Noodén L D, Blakley K A, Grzybowski J M
Botany Department, University of Michigan, Ann Arbor, Michigan 48109-1048.
Plant Physiol. 1985 Oct;79(2):543-5. doi: 10.1104/pp.79.2.543.
Although the seed coat, through its thickness and permeability, often regulates seed germination, very little is known about the control of its development. Using soybean (Glycine max [L.] Merrill) explants, podbearing cuttings in which defined solutions can be substituted for the roots, we have demonstrated that cytokinin and mineral nutrients moving through the xylem can control soybean seed coat development. Lack of cytokinin and minerals in the culture solution, causes a thicker, less permeable seed coat to develop. The seeds with thickened coats will imbibe water rapidly if scarified; furthermore, these scratched seeds also germinate and produce normal plants. Inasmuch as stress (e.g. drought) decreases mineral assimilation and cytokinin production by the roots, the resulting delay in germination could be an adaptive response to stress.
尽管种皮常常通过其厚度和通透性来调节种子萌发，但对于其发育的控制却知之甚少。利用大豆（Glycine max [L.] Merrill）外植体，即可以用特定溶液替代根系的带荚插条，我们已经证明，通过木质部运输的细胞分裂素和矿质养分能够控制大豆种皮的发育。培养液中缺乏细胞分裂素和矿物质会导致种皮发育得更厚、通透性更低。种皮增厚的种子如果经过划破处理就能迅速吸水；此外，这些划破的种子也能发芽并长成正常的植株。由于胁迫（如干旱）会降低根系对矿物质的吸收和细胞分裂素的产生，由此导致的萌发延迟可能是对胁迫的一种适应性反应。
