木质化作用是植物应对环境胁迫的重要免疫机制之一。申请者前期研究发现连作地黄根系木质化作用抑制其块根的膨大。为了深入解析木质化作用在连作地黄块根膨大受阻中的分子机制，本项目拟在大田和模拟条件下对头茬和连作地黄开展以下研究：①采用硫酸消化法和组织染色法测定头茬和连作地黄根部木质素沉积的关键期和时空分布；②运用qRT-PCR、Northern Blot技术结合Western Blot方法，研究连作地黄根系内木质素合成关键酶的表达变化，锁定阻碍连作地黄块根膨大的木质素合成通路；③利用RACE技术获取木质素合成通路关键酶的全长序列，并用基因过表达和RNAi技术验证其功能；④用不同木质素合成酶抑制剂处理连作地黄根部，观察细胞木质素合成变化及块根发育状态，筛选最佳木质素合成酶抑制剂。本项目为解决连作条件下地黄块根不能正常膨大的难题，提供重要的理论依据和技术支撑。

The lignifications are one of the important immune mechanisms in response to environmental stress in plants. Our preliminary study found that the lignifications in root of consecutive monoculture Rehmannia glutinosa L. inhibited tuberous root formation. To study the role of lignifications in tuberous formation in R.glutinosa, we will conduct following analysis by comparing first and consecutive monoculture R.glutinosa based on the field and simulation experiments. (1) the difference of lignin deposition (spatial and temporal) in root will be determined by Sulfuric acid digestion and Tissue staining method, respectively. (2) the different expression of genes related to lignin biosynthesis will be detected by qRT-PCR, Northern Blot and Western Blot. (3) RACE technology was used to clone the core gene full length, whose function were confirmed by RNAi and over expressed technology. (4) the different lignin synthesis inhibitor will be applied to treat consecutive monoculture R. glutinosa to reveal the effect for the inhibitors on the inhabitation of disposition of lignin in root. The analysis on the association of lignification and root tuberization will shed light on the solving of root tuberization for the consecutive monoculture of R. glutinosa.