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ISBN: (纸本)7030018435

关键词： 植物学∶分子生物学   文集   分子生物学∶植物学   文集   生物工程   文集  

关键词： BOTANY  

摘要： The development of nitrogen fixing root nodules on the roots of leguminous plants is induced by soil bacteria (for example, from the genus Rhizobium ). The formation of this plant organ involves specific activation of genes in both plant and bacterium. Analysis of these genes gives insight into the way in which plant and bacterium succeed in coordinating plant development.

摘要： An editorial discusses the growing importance of plant biology in a world whose atmosphere is becoming more polluted and whose growing population cannot be fed. New advances in plant biology are discussed.

摘要： Progress in plant molecular biology has been dependent on efficient methods of introducing foreign DNA into plant cells. Gene transfer into plant cells can be achieved by either direct uptake of DNA or the natural process of gene transfer carried out by the soil bacterium Agrobacterium. Versatile gene-transfer vectors have been developed for use with Agrobacterium and more recently vectors based on the genomes of plant viruses have become available. Using this technology the expression of foreign DNA, the functional analysis of plant DNA sequences, the investigation of the mechanism of viral DNA replication and cell to cell spread, as well as the study of transposition, can be carried out. In addition, the versatility of the gene-transfer vectors is such that they may be used to isolate genes not amenable to isolation using conventional protocols. This review concentrates on these aspects of plant molecular biology and discusses the limitations of the experimental systems that are currently available.

关键词： 被子植物   生殖生物学   古植物学  

关键词： Olax   root hemiparasite   mineral nutrition   haustoria   resource allocation  

摘要： Olax phyllanthi was found to parasitize a wide range of taxa in the native habitat in coastal heath, South-West Australia. All major life and growth forms were regularly exploited, including most woody dicotyledons (except members of the Myrtaceae), a few monocotyledons and cohabiting root hemiparasites. Initiation of haustoria occurred mostly in autumn (Southern hemisphere), with some senescing the following summer, and others surviving until replaced by a new generation of haustoria the following autumn. Seedlings increased in dry matter and contents of N, P, K, Mg and Ca during preparasitic development, but did not survive beyond 6 months if failing to establish haustoria on a suitable host. Plant dry matter, mineral content and haustorial number increased exponentially during subsequent parasitic development. Mean shoot:root d. wt ratios of 1st to 3rd-year plants lay within the range 1.2-1.4. Root systems were laterally extensive and restricted to the top 40 cm of rooting substrate. Mean total root lengths of 2nd- and 34d-year plants were 7.1 m (n = 5) and 60.9 m (n = 5), respectively. Haustoria comprised 0.7-3.5% of plant d. wt, with a mean of 7.9 haustoria (n = 10, 2nd- and 3rd-year plants) per metre of root length. Comparisons of mineral concentrations in dry matter of O. phyllanthi and of a range of commonly parasitized hosts showed the parasite to be much richer on average than its hosts in K, P, and to a lesser extent in N, but not noticeably different in Mg and Ca.

关键词： 植物精子细胞   精细胞生物学  

摘要： 自俄国胚胎学家纳瓦申(1898)发现被子植物双受精作用以来,已整整经历接近一个世纪的漫长岁月,在这期间,关于精子的结构与功能的研究工作,尚无实质性的进展。而受精作用则是植物有性生殖过程的重要环节。

关键词： Steatococcus   Cryptostegia grandiflora   biological control   Steatococcus   Cryptostegia grandiflora   lutte biologique  

摘要： The soft scale, Stetatococcus new species, occurs on cryptostegia grandiflora R. Br. in Madagascar. Studies on its biology and host plant range showed colonies could survive for up to 6 months on some genera in the Apocynaceae and indefinitely on many genera in the family Asclepiadaceae. The species was therefore rejected as a biological control agent for C. grandiflora, a serious weed in northern Queensland, Australia.