航天医学与医学工程

目的 以樱桃番茄（Solanum lycopersicum L.）为研究对象，探究空间微重力环境对其水分与养分代谢及胁迫响应的影响机制。方法 开展空间站微重力栽培试验，并进行地面同步对照，结合基质理化分析、植株表型观测、生理生化检测及基因表达分析，系统探究微重力的作用路径。结果 微重力下樱桃番茄营养生长与生殖生长双重异常：主茎徒长、侧枝萌发受抑且生长方向随机，叶片呈缺铁性黄化；开花结果延迟，成花坐果率低，果实形态与产量偏离地面水平。机理方面，微重力干扰基质水气流体特性与养分迁移，引发多重胁迫：水分蒸发导致表层养分富集形成局部高盐环境，水分包裹根系造成内涝缺氧，激活无氧呼吸通路并引发氧化损伤；根系缺氧抑制铁离子转运蛋白功能与基因表达，导致功能性缺铁。生理生化与基因表达数据证实，微重力破坏重力感应-激素平衡-物质运输调控网络，造成水分与养分代谢失衡。结论 初步阐明微重力影响樱桃番茄水分与养分代谢及生长发育的多途径规律与机制，为解析太空植物生长限制因子、构建适应性栽培策略提供理论基础。

Objective In investigate the impact of space microgravity on water, nutrient metabolism and stress responses in cherry tomato(Solanum lycopersicum L.). Methods A microgravity cultivation experiment was conducted aboard the space station, with ground-based synchronous controls. Integrated analyses included physicochemical characterization of the growth substrate, phenotypic observation of plants, physiological and biochemical assays, and gene expression profiling to systematically elucidate the mechanisms of microgravity action. Results Cherry tomatoes showed double abnormalities in vegetative and reproductive growth under microgravity: the main stem was leggy, lateral bud germination was inhibited with random growth direction, and leaves showed iron-deficiency chlorosis. Delayed flowering and fruiting occur alongside low flower-to-fruit transition rates, with fruit morphology and yield deviating from ground-level standards. Mechanistically, microgravity interfered with the hydro-gas fluid characteristics and nutrient migration in the matrix, inducing multiple stresses: water evaporation led to surface nutrient enrichment forming a local high-salt environment, and water wrapping around the root system caused waterlogging and hypoxia, activating the anaerobic respiration pathway and triggering oxidative damage; root hypoxia inhibited the function and gene expression of iron ion transporters, resulting in “functional iron deficiency”. Physiological, biochemical and gene expression data confirmed that microgravity destroyed the regulatory network of gravity sensing-hormone balance-substance transport, causing imbalance of water and nutrient metabolism. Conclusion The multi-pathway laws and preliminary mechanisms of microgravity affecting water and nutrient metabolism and growth of cherry tomatoes are initially clarified, which provides a theoretical basis for analyzing the growth-limiting factors of space plants and constructing adaptive cultivation strategies.