端粒、端粒酶和肿瘤、细胞衰老

端粒和端粒酶是现代生物学研究的热点,端粒的缺失与细胞的衰老,端粒酶的活性与细胞的老化及癌化均有密切的关系.文章综述了端粒和端粒酶的结构和功能及其与细胞衰老及肿瘤的关系,并在此基础之上展望了端粒酶在抗衰老、抑制肿瘤等方面的应用.     

蕨状满江红幼孢子体中的子叶和初生叶的超微结构

蕨状满江红(Azolla filiculoides)的幼孢子体中的子叶细胞壁中,没有明显的胞间连丝,子叶细胞内液泡数量多,而初生叶细胞壁中的胞间连丝却十分明显.两种叶都各有分化程度不同的叶绿体以及前质体、线粒体和内质网等细胞器.     

Proline accumulation as a reliable indicator of monocarpic senescence in rice cultivars

Summary Proline content proportionally increased with leaf age as well as during aging in darkness of excised leaf segments collected from the flag, second and third leaves of the Jaya cultivar of rice. BA significantly suppressed, whereas ABA augmented, the rise of proline level in the leaf segments. Proline also increased in the attached flag, second and third leaves of all the 4 rice cultivars with the progress of reproductive development but the pattern of its accumulation was non-sequential in Jaya and Ratna and sequential in Masuri and Kalojira. Although proline accumulation was retarded and enhanced by treatment with BA and ABA, respectively, as foliar sprays, the mode of proline accumulation (non-sequential or sequential) remained unaltered.The financial assistance of the C.S.I.R., New Delhi, in the form of a research grant to MAC for carrying out the present investigation is acknowledged.     

某些硫代甲基膦酸酯类化合物的植物生长调节活性的研究

本文报道本所最近合成的某些硫代甲基膦酸酯类化合物的植物生长调节活性。合成的８个化合物中，７个化合物具有明显的植物生长调节活性：１０ｐｐｍ处理后均明显促进黄瓜子叶扩张，１００ｐｐｍ处理后明显抑制小麦胚芽鞘伸长。本文以Ｓ－乙基Ｏ－（２－氯－４－溴苯基）甲基膦酸酯（下文称２号化合物）为代表重点报道其对黄瓜子叶扩张，叶绿素含量的促进作用及对油菜下胚轴伸长的抑制作用。     

钾和菊酸诱导的离体黄瓜子叶生根与吲哚乙酸氧化酶和质膜H~＋－泵ATP酶之间的关系

本文研究了钾和菊酸诱导的离体黄瓜子叶生根中吲哚乙酸氧化酶活性的变化和钒酸钠（质膜Ｈ＋－泵ＡＴＰ酶专一性抑制剂）对钾与菊酸诱导生根的影响。试验结果表明：①ＫＣｌ和菊酸钠促进生根的最适浓度分别为１３．４ｍｍｏｌ／Ｌ和０．６ｍｍｏｌ／Ｌ．②钾和菊酸诱导的离体黄瓜子叶生根过程中毫克干重子叶的ＩＡＡ氧化酶活性逐天增加，而毫克鲜重子叶的ＩＡＡ氧化酶活性第三天达到高峰，之后趋于恒定。③１０─３００μｍｏｌ／Ｌ的钒酸钠明显抑制钾和菊酸诱导的离体黄瓜子叶的生根。可能钾和菊酸对于离体黄瓜子叶生根的促进作用与质膜Ｈ~＋－泵ＡＴＰ酶密切相关。     

Gigantenone,a novel sesquiterpene phytohormone mimic

Summary Gigantenone, a new eremophilane diepoxide, was isolated from the fungal plant pathogenDrechslera gigantea. It displays unique biological activity on higher plants. On most graminaceous species, the application of 18 nanomoles to a leaf surface results in the formation of green islands — localized areas of chlorophyll retention. Gigantenone is structurally unrelated to the cytokinins, yet induces the green island effect associated with these phytohormones at comparable concentrations. However, on dicotyledonous species it generally causes necrotic lesions. On host plants ofD. gigantea, gigantenone induced lesions closely resembling those appearing in natural infections. Gigantenone also induces root formation in mung bean hypocotyls and shows a high level of activity in several plant tissue culture systems.We thank the US-National Science Foundation (Grant DMB-8607347) for partially supporting this work.     

马蹄金再生体系的构建

以马蹄金无菌苗为试材,子叶为外植体,研究了不同植物生长调节剂种类的组合及浓度的配比对愈伤组织诱导、分化的影响,结果表明：含2,4-D、NAA、IAA和细胞分裂素6-BA的诱导培养基对愈伤组织的诱导频率差别不明显,诱导率均达80％～100％,但愈伤的质地却有很大的不同,以5．0mg／L6-BA＋0．1mg／LNAA和0．5mg／LIAA＋1.5mg／L6-BA效果较好,其中0．5mg／LIAA＋1．5mg／L6BA可直接诱导出不定芽,诱导率高达82．61％;AgNO3对愈伤组织的分化起着重要的作用,以0．1mg／LNAA＋3．0mg／L6-BA＋2．0mg／LAg—NO3分化的效果最好,分化频率高达76％;最佳的生根培养基为1／2MS＋0．5mg／LIBA,生根率可达100％．     

莲子贮存蛋白基因的表达与子叶叶肉细胞的变构

莲子贮存蛋白基因（ＳＰＧ）的表达受发育调控。子叶叶肉细胞变构早于ＳＰＧ的开始表达,随发育过程加剧。在贮存组织中细胞变构的发生有严格的时空顺序性。变构主要表现在细胞核体积增大,外形变不规则,染色质分布不均匀化,核膜局部消失。     

绿豆子叶脂氧合酶生理功能初探

为了阐明脂氧合酶（ＬＯＸ）与植物生长、发育之间的关系,用氧极谱法测定了器官衰老过程中以及胁迫处理下植物器官内脂氧合酶的活性变化,结果表明：绿豆、黄瓜、西葫芦和白兰瓜干种子中无脂氧合酶活性,而在萌发后２￣３ｄ内活性迅速达到高峰。在绿豆子叶从萌发至衰老整个生活周期中,脂氧合酶只在萌发初期有高的活性,但在衰老阶段无明显活性。质量分数为１．２％ＮａＣｌ和６％ＰＥＧ所产生的渗透胁迫均能诱导绿豆子叶和叶片的脂