Hempel F D, Zambryski P C, Feldman L J
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA.
Plant Cell. 1998 Oct;10(10):1663-76. doi: 10.1105/tpc.10.10.1663.
Far-red light and long photoperiods promote flowering in Arabidopsis. We report here that when 30-day-old vegetative plants were induced with a continuous light treatment enriched in far-red light, flowers developed directly from previously initiated primordia. Specifically, plants induced with our continuous incandescent-enriched (CI) treatment produced an average of two primary-axis nodes with a leaf/flower phenotype, indicating that approximately two leaf/paraclade primordia per plant produced an individual flower from tissue that typically would differentiate into a paraclade (secondary inflorescence). Assays for APETALA1::beta-glucuronidase activity during the CI photoinduction treatment indicated that the floral meristem identity gene APETALA1 was transcriptionally activated in primordia with a leaf/paraclade bias and in primordia committed to leaf/paraclade development. APETALA1::beta-glucuronidase activity levels were initially highest in young primordia but were not correlated strictly with primordium fate. These results indicate that primordium fate can be modified after primordium initiation and that developing primordia respond quantitatively to floral induction signals.
远红光和长光周期可促进拟南芥开花。我们在此报告，当用富含远红光的连续光照处理诱导30日龄的营养植株时，花直接从先前起始的原基发育而来。具体而言，用我们的连续富白炽灯（CI）处理诱导的植株平均产生两个具有叶/花表型的主轴节，这表明每株植物约有两个叶/侧枝原基从通常会分化为侧枝（二级花序）的组织中产生一朵单独的花。在CI光诱导处理期间对APETALA1::β-葡萄糖醛酸酶活性的检测表明，花分生组织特征基因APETALA1在具有叶/侧枝偏向的原基以及致力于叶/侧枝发育的原基中转录激活。APETALA1::β-葡萄糖醛酸酶活性水平最初在幼嫩原基中最高，但与原基命运并不严格相关。这些结果表明，原基命运在原基起始后可以改变，并且发育中的原基对花诱导信号有定量响应。
