文冠果是我国北方珍贵的木本油料植物，但坐果率低成为制约其产业发展的瓶颈。前期研究发现，在文冠果部分胚珠内，游离核胚乳首先出现异常而后败育，导致合子及胚珠败育。本项目首次聚焦游离核胚乳的败育问题，拟开展：（1）采用光学及电子显微技术研究不同发育时期游离核胚乳的细胞学，揭示哪些细胞亚显微结构首先出现异常而导致胚乳败育；（2）通过显微检测和不同试剂处理胚珠，研究活性氧（ROS）与游离核胚乳发育的关系；（3）通过激光显微切割和高通量测序技术，研究游离核胚乳特异细胞的转录组学，揭示ROS相关网络基因及其它细胞重要调控基因的表达；（4）基于转录组数据，选择异常发育胚乳中调控ROS途径的关键基因若干个，通过原位杂交、异源超表达或RNAi技术研究这些基因的功能。通过以上研究，阐明游离核胚乳败育的细胞及分子机理。本项目不仅填补植物胚胎学对游离核胚乳败育研究的空白，而且对提高文冠果坐果率研究也有重要价值。

Xanthoceras sorbifolium, a precious tree native to north China, is grown for seed oil but limited for industrial development due to its low fruit-set rate. My previous studies revealed that the syncytial endosperm aberrantly developed and then aborted in some of the ovules of X. sorbifolium, resulting in the abortion of zygotes and ovules. Based on the previous works, this project will focus on the studies of abortion of the syncytial endosperm and investigate (1) the cytological characters of syncytial endosperm in different developmental stages, using light and electron microscopy, to reveal the submicroscopic structures that firstly become aberrant and result in endosperm abortion; (2) the effect of the level of reactive oxygen species (ROS) on syncytial endosperm development through microscopic measurement of ROS and different treatments of developing ovules; (3) the transcriptomics of syncytial endosperm through the combination of laser capture microdissection and RNA-Seq technology to reveal the expression of ROS network genes and other key regulation genes of cell growth and division; (4) the functions of key genes that regulate the ROS pathway in the aberrant development of syncytial endosperm, using RNA in-situ hybridization, heterogeneous overexpression and RNA interference technique. The goal of these studies is to discover the cytological and molecular mechanisms of the syncytial endosperm abortion in X. sorbifolium. This project will not only fill the gap of researches in syncytial endosperm abortion in plant embryology, but also will be of significant value for improvement of fruit-set of X. sorbifolium.