Q.14 In Bryophytes:

1. Sporophyte is fully or partially dependent on gametophytes
2. Xylem and phloem are the main water and food conducting tissues
3. Spore dispersal takes place by means of peristomial teeth only
4. Heterospory and seed habit evolved in higher bryophyte

   Correct Statement About Bryophytes: Sporophyte Dependency on Gametophyte

   In bryophytes, the sporophyte remains fully or partially dependent on the gametophyte, distinguishing them from vascular plants. All other statements are incorrect, as bryophytes lack true vascular tissues and advanced reproductive features.

   Introduction

   Bryophytes represent the gametophyte-dominant phase in plant evolution, where the sporophyte is fully or partially dependent on gametophytes. This key feature separates them from higher plants. This guide dissects each statement for accurate exam preparation in botany.

   Statement Analysis

   Examine each option regarding bryophytes (mosses, liverworts, hornworts) to identify the correct one.

   • Sporophyte is fully or partially dependent on gametophytes: Correct. The diploid sporophyte grows attached to the dominant haploid gametophyte, relying on it for nutrition and water via haustoria or direct attachment; gametophyte is photosynthetic and independent.

   • Xylem and phloem are the main water and food conducting tissues: Incorrect. Bryophytes lack true vascular tissues (xylem, phloem); they use hydroids (water) and leptoids (food) in some mosses, but conduction occurs via diffusion or osmosis through thin cell walls.​

   • Spore dispersal takes place by means of peristomial teeth only: Incorrect. Peristome teeth (in mosses) aid hygroscopic spore release, but dispersal also involves wind, water, rain splashes, animal vectors, or capsule explosions (e.g., liverworts); not exclusive to peristome.​

   • Heterospory and seed habit evolved in higher bryophyte: Incorrect. Bryophytes exhibit homospory (all spores same size); heterospory (micro/megaspores) and seed habit evolved in vascular plants (pteridophytes, seed plants); no bryophyte shows these traits.​

   Life Cycle Features

   Bryophytes display alternation of generations with gametophyte dominance.

   Core traits:

   • Gametophyte: Haploid, thalloid/leaflike, produces gametes (antheridia/archegonia).

   • Sporophyte: Diploid, unbranched, spore-producing capsule on gametophyte; meiosis yields homospores.

   • No roots/stems/leaves; rhizoids for anchorage.

   Evolutionary Significance

   Bryophytes bridge algae and vascular plants:

   • First land plants (~450 MYA), adapted to moist habitats.

   • Dependency reflects primitive condition; independence evolves in tracheophytes.

   • Exam tip: Contrast with pteridophytes (sporophyte dominant, independent).​

   Exam Relevance

   For GATE Life Sciences, emphasize gametophyte dominance and vascular absence. Visual: Moss sporophyte as “stalk” on green gametophyte mat.​