Question

Monoecious plant of Chara shows the occurrence of
(a) Upper oogonium and lower antheridium on the same plant
(b) Antheridiophore and archegoniophore on the same plant
(c) Stamen and carpel on the same plant
(d) Upper antheridium and lower oogonium on the same plant

Answer 1

Hint: Chara is a genus of green algae within the family Characeae. They are multicellular and superficially resemble land plants due to stem-like and leaf-like structures.

Complete answer: Chara is multicellular organisms of genus green algae, they superficially resemble land plants because of stem-like and leaf-like structures. They are found mostly in freshwater. Chara reproduces by both sexual and vegetative modes. The sexual reproduction of Chara is a complicated oogamous type. The sex organs are multicellular and large. The male sex organ is called globule or antheridium. The female sex organ is called nucule or oogonium. Oogonium is situated upper and antheridium is slightly lower on the same plant Most of the species are homothallic or monoecious (i.e. male and female sex organs develop on the same plant) but some are heterothallic or dioecious (i.e. male and female sex organs on different plants) . After fertilization, the zygote develops into an oospore.
They are found in water, particularly in limestone areas throughout the northern Temperate Zone, where they grow submerged, attached to the muddy bottom. The plant body is a gametophyte. It consists of the main axis (differentiated into nodes and internodes), dimorphic branches (Long Branch of unlimited growth and short branches of limited growth), rhizoids (multicellular with oblique septa) and stipulodes (needle-shaped structures at the bottom of secondary laterals).
So, the correct answer is ‘Upper oogonium and lower antheridium on the same plant’.

Note: Chara is covered with calcium carbonate deposits and are commonly known as stoneworts. Cyanobacteria are found growing as epiphytes on the surfaces of Chara, where they'll be involved in fixing nitrogen, which is vital to plant nutrition.