SporePlants213-page17

SporePlants213-page17 - or prothallus, is small but...

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Spore-Dispersing Vascular Plants - 17 In most ferns, the sporangium structure is unique, arising from a single initial. These ferns are called leptosporangiate ferns. Sporangia in all other vascular plants, and in some ferns arise from multiple layers of cells. These sporangia are called eusporangiate. Spores are released when a layer (called the annulus) of a leptosporangiate sporangium responds to humidity – lip cells of the annulus break open and this essentially catapults the spores out of the sporangium. Sorus, ls with sporangia The fern gametophyte, often called a prothallium,
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Unformatted text preview: or prothallus, is small but independent from the sporophyte and photosynthetic. It is often heart shaped. The motile sperm require H 2 0 for transport to egg. Most ferns are homosporous. Antheridia and archegonia may be on the same gametophyte or on separate gametophytes. After fertilization, the zygote and young sporophyte develop from within the archegonium. . The sporophyte rapidly becomes independent, however, and the gametophyte plant dies. Fern gametophyte Antheridia, ls Antheridia from surface...
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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