Embryo sac formation and early embryo development in Agave tequilana (Asparagaceae)

Abstract

Agave tequilana is an angiosperm species that belongs to the family Asparagaceae (formerly Agavaceae). Even though there is information regarding to some aspects related to the megagametogenesis of A. tequilana, this is the first report describing the complete process of megasporogenesis, megagametogenesis, the early embryo and endosperm development process in detail. The objective of this work was to study and characterize all the above processes and the distinctive morphological changes of the micropylar and chalazal extremes after fertilization in this species. The agave plant material for the present study was collected from commercial plantations in the state of Jalisco, Mexico. Ovules and immature seeds, previously fixed in FAA and kept in ethanol 70%, were stained based on a tissue clarification technique by using a Mayer’s-Hematoxylin solution. The tissue clarification technique was successfully used for the characterization of the megasporogenesis, megagametogenesis, mature embryo sac formation, the early embryo and endosperm development processes by studying intact cells. The embryo sac of A. tequilana was confirmed to be of the monosporic Polygonum-type and an helobial endosperm formation. Also, the time-lapse of the developmental processes studied was recorded.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-3-575) contains supplementary material, which is available to authorized users.

Somatic Embryogenesis: Fundamental Aspects and Applications

“…Nowadays, the genus Agave is distributed in the tropical and subtropical areas of the world and represents a large group of succulent plants, and its center of origin is probably limited to México (Gentry 1982 (Gentry 1972). Nowadays, the genus Agave is distributed in the tropical and subtropical areas of the world and represents a large group of succulent plants, and its center of origin is probably limited to México (Gentry 1982 (Gentry 1972).…”

“…Nowadays, the genus Agave is distributed in the tropical and subtropical areas of the world and represents a large group of succulent plants, and its center of origin is probably limited to México (Gentry 1982 (Gentry 1972). The subgenus Agave and particularly the sections Rigidae and Sisalanae are cultivated because of their commercial importance for diverse purposes: (a) alcoholic beverages such as tequila and mezcal; (b) natural long and hard fibers; and (c) sapogenins as natural precursors of steroidal compounds and medicinal principles as those species of the Amolae group (Blunden et al 1980;Gentry 1982;Cedeño 1995); and unarmed species lacking spines are frequently used as ornamental plants among many other uses. The subgenus Agave and particularly the sections Rigidae and Sisalanae are cultivated because of their commercial importance for diverse purposes: (a) alcoholic beverages such as tequila and mezcal; (b) natural long and hard fibers; and (c) sapogenins as natural precursors of steroidal compounds and medicinal principles as those species of the Amolae group (Blunden et al 1980;Gentry 1982;Cedeño 1995); and unarmed species lacking spines are frequently used as ornamental plants among many other uses.…”

Somatic Embryogenesis in Agave spp.

“…The subgenus Agave and particularly the sections Rigidae and Sisalanae are cultivated because of their commercial importance for diverse purposes: (a) alcoholic beverages such as tequila and mezcal; (b) natural long and hard fibers; and (c) sapogenins as natural precursors of steroidal compounds and medicinal principles as those species of the Amolae group (Blunden et al 1980;Gentry 1982;Cedeño 1995); and unarmed species lacking spines are frequently used as ornamental plants among many other uses. Agave tequilana Weber var.…”

“…Nowadays, the genus Agave is distributed in the tropical and subtropical areas of the world and represents a large group of succulent plants, and its center of origin is probably limited to México (Gentry 1982). The genus Agave has about 200 species of which approximately 150 are endemic to México (García-Mendoza 2002), and it is divided into two subgenera, Littaea and Agave, based on the architecture of the inflorescence; subgenus Littaea has a spicate or racemose inflorescence while plants of the subgenus Agave bear a paniculate inflorescence with flowers in umbellate clusters on lateral branches (Gentry 1972).…”

“…A. fourcroydes is a pentaploid, long-lived plant, asexually propagated and grown mainly for the manufacture of ropes, woven sacks of high quality, and for the extraction of medicinal precursors (Gentry 1982). Recently, Monja-Mio and Robert (2013) reported the direct somatic embryogenesis in this species through thin cell layer culture (tTCLs), which will be a useful biotechnological technique for in vitro germplasm conservation, genetic improvement and for micropropagation as it has been reported for many plant species.…”