Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; Gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.

Plantae includes all photosynthetic multicellular plant groups comprising algae, bryophytes, pteridophytes, gymnosperms and angiosperms.

2. Algae:

(i) Algae have three classes mainly on the basis of pigments- Chlorophyceae (green algae), Phaeophyceae (brown algae) and Rhodophyceae (red algae).

(ii) All algae lack vascular tissue and thalli are mostly haploid. The sex-organs are normally one-celled without any sterile jacket.

3. Bryophytes:

(i) Bryophytes are first land plants with a main plant body of gametophytic nature.

(ii) Bryophytes are similar to algae in being thalloid and non-vascular but dissimilar to algae in having multicellular jacketed sex organs.

(iii) The sex organs are antheridia and archegonia in both bryophytes and pteridophytes.

(iv) Sperms are always biflagellate in bryophytes whereas in pteridophytes they may be biflagellate or multiflagellate.

(v) In bryophytes, the adult sporophyte is always dependent on gametophyte.

4. Pteridophytes:

(i) Pteridophytes are first vascular cryptogams (non-seed plants similar to algae and bryophytes).

(ii) The main plant body of pteridophyte evolved into sporophyte bearing stem, roots and leaves.

(iii) Pteridophytes have spore producing organs sporangia which may be organised into cones.

(iv) Pteridophytes show homospory and heterospory.

(v) In pteridophytes, sporophytic and gametophytic generations are independent to each other.

5. Gymnosperms:

(i) Gymnosperms are the most ancient seed plants.

(ii) Gymnosperms possess naked seeds derived from naked ovules after fertilisation.

(iii) Male and female reproductive organs are organised into male and female cones in gymnosperms.

(iv) Pollen grains were first developed in gymnosperms and these were dispersed by wind (anemophily).

6. Angiosperms:

(i) Angiosperms are highly evolved plant group with flowers and fruits. Seeds are enclosed within fruits.

(ii) The sporophytic plant body is highly elaborated in angiosperms. Stem, roots and leaves are well-developed.

(iii) Angiosperms show stratification into herbs, shrubs and trees.

(iv) Angiosperms are subdivided into dicotyledons and monocotyledons.

(v) Pollination shows anemophily, hydrophily and zoophily based on agents of pollination.

(vi) There can be self-pollination (autogamy) and cross-pollination (allogamy).

(vii) Cross-pollination has two subtypes geitonogamy and xenogamy.

(viii) In geitonogamy pollen transfer takes place from one flower to another flower on the same plant and in xenogamy it is from one plant to another plant.

(ix) Double fertilisation (syngamy + triple fusion) is present only in angiosperms.

(x) In angiosperms, syngamy is followed by triple fusion. Syngamy leads to embryo formation and triple fusion gives rise to Primary Endosperm Nucleus (PEN). It gives rise to triploid endosperm.

7. Plant Life Cycles and Alternation of Generations:

(i) In Kingdom Plantae, there are three patterns of life cycle, viz., haplontic, diplontic and haplodiplontic.

(ii) Haplontic type is present in green algae and diplontic type is present in gymnosperms and angiosperms.

(iii) Haplodiplontic life cycle is exhibited by bryophytes and pteridophytes. Some brown and green algae also show this pattern of life cycle.