植物的色香味与植物液泡

植物的色香味与植物液泡植物细胞具有酸甜苦涩等味道,植物的花果叶也具有红橙黄绿等颜色,有些植物还具有特殊的香气,这都与植物的液泡有关系。植物液泡中的液体是细胞代谢活动的产物,其中主要成分是水和溶于水的糖、丹宁、有机酸、植物碱、色素和盐类。由于植物的种类...     

植物防御的新发现: 植物-植物相互交流

 植物和昆虫在长期的相互作用过程中形成了复杂的防御体系。近年来, 人们发现植物在受到外界伤害后, 它们邻近的健康植物能够感受到威胁来临, 并积极表达抗性基因和产生防御物质。这种现象被称为“植物-植物相互交流”。一系列的相关研究表明: 绿叶挥发物和萜烯类物质是受伤害植物对邻近健康植物发送的主要信号, 邻近的健康植物在接收到这些挥发性有机化合物信号后, 直接防御和间接防御能力都能够迅速提升。人们猜测植物挥发性有机化合物“启动”了邻近健康植物的多种防御反应, 使它们在面临真正威胁时迅速做出防御反应。然而, 植物-植物交流的分子机制至今尚不清楚。我们运用拟南芥(Arabidopsis thaliana)全基因组芯片技术和突变体材料, 对植物-植物交流的分子机理进行了探讨。结果发现: 有效的挥发性有机化合物并不限于绿叶挥发物和萜烯类物质, 且挥发性有机化合物的种类和节律能够相互配合, 从而达到最佳效果; 邻近健康植物的乙烯信号途径在植物-植物交流过程中是不可或缺的, 茉莉酸信号起到了辅助和信号放大的作用。     

植物的感应性与植物的运动

一、植物感应性的一般概念感应性是一切生物都具有的基本属性,它乃是指生物能够“感受”外界条件的变化并对之积极地发生“反应”而呈现出各种活动状态的属性。大家都知道有机体是在不断地与外界环境进行新陈代谢中来维持生存、生长、与生殖的。而外界条件随时随地在变化之中,有机体若不能随机应变,获取与趋就有利的条件,     

植物患癌，植物致癌，植物治癌

植物患癌,植物致癌,植物治癌刘德明,曹宏文（山西大同浑源师范,０３７４００）植物与动物及人类一样,也会患癌症。当有些植物在受到损伤以后,它的伤口有时容易受到细菌,病毒等微生物的侵袭,造成畸形生长,生肿根病甚至患上癌症。这是什么原因呢？原来,植物从胚胎...     

植物

高等植物九寨沟地处温带与亚热带之交,土壤肥沃,水源充沛,地貌复杂,植物种类十分丰富,据1977年至1987年为时十年的普查材料统计,有高等植物二干余种,低等植物数百种。茂密的森林,参天的古木,斑斓如锦的草甸,五颜六色的藻类,使九寨沟呈现峰峦叠翠,林木掩映,奇湖错落,蓝侵绿染的绚丽景色。     

优于C_4植物的C_3植物

设在诺威奇的约翰因内斯研究所的科学家们发现了毛颖草(Alloteropsis semialata)的一种异常生理现象的原因.毛颖草在光合作用初期可能采用两条生化途径中的一条.C_3植物用三磷酸等油酸作为中间体固定二氧化碳,C_4植物则用草醋酸盐作为中间体.在此以前,植物学家一直认为植物不属C_3植物便属于C_4植物,而米莉森特·弗雷恩(Millice-     

中国华夏植物区的科达植物化石

总结了过去了几十年来,特别是近４０年来有关中国华夏植物区科在植物研究的资料,将中国华夏植物区的科达植物化石归为４种类型：印痕,压型,髓模及矿化化石等。在科达植物各种器官中,分布最广,数量最多,时代延续最长的是其叶化石,最早出现于早石炭世的维宪期（Ｖｉｓｅａｎ）,但数量较少,分布零星。在华北,一直至晚石炭世的斯梯芬期（Ｓｔｅｐｈａｒｉａｎ）和早二叠世,科达中化石数量才逐渐增多,特别在早二叠世,达到最     

植物的刺

在进行野外观察和采集植物标本活动时,学生常会提出许多关于植物刺方面的问题,并希望能得到满意的解答.现就此问题作一简要说明:     

植物的防卫

植物对动物的防卫大体可分为机械防卫和化学防卫两大类。机械防卫主要表现在植物体表具刺、毛和高度角质化与发达的韧皮纤维的产生。化学防卫,即植物体内次级代谢物质的产生。次级代谢物质虽然与植物本身生长发育没有多大关系但它对动物的防卫面广量大,远较物理防卫重要。本文除了介绍物理防卫的一般情况外,重点介绍了次级代谢物的分布,对动物的影响,和昆虫对它的利用。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism