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关键词： 聚合果   离生心皮   实概念   子房发育   单雌蕊   果实   《辞海》   植物生物学   复雌蕊   高等教育出版社  

摘要： 关于几种果实概念的商榷刘祥栋（辽宁省锦州师范高等专科学校，锦州１２１０００）ＤＩＳＣＵＳＳＩＮＧＯＮＴＨＥＣＯＮＣＥＰＴＯＦＡＦＥＷＦＲＵＩＴＳＬｉｕＸｉａｎｇｄｏｎｇ（ＪｉｎｚｈｏｕＮｏｒｍａｌＣｏｌｅｇｅ，Ｌｉａｏｎｉｎｇ，Ｊｉｎｚｈｏｕ１２１...

关键词： mycelium   nitrogen mobilization   chitin   mycorrhiza   heathland soil  

摘要： Measurements of the chitin content of the rooting horizons of a typical mor-humus heathland soil, indicate that chitin can contain in excess of 20 % of the total nitrogen in the litter (L) horizon and 30 % in the fermentation (F) horizon. Much of this chitin-nitrogen is thought to be contained in the mycelial walls of soil fungi. Experiments were therefore designed to test the hypothesis that such sources of N could be rendered accessible to the ericaceous plants by their fungal endophytes. Mycelium of the ericoid endophyte Hymenoscyphus ericae (Read) Korf & Kernan and of the ectomycorrhizal fungus Suillus bovinus (Fr.) O. Krantze were grown in liquid culture before being killed and added either in the intact condition, or after fractionation, as sole sources of N to sterile media upon which were grown H. ericae in pure culture, or mycorrhizal and non-mycorrhizal plants of Vaccinium macrocarpon Ait. and Calluna vulgaris L. The abilities of the test organisms to utilize the nitrogen contained in the intact mycelial necromass, or in its fractions, were assessed by determining their yields and nitrogen concentrations of their tissues. It was revealed that H. ericae was able to produce significantly higher yield when grown on intact fungal necromass than when provided with equivalent concentrations of N in the form of ammonium. Its yields on mycelial fractions were lower, but still significantly greater than those obtained in the controls lacking N. Significantly greater yields and N contents were also found in the ericaceous plants grown with these nitrogenous substrates in the mycorrhizal condition. Without H. ericae they had no access to the substrates. The possible ecological implications of these results are discussed.

关键词： 植物   抗病性   抗病基因   分子生物学  

摘要： 植物在长期的进化过程中,需要不断地抵抗病原微生物、昆虫甚至食草动物的侵害。在这种长期相互作用、相互影响的共进化过程中,植物逐渐获得了一系列复杂的防御机制来保护自己。这里既有专一性的抗性,也有非专一性抗性,有的表达是组成型的而有的是诱导型的。在植物抵抗病原侵染的过程中,关键环节是病原与寄主植物间的相互识别及其随后诱发的一系列反应。人们虽然对植物抗病机理及植物抗病性在生产应用等方面做了大量的工作,积累了相当多的资料,但由于一直未能克隆到植物的抗病基因,所以在90年代初期以前有关植物抗病性的分子生物学研究进展一直都很缓慢。而最近的几年里,人们克隆到了一些植物的抗病基因,使得对寄主-病原相互作用分子机理的研究得到迅速的发展,并为抗病基因在生产中的应用带来了新的前景。

关键词： 桑寄生植物   生物学特性   危害  

摘要： 桑寄生植物从寄主板栗树的体内吸取水分和矿质营养,对寄主构成危害,其危害程度与寄生植物的生物学特性和环境条件有关,而不同种类的寄生植物对寄主个体和种群造成的危害亦不相同.

关键词： 植物生物学   花粉   种子   散布   湍流   梯度   输送模型  

摘要： 运用梯度──输送理论分析了植物花粉、种子湍流扩散的不同情况,导出了植物花粉、种子散布的湍流扩散模型,并运用此模型研究了亚热带常绿阔叶林优势种四川大头茶的种子散布格局.

关键词： 植物   胞质雄性不育   分子生物学   作物  

关键词： flavonol sulfotransferase   glucosinolate   choline sulfate   flavonoid   gallic acid  

摘要： It is now well established that, in mammals, sulfate conjugation constitutes an important reaction in the transformation of xenobiotics and in the modulation of the biological activity of steroid hormones and neurotransmitter (1, 2). The presence of a sulfate group on some molecules can also be a prerequisite for their biological function. For example, it is well known that the sulfate groups are directly involved in the molecular interaction between heparin and antithrombin III (3). In plants, sulfation also seems to play an important role in the intermolecular recognition and signaling processes, as indicated by the requirement of a sulfate moiety for the biological activity of gallic acid glucoside sulfate in the seismonastic and gravitropic movements of plants (4), and of Nod RM1 in the cortical cell division during early nodule initiation in Rhizobium meliloti-alfalfa interaction (5). In addition, recent studies indicate that flavonoid conjugates, including the sulfate esters, may play a role in the regulation of plant growth by strongly binding the naphthylphthalamic acid receptor, thus blocking the quercetin-stimulated accumulation of the auxin phytohormone (6). Although several sulfated metabolites are known to accumulate in a variety of plant species (7), the study of enzymes that catalyze the sulfation reaction in plants lagged considerably compared to those conducted with their mammalian homologs. This apparent lack of interest may have been because the function of plant-sulfated metabolites is difficult to predict, since their accumulation is often restricted to a limited number of species. Despite this limitation, several plant sulfotransferases (STs) have been characterized at the biochemical level, and the cDNA clones encoding six plant STs have been isolated. Based on sequence homology, the plant ST coding sequences are grouped under the SULT3 family, also known as the flavonol ST family. This review summarizes our current knowledge of the plant STs

摘要： Recent empirical studies hint at an end to the historical solitude between pollination and mating system approaches to plant reproductive character evolution. Now is an opportune time to distill theoretical results into comprehensible insight, and to integrate these findings into the emerging new plant reproductive biology. We outline four theoretical insights for understanding;the evolution of reproductive characters, and show how these allow researchers to dissect complex ecological scenarios into clear and evolutionarily relevant components.

摘要： Presents a brief summary of research on plant molecular biology in Tunisia, Morocco, and Algeria. Molecular study of PVY (potato virus Y), PVMV (pepper veinal mottle virus), CMV (cucumber mosaic virus) in Tunisia; Molecular analysis of resistance to Fusarium oxysporum in P. dactylifera in Morocco; Study of isozymes of cultivated and wild plants in Algeria.