水稻小孢子发育过程中花药超微结构研究

Ultrastructural Observations of Rice Pollen Developments

【目的】水稻小孢子发育过程直接影响成熟花药的育性,进行系统的细胞学研究揭示不同发育时期的结构特征具有重要意义。【方法】结合形态观察与光镜分析,运用扫描电镜以及透射电镜技术,分别对小孢子发育过程中水稻花药外表皮角质层的发育过程以及内部细胞的形态发育进行了系统观察和分析。【结果】(1)在花粉发育过程中,绒毡层细胞结构变化最为明显。减数分裂前期,绒毡层细胞结构完整,随着减数分裂的进行,绒毡层细胞质浓缩,细胞内呈现空泡化,内质网清晰可见,此后逐渐消失。(2)空泡期早期花药表皮细胞外部逐渐增厚,最终形成具有保护功能且对花药正常发育至关重要的角质层。(3)乌氏体作为绒毡层细胞向雄配子体运输物资的直接通道,是在小孢子早期在绒毡层靠近雄配子体侧开始形成,参与绒毡层细胞内脂肪酸以及其他营养物质的运输。(4)在乌氏体形成的同时,小孢子外壁物质快速沉积,最后形成小孢子外壁结构。【结论】本研究观察了花药发育多个关键时期的细胞学特征,且发现了不同组织与功能相关的精细结构,对花药发育的研究具有指导作用。

【Objective】The development of microspores directly affected the fertility of mature anthers,and it is critical important to carry out the systematic cytological study which reveals the structural characteristics of different developmental stages.【Method】In combination with morphology observation and light microscope analysis,by using scanning electron microscopy（ SEM） and transmission electron microscopy（ TEM） observation,an extensively cytological study of rice anther outer epidermis cutin layer and the internal cells was conducted on the pollen development of SI HUI 498,an indica cultivar. 【Result】（ i） During pollen development process,ultrastructural change of tapetum was most dramatic： Tapetum cells had complete structure before meiosis; Following meiosis,tapetum cytoplasm condensed and vacuoles formed; The endoplasmic reticulums population rapidly increased and were clearly visible. These changes mean that endoplasmic reticulum may play a major role in the pollen development.（ ii） From early vacuolated pollen stage,cell wall of anther outer epidermis gradually thickened,and finally cuticle formed protecting the microspore from various environmental and biological stresses.（ iii） Orbicule,as nutrition direct access from tapetum cells to male gametophytes,was not visible until early spore pollen stage,participating in transportation of fatty acids and protein from tapetum cells.（ iv） At the same time of orbicule formation,sporopollenins begin to deposit on the surface of spores and finally produced the structure of exine. 【Conclusion】Our results uncovered the cytological characteristics of anther development of several key development stages and found that the fine structure associated with their distinct functions in different tissues,which could guide the study of anther development.