种子休眠与萌发的分子生物学的研究进展

休眠与萌发是植物种子对环境变化的适应特征,受许多基因调控和环境因子的影响。利用数量遗传学方法（如QTL 分析）和突变等手段已对休眠和萌发特性进行了深入的遗传学研究。近些年来,随着分子生物学的快速发展,种子休眠和萌发研究已经深入到分子水平。分子生物学技术的运用,特别是基因表达、基因组测序和以双向凝胶电泳及质谱分析为技术基础的蛋白质组学分析,已成为研究种子休眠和萌发的新工具和新方向。本文主要就利用分子生物学方法研究种子休眠与萌发的进展给予简要综述。     

蔷薇种子的休眠及解除方法

分析了蔷薇(Rosa L.)种子休眠原因、解除休眠方法以及环境条件对休眠与萌发的影响.蔷薇种子休眠的主要原因有瘦果果皮和种皮的限制作用,胚生理休眠以及果肉、瘦果果皮、种皮和胚中的抑制物质.解除休眠的方法包括去除瘦果果皮限制、解除胚的生理休眠、去除抑制物质等.种子发育过程中及成熟后,环境因子,如温度、水分和光照,对种子休眠和萌发有影响.此外,微生物、果实采集时间也对种子休眠及萌发有较大影响.蔷薇种子的休眠机制复杂,且种间差异很大.     

药用植物种子休眠类型及休眠解除研究进展

种子休眠是植物在长期发育过程中形成的对不良环境条件主动适应的现象。介绍了常见药用植物种子休眠的原因,根据休眠原因对种子休眠与萌发的影响将种子休眠划分的几种类型,总结了对不同休眠类型的种子应分别采用的休眠解除方法,并评述了目前的研究进展。     

曼陀罗种子休眠机理与破眠方法研究

通过对曼陀罗种子生活力测定、发芽试验、吸水率测定及种子萌发抑制物研究,揭示曼陀罗种子休眠机理,并利用物理、化学法处理曼陀罗种子,以探寻打破曼陀罗种子休眠的最佳方法.结果表明:(1)新采收的曼陀罗种子为综合休眠,休眠原因包括:种皮障碍、缺少萌发所需激素以及种皮和种仁中存在萌发抑制物,其中种皮障碍是限制种子萌发的首要因素.(2)室温存储6个月可解除曼陀罗种子种仁的休眠,但种皮障碍始终是其种子萌发的限制因素.(3)机械摩擦、浓H2SO4处理和NaOH处理均可打破除曼陀罗种皮的休眠障碍,促进种子萌发,其中用10% NaOH处理90 min为破除曼陀罗种皮休眠障碍的最佳方法,且发芽率比对照提高了83%.     

种子的休眠与萌发

讨论种子休眠与萌发的相关概念,包括休眠、萌发、初生休眠、次生休眠、休眠种子、非休眠种子及休眠循环等;同时介绍2个影响较大的种子休眠类型的分类体系,并对休眠与萌发的调控机制进行综述。     

光信号与激素调控种子休眠和萌发研究进展

休眠是种子植物在长期进化过程中产生的适应性性状, 通过抑制种子在不适宜的环境中萌发进而保证植物能够在逆境中生存。此外, 休眠有助于种子的长距离运输和扩散, 因此休眠对种子延续和物种保存具有重要意义。种子由休眠向萌发的发育转变不仅关系到物种的繁衍, 而且对保证农业生产中作物的产量和品质也具有重要作用。种子的休眠和萌发受到内源激素和外源光信号的共同调控。其中, 外源光信号主要通过调控内源ABA和GA的生物合成及信号转导进而调控种子休眠和萌发。该文系统综述了外源光信号和内源激素调控种子休眠和萌发的作用通路以及两类信号通路之间的交互作用, 旨在为农业生产中利用光和激素调控种子休眠与萌发提供参考。     

光信号与激素调控种子休眠和萌发研究进展

休眠是种子植物在长期进化过程中产生的适应性性状, 通过抑制种子在不适宜的环境中萌发进而保证植物能够在逆境中生存。此外, 休眠有助于种子的长距离运输和扩散, 因此休眠对种子延续和物种保存具有重要意义。种子由休眠向萌发的发育转变不仅关系到物种的繁衍, 而且对保证农业生产中作物的产量和品质也具有重要作用。种子的休眠和萌发受到内源激素和外源光信号的共同调控。其中, 外源光信号主要通过调控内源ABA和GA的生物合成及信号转导进而调控种子休眠和萌发。该文系统综述了外源光信号和内源激素调控种子休眠和萌发的作用通路以及两类信号通路之间的交互作用, 旨在为农业生产中利用光和激素调控种子休眠与萌发提供参考。     

箭叶淫羊藿种子的休眠类型与萌发研究

箭叶淫羊藿具有重要的药用价值和较大的市场需求,但其种子休眠和萌发特性目前仍不够清楚,严重影响了其产业化育苗与栽培。为探明其种子的休眠类型及释放休眠和促进休眠的最适方法,该文以箭叶淫羊藿的成熟种子为材料,研究种子对水分的吸收、种子的脱水耐性,以及温度、层积和植物激素对种子休眠与萌发的影响。结果表明:(1)箭叶淫羊藿种子不具有物理休眠,而具耐脱水性。(2)在4～25 ℃和黑暗条件下,种子萌发率为零,具有休眠特性。(3)胚与种子的比值非常小,4 ℃和10 ℃及变温层积能显著地促进胚的生长发育以及增加种子的萌发速率和萌发率。(4)赤霉素和氟啶酮显著增加种子的萌发速率和萌发率。综上认为,箭叶淫羊藿种子的休眠类型为形态生理休眠(MPD),释放休眠和促进萌发的最适方法是先将种子在10 ℃中层积30 d,再置于4 ℃环境中让其萌发。该研究结果为箭叶淫羊藿的产业化育苗提供了参考。     

种子休眠的研究进展

种子休眠是植物在长期系统发育进程中获得的一种适应环境变化的特性。这种特性能够确保物种在恶劣的环境中存活, 减少同一物种中个体之间的竞争, 以及防止种子在不适宜的季节萌发。该文综述了种子休眠的类型、种子休眠的发育与连续群、种子休眠的调节、与休眠诱导、维持和释放有关的蛋白以及种子休眠的进化, 并提出了今后种子休眠研究的主要问题。     

种子休眠的研究进展

种子休眠是植物在长期系统发育进程中获得的一种适应环境变化的特性。这种特性能够确保物种在恶劣的环境中存活,减少同一物种中个体之间的竞争,以及防止种子在不适宜的季节萌发。该文综述了种子休眠的类型、种子休眠的发育与连续群、种子休眠的调节、与休眠诱导、维持和释放有关的蛋白以及种子休眠的进化,并提出了今后种子休眠研究的主要问题。     

生长素调控种子的休眠与萌发

植物种子的休眠与萌发,是植物生长发育过程中的关键阶段,也是生命科学领域的研究热点。种子从休眠向萌发的转换是极为复杂的生物学过程,由外界环境因子、体内激素含量及信号传导和若干关键基因协同调控。大量研究表明,植物激素脱落酸(Abscisic acid, ABA)和赤霉素(Gibberellin acid, GA)是调控种子休眠水平,决定种子从休眠转向萌发的主要内源因子。ABA与GA在含量和信号传导两个层次上的精确平衡,确保了植物种子能以休眠状态在逆境中存活,并在适宜的时间启动萌发程序。生长素(Auxin)是经典植物激素之一,其对向性生长和组织分化等生物学过程的调控已有大量研究。但最近有研究证实,生长素对种子休眠有正向调控作用,这表明生长素是继ABA之后的第二个促进种子休眠的植物激素。本文在回顾生长素的发现历程、阐释生长素体内合成途径及信号传导通路的基础上,重点综述了生长素通过与ABA的协同作用调控种子休眠的分子机制,并对未来的研究热点进行了讨论和展望。     

Elucidating hormonal/ROS networks during seed germination: insights and perspectives

While authors have traditionally emphasized the deleterious effects of reactive oxygen species (ROS) on seed biology, their role as signaling molecules during seed dormancy alleviation and germination is now the focus of many studies around the world. Over the last few years, studies using “-omics” technologies together with physiological and biochemical approaches have revealed that seed germination is a very complex process that depends on multiple biochemical and molecular variables. The pivotal role of phytohormones in promoting germination now appears to be interdependent with ROS metabolism, involving mitogen-activated protein kinase cascade activation, gene expression and post-translational protein modifications. This review is, thus, an attempt to summarize the new discoveries involving ROS and seed germination. The study of these interactions may supply markers of seed quality that might eventually be used in breeding programs to improve crop yields.     

Seed germination and dormancy: The classic story,new puzzles,and evolution

This review highlights recent progresses in seed germination and dormancy research.Research on the weakening of the endosperm during germination,which is almost a classic theme in seed biology,was resumed byα-xylosidase studies.Strong genetic evidence was presented to suggest that the quality control of xyloglucan biosynthesis in the endosperm(and the embryo)plays a critical role in germination.Further analyses on the endosperm and the adjace nt layers have suggested that the cutin coat in the endosperm-testa interphase negatively affects germination while the en dosperm-embryo in terphase produces a sheath that facilitates germination.These progresses significantly advanced our understanding of seed germination mechanisms.A breakthrough in dormancy research,on the other hand,revealed the unique abscisic acid signaling pathway that is regulated by DELAY OF GERMINATION1(DOG1).The detailed analysis of DOC1 expression uncovered the intriguing story of reciprocal regulation of the sensean tisense pair,which gen erated new questions.Recent studies also suggested that the DOG1 function is not limited to dormancy but extended through general seed maturation,which provokes questions about the evolution of DOG1 family proteins.Seed biology is becoming more exciting with the classic stories being revitalized and new puzzles emerging from the frontier.     

The role of light in regulating seed dormancy and germination

Seed dormancy is an adaptive trait in plants. Breaking seed dormancy determines the timing of germination and is, thereby essential for ensuring plant survival and agricultural production. Seed dormancy and the subsequent germination are controlled by both internal cues (mainly hormones) and environmental signals. In the past few years, the roles of plant hormones in regulating seed dormancy and germination have been uncovered. However, we are only beginning to understand how light signaling pathways modulate seed dormancy and interaction with endogenous hormones. In this review, we summarize current views of the molecular mechanisms by which light controls the induction, maintenance and release of seed dormancy, as well as seed germination, by regulating hormone metabolism and signaling pathways.     

Dormancy and germination: How does the crop seed decide?

Whether seeds germinate or maintain dormancy is decided upon through very intricate physiological processes. Correct timing of these processes is most important for the plants life cycle. If moist conditions are encountered, a low dormancy level causes pre‐harvest sprouting in various crop species, such as wheat, corn and rice, this decreases crop yield and negatively impacts downstream industrial processing. In contrast, a deep level of seed dormancy prevents normal germination even under favourable conditions, resulting in a low emergence rate during agricultural production. Therefore, an optimal seed dormancy level is valuable for modern mechanised agricultural systems. Over the past several years, numerous studies have demonstrated that diverse endogenous and environmental factors regulate the balance between dormancy and germination, such as light, temperature, water status and bacteria in soil, and phytohormones such as ABA (abscisic acid) and GA (gibberellic acid). In this updated review, we highlight recent advances regarding the molecular mechanisms underlying regulation of seed dormancy and germination processes, including the external environmental and internal hormonal cues, and primarily focusing on the staple crop species. Furthermore, future challenges and research directions for developing a full understanding of crop seed dormancy and germination are also discussed.     

脱落酸调控种子休眠和萌发的分子机制

脱落酸(ABA)是调控种子休眠和萌发过程的主要植物激素。种子内源ABA含量和种胚对ABA敏感性共同调控种子休眠和萌发过程, 确保植物种子以休眠状态在逆境中保持其自身繁衍能力, 并在适宜的环境下启动萌发程序。种子ABA合成代谢和ABA信号转导途径涉及许多重要基因家族, 它们通过复杂的调控网络精确地控制着种胚发生、种子成熟、休眠及萌发进程。该文对ABA调控种子休眠和萌发的分子机制最新研究进展进行综述, 并展望了今后的研究方向。     

细胞分裂素调控种子发育、休眠与萌发的研究进展

种子萌发是子代植株建立、生长和繁育的重要阶段, 在种子植物生命周期中起重要作用。种子休眠是在发育过程中形成的, 在生理成熟期达到峰值。种子休眠与萌发的植物激素调控可能是种子植物中一种高度保守的机制。细胞分裂素(CK)是植物体内的一种重要信号分子, 调控植物生长发育的许多方面。生物活性CK的水平由其生物合成、活化、失活、再活化和降解之间的平衡所调控, 种子的发育、休眠与萌发受生物活性CK的水平和信号转导途径调控。该文综述了CK的生物合成与代谢、信号转导以及对种子发育、休眠与萌发的调控作用, 提出了在本领域需要进一步研究的科学问题, 旨在为理解CK调控种子发育、休眠与萌发的分子机理提供参考。