Institute of Plant Development, Birge Hall, University of Wisconsin, Madison, Wisconsin 53706.
Plant Physiol. 1969 Oct;44(10):1402-6. doi: 10.1104/pp.44.10.1402.
The formation of flowers has been studied in stem tissue excised from flowering plants of Nicotiana tabacum variety Wisconsin No. 38, and cultured in vitro on Murashige and Skoog nutrient medium. A procedure for quantitative evaluation of factors influencing floral expression has been developed and effects of the growth substances, indole-3-acetic acid (IAA), kinetin and gibberellic acid (GA(3)), on the process are reported.Although a low (1 mum) level of IAA was required for the development of normal flowers on stem segments, higher concentrations tended to inhibit flowering. The decrease in floral buds was rapid in the 3 to 15 mum range. IAA concentrations up to 75 mum increased vegetative bud formation so as to effect a transition from floral to vegetative buds rather than merely an inhibition of bud formation. Higher IAA concentrations inhibited both vegetative and floral bud formation.Kinetin in high concentrations greatly increased the number of vegetative buds but had no significant effect on the number of floral buds per segment. High kinetin concentrations also permitted branching of floral shoots so that flower clusters were formed.GA(3) applied in the medium from the start, strongly inhibited bud formation on the stem segments, but when applied to young floral buds after they had formed, it promoted their further development ("bolting").Flower formation occurred in complete darkness, but light of moderate intensity was required for the development of normal flowers.
已从烟草品种 Wisconsin No. 38 的开花植物的茎组织中切取组织并在 Murashige 和 Skoog 营养培养基上进行体外培养，以研究花的形成。已经开发出一种用于定量评估影响花表达因素的程序，并报告了生长物质吲哚-3-乙酸（IAA）、激动素和赤霉素（GA（3））对该过程的影响。尽管茎段上正常花朵发育需要低（1 µm）水平的 IAA，但较高浓度往往会抑制开花。在 3 到 15 µm 的范围内，花芽的减少迅速。高达 75 µm 的 IAA 浓度增加了营养芽的形成，从而使花芽从花状芽向营养芽过渡，而不仅仅是抑制芽的形成。较高的 IAA 浓度抑制营养芽和花芽的形成。高浓度的激动素大大增加了营养芽的数量，但对每个节段的花芽数量没有显著影响。高浓度的激动素还允许花茎分枝，从而形成花簇。GA（3）从开始就应用于培养基中，强烈抑制茎段上的芽形成，但当应用于已经形成的幼花花芽时，它促进了它们的进一步发育（“抽薹”）。在完全黑暗的条件下发生花形成，但需要中等强度的光照才能发育出正常的花朵。
