Evaluation of microspore culture in germplasm preservation, lipid biosynthesis and DNA uptake studies in rapeseed (Brassica napus L.).

摘要

Microspore culture technology has the potential to be powerful tool, both in breeding and in vitro studies of oilseed rape (Brassica napus L.). In this thesis, three aspects of microspore culture technology were investigated: its potential for cryopreservation; the pattern of lipid biosynthesis; and the possibility of transformation through DNA uptake.;In cryopreservation studies, a cooling (cold treatment before quenching in liquid nitrogen) rate of 15;Oil content, triacylglycerol (TAG) fatty acids and free fatty acids were compared for their developmental accumulations in both seeds and microspore-derived embryos of low erucic acid and high erucic acid rapeseed lines. The accumulation patterns showed that microspore-derived embryos had a TAG fatty acid profile similar to see during embryo development, within each line. The oil accumulation in microspore-derived embryos after 36 days in culture approached levels similar to those in zygotic seed 25 days after flowering. Microspore-derived embryos had a significantly higher level of total free fatty acids than seed and had a different accumulation pattern from seed in free linoleic, linolenic, eicosenoic and erucic acids during the developmental period. Preliminary efforts to obtain DNA uptake by microspores and microspore-derived embryos through a desiccation-imbibition process and microprojectile bombardment failed to yield any transformants. However, dry seed imbibition may become a possible approach for DNA uptake, but the reliability of such a random method has to be improved.