The character and relative extent of the two phases vary greatly among different groups of plants and algae. Over the course ofevolution, the gametophyte stage has become progressively reduced. Thus, the gametophyte stage is dominant in the moreprimitive(nonvascular) plants (bryophytes), whereas the...
:thehaploid, multicellular, sexual reproductive stage in plants and algae that develops fromsporesand that gives rise to the male and femalegameteswhich unite during fertilization to form thezygote Note:In plants, both the gametophyte and sporophyte stages are present on one plant, but one of the...
Charlesworth D, Charlesworth B (1992a). The effects on genetic load of selection in the gametophyte stage. In: Ottaviano E, Mulcahy DL, Gorla MS, Mulcahy GB (eds) Angiosperm Pollen and Ovules, Springer-Verlag: Berlin. pp 401-407.
All species in the order have a small gametophyte stage and a smaller, relatively short-lived, spore-bearing stage. WikiMatrix Seed plant gametophytes are extremely reduced in size; the archegonium consists only of a small number of cells, and the entire male gametophyte may be represented by...
An evolutionary association between the free nuclear gametophyte stage in cycads has been made with the free nuclear stage during angiosperm endosperm development [2]. Both tissues serve a nutritive role for the embryo and both the megagametophyte and endosperm undergo cellularization later in ...
During the initiation stage when a meristem was not morphologically distinguishable yet, most progenitor cells showed 1–3 division events (Figs. 4a, b, 5b; Supplementary Data 1 and 2). The active division at the central region and reduced division at the spore end of the gametophyte led to...
Mutations in theARGONAUTE9(AGO9) gene result in the formation of ectopic MMCs in the ovule; only the normally positioned MMC will form an embryo sac, but an ectopic MMC can differentiate without undergoing meiosis into a diploid megaspore that arrests at the one-nuclear stage (Olmedo-Monfilet...
and Cham.. The studied species presented various responses on culture conditions depending on the level of stage of development. Time required for spores germination differed between species and took from only a few to 16 weeks. Prothalium formations showed various types of growth presented by ...
Effects of water stress on male gametophyte development in plants Male reproductive development in plants is highly sensitive to water deficit during meiosis in the microspore mother cells. Water deficit during this stage... HS Saini - 《Sexual Plant Reproduction》 被引量: 351发表: 1997年 ...
The haploid multicellular stage of the land plant lifecycle. When the spores are not equivalent, with some spores giving rise tomale gametophytesand others, to female gametophytes. Homospory When the spores are all equivalent in potential and give rise to gametophytes that are hermaphroditic or ...