AP BIOLOGY

Detailed explanation-1: -Bryophytes have neither pollen nor flowers and rely on water to carry the male sperm to the female eggs. The spore capsules are produced after a male gamete (the sperm) has fertilized a female gamete (the egg). Hence the spores are part of the sexual reproductive cycle.

Detailed explanation-2: -Inside the sporangium, haploid spores are produced by meiosis. These are dispersed, most commonly by wind, and if they land in a suitable environment can develop into a new gametophyte.

Detailed explanation-3: -Spores of bryophytes are generally small, 5–20 micrometres on the average, and usually unicellular, although some spores are multicellular and considerably larger. Spores have chlorophyll when released from the sporangium. They are generally hemispheric, and the surface is often elaborately ornamented.

Detailed explanation-4: -The sporophyte is the diploid generation of a plant that produces haploid spores via meiotic divisions. In bryophytes, the sporophytes are always unbranched and produce a single sporangium (spore-producing capsule), but each gametophyte can give rise to several sporophytes at once.

Detailed explanation-5: -Asexual reproduction in bryophytes is accomplished by fragmentation or by tiny vegetative “sprouts” called gemmae, which form in special little structures called gemmae cups. Mosses and liverworts are lumped together as bryophytes, plants lacking true vascular tissues, and sharing a number of other primitive traits.