Q47. Which ONE of the following plant taxa contains vascular tissue (xylem and
phloem) but not woody tissue?
(A) Oak
(B) Moss
(C) Pine
(D) Fern
Vascular plants transport water and nutrients through xylem and phloem, but woody tissue arises from secondary growth via vascular cambium, producing lignified xylem that forms wood. Among the options, only ferns fit as vascular yet herbaceous, lacking true wood. This matches CSIR NET Life Sciences concepts on plant anatomy and evolution.
Option Analysis
Oak (A)
Oak (Quercus spp.) belongs to angiosperms with well-developed vascular tissue including xylem vessels and phloem. These trees exhibit secondary growth from vascular cambium, forming extensive woody trunks and branches rich in lignified secondary xylem.
Thus, oak has both vascular and woody tissue, eliminating this option.
Moss (B)
Mosses (Bryophyta) represent non-vascular bryophytes, relying on diffusion for water and nutrients via simple tissues without true xylem or phloem. They lack specialized conducting cells and lignified support, restricting growth to small sizes in moist habitats.
Moss fails due to absence of vascular tissue.
Pine (C)
Pine (Pinus spp.), a gymnosperm, features vascular bundles with tracheids in xylem and sieve cells in phloem. Secondary growth via vascular cambium produces woody stems, as seen in coniferous wood with annual rings.
Pine possesses both vascular and woody tissue.
Fern (D)
Ferns (Pteridophyta) are vascular plants with xylem (tracheids) and phloem in steles for transport. As herbaceous pteridophytes, they undergo only primary growth without vascular cambium, producing no secondary xylem or true woody tissue.
Fern meets the criteria perfectly.
Correct Answer
(D) Fern
Ferns represent the plant taxon with vascular tissue (xylem and phloem) but no woody tissue, key for competitive exams like CSIR NET.
Evolutionary Context
Vascular tissue evolved in tracheophytes around 430 million years ago, enabling taller growth than bryophytes. Woody tissue further arose in lignophytes (gymnosperms, angiosperms) via secondary growth, absent in ferns which remain herbaceous despite vascular systems. This distinction aids in classifying plant groups by tissue differentiation.
