Department of Biological Sciences, University of Calgary, Calgary Alberta, Canada, T2N 1N4.
Plant Physiol. 1991 Feb;95(2):399-405. doi: 10.1104/pp.95.2.399.
A number of effects on embryogenesis of the putative phytohormone jasmonic acid (JA), and its methyl ester (MeJA), were investigated in two oilseed plants, repeseed (Brassica napus) and flax (Linum usitatissimum). Results from treatments with JA and MeJA were compared with those of a known effector of several aspects of embryogenesis, abscisic acid (ABA). Jasmonic acid was identified by gas chromatography-mass spectrometry as a naturally occurring substance in both plant species during embryo development. Both JA and MeJA can prevent precocious germination of B. napus microspore embryos and of cultured zygotic embryos of both species at an exogenous concentration of >1 micromolar. This dose-response was comparable with results obtained with ABA. Inhibitory effects were also observed on seed germination with all three growth regulators in rapeseed and flax. A number of molecular aspects of embryogenesis were also investigated. Expression of the B. napus storage protein genes (napin and cruciferin) was induced in both microspore embryos and zygotic embryos by the addition of 10 micromolar JA. The level of napin and cruciferin mRNA detected was similar to that observed when 10 micromolar ABA was applied to these embryos. For MeJA only slight increases in napin or cruciferin mRNA were observed at concentrations of 30 micromolar. Several oilbody-associated proteins were found to accumulate when the embryos were incubated with either JA or ABA in both species. The MeJA had little effect on oilbody protein synthesis. The implications of JA acting as a natural regulator of gene expression in zygotic embryogenesis are discussed.
研究了拟植物激素茉莉酸（JA）及其甲酯（MeJA）对两种油料作物——油菜（Brassica napus）和亚麻（Linum usitatissimum）胚胎发生的多种影响。将 JA 和 MeJA 的处理结果与作为几种胚胎发生方面的已知效应物的脱落酸（ABA）的处理结果进行了比较。在胚胎发育过程中，通过气相色谱-质谱法鉴定出 JA 是这两种植物中天然存在的物质。JA 和 MeJA 均可防止油菜小孢子胚胎过早萌发，以及这两种植物的培养合子胚胎在 >1 微摩尔的外源浓度下过早萌发。这种剂量反应与 ABA 获得的结果相当。在油菜和亚麻中，这三种生长调节剂对种子萌发也有抑制作用。还研究了胚胎发生的一些分子方面。在添加 10 微摩尔 JA 后，油菜小孢子胚胎和合子胚胎中 B. napus 贮藏蛋白基因（napin 和 cruciferin）的表达均被诱导。检测到的 napin 和 cruciferin mRNA 的水平与将 10 微摩尔 ABA 应用于这些胚胎时观察到的水平相似。对于 MeJA，仅在 30 微摩尔浓度下观察到 napin 或 cruciferin mRNA 的轻微增加。在这两个物种中，当胚胎与 JA 或 ABA 孵育时，发现几种油体相关蛋白积累。MeJA 对油体蛋白合成几乎没有影响。讨论了 JA 作为合子胚胎发生中基因表达的天然调节剂的作用意义。
