Kingdom Of Plantae

Kingdom plantae

characteristic

i.    Plants are multicellular, autotrophic, eukaryotes.

ii.   Possess cell walls made of cellulose and store food in

  the form of starch.

iii.   Have chloroplasts containing chlorophyll and other

  pigments.

iv.   Most plants are terrestrial although there are some

  exceptions.

v.   Plant life cycles have two alternating phases, a haploid (n) phase and a diploid (2n) phase. The diploid phase is called the sporophyte and produces spores, while the haploid is called the gametophyte and produces gametes. The term diploid means having a complete set of chromosomes. Haploid means a having half a set of chromosomes.

Alternation of Generation

•         The life cycles of all land plants alternate between two generations of multicellular organisms; gametophytes & sporophytes.

•         Gametophyte represents haploid (n) generation.

•         Sporophyte represents diploid (2n) generation.

•         The haploid generation is called the gametophyte because it undergoes sexual reproduction to produce gametes.

            Production of gametes involves mitosis, so the gametes also haploid

•         The gametes fuse to form a diploid zygote which grows into the next generation, the diploid sporophyte generation.

•         It is called the sporophye because it undergoes asexual reproduction to produce spores.

•         Production of spores involves meiosis, so that there is a return to the haploid condition.

•         The haploid spores give rise to the gametophyte generation.

•         One of the generation is always more conspicuous and occupies a greater proportion of the life cycle; this is said to be the dominant generation.