anthoceropsida class 11 | life cycle of hornworts

Описание: Anthoceropsida (Horn Worts)
This group of bryophytes difers in many respects and is slightly advanced than Bryopsida and
Hepaticopsida. The gametophyte is highly lobed and irregular in outline. Except for a little early
stage of development, the sporophyte is not dependent upon gametophyte for nourishment
and protection. Antheridia and archegonia are partially sunken in the gametophytic tissue.
The sporophyte exhibit many advanced characters due to which it can thrive better on land as
compared to other groups. The sporophyte has stomata and chloroplasts in the epidermis and can
thus photosynthesize its own food rather than obtaining it from gametophyte. It also has a waxy
cuticle to check excessive loss of water (desiccation). Furthermore, at the junction of foot and spore
producing region there is a band of meristematic tissue. This tissue keeps on adding cells towards
the spore-producing region during the formation, maturation and dispersal of spores from the
opposite end. Due to the fast growth rate of this meristematic tissue the sporophyte keeps on increasing in length for an indeinite period of time. Due to these characters the sporophyte
continues to survive as such even after the death and decay of the gametophyte. One good example
of Anthoceropsida is Anthoceros which is also found in the hilly areas of Pakistan (Fig. 9.9)
#visiblescience
#anthoceropsidaclass11
#hornworts
#alevelbiology