Govt. Exams
Entrance Exams
Sieve tube elements and companion cells are the conducting and supporting elements of phloem tissue in angiosperms for translocation of organic solutes.
The embryo sac represents the female gametophyte in angiosperms, typically containing 8 nuclei in a 7-celled structure (Polygonum type).
Cycas and Ginkgo retain the primitive character of motile sperms, while other gymnosperms like Pinus have non-motile sperm.
In gymnosperms, the pollen grain is the male gametophyte. It contains generative and vegetative nuclei before pollination.
Selaginella is a pteridophyte - it has vascular tissue but reproduces via spores, not seeds. Pinus is a gymnosperm with seeds.
The prothallus is the gametophyte of ferns - a small, green, heart-shaped structure that is photosynthetically active and independent.
Pteridophytes were the first plants to develop true vascular tissue (xylem and phloem), allowing them to grow taller and transport water efficiently.
In bryophytes like Riccia, the capsule is the sporophyte that produces spores. It remains embedded in the gametophyte.
Bryophytes have a waxy cuticle that reduces water loss, though it's not as effective as in higher plants due to absence of stomata.
