Question

Complete the sentence by filling in the blank and explain those statements (Angiosperms, Gymnosperms, Spore, Bryophyta, Thallophyta, Zygote) _________plants have a soft and fibre-like body.

Answer 1

Hint: The soft and fibre-like body present in those plants in which roots, stem and leaves are not differentiated and the vascular system is absent. These types of plants are known as algae and they are mostly green and all algae groups perform photosynthesis.

Complete answer:
Thallophyta plants have a soft and fibre-like body. It is not differentiated into roots, stems and leaves, it has a thallus like body structure with cellulose walls around the cells. Its size varies from unicellular colonies to filamentous forms. The mucilage covering around the cells helps to protect the thallus from desiccation and decay. Thallophyta is mostly found in aquatic habitat and some found on soil, stone, wood etc. The vascular tissue in thallophyta is absent due to its presence in and around water and due to the absence of vascular and mechanical tissue, its body is flexible. Reproduction generally takes place by fragmentation and the fragments later develop into a thallus. Some thallophyta show sexual reproduction by fusion of gametes like anisogamous, isogamous and oogamous. Depending upon the body structure algae show all three types of life cycle like haplontic, diplontic and haplodiplontic but most of them show haplontic life cycle where zygote gets produced after mitosis and they are known as haplontic.

So the correct answer is ‘Thallophyta plants have a soft and fibre-like body.’

Note:
Thallophyta term was coined by Stephen Endlicher as similar to Embryophyta and its biological classification was given by Linnaeus and the algae term is also first coined by Linnaeus. The definition of thallophyta which was given by Endlicher is similar to that of protophyta which was not defined further.