In plant classification, which of the following statements is NOT true about angiosperms (flowering plants)?

Introduction / Context:

Angiosperms, or flowering plants, form the largest and most advanced group in the plant kingdom. They dominate most terrestrial ecosystems and are a frequent topic in school level and competitive biology exams. To answer questions about angiosperms correctly, students must know which life cycle stage is dominant, whether vascular tissues are present, how spores and seeds are produced, and what special reproductive processes such as double fertilisation occur. This question presents several statements about angiosperms and asks which one is not true, so the learner must discriminate between accurate and inaccurate features.

Given Data / Assumptions:

• The organisms under discussion are angiosperms, that is, flowering plants.
• Statements mention the dominant phase, vascular bundles, heterospory, covered seeds, and double fertilisation.
• We assume standard alternation of generations with sporophyte and gametophyte phases.
• We also assume basic textbook knowledge of angiosperm reproductive biology.

Concept / Approach:

In angiosperms, the main visible plant body (roots, stems, leaves, flowers) is the diploid sporophyte. The gametophyte generation is highly reduced and dependent on the sporophyte. Angiosperms have well developed vascular bundles composed of xylem and phloem. They are heterosporous because they form microspores (leading to male gametophytes in pollen) and megaspores (leading to female gametophytes in ovules. Their seeds are enclosed within fruits, unlike gymnosperms where seeds are naked. A unique feature of angiosperms is double fertilisation, where one male gamete fuses with the egg and the other fuses with the secondary nucleus to form endosperm. Therefore, the only incorrect statement would be one that claims the gametophyte is the dominant phase.

Step-by-Step Solution:

Step 1: Recall that in all seed plants, including angiosperms, the dominant and independent generation is the diploid sporophyte. Step 2: Note that the gametophyte in angiosperms is microscopic and dependent, existing inside the pollen grain and inside the ovule. Step 3: Confirm that angiosperms have well developed vascular tissues and are fully heterosporous. Step 4: Recall that angiosperm seeds are enclosed within fruits, and double fertilisation is a defining characteristic. Step 5: Conclude that the statement about the dominant phase being the gametophyte is not true for angiosperms.

Verification / Alternative check:

Standard plant life cycle diagrams show a large branching sporophyte with flowers, and small gametophyte stages confined to pollen grains and embryo sacs. Textbooks explicitly state that bryophytes have a dominant gametophyte, pteridophytes and seed plants have a dominant sporophyte. Tables comparing gymnosperms and angiosperms also emphasise that angiosperms are heterosporous, have enclosed seeds, and exhibit double fertilisation. These multiple cross checks reinforce that all listed features except the gametophyte dominance statement are correct.

Why Other Options Are Wrong:

Option B is correct because angiosperms possess well developed vascular bundles for conduction and support. Option C is correct because they produce microspores and megaspores, which is the definition of heterospory. Option D is correct since seeds in angiosperms are enclosed within fruits formed from ovaries. Option E is correct because double fertilisation is a unique and defining event in angiosperm reproduction. These are therefore not the incorrect statements asked for in the question.

Common Pitfalls:

A very common mistake is to confuse the life cycle of bryophytes with that of angiosperms. Students who remember that mosses have a dominant gametophyte may wrongly extend that idea to all plants. Others may misread the question and pick a true statement thinking the question asks which one is true. To avoid such errors, learners should carefully note the phrase “not true” in the stem and memorise a simple rule: non seed plants like bryophytes have dominant gametophytes, while seed plants, including angiosperms, have dominant sporophytes.

Final Answer:

The statement that is not true about angiosperms is that the dominant phase is the gametophyte generation.