Question

Arrange the following events of the life cycle of Bryophytes in the correct sequence
I.Germination of spore
II.Gamete formation
III.Formation of gametophyte
IV. Fertilization
V. Embryo formation
(a)I,II,IV,VII
(b)II,IV,I,V,III
(c)III,II,IV,V,I
(d)V,I,II,III,IV

Answer 1

Hint Bryophytes are more advanced and highly organized than green algae. In the life cycle of Bryophytes, there is a regular and cyclic alternation between morphologically distinct gametophytic and sporophytic phases.

Complete answer:
Bryophytes have a life cycle with alternation of generation. In its life cycle, the gametophyte is haploid, independent, autotrophic and it represents the sexual generation. It develops from haploid spores, produced by sporophyte. It bears sex organs in which gametes are produced. Gametes represent the last stage of the gametophytic phase. Male and female gametes fuse and form the diploid zygote which is the first stage of the sporophytic phase. Zygote directly develops into a sporangium which completely depends upon the gametophyte. Its sporogenous cells undergo reduction division and form haploid spores which function as the mother cells of the gametophytic phase. On germination, these spores form gametophytes, thus completing the life cycle. It becomes very clear that the sexual gametophytic generation begins with meiosis and continues until fertilization, whereas the asexual sporophoric generation begins with zygote formation after fertilization and continues up to the beginning of meiosis.

Additional information:
-Bryophyta is a group of non-vascular plants, commonly called the amphibians of the plant kingdom. They are the simplest and most primitive plants which occupy a position of intermediate between green thallophytes and pteridophytes.
-The group comprises liverworts, mosses, and hornworts. Bryophytes are common in most parts of the earth, wherever there is sufficient moisture to sustain them. They usually occur in humid and shady localities at higher altitudes.
-Though they are referred to as terrestrial plants, they can be seen in diverse conditions. Some are almost permanently submerged in water.

Note:
-In Bryophytes roots are absent and fixation and absorption are affected by root-like and filamentous rhizoids.
-Rhizoids are either multicellular and unbranched or are multicellular and branched.
-Their reproduction is by vegetative mad sexual methods.