Molecular and physiological regulation of adventitious root formation in Petunia cuttings in response to nutrient supply and dark exposure

观赏植物的无性繁殖依赖于插条不定根的形成，而不定根的形成与园艺生产中的经济损失密切相关。基于已建立的转录组研究芯片、生化和转化平台，矮牵牛将被用于研究茎尖扦插中ARF的环境调节背后的分子生理调控。这一概念依赖于这样一个事实，即ARF依赖于在茎基部建立新的库，并受到与茎尖竞争同化和营养供应的限制。叶片被认为是潜在的源器官，生长素预计是一个关键因素。项目A部分遵循以下假设，即对供体植物的高氮供应和扦插的黑暗暴露通过增强扦插内的氮再动员和增强信号分子生长素和一氧化氮的转运和积累来促进ARF。在B部分中，假设ARF受到宏量和微量元素的阶段特异性缺乏的限制，这可以通过在某些发育阶段向茎基部提供有针对性的营养来满足。特别是，硝酸盐和尿素在植物激素的体内平衡中的作用被认为是。在这两个项目部分中，生长素和细胞分裂素水平的GC-和LC-MS/MS分析将补充生长素活性的组织化学定位通过DR 5生长素报告。组分的调节作用将通过生理和药理学处理以及在具有修饰的候选基因表达的转基因矮牵牛中进行验证。

The vegetative propagation of ornamental plants depends on adventitious root formation (ARF) in cuttings, which is related to economic losses in horticulture. Based on the established microarray for transcriptome studies, a biochemical and a transformation platform, Petunia will be used to investigate the molecular physiological regulation behind environmental modulation of ARF in shoot tip cuttings. The concept relies on the fact that ARF depends on establishment of the new sink in the stem base and is restricted by competition with the shoot apex for assimilate and nutrient provision. Leaves are considered as potential source organs and auxin is expected to be a key factor. Project part A follows the hypotheses, that high nitrogen supply to donor plants and dark exposure of cuttings promote ARF by enhanced nitrogen remobilization within the cutting and enhanced translocation and accumulation of the signalling molecules auxin and nitric oxide. In part B it is hypothesized that ARF is restricted by phase specific deficiency of macro- and microelements, which can be met by targeted nutrient supply to the stem base during certain developmental stages. In particular, the role of nitrate and urea in homeostasis of phytohormones is regarded. In both project parts, analysis of auxin and cytokinin levels by GC- and LC-MS/MS will be complemented by histochemical localization of auxin activity via the DR5 auxin reporter. The regulatory role of components will be verified by physiological and pharmacological treatments and in transgenic Petunia with a modified expression of candidate genes.