Solution-Class-11-Science-Biology-Chapter-3-Kingdom Plantae-Maharashtra Board

(c) Sporophyte

(a) Sequoia sempervirens

(b) sporophyte is partially dependent upon gametophyte

(d) Double fertilization

(a) Monocotyledons and (d) Enclosed seed - Both

• After monsoon, plants like mosses (bryophytes), ferns (pteridophytes), small herbaceous plants, etc become dry, due to which land becomes barren.
• However, spores of bryophytes, pteridophytes and seeds of herbaceous plants, grass remain in barren land.
• During next monsoon, these spores and seeds germinate due to availability of water and other favourable conditions.
• Bryophytes and pteridophytes require water for reproduction. Hence they flourish during monsoon season.
• Along with bryophytes and pteridophytes varieties of higher plants like grasses, some seasonal herbs or shrubs grow on barren land during monsoon due to favourable conditions.

• Fern belongs to sub-kingdom Cryptogamae.
• Cryptogams produce spores but do not produce seeds.
• Also, in cryptogams the sex organs are concealed.
• Phanerogams are seed producing plants and their sex organs are visible.

Hence, fem is a vascular plant. Yet it is not considered a Phanerogams.

• Both Chlamydomonas and Sargassum belong to division Thallophyta.
• Members of Thallophyta range from unicellular (e.g. Chlamydomonas) to multicellular (e.g. Sargassum).
• Both are aquatic plants containing photosynthetic pigments.
• In both Chlamydomonas and Sargassum plant body is not differentiated into root, stem and leaves.
• The stored food is mainly in the form of starch and its other forms.
• Cell wall is made up of cellulose and other components. Due to these characters, both Chlamydomonas and Sargassum are included in one group i.e. Thallophyta.

• Maize plant belongs to class monocotyledonae.
• In monocotyledonous plants, vascular bundles are closed type.
• Thus, cambium is absent between xylem and phloem, due to which secondary growth does not occur in these plants.
• Increase in girth of a stem occurs by secondary growth.
• Thus, girth of a maize plant does not increase over a period of time.

The plant observed by Radha belongs may belong to division Bryophyta, as it shows root like structures i.e. rhizoids and absence of vascular tissue.

1. Seed producing plants : Phanerogams (Angiospermae and Gymnospermae)
2. Spore producing plants : Cryptogams (Thallophyta, Bryophyta and Pteridophyta)
3. Plant body undifferentiated into Root, Stem and leaves : Thallophyta, Bryophyta
4. Plant need water for fertilization : Thallophyta, Bryophyta, Pteridophyta
5. First vascular plants : Pteridophytes

• These plants have neither fruits nor flowers.
• Some ferns are used as food, medicine or as ornamental plants.

• Nephrolepis belongs to division pteridophyta.
• They grow abundantly in cool, shady, moist places. ,
• Roots are adventitious (fibrous) growing from the underground stem.
• Leaves are well developed on the stem (Rhizome).
• They show presence of well-developed conducting system for transportation of water and food.
• They reproduce asexually by spores produced within sporangia, which are present in sori. These sori are located along the posterior surface of leaflets.

Coralloid roots of Cycas:

• Coralloid roots of Cycas show association with blue green algae for nitrogen fixation.
• Coralloid roots are coral-like, dichotomously branched and fleshy. They grow upward toward the surface of the soil. These roots arise from the lateral branches of normal roots.

Scale leaf of Cycas:

• In Cycas leaves are dimorphic i.e. foliage leaves and scale leaves. Scale leaves are minute, membranous and brown. These are non- photosynthetic and provide protection to the stem apex.

Megasporophyll of Cycas:

• Megasporophylls are usually arranged in compact structures called female cones or female strobili.
• Megasporophyll contains megasporangia (ovule) which produce megaspores.

• The given figure indicates alternation of generation.
• The life cycle of a plant includes two generations, sporophytic (diploid = 2n) and gametophytic (haploid = n)
• Some special diploid cells of sporophyte divide by meiosis to produce haploid cells.
• These haploid cells divide mitotically to produce gametophyte.
• On maturation, gametophyte produces male and female gametes which fuse during fertilization and produce diploid zygote.
• Diploid zygote divides by mitosis and forms diploid sporophyte.