The Amsterdam petunia germplasm collection: A tool in plant science.

Petunia hybrida is a plant model system used by many researchers to investigate a broad range of biological questions. One of the reasons for the success of this organism as a lab model is the existence of numerous mutants, involved in a wide range of processes, and the ever-increasing size of this collection owing to a highly active and efficient transposon system. We report here on the origin of petunia-based research and describe the collection of petunia lines housed in the University of Amsterdam, where many of the existing genotypes are maintained.

Influence of sediment quality on the responses of benthic invertebrates after treatment with the fungicide triphenyltin acetate.

After decades of pollution, benthic communities in floodplain lake ecosystems are likely to be exposed to a diverse assortment of sediment-bound historical toxicants and nutrients as well as pulses of newly discharged or deposited toxicants. The aim of this study was therefore to analyze the effects of background sediment pollution on the responses of benthic invertebrates to an experimental toxic shock in a laboratory setting. Sediment from a relatively clean and a historically polluted floodplain lake located along the River Waal, a branch of the River Rhine, The Netherlands, was selected, and the fungicide triphenyltin acetate (TPT) was used as the acute stressor. Juvenile stages of the mayfly Ephoron virgo and the midge Chironomus riparius were chosen as test organisms because of their different response to sediment-bound toxicants and food quantity and quality. Our results demonstrated that the type of sediment had no effect on survival and growth of C. riparius when exposed to sediment-associated TPT and that E. virgo was more affected by sediment-associated TPT on clean sediment than on polluted sediment. For the mayfly, no cumulative response of the historical pollution and the recent toxic shock was observed. This observation is discussed in view of the variable content of organic matter, acting both as food and as sorbent, and leads to the hypothesis that a very strong sequestering of TPT in historically polluted sediment prevents expression of toxic effects.