Developmental and germinative events can occur concurrently in precociously germinating Chinese cabbage (Brassica rapa ssp. Pekinensis) seeds

• Published in: Journal of experimental botany 1999-12, Vol.50 (341), p.1751-1761
• Main Authors: Ren, Chengwei, Bewley, J. Derek
• Format: Article
• Language: English
• Subjects: ABA; Abscisic acid; Agronomy. Soil science and plant productions; Biological and medical sciences; Brassica rapa; Cabbages; Cell and Molecular Biology, Biochemistry and Molecular Physiology; Chinese cabbage; Developmental biology; Economic plant physiology; Embryo development. Germination; Embryos; Enzymes; Fundamental and applied biological sciences. Psychology; Germination; Germination and dormancy; Growth and development; Imbibition; Isocitrates; Plant physiology and development; Plants; precocious germination; Seed development; Seeds; stored reserves
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/50.341.1751

During germination in the siliquae of developing seeds of a precociously germinating (PG) line of Chinese cabbage (Brassica rapa ssp. Pekinensis), the synthesis of cruciferin and oleosins was maintained and the activities of isocitrate lyase and malate synthase increased. Thus, both developmental and germinative/post-germinative events coexisted within the same PG seeds. Drying of the seeds resulted in the developmental events being switched off and germinative/post-germinative ones being initiated. Only about 18% of the seeds of the PG line completed germination in the siliquae, so the potential for germination of the remaining non-germinating seeds was tested during their development. Isolation of these developing seeds from the siliquae and imbibition in water induced PG, but developmental events were terminated and the seeds entered a germ inative/post-germinative programme. This termination of developmental events in the induced PG seeds was not permanent, however, and they could be re-induced by incubating the seeds in ABA on Murashige and Skoog (MS) medium. If incubated on MS medium plus a low concentration of ABA, both developmental and germ inative/post-germinative events could be induced to coexist in the PG seeds up to the time of establishment of the seedlings. Control of the developmental and germ inative/postgerminative events in the seeds was influenced by the environment in which they were developing, which could be mimicked by manipulating the nutritional status and ABA content in which the seeds were in contact.