Plant Nutrition

• 1.     Gametophyte - stage of the life cycle of a plant that is haploid; the stage that produces gametes via mitosis; these gametes fuse to form a zygote that develops into a sporophyte
• 1.     Sporophyte - Stage of the life cycle of a plant that is diploid; it is the most recognizable structure in most flowering plants; it produces haploid spores by meiosis in structures called sporangia
• 1.     Haplontic life cycle - Life cycle where the haploid stage (gametophyte) is multicellular and the only diploid stage is the fertilized egg cell
• 1.     Haplodiplontic life cycle - Life cycle that includes multicellular diploid (sporophyte) and haploid (gametophyte) generations
• 1.     Diplontic life cycle - Life cycle where the diploid stage (sporophyte)is multicellular and the haploid stage (gametophyte) is represented by the single-celled gametes
• 1.     Angiosperms - Also known as flowering plants; a group of plants that produce reproductive structures called flowers in their sporophyte stages
• 1.     Flower - Reproductive structure in flowering plants; made up of four major whorls
• 1.     Sepals - The outermost whorls of a flower; collectively called the calyx
• 1.     Petals - Whorl inner to the sepals; may be brightly colored in some; collectively called the corolla
• 1.     Anther - Part of the stamen that contains the microsporangia that develop into pollen grains
• 1.     Stamen - Whorl inner to the petals; the male reproductive structure of the flower; bears the male sporangia (also known as microsporangia)
• 1.     Filament - Part of the stamen that serves as the stalk of the anther
• 1.     Pistil or carpels - Innermost whorl of the flower; the female reproductive structure of the flower; bears the female sporangia (also known as the megasporangia)
• 1.     Stigma - Part of the pistil where the pollen grain derived from the microsporangium attaches during pollination
• 1.     Style - Part of the pistil that serves as the stalk of the stigma; leads to the ovary
• 1.     Ovary - Found at the base of the pistil; contains one or more ovules; eventually becomes the fruit
• 1.     Ovule - Contains the female sporangia or megasporangia; eventually becomes the seed
• 1.     Complete flower - A flower with sepals, petals, stamens, and carpels
• 1.     Incomplete flower - A flower that lacks one or more of the floral whorls
• 1.     Perfect flower - A flower that has both stamens and carpels; a bisexual structure
• 1.     Imperfect flower - A flower that has only either the stamens (staminate flower) or the carpels (carpellate flower); also known as a unisexual flower
• 1.     Monoecious plant - A plant having perfect flowers or both staminate and carpellate flowers on the same individual
• 1.     Dioecious plant - A plant having only either the staminate or carpellate flower
• 1.     Pollination - The placement of the pollen grain from the anther to the stigma of a carpel
• 1.     Pollen grain - The immature male gametophyte that develops within the anthers of stamens; derived from the microsporocytes inside the microsporangia of anthers. Inside the mature pollen grain, there is a tube cell and a generative cell. The tube cell develops into the pollen tube as it enters the style and eventually enters the micropyle of the ovule. The generative cell divides into two sperm nuclei and traverses the pollen tube
• 1.     Embryo sac - The female gametophyte found inside the ovule; derived from the megasporocyte inside the megasporangia; a mature embryo sac contains 8 nuclei. Eventually, these nuclei become enveloped by membranes to become real cells. These are the one egg cell; two synergids that flank the egg; two polar cells that are often fused; and three antipodals opposite the synergids and egg.
• 1.     Micropyle - The opening through the integuments of the ovule that surrounds the embryo sac; this is where the pollen tube enters in order to reach the embryo sac
• 1.     Endosperm - Part of the mature seed that is derived from the fusion of the sperm nucleus and the two polar nuclei of the embryo sac. This becomes a nutritive tissue with triploid cells that serves to store food for the developing embryo
• 1.     Zygote - Part of the mature seed that forms as a result of the fusion of the egg and one of the sperm nuclei
• 1.     Cotyledon - Embryonic leaf that forms inside the seed
• 1.     Monocot - A plant with only one cotyledon inside its seed (monocotyledonous)
• 1.     Dicot - A plant with two cotyledons inside its seed (dicotyledonous)
• 1.     Seed germination - Process that transforms a seed into a seedling
• 1.     Imbibition - The first step in seed germination; absorption of water
• 1.     Radicle - Embryonic root that emerges from the seed
• 1.     Plumule - Embryonic shoot that emerges from the seed and breaks through the soil surface
• 1.     Epicotyl - Part of the plumule above the cotyledon
• 1.     Hypocotyl - Part of the plumule below the cotyledon
• Male gametophyte - The microsporangium in the anther contains numerous microsporocytes. Each microsporocyte will undergo meiosis to produce four haploid microspores each microspore develops into a pollen grain (containing two sperm nuclei and one tube nucleus
• A.    Female gametophyte - The megasporangium in the ovule contains megasporocytes. One megasporocyte will undergo meiosis to produce four haploid megaspores three megaspores degenerate remaining megaspore divides mitotically three times, and an embryo sac with eight haploid nuclei membranes partition to make the embryo sac multicellular