松嫩盐碱草地典型植物种子繁殖性状变异的地理格局及形成机制

The relationship between plant functional traits and environmental factors is a critical scientific problem in the subject of biogeography. Plant traits under saline envionronment reflect the interactions among geoenvironmental factors, stress degrees and the biological processes. Until now, much more work focuses on the functional traits of plant leaves while lack of researches in seed reproductive traits thought this is critical for understanding of the variations of gegographical patterns in plants growing in saline soils. In this proposal, we will choose the Songnen grassland as the main study area. Based on field experimentation, common garden experiments, reciprocal transplant experiments, controlled environmental studies and the simulation experiments, we will clarify the variations of seed functional traits among different provenances so as to reveal the morphology, physiology and chemical composition relating to seed dormancy and germination and the variation patterns with the change of saline-sodic gradients. In addition, we will investigate the roles and contributions of seed morphology characteristics and the environmental factors on seed rproductive trait variations among different gegoraphical provenances. Based on the above work, we will construct a response model that integrates the critical environmental factors, typical seed traits and the core reproductive ecological processes and variations. The model will explain the formation mechanisms the geographical patterns in seed productive traits of plants growing in saline-sodic soils. This proposed work would aid better understanding the response mechanism of plants to multiple abiotic stresses for the vegetation restoration and conservation in saline-sodic grasslands.

植物功能性状与地理环境间的关系是生物地理学的关键科学问题。盐碱环境下植物性状格局，反应了地理环境、胁迫梯度和生物过程间的时空互作关系。盐碱草地现有研究多关注植物叶片性状，对种子繁殖性状缺少系统深入研究，而这是阐释盐碱植物地理格局变异及机制的关键。选择松嫩盐碱草地作为研究对象，运用野外定位、同质园实验、交互移植、环境梯度控制和室内模拟等方法，阐明盐碱环境梯度下典型植物种子功能性状的地理格局分异特征，揭示种子形态、生理和化学组分等与种子休眠、萌发的关系及其随盐碱梯度的变异规律，阐明繁殖性状与环境要素的关系，明确种子自身特征和地理环境对种子繁殖性状地理格局的作用和贡献，构建融合关键环境要素、典型种子性状和主要繁殖生物过程及其变异关系的定量模型，阐明典型盐碱植物种子繁殖性状地理格局变异的形成机制。研究将深入植物对多种非生物逆境交叉响应机理的理解，指导盐碱草地植被恢复和保护。

盐碱环境下植物性状格局，反应了地理环境、胁迫梯度和生物过程间的时空互作关系。盐碱草地现有研究多关注植物叶片性状，对种子繁殖性状缺少系统深入研究，而这是阐释盐碱植物地理格局变异及机制的关键。本项目以松嫩盐碱草地的羊草、碱蓬和尾草等典型植物为研究对象，运用野外定位、同质园实验、环境梯度控制和室内模拟等方法，阐明盐碱环境梯度下碱蓬、虎尾草和羊草种子功能性状的地理格局分异特征，揭示了种子性状、种子休眠、萌发的特性及其随盐碱梯度的变异规律，阐明繁殖性状与环境要素的关系，明确种子自身特征和地理环境对种子繁殖性状地理格局的作用和贡献，解释植物种子繁殖性状地理格局变异的形成机制。主要发现包括以下几个方面：1）不同地理种源的碱蓬、虎尾草和羊草种子在千粒重、长和宽及解释特性等方面均存在显著差异，例如羊草的千粒重变异系数在2.90%-16.2%之间，种子长变异系数在6.50%-16.71%之间，种子宽变异系数在7.42%-11.33%之间，表明松嫩典型植物种子在表观性状存在显著的差异，具有丰富的表观多样性；2）不同地理种源的碱蓬、虎尾草和羊草等物种的种子休眠和萌发特性及对NaCl、Na2CO3、NaHCO3等盐碱环境因子的响应也存在显著种内变异，例如对11个地点的虎尾草种子萌发对盐碱胁迫的响应研究表明，超等的碱蓬和虎尾草种子耐盐碱能力最强，在100 mM的NaCl胁迫下发芽率没有受到显著抑制；3）四年的同质园实验结果表明，羊草表型特征在种源间仍存在显著差异，这是在长期的土壤环境适应中形成的结果，形成了具有稳定遗传的特性，种子繁殖性状变异的地理格局形成是受环境和遗传双重因素控制。本研究解释了松嫩苏打盐碱地上不同种源羊草表型特征分化的差异性，为研究羊草在未来适应多变的环境提供了理论基础和科学依据。本项目资助下，发表学术论文14篇，出版专著5部；获得吉林省自然科学奖二等奖1项，吉林省学术成果三等奖1项；授权发明专利3项，受理发明专利6项：制定地方标准2项；培养硕士研究生5名，博士后1名。