2007-03-04 18:27:26 · 2 answers · asked by holgado e 1 in Science & Mathematics ➔ Botany
The following are the major steps in dispersal of spores.
A) After fertilization the moss sporophyte or the sporogonium begins to develop rapidly.
The foot goes deep in the leafy shoot for nourishment (It is haustorial and invisible).
The seta elongates rapidly and carries the capsule high above the leafy shoot.
The calyptra (remnant of the archegonia) is seen above the capsule. It soon falls off.
Click the links below to see the pictures.
1) http://dbs.umt.edu/courses/sci226/gifs/i...
2) http://homepages.vvm.com/~jevans/sfbotan...
this link shows good calyptra
B) As the calyptra falls off the peristome or the mouth of the capsule is seen
3) this link will show you the peristome which is of different colour than the rest of the capsule.
http://www.science.siu.edu/plant-biology...
It is guarded by a large number of peristomal teeth which are hygroscopic( Sensitive to atmospheric moisture).
When the air is dry the pristomal teeth open and allow the spore dispersal by wind ( Capsule shakes in the wind)
4) This link will show open capsule with peristomal teeth projected out.
http://www.botany.ubc.ca/bryophyte/pictu...
When the air is moist , the peristomal teeth curl in and close the capsule mouth to prevent spore dispersal ( In this condition they cannot go far)
5) This link will show closed teeth of the peristome.
http://www7.ocn.ne.jp/~hattorib/moss027....
2007-03-08 14:56:52 · answer #1 · answered by Anonymous · 0⤊ 0⤋
These plants absorb water and minerals through their entire body surface. Their sperm cells swim to the egg cells when the body of the plant is covered with rainwater or dew.
2007-03-04 18:37:39 · answer #2 · answered by michelle 5 · 0⤊ 1⤋