Department of Plant Physiology, Swedish University of Agricultural Sciences, P.O.B. 7047, S-750 07, Uppsala, Sweden.
Theor Appl Genet. 1991 Jul;82(4):515-20. doi: 10.1007/BF00588608.
A time-course study of lipid accumulation in microspore-derived embryos and developing zygotic embryos of rapeseed (Brassica napus L. ssp.oleifera) is presented. Rapid storage fat (triacylglycerol) biosynthesis was induced in microspore-derived embryos of oilseed rape (cv 'Topas') when the embryos were transferred from standing cultures (10 ml) to fresh medium (75 ml) and shake cultured. Triacylglycerols accumulated, after a lag period of 7 days, at a linear rate of approximately twice that of the developing zygotic embryo. The fatty acid composition of triacylglycerols in microspore-derived embryos closely parallelled that of the developing zygotic embryos. In the microspore-derived embryos, the amount of phosphatidylcholine, the major substrate for the production of polyunsaturated fatty acids in oilseeds, remained constant during the linear phase of triacylglycerol production, whereas it increased steadily in the zygotic embryos. The fatty acid composition of individual cotyledons from microspore embryos shake cultured for 15 days was compared with that of individual mature seeds. Relative amounts of the major fatty acids, i.e. palmitic, oleic and linoleic acids, were essentially the same, whereas the microspore-derived embryos had about 35% less stearic acid and 35% more linolenic acid than the mature seeds. Variation in the amounts of oleic, linoleic and linolenic acids between seeds was similar to that found between cotyledons of microspore-derived embryos, whereas variation in palmitic and stearic acid levels was significantly lower between microsporederived cotyledons than between the seeds. The results indicate that microspore-derived embryos from shake cultures should be convenient for use in studying the regulation of oil biosynthesis and for rapidly screening for oil quality in genetically altered rapeseed.
油菜（甘蓝型油菜亚种甘蓝型油菜）小孢子胚胎和发育合子胚胎中脂质积累的时程研究。油菜（品种“Topas”）小孢子胚胎在转移到新鲜培养基（75ml）并摇床培养时，迅速诱导快速储存脂肪（三酰基甘油）合成。三酰基甘油在 7 天的滞后期后以大约合子胚胎发育两倍的线性速率积累。小孢子衍生胚胎中三酰基甘油的脂肪酸组成与发育中的合子胚胎非常相似。在小孢子衍生胚胎中，作为油料中多不饱和脂肪酸产生的主要底物的磷脂酰胆碱在三酰基甘油产生的线性阶段保持不变，而在合子胚胎中则稳定增加。摇床培养 15 天的小孢子胚胎单个子叶的脂肪酸组成与单个成熟种子进行了比较。主要脂肪酸，即棕榈酸、油酸和亚油酸的相对含量基本相同，而小孢子衍生胚胎中的硬脂酸含量比成熟种子低 35%，亚麻酸含量高 35%。种子间油酸、亚油酸和亚麻酸的含量变化与小孢子衍生胚胎中子叶间的变化相似，而棕榈酸和硬脂酸水平的变化在小孢子衍生子叶间明显低于种子间。结果表明，摇床培养的小孢子衍生胚胎应该方便用于研究油脂生物合成的调控，以及用于快速筛选遗传改良油菜的油脂品质。
