4 public questions tagged with this topic.
Phloem transports organic nutrients like sucrose from the leaves to other parts of the plant.
Ref: NCERT Class 11 Biology Chapter 6: Anatomy of Flowering Plants Secondary Growth - Dicot Stem Root and Wood
Tracheophytes, or vascular plants, are defined by evolution of lignified conducting tissues, a key innovation absent in bryophytes. Xylem contains tracheids and later vessel elements with lignin-reinforced secondary walls enabling efficient long-distance water transport under tension and mechanical rigidity for upright growth. Phloem, non-lignified, distributes photosynthates. This combination permitted development of true roots, stems, megaphyllous and microphyllous leaves, increased size, drought tolerance, and colonization of drier habitats during Silurian-Devonian radiation, distinguishing Tracheophyta from nonvascular lineages. This structural framework illustrates phylogenetic relationships and adaptive significance highlighted in competitive examinations focusing on comparative plant morphology and systematics.
Ref: Campbell Biology 12th ed., Chapter 29: Plant Diversity I; Raven Plant Biology, Tracheophyta
Gymnosperm secondary xylem traditionally called softwood lightweight composed more than ninety percent tracheids, elongated imperforate elements with tapered overlapping ends and bordered pits featuring torus-margo membrane in Pinaceae pines firs providing both mechanical support and water conduction without vessels, preventing spread embolism. Absence vessels simple perforation plates reduces conductivity but improves safety against cavitation freezing in boreal habitats cold. Xylem parenchyma sparse living cells, resin canals present some groups. Tracheids plus rays form dominant wood cylinder accounting mechanical strength. This tracheid-only system distinguishes typical gymnosperms from angiosperm hardwoods which additionally contain wide vessels, fibers and abundant axial parenchyma.
Ref: NCERT Class 11 Biology, Chapter 6: Gymnosperm xylem tracheids only softwood anatomy
Tracheophytes (B) is correct here. This is core BASICS of PLANT: once you know the definition or pathway step, Tracheophytes is the clear fit. The wrong ones are A) Bryophytes; C) Thallophytes; D) Pteridophytes. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.
