In vitro Douglas fir pollen germination: influence of hydration, sucrose and polyethylene glycol

Abstract

-Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) pollen stored at low moisture content experiences imbibition shock when put directly onto culture media. This can be overcome by rehydrating the pollen in 100 % relative humidity prior to culturing. The long-term effect of rehydration on pollen tube growth was investigated. The impact that osmoticants such as sucrose and polyethylene glycol (PEG) have on pollen elongation and tube formation was also studied, using culture media of increasing osmotic potentials obtained with different sucrose/PEG ratios. Rehydration not only improved survival and pollen development on all media but also enhanced pollen tube induction and growth on most of them. Douglas fir pollen produced tubes over a wide range of osmotic potentials (-0.73

In vitro germination of western larch pollen

“…Their behaviour on artificial substrates is also very similar. In contrast to other Pinaceae that readily germinate in vitro on media of high osmotic potential, western larch and Douglas-fir both require relatively low osmotic potentials (Dumont-BéBoux et al 1999). While pine or spruce pollen grains germinate within 2 days, western larch and Douglas-fir pollen take a minimum of 1 week to start producing tubes.…”

“…Western larch pollen has been successfully induced to produce pollen tubes in vitro by applying the methods developed for the closely related Douglas-fir pollen, another pollen that germinates in vitro only with difficulty (DumontBéBoux and von Aderkas 1997; Dumont-BéBoux et al 1999). Sucrose affected western larch pollen early development, while tube induction and growth were largely influenced by the substrate.…”

“…Franco), which is closely related, has pollen that shares many developmental and physiological traits. Douglas-fir pollen require media with low osmotic potential to germinate in vitro (Dumont-BéBoux et al 1999). Flavonols, essential to the production of functional pollen tubes in maize (Zea mays L.) and petunia (Petunia hybrida Vilm.)…”