights into the impact of cytokinin on the balance between jasmonate and salicylic acid pathways in Arabidopsis. Targeted experiments validate model simulations monitoring bacterial growth in wild type plants as well as in jasmonate pathway mutants. An integrated analysis shows that CK promotes the SA pathway of plant immunity and does not promote JA-mediated Arabidopsis susceptibility against infection with Pst DC3000. Finally, we discuss these results in the context of an emerging model of auxin-cytokinin antagonism in plant immunity.     

Alternative splicing model for the synthesis and secretion of the 20 kilodalton form of rat growth hormone

The characterization of a 20 kilodalton (20 kD) variant of rat growth hormone is reported. The 20 kD variant from rat pituitary gland extracts was identified on Western immunoblots of polyacrylamide gels. It was also shown that pituitary tissue maintained in culture secretes the 20 kD form. A rat growth hormone cDNA fragment was used as a probe in S1 nuclease mapping experiments of rat pituitary poly (A) mRNA to detect the presence of two growth hormone mRNAs in the rat pituitary gland. The protected mRNAs correspond to the predicted sizes that would encode the 22 kD and 20 kD forms of growth hormone. The site of variation between the mRNAs maps to a potential alternative 3' splice site in the 5' end of exon 3 of the coding sequence. The results support the hypothesis that the 20 kD variant in rat is the product of an mRNA alternatively spliced in exon 3, as is the case for the human growth hormone.     

Rhizobacterial mediation of plant hormone status

Plant growth-promoting rhizobacteria are commonly found in the rhizosphere (adjacent to the root surface) and may promote plant growth via several diverse mechanisms, including the production or degradation of the major groups of plant hormones that regulate plant growth and development. Although rhizobacterial production of plant hormones seems relatively widespread (as judged from physico-chemical measurements of hormones in bacterial culture media), evidence continues to accumulate, particularly from seedlings grown under gnotobiotic conditions, that rhizobacteria can modify plant hormone status. Since many rhizobacteria can impact on more than one hormone group, bacterial mutants in hormone production/degradation and plant mutants in hormone sensitivity have been useful to establish the importance of particular signalling pathways. Although plant roots exude many potential substrates for rhizobacterial growth, including plant hormones or their precursors, limited progress has been made in determining whether root hormone efflux can select for particular rhizobacterial traits. Rhizobacterial mediation of plant hormone status not only has local effects on root elongation and architecture, thus mediating water and nutrient capture, but can also affect plant root-to-shoot hormonal signalling that regulates leaf growth and gas exchange. Renewed emphasis on providing sufficient food for a growing world population, while minimising environmental impacts of agriculture because of overuse of fertilisers and irrigation water, will stimulate the commercialisation of rhizobacterial inoculants (including those that alter plant hormone status) to sustain crop growth and yield. Combining rhizobacterial traits (or species) that impact on plant hormone status thereby modifying root architecture (to capture existing soil resources) with traits that make additional resources available (e.g. nitrogen fixation, phosphate solubilisation) may enhance the sustainability of agriculture.     

Molecular interactions between light and hormone signaling to control plant growth

As sessile organisms, plants modulate their growth rate and development according to the continuous variation in the conditions of their surrounding environment, an ability referred to as plasticity. This ability relies on a web of interactions between signaling pathways triggered by endogenous and environmental cues. How changes in environmental factors are interpreted by the plant in terms of developmental or growth cues or, in other words, how they contribute to plant plasticity is a current, major question in plant biology. Light stands out among the environmental factors that shape plant development. Plants have evolved systems that allow them to monitor both quantitative and qualitative differences in the light that they perceive, that render important changes in their growth habit. In this review we focus on recent findings about how information from this environmental cue is integrated during de-etiolation and in the shade-avoidance syndrome, and modulated by several hormone pathways—the endogenous cues. In some cases the interaction between a hormone and the light signaling pathways is reciprocal, as is the case of the gibberellin pathway, whereas in other cases hormone pathways act downstream of the environmental cue to regulate growth. Moreover, the circadian clock adds an additional layer of regulation, which has been proposed to integrate the information provided by light with that provided by hormone pathways, to regulate daily growth.     

植物生长调节物质的研究进展

述评了近几年国内外在植物激素与植物体内信使的传递、植物激素与基因诱导和表达、植物生长物质的复合使用、新型植物生长物质的开发及植物激素对提高植物抗逆性的作用等方面的研究进展,并展望了植物生长物质的发展趋势。     

Chemical regulators of plant hormones and their applications in basic research and agriculture*

Plant hormones are small molecules that play versatile roles in regulating plant growth, development, and responses to the environment. Classic methodologies, including genetics, analytic chemistry, biochemistry, and molecular biology, have contributed to the progress in plant hormone studies. In addition, chemical regulators of plant hormone functions have been important in such studies. Today, synthetic chemicals, including plant growth regulators, are used to study and manipulate biological systems, collectively referred to as chemical biology. Here, we summarize the available chemical regulators and their contributions to plant hormone studies. We also pose questions that remain to be addressed in plant hormone studies and that might be solved with the help of chemical regulators.     

Anti-idiotypic antibody: A new strategy for the development of a growth hormone receptor antagonist

In general, traditional growth hormone receptor antagonist can be divided into two major classes: growth hormone (GH) analogues and anti-growth hormone receptor (GHR) antibodies. Herein, we tried to explore a new class of growth hormone receptor (GHR) antagonist that may have potential advantages over the traditional antagonists. For this, we developed a monoclonal anti-idiotypic antibody growth hormone, termed CG-86. A series of experiments were conducted to characterize and evaluate this antibody, and the results from a competitive receptor-binding assay, Enzyme Linked Immunosorbent Assays (ELISA) and epitope mapping demonstrate that CG-86 behaved as a typical Ab2β. Next, we examined its antagonistic activity using in vitro cell models, and the results showed that CG-86 could effectively inhibit growth hormone receptor-mediated signalling and effectively inhibit growth hormone-induced Ba/F3–GHR638 proliferation. In summary, these studies show that an anti-idiotypic antibody (CG-86) has promise as a novel growth hormone receptor antagonist. Furthermore, the current findings also suggest that anti-idiotypic antibody may represent a novel strategy to produce a new class of growth hormone receptor antagonist, and this strategy may be applied with other cytokines or growth factors.     

Growth Control by Ethylene: Adjusting Phenotypes to the Environment

Plants phenotypically adjust to environmental challenges, and the gaseous plant hormone ethylene modulates many of these growth adjustments. Ethylene can be involved in environmentally induced growth inhibition as well as growth stimulation. Still, ethylene has long been considered a growth inhibitory hormone. There is, however, accumulating evidence indicating that growth promotion is a common feature in ethylene responses. This is evident in environmental challenges, such as flooding and competition, where the resulting avoidance responses can help plants avoid adversity. To show how ethylene-mediated growth enhancement can facilitate plant performance under adverse conditions, we explored a number of these examples. To escape adversity, plants can optimize growth and thereby tolerate abiotic stresses such as drought, and this response can also involve ethylene. In this article we indicate how opposing effects of ethylene on plant growth can be brought about, by discussing a unifying, biphasic ethylene response model. To understand the mechanistic basis for this multitude of ethylene-mediated growth responses, the involvement of ethylene in processes that control cell expansion is also reviewed.