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At least 595 records · Page 33Linked to original sources
PubMed2002

A fortunate choice: the history of Arabidopsis as a model plant.

During the past 20 years, the flowering plant Arabidopsis thaliana has been adopted as a model organism by thousands of biologists. This community has developed important tools, resources and experimental approaches that have greatly stimulated plant biological research. Here, we review some of the key events that led to the uptake of Arabidopsis as a model plant and to the growth of the Arabidopsis community.

Arabidopsis↗
PubMed2005

A novel in vitro system for gamete fusion in maize.

Various systems by using electric pulse, calcium, or polyethylene glycol have been developed in the past decade for the in vitro fusion of plant gametes. These in vitro systems provide a new way to study the fertilization mechanisms of plants. In this study, we developed a bovine serum albumin (BSA)-mediated fusion system for the in vitro fusion of maize gametes. The in vitro fusion of the isolated single egg cell and sperm cell of maize was observed microscopically in the BSA solution and the fertilized egg cell showed normal cell wall regeneration and nuclear division. The effects of the BSA concentration, pH value and calcium level on the efficiency of the maize gamete fusion were also assessed. BSA concentration and pH value did significantly affect the efficiency of the gamete fusion. Calcium was not necessary for the gamete fusion when BSA was present. The optimal solution for the gamete fusion contained 0.1% BSA, pH 6.0. The fusion frequency was as high as 96.7% in that optimal solution. This new in vitro fertilization system offers an alternative tool for the in vitro study of fertilization mechanisms with much simpler manipulating procedure than PEG system, and it will be especially useful for the in vitro study of the calcium dynamics during plant fertilization.

Botany↗
PubMed2003

History and evolution of the arctic flora: in the footsteps of Eric Hultén.

A major contribution to our initial understanding of the origin, history and biogeography of the present-day arctic flora was made by Eric Hultén in his landmark book Outline of the History of Arctic and Boreal Biota during the Quarternary Period, published in 1937. Here we review recent molecular and fossil evidence that has tested some of Hultén's proposals. There is now excellent fossil, molecular and phytogeographical evidence to support Hultén's proposal that Beringia was a major northern refugium for arctic plants throughout the Quaternary. In contrast, most molecular evidence fails to support his proposal that contemporary east and west Atlantic populations of circumarctic and amphi-Atlantic species have been separated throughout the Quaternary. In fact, populations of these species from opposite sides of the Atlantic are normally genetically very similar, thus the North Atlantic does not appear to have been a strong barrier to their dispersal during the Quaternary. Hultén made no detailed proposals on mechanisms of speciation in the Arctic; however, molecular studies have confirmed that many arctic plants are allopolyploid, and some of them most probably originated during the Holocene. Recurrent formation of polyploids from differentiated diploid or more low-ploid populations provides one explanation for the intriguing taxonomic complexity of the arctic flora, also noted by Hultén. In addition, population fragmentation during glacial periods may have lead to the formation of new sibling species at the diploid level. Despite the progress made since Hultén wrote his book, there remain large gaps in our knowledge of the history of the arctic flora, especially about the origins of the founding stocks of this flora which first appeared in the Arctic at the end of the Pliocene (approximately 3 Ma). Comprehensive analyses of the molecular phylogeography of arctic taxa and their relatives together with detailed fossil studies are required to fill these gaps.

Arctic Regions↗
PubMed1997

Seal-promoting solutions and pipette perfusion for patch clamping plant cells.

Patch-clamp technology has greatly increased our knowledge of plant membrane transport. However, the success of patch clamping crucially relies on establishing a high resistance (G omega) seal between the membrane and the patch-clamp pipette. This can prove problematic in many plant-cell preparations. It is therefore of great importance to develop protocols for protoplast isolation, maintenance and seal formation that improve seal rate. This study investigated whether the pH and the K+ and the Cl(-)concentration of the pipette solution had an effect on the seal formation. High pH and absence of K+ significantly promoted membrane sealing, whereas the concentration of Cl- had no effect. To reap the benefit of seal-promoting pipette solutions and yet retain the option to adjust this solution to experimental requirements, a pipette perfusion apparatus was implemented. The perfusion system was successfully applied in cell-attached patch, excised-patch and whole-cell configurations, using plasma membrane and tonoplast of three different species. The system enables complete solution exchange within minutes and is potentially of great benefit in the study of channel selectivity, the application of (cytoplasmic) channel blockers and the study of primary and secondary transport.

Arabidopsis↗
PubMed2005

[The botanist and doctor Pietro Andrea Matthioli].

The physician Pietro Andrea Mattioli (1500 - 1577) is known for his Italian translation and commentary of the work of the Greek botanist Pedanios Dioscurides: "Di Pedacio Dioscoride Anazerbeo libri cinque ..." (first published in 1544). The physician broadened Dioscurides' studies by including new medicinal plants and numerous detailed woodcuts. In 1554 the fifth edition had already been published: "I Discorsi di M. Pietro Andrea Matthioli Sanese, Medico Cesareo ... Di Pedacio Dioscuride Anacarbeo della materia Medicinale ...". The book was also translated into Latin, French, Spanish, German and Bohemian. Matthioli describes plants, that can be used to treat eye-diseases.

Botany↗