Falcioni Renan, Moriwaki Thaise, de Oliveira Dyoni Matias, Andreotti Giovana Castelani, de Souza Luiz Antônio, Dos Santos Wanderley Dantas, Bonato Carlos Moacir, Antunes Werner Camargos
Laboratório de Ecofisiologia Vegetal, Departamento de Biologia, Universidade Estadual de Maringá, Maringá, Brazil.
Laboratório de Bioquímica de Plantas, Departamento de Bioquímica, Universidade Estadual de Maringá, Maringá, Brazil.
Front Plant Sci. 2018 Sep 20;9:1391. doi: 10.3389/fpls.2018.01391. eCollection 2018.
Light intensity and hormones (gibberellins; GAs) alter plant growth and development. A fine regulation triggered by light and GAs induces changes in stem cell walls (CW). Cross-talk between light-stimulated and GAs-induced processes as well as the phenolic compounds metabolism leads to modifications in lignin formation and deposition on cell walls. How these factors (light and GAs) promote changes in lignin content and composition. In addition, structural changes were evaluated in the stem anatomy of tobacco plants. GA was sprayed onto the leaves and paclobutrazol (PAC), a GA biosynthesis inhibitor, via soil, at different irradiance levels. Fluorescence microscopy techniques were applied to detect lignin, and electron microscopy (SEM and TEM) was used to obtain details on cell wall structure. Furthermore, determination of total lignin and monomer contents were analyzed. Both light and GAs induces increased lignin content and CW thickening as well as greater number of fiber-like cells but not tracheary elements. The assays demonstrate that light exerts a role in lignification under GA supplementation. In addition, the existence of an exclusive response mechanism to light was detected, that GAs are not able to replace.
光照强度和激素（赤霉素；GAs）会改变植物的生长和发育。由光照和GAs引发的精细调控会诱导干细胞壁（CW）发生变化。光照刺激过程与GAs诱导过程之间的相互作用以及酚类化合物代谢会导致木质素形成和在细胞壁上沉积的改变。这些因素（光照和GAs）如何促进木质素含量和组成的变化。此外，还对烟草植株茎部解剖结构的变化进行了评估。在不同光照强度水平下，通过土壤向烟草植株叶片喷施GA，并向土壤中施加GA生物合成抑制剂多效唑（PAC）。应用荧光显微镜技术检测木质素，利用电子显微镜（扫描电子显微镜和透射电子显微镜）获取细胞壁结构的详细信息。此外，还分析了总木质素和单体含量的测定结果。光照和GAs均会诱导木质素含量增加、细胞壁增厚以及纤维状细胞数量增多，但不会使管状分子数量增加。这些分析表明，在GA补充的情况下，光照在木质化过程中发挥作用。此外，还检测到存在一种光照独有的响应机制，GA无法替代。
