Correct Answer: Pisum

Pisum (pea plant) exhibits the classic tunica-corpus organization in its shoot apical meristem, a feature typical of many angiosperms. This organization divides the meristem into outer tunica layers (anticlinal divisions for surface growth) and inner corpus (random divisions for volume increase).

Option Explanations

Araucaria: This gymnosperm (monkey puzzle tree) shows a simplex or monoplex shoot apex organization with a single initial cell layer, lacking distinct tunica-corpus zonation common in angiosperms.

Ephedra: As a gymnosperm in Gnetales, Ephedra has a simple meristem structure without clear tunica-corpus separation; its apex follows a more primitive pattern unlike dicots.

Pisum: The pea plant (a dicot angiosperm) demonstrates two to three tunica layers over a corpus zone, forming epidermis from tunica and vascular/ground tissues from corpus.

All the above: Incorrect, as gymnosperms like Araucaria and Ephedra do not exhibit this organization, which is primarily angiosperm-specific.

Which plants exhibits Tunica-Corpus organization? Pisum (pea) shows this in its shoot apical meristem, where tunica layers cover the corpus for structured growth. Gymnosperms like Araucaria and Ephedra lack it, highlighting angiosperm specificity vital for exams.

Tunica-Corpus Structure

Tunica-corpus divides the shoot apex: tunica (1-3 outer layers, anticlinal divisions) forms epidermis; corpus (inner mass, all planes) builds cortex and stele.

Biological Role

In Pisum, tunica ensures surface expansion for leaves/stems; corpus adds bulk for vascular tissues. Absent in gymnosperms, this aids angiosperm diversity in organ formation.

Mastering tunica-corpus organization clarifies meristem evolution for life sciences students preparing competitive exams.