Centre National de la Recherche Scientifique, 91190 Gif-sur-Yvette, France.
Plant Physiol. 1983 May;72(1):33-6. doi: 10.1104/pp.72.1.33.
The nature of organs neoformed from tobacco (Nicotiana tabacum cv Samsun) thin cell layers is influenced by the quantity of light supplied and on the sequence of this supply. It is observed that glucose exhibits similar effects. In the presence of glucose at 167 millimolar, continuous light of 50 watts per square meter is required for optimal flower differentiation in vitro. However, 50 watts per square meter irradiance limited to 6 days is sufficient to trigger flower formation in 80% of the explants provided that light is applied from day 6 to day 11 of culture. This critical phase may correspond to the initiation phase during which soluble sugars are mainly needed as carbon energy source rather than as osmoregulators. Under continuous or precise sequential sugar deprivations, either no organogenesis occurs, or abnormal structures or buds are formed. Therefore, light per se is not sufficient to induce flower differentiation. Conversely, a specific quantitative combination of glucose and sucrose almost substitutes for the light requirement for differentiation of anthers and pistils. These observations suggest that, during the sequence of events leading to flower differentiation, light acts on energy-dependent sugar uptake and metabolism and on the increase of reducing potential of chloroplasts.
由烟草（Nicotiana tabacum cv Samsun）薄壁细胞层形成的器官的性质受光照量和光照顺序的影响。研究表明，葡萄糖也具有类似的作用。在 167 毫摩尔葡萄糖存在的情况下，离体最佳花分化需要每平方米 50 瓦的连续光照。然而，只要光照从培养的第 6 天持续到第 11 天，仅 6 天每平方米 50 瓦的辐照度就足以使 80%的外植体形成花。这个关键阶段可能对应于起始阶段，在此期间，作为碳能源来源的可溶性糖主要需要而不是作为渗透调节剂。在连续或精确的顺序糖剥夺下，要么没有器官发生，要么形成异常结构或芽。因此，光本身不足以诱导花分化。相反，葡萄糖和蔗糖的特定定量组合几乎可以替代花分化所需的光照条件来分化花药和雌蕊。这些观察结果表明，在导致花分化的一系列事件中，光作用于依赖能量的糖吸收和代谢以及叶绿体还原势的增加。
