sporophyte


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sporophyte:

see gametophytegametophyte
, phase of plant life cycles in which the gametes, i.e., egg and sperm, are produced. The gametophyte is haploid, that is, each cell contains a single complete set of chromosomes, and arises from the germination of a haploid spore.
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Sporophyte

 

an asexual generation in plants which is formed from a zygote and in which alternation of generations is part of the developmental cycle. Sporophytes develop sporangia, which bear spores by means of meiosis. The sporophyte alternates with the gametophyte—the sexual generation—which is formed from a spore and which forms gametes. The merging of gametes produces a zygote. The cells of the sporophyte and those of the zygote have a diploid set of chromosomes, whereas the cells of the gametophyte have a haploid set.

The sporophyte represents different stages in the developmental cycles of different plants. In gymnosperms and angiosperms it plays a dominant role, ensuring the development of greatly reduced gametophytes (male gametophytes are pollen grains; female ones are the primary endosperm and the embryo sac). It also dominates in ferns and laminarians, whose gametophytes (prothallia) exist separately from the sporophytes. The sporophyte occupies a subordinate position in mosses, where it is represented by a sporogonium on the gametophyte, and in a few brown algae, where it exists independently.

In plants with isomorphic cycles of development, such as some green and brown algae, independently existing sporophytes and gametophytes are marked by a morphologically similar development. In a majority of Florideae (red algae) the sporophyte seems to have two phases of development: the first, the carpospo-rophyte, develops on the gametophyte; the second lives independently and develops similarly to the gametophyte. Hetero-morphic cycles of development, with a sporophyte that produces numerous spores, are especially characteristic of all higher plants except mosses. The establishment in plants of such cycles of development is due to the emergence of algal ancestors onto dryland, where reproduction by spores was more advantageous. The transition from isospory to heterospory led to the development of seeds and to a more perfect type of reproduction in plants—seed reproduction.

A. N. SLADKOV

sporophyte

[′spȯr·ə‚fīt]
(botany)
An individual of the spore-bearing generation in plants exhibiting alternation of generation.
The spore-producing generation.
The diplophase in a plant life cycle.
References in periodicals archive ?
2011), we counted the number of mature spores in four sporangia of different sporophytes in order to detect a deviation from the normal production.
They also found forest age positively correlated with sporophyte numbers and negatively correlated to the percentage of non-expressed shoots.
Stolon parts were treated for 5-10 min, spore, leaf primordium, circinate part of young fronds and leaf primordium, procured from in vitro-raised sporophytes, were treated for 2-5, 2-10, 5-10, and 1-2 min, respectively.
During the 14-day experiment, we monitored a total of 60 amphipods that were distributed over 12 containers, each with one sporophyte of Macrocystis pyrifera.
These authors reported that after harvesting of Laminaria hyperborea by trawling, though the young kelps grew up rapidly to replace the mature sporophytes, the epiphytes and holdfast fauna populations took significantly longer to recover.
The sporophyte generation produces spores, each of which develops into a gametophyte, which produces gametes.
Sporophyte is differentiated into foot, seta and capsule.
The first phase begins in spring and is called conchocelis phase cultivation, and is performed in installations on land; its purpose is to grow and cultivate the filamentous sporophytes. The second phase is the controlled inoculation of the cultivation substrates, which can be performed on dry land or in the aqueous medium and consists of fixing the greatest possible number of conchocelis spores on to the nets; generally attachment is ensured by means of appropriate environmental manipulation of the first phase and the use of cultivation tanks to perform the inoculation.
Pollen genotype female sporophyte and pollen storage interactions.
Almost all of the more than 250,000 extant species of seed plants engage in a complex life cycle that alternates between two organismal generations, the sporophyte and the unisexual male and female gametophytes.