马尾松是我国南方生态建设与造林用材主要树种，种苗良种化是限制马尾松产业发展的关键。马尾松生根不稳定，不定根发生机理不明确。激素与不定根发生密切相关，其中赤霉素(GA)在不定根发育中分布、代谢及生理功能属于科研领域的“荒芜地”。在我们首次发现高浓度GA引起马尾松根茎组织中Ca2+浓度大幅增加，诱生根原基细胞分裂困难，不定根发育受阻，而适当补充外源性GA可有效促进不定根伸长与表达的基础上，本课题拟用多层次(组织-细胞-分子)和多手段(胶体免疫金、膜片钳、分子生物学等)相结合的方法，观察马尾松不定根形成中GA含量及其代谢酶活性的变化规律，分析GA对马尾松不定根发育中解剖构造、生理生化及分子水平方面的影响，探讨GA引起根茎细胞中Ca2+浓度增加的机制和信号转导途径，揭示马尾松不定根发生与GA代谢的内在关系，多角度证实我们首先提出的“GA是把双刃剑”的假说，为马尾松高效生根技术体系的构建提供新靶点。

Pinus massoniana, as a main tree species used for ecological construction and timber in the south of China, is highly limited to be developed resulting from the absence of certified seed industrialization. P. massoniana is recalcitrant to root, and the mechanism of its adventitious rooting remains little known. Hormones are closely related to the initiation of adventitious root for plants, however, the distribution, metabolism and physiological function of gibberellin (GA) during the development of adventitious root is a wilderness in research fields. Based on the first findings that high concentration of GA caused the obvious increase in the concentration of Ca2+, the difficulty in cell division of induced root primordium and the frustration in the development of adventitious root, while the optimum exogenous GA was able to promote the elongation and express of adventitious root, we’ll investigate variation laws for the GA concentration and metabolic enzymes activities, analyze the influence of GA on anatomical structure, physiological biochemistry and molecular biology, and explore mechanisms on the increased Ca2+ concentration and related signal transduction induced by GA in rhizoma cells in P. massoniana using multilevel (tissue, cell and molecule) and multi-technology (immune colloidal gold technique, patch clamp, molecular biology, etc) in this study. We aim to clarify the internal relationship between GA metabolism and adventitious rooting in P. massoniana, demonstrate the hypothesis that GA has a dual effect in the process of adventitious root formation, and provide a new target for the development of efficient rooting technology in P. massoniana.