Tea seedlings (Camellia sinensis) have a well-developed root system with a strong taproot and lateral roots. Compared with ordinary cuttings, tea has stronger vitality and environmental adaptability, thus facilitating the promotion of good varieties. However, there is less of detailed research on the rooting and germination process of tea seeds. In this study, matrix-assisted laser desorption ionization time-of-flight–mass spectrometry was used to conduct non-targeted spatial mass spectrometry imaging of the main organs during growth of tea seedlings. A total of 1234 compounds were identified, which could be divided into 24 classes. Among them, theanine, as the most prominent nitrogen compound, was synthesized rapidly at the early stage of embryo germination, accounting for >90% of the total free amino acids in the radicle, and it was then transferred to each meristem region through the mesocolumnar sheath, indicating that theanine-based nitrogen flow plays a decisive role in organ formation during the development of tea seedlings. Nutrients stored in the cotyledon were rapidly hydrolyzed to dextrin and 3-phosphoglyceraldehyde at the early stages of germination, and subsequently converted to other forms that provided carbon and energy for development, such as raffinose and d-galactose (glucose), which were mainly distributed in the growing zones of the root apex and the apical meristems of the stem. This study provides a new perspective on the synthesis and metabolism of substances during the development of tea seedlings and contributes to a better understanding of the biological characteristics of tea varieties.

中文翻译：

---

基于基质辅助激光解吸/电离-质谱成像的茶苗 （Camellia sinensis） 代谢物分布可视化


茶苗 （Camellia sinensis） 具有发达的根系，具有强壮的主根和侧根。与普通扦插相比，茶叶具有更强的生命力和环境适应性，从而有利于良种的推广。然而，关于茶种子的生根和发芽过程的详细研究较少。本研究采用基质辅助激光解吸电离飞行时间质谱法对茶树苗生长过程中的主要器官进行非靶向空间质谱成像。共鉴定出 1234 种化合物，可分为 24 类。其中，茶氨酸作为最突出的氮化合物，在胚芽初期迅速合成，占胚根总游离氨基酸的>90%，然后通过中柱状鞘转移到各分生组织区，表明茶氨酸基氮流在茶树苗发育过程中对器官形成起决定性作用。储存在子叶中的养分在发芽初期被迅速水解为糊精和 3-磷酸甘油醛，随后转化为其他形式，为发育提供碳和能量，如棉子糖和 d-半乳糖 （葡萄糖），主要分布在茎根尖和顶端分生组织的生长区。本研究为茶树苗发育过程中物质的合成和代谢提供了新的视角，有助于更好地了解茶叶品种的生物学特性。