Question

Which does not occur in the thallus of Marchantia?
A. Nostoc
B. Oil cells
C. Starch grains
D. Reticulate thickenings

Answer 1

Hint: Marchantia is a dioecious bryophyte. Marchantia belongs to the class of liverworts or hepaticopsida of bryophytes. The members of liverworts have a body structure that is similar to the liver.

Complete answer: Marchantia is a thalloid bryophyte, i.e., its body is undifferentiated into roots, stems and leaves. Their bodies are green, flat, dorsiventral and dichotomously branched.
Nostoc – Nostoc is a type of blue-green algae or cyanobacteria. It fixes the atmospheric nitrogen naturally. It has special heterocyst cells for the fixation of nitrogen. Nostoc does not occur in the thallus of Marchantia.
Oil cells – The oil-producing cells are found on the thallus of Marchantia. Not only on Marchantia, but oil cells are also present on the thallus of all the liverworts.
Starch grains – The starch grains are present on the thallus of the Marchantia. The starch grains are used to store starch on the thallus. Apart from that, the thallus also stores proteins.
Reticulate thickenings – Reticulate thickenings are present on the thallus of Marchantia. This is because a complicated, mesh-like network of veins is seen on the thallus of the Marchantia that is known as the reticulate thickenings.
Hence, the correct answer is option A.

Note: The thallus of Marchantia has sex organs that are borne on the stalked upright receptacles or special branches known as gametophores. The gametophore of the male thallus is the antheridiophore, over which the male sex organ antheridium grows. The gametophore of the female thallus is the archegoniophore, over which the female sex organ archegonium grows.