笔竹大小孢子发生及雌雄配子体发育研究

Sporogenesis and gametogenesis of Pseudosasa viridula

关键词:  笔竹, 大孢子发生, 小孢子发生, 雌配子体, 雄配子体

Key words:  Pseudosasa viridula, megaspogenesis, microsporogenesis, female gametophyte, male gametophyte

摘要:

为探讨笔竹(Pseudosasa viridula)结实率低的原因,该文通过采用石蜡切片的方法结合显微技术对笔竹大小孢子发生及雌雄配子体的发育过程进行研究。结果表明:(1)笔竹的雄蕊多为3枚,极少有6枚,每枚花药具有4个花粉囊。(2)花药壁发育为基本型,由4层细胞构成,由外向内依次为表皮细胞、药室内壁细胞、中层细胞和绒毡层细胞,绒毡层发育为腺质型。(3)小孢子母细胞减数分裂中的胞质分裂为连续型,四分体为左右对称型。(4)成熟花粉粒为2-细胞型和3-细胞型,出现畸形或空腔花粉粒,败育多发生在花粉单核期。(5)笔竹的子房1室,胚珠倒生,珠被2层,厚珠心。(6)胚囊为蓼型,成熟胚囊由卵器、极核和3个反足细胞构成。从大小孢子发生及雌雄配子体发育的整个过程看,雌蕊结构完整,胚囊发育正常,而花粉败育可能是导致结实率低的主要原因之一。该研究阐明了笔竹大小孢子发生及雌雄配子体发育过程,初步揭示了该物种低结实率的原因,为笔竹杂交育种研究提供了基础资料。

Abstract:

To reveal the causes of low seed-setting rate of Pseudosasa viridula, the process of sporogenesis and gametogenesis of P. viridula were studied using traditional paraffin section and microscopy techniques. The results were as follows:(1)Each flower contained three anthers(rarely 6)and an anther with four pollen sacs.(2)The anther wall belonged to the basic type, which composed of four layers of cells, which were epidermis, endothecium, middle layer and tapetum from outside to inside.(3)The cytokinesis microspore mother cell in meiosis division in successive and the microspore tetrads were medially zygomorphic.(4)Mature pollen grains were 2-cell type or 3-cell type, and some abortions occurred in the mononuclear stage of microspores.(5)Its ovary was unilocular, with parietal placenta was anatropous, double integument and crassinucellate.(6)The embryo sac was the polygonum type composed of an egg organ, a polar nucleus and three antipodal cells. The pistil structure was complete with embryo sac normal development, and the microspore abortion occurs in the single nuclear pollen stage. It is the typical male sterility and pollen abortion that may be the main reasons for the low seed-setting rate of P. viridula. This study clarified the process of sporogenesis and gametogenesis of P. viridula, and initially revealed the reasons for the low seed-setting rate of this species, which provides basic information for the study of cross breeding of P. viridula.