Question

Monoecious plant of Chara shows the occurrence of
A. Stamen and carpel on the same plant
B. Upper antheridium and lower oogonium on the same plant
C. Upper oogonium and lower antheridium on the same plant
D. Antheridiophore and archegoniophore on the same plant

Answer 1

Chara has the capability to reproduce both sexually and in a vegetative mode. In sexually reproducing plants, if male and female organs are located on the same plant, it is called a monoecious plant.

Complete answer: In both the sexual and vegetative modes, Chara can reproduce. Their sexual reproduction is of an advanced oogamous type. Their sex organs are comparatively larger and macroscopic. The male sex organ is called the globule. It is yellow to red in colour. The female sex organ is called nucule or oogonium. It is more or less oval-shaped and green in colour. On maturity, antheridia filaments (made up of antheridium cells) develop from globules. Oogonium is often found separately above the antheridium or globule. If antheridia and oogonia occur on separate plants it is known as dioecy. Most of the plants are homothallic or monoecious (i.e. the same plant has male and female sex organs developed on it). The zygote transforms into an oospore following fertilisation. Tubers, amylum stars and secondary protonema are used for vegetative reproduction of Chara. The branching system of Chara species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately.
So, the correct answer is option C.

Note:Chara is a green algae. They are multicellular and resemble land plants, superficially. They are able to thrive on less oxygenated, hard water. Calcium carbonate deposits form a covering for these algae and hence they are popularly known as ‘stoneworts’.