Barón Edgar Javier Rincón, Landazábal Leidy Vivivana Gélvez, Ballesteros Helkin Giovany Forero, Prieto Dagoberto Arrieta, Hleap José Sergio
Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia.
Rev Biol Trop. 2009 Dec;57(4):1141-52.
Huperzia brevifolia is one of the dominant species of the genus Huperzia living in paramos and superparamos from the Colombian Andes. A detailed study of the sporangium's ontogeny and sporogenesis was carried out using specimens collected at 4200m above sea level, in Parque Natural Nacional El Cocuy, Colombia. Small pieces of caulinar axis bearing sporangia were fixed, dehydrated, paraffin embedded, sectioned in a rotatory microtome, and stained using the common Safranin O-Fast Green technique; handmade cross sections were also made, stained with aqueous Toluidine Blue (TBO). The sporangia develops basipetally, a condition that allows observation of all the developmental stages taking place throughout the caulinar axis of adult plants. Each sporangium originates from a group of epidermal cells, axilar to the microphylls. These cells undergo active mitosis, and produce new external and internal cellular groups. The sporangium wall and the tapetum originate from the external group of cells, while the internal cellular group leads to the sporogenous tissue. Meiosis occur in the sporocytes and produce simultaneous types tetrads, each one giving rise four trilete spores, with foveolate ornamentation. During the sporangium ripening, the outermost layer of the wall develops anticlinally, and inner periclinal thickenings and the innermost one perform as a secretory tapetum, which persists until the spores are completely mature. All other cellular layers colapse.
短叶石杉是石杉属的优势物种之一,生长在哥伦比亚安第斯山脉的高山草甸和超高山草甸中。利用在哥伦比亚科库伊国家自然公园海拔4200米处采集的标本,对孢子囊的个体发育和孢子发生进行了详细研究。带有孢子囊的茎轴小块被固定、脱水、石蜡包埋,在旋转切片机上切片,并用常用的番红O-固绿技术染色;还制作了手工横切面,用甲苯胺蓝水溶液(TBO)染色。孢子囊基部向顶发育,这种情况使得能够观察到成年植株整个茎轴上发生的所有发育阶段。每个孢子囊起源于一组叶腋处的表皮细胞。这些细胞进行活跃的有丝分裂,并产生新的外部和内部细胞群。孢子囊壁和绒毡层起源于外部细胞群,而内部细胞群产生孢子体组织。减数分裂发生在孢子母细胞中,产生同时型四分体,每个四分体产生四个具三缝的孢子,具蜂窝状纹饰。在孢子囊成熟过程中,壁的最外层进行垂周分裂,内部平周加厚,最内层作为分泌绒毡层,一直持续到孢子完全成熟。所有其他细胞层都解体。