327 - 11th Botany Textbook Volume 1

differentiated into foot, seta and capsule
(Figure 2.22). The foot is small, conical and
is embedded in the gametophyte. The seta
Operculum
Annulus
Spores
Spores sac
Columella
Trabeculae
Epidermis
Apophysis
Seta
Figure 2.22: L.S. of capsule
is long, slender and conducts water and
nutrients to the capsule . The capsule is
differentiated into apophysis, theca proper
and operculum. The cells constituting the
wall of the capsule contain chloroplasts in
them. The apophysis is the lowermost
sterile region and connects the capsule
with seta. The epidermis contains stomata
which help in exchange of gases. The cells
of the apophysis are photosynthetic, hence
the sporophyte of Funaria partially depends
on the gametophyte. The theca proper is
the middle part and is fertile region of the
capsule. It consists of a central columella
surrounded by spore sac. The spore sac is
surrounded by a single cylindrical air sac
traversed by delicate filaments made up of
parenchyma cells called trabeculae. The
trabeculae extend from the outer wall of
the spore sac to the innermost layer of the
capsule wall. The spore sac contains spore
mother cells which undergo meiotic
division to produce haploid spores. The
apical region consists of the operculum and
peristome. The operculum is the lid of the
capsule and comes out as a circular cup
shaped lid after the dehiscence of the
capsule. The peristome has one or two rows
of thickened, tooth like projections found
on the top of the capsule. They are
hygroscopic and help in the dispersal of the
spores. During favourble conditions the
spores germinate to produce thread like
green branched structure called protonema.
It produces rhizoids and number of lateral
buds which develop into new plants. In the
life cycle of Funaria the haploid
gametophytic phase (n)alternates with
diploid sporophytic phase (2n) and shows
alternation of generation (Figure 2.23).
BUDS
(n)
PRIMARY
PROTONEMA
(n)
GERMINATION
MEIOSPORES
(n)
MEIOSIS (R/D)
SPORE MOTHER
CELLS (2n)
BULBILS (TUBERS) ON RHIZOIDS
PROTONEMA
SECONDARY PROTONEMA (n)
MULTIPLICATION OF
PROTONEMAL STAGE
BUDS
(n)
BUDS
Vegetative BUDS
Reproduction
SPORE CAVITY
(2n)
(n)
(n)
FUNARIA
(n)
Sexual
Reproduction
GAMETOPHYTE
GENERATION
(n)
SPOROPHYTE
GENERATION
(2n)
FEMALE
BRANCH
(n)
MALE
BRANCH
(n)
PERICHAETIUM
(n) PERIGONIUM
(n)
ARCHEGONIUM
(n)
OOSPHERE
(n)
ANTHERIDIUM
(n)
FERTILISATION
ZYGOTE
(2n)
ANTHEROZOID
(n)
SPOROGONIUM
(2n)
Figure 17.21. Funaria. Graphic representation
Figure 2.23: Life cycle of Funaria
of the life cycle
68