TN State Board 12th Botany Question Paper 2024

Coleorhiza is a protective sheath covering the radicle in monocotyledonous seeds. Among the options, Paddy (Oryza sativa) is a monocot, while Pea, Tridax, and Bean are dicots. Therefore, Coleorhiza is found in Paddy.

(1) Totipotency refers to the property of a living cell to develop into an entire plant (iii). (2) Dedifferentiation is the reversion of mature cells into meristematic tissue (i). (3) Explant is the selected plant tissue transferred to a culture medium (iv). (4) Differentiation is the biochemical and structural changes occurring in cells (ii). Matching these results in (1)-(iii), (2)-(i), (3)-(iv), (4)-(ii).

Regulating services include processes like climatic regulation and invasion resistance. Genetic resources are classified as 'Provisioning services', and recreation/aesthetic values are classified as 'Cultural services'. Thus, (i) and (ii) are not regulating services.

Splicing is the post-transcriptional modification process in eukaryotes where non-coding introns are removed and coding exons are joined together to form mature mRNA.

In about 60% of angiosperms, the pollen grain is shed at the 2-celled stage, consisting of one vegetative cell and one generative cell.