microsporangium
Quick Summary
A microsporangium is a plant structure that produces only microspores. These microspores develop into male gametophytes, which produce sperm. This is part of the heterosporous life history found in some vascular plants, including all seed plants. The microsporangium itself is often borne on a microsporophyll, which is a specialized leaf. In seed plants, microsporangia are found in structures like male cones (microstrobili) in gymnosperms and stamens in angiosperms.12
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plantHeterosporous life historiesMicrosporangia (male sporangia) produce microsporocytes (micromeiocytes) that yield microspores. Megasporangia (female sporangia) produce megasporocytes (megameiocytes) that yield megaspores. The sporangia may be borne in specialized structures such as sori in ferns, cones (strobili) in some pteridophytes and most gymnosperms, or flowers in angiosperms.
Read MoreMicrosporangia (male sporangia) produce microsporocytes (micromeiocytes) that yield microspores. Megasporangia (female sporangia) produce megasporocytes (megameiocytes) that yield megaspores. The sporangia may be borne in specialized structures such as sori in ferns, cones (strobili) in some pteridophytes and most gymnosperms, or flowers in angiosperms.
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plant reproductive systemLycopsids…megaspores, and microsporophylls that contain microsporangia, which will yield microspores. Although the evolutionary origin of two kinds of spores (dimorphism) is unknown, the development of megaspores in living plants suggests that differences in nutrition in the two kinds of sporangia are significant. In a microsporangium, most of the microsporocytes undergo…
Read More…megaspores, and microsporophylls that contain microsporangia, which will yield microspores. Although the evolutionary origin of two kinds of spores (dimorphism) is unknown, the development of megaspores in living plants suggests that differences in nutrition in the two kinds of sporangia are significant. In a microsporangium, most of the microsporocytes undergo…
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angiospermThe androecium…in terminal saclike structures (microsporangia) called anthers. The number of stamens comprised by the androecium is sometimes the same as the number of petals, but often the stamens are more numerous or fewer in number than the petals. There are generally two pairs of spore-containing sacs (microsporangia) in a…
Read More…in terminal saclike structures (microsporangia) called anthers. The number of stamens comprised by the androecium is sometimes the same as the number of petals, but often the stamens are more numerous or fewer in number than the petals. There are generally two pairs of spore-containing sacs (microsporangia) in a…
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flowerPollinationThe stamen bears microsporangia (spore cases) in which are developed numerous microspores (potential pollen grains); the pistil bears ovules, each enclosing an egg cell. When a microspore germinates, it is known as a pollen grain. When the pollen sacs in a stamen’s anther are ripe, the anther releases…
Read MoreThe stamen bears microsporangia (spore cases) in which are developed numerous microspores (potential pollen grains); the pistil bears ovules, each enclosing an egg cell. When a microspore germinates, it is known as a pollen grain. When the pollen sacs in a stamen’s anther are ripe, the anther releases…
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gymnospermGeneral featuresMicrosporangia, or pollen sacs, are borne on the lower surfaces of the microsporophylls. The number of microsporangia may vary from two in many conifers to hundreds in some cycads. Within the microsporangia are cells which undergo meiotic division to produce haploid microspores.
Read MoreMicrosporangia, or pollen sacs, are borne on the lower surfaces of the microsporophylls. The number of microsporangia may vary from two in many conifers to hundreds in some cycads. Within the microsporangia are cells which undergo meiotic division to produce haploid microspores.
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coniferStrobili…all conifers the organs containing microsporangia (“male”) are separate from those bearing megasporangia (“female”), and in Cephalotaxus, some junipers (Juniperus), and the family Taxaceae they are found on different individuals.
Read More…all conifers the organs containing microsporangia (“male”) are separate from those bearing megasporangia (“female”), and in Cephalotaxus, some junipers (Juniperus), and the family Taxaceae they are found on different individuals.
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cycadophyteSporophyte phase…bearing large pollen sacs (microsporangia) in clusters (sori) on their lower (abaxial) surfaces. Up to 200 cubic cm (12 cubic inches) of pollen are produced by a single cone of Cycas rumphii, and some other species produce similar volumes. It was once estimated that one pollen cone of Encephalartos…
Read More…bearing large pollen sacs (microsporangia) in clusters (sori) on their lower (abaxial) surfaces. Up to 200 cubic cm (12 cubic inches) of pollen are produced by a single cone of Cycas rumphii, and some other species produce similar volumes. It was once estimated that one pollen cone of Encephalartos…
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gnetophyteReproductive structures and function…a cluster of sporangia, called microsporangia, that house the haploid reproductive cells (spores). The microsporangia are surrounded by a pair of bracteoles (scalelike leaves). Meiotic divisions in cells of the microsporangia produce the haploid pollen grains.
Read More…a cluster of sporangia, called microsporangia, that house the haploid reproductive cells (spores). The microsporangia are surrounded by a pair of bracteoles (scalelike leaves). Meiotic divisions in cells of the microsporangia produce the haploid pollen grains.
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