Department of Botany, University of Delhi, 110007, Delhi, India.
Planta. 1974 Dec;115(4):319-28. doi: 10.1007/BF00388614.
In the presence of kinetin, a supposedly gametophytic bud inducing substance, the secondary protonema of the moss Physcomitrium pyriforme Brid., as well as producing leafy gametophytes, continued to exhibit its normal tendency of forming sporophytic buds (i.e. buds with apical cells having two cutting faces). Also remarkable was that callus derived from the secondary protonema, when cultured in a kinetin supplemented liquid medium, formed exclusively apogamous sporophytic buds with a virtual exclusion of gametophytes. In the presence of abscisic acid, the elongation of protonemal cells as well as their differentiation was markedly suppressed. This effect was manifest even when abscisic acid was used in conjunction with kinetin. It is suggested that rather than having a morphoregulatory role, kinetin may be responsible merely for enhancing cell proliferation. The determination of an apical cell with two cutting faces (sporophytic) or one with three cutting faces (gametophytic) is under the control of other factors both external, (e.g. sucrose) and internal. It is proposed that abscisic acid can suppress the usual differentiational capacity of the moss tissue, even in a favourable environment.
在激动素存在的情况下，一种假定的配子体芽诱导物质，苔藓Physcomitrium pyriforme Brid. 的次生原丝体不仅产生了有叶的配子体，还继续表现出其形成孢子体芽（即具有两个切割面的顶端细胞的芽）的正常趋势。值得注意的是，从次生原丝体衍生的愈伤组织在添加激动素的液体培养基中培养时，仅形成无性孢子体芽，几乎没有配子体。在脱落酸存在的情况下，原丝体细胞的伸长及其分化明显受到抑制。即使在与激动素一起使用时，这种效果也很明显。这表明，激动素可能仅仅负责增强细胞增殖，而不是具有形态调节作用。具有两个切割面（孢子体）的顶端细胞或具有三个切割面（配子体）的顶端细胞的决定受到外部（例如蔗糖）和内部其他因素的控制。有人提出，脱落酸可以抑制苔藓组织的通常分化能力，即使在有利的环境中也是如此。
