PLANT REPRODUCTION

Asexual (Vegetative) Reproduction

I.  Axillary Buds on Modified Stems

     A. Stolen (Runner) = prostrate, elongated internodes

     B. Rhizome = underground, prostrate, +- normal

     C. Corm = underground, vertical, node/internode thickened 
               Contractile Roots

     D. Tuber = underground, regions of thickened node/internode
                of Rhizomes

     E. Bulb = underground, vertical, thickened leaves
               Contractile Roots

II.  Parthenogenesis = embryo develops from unfertilized egg

III. Vegetative Propagation

     A. Stems, Leaves, or Roots severed from parent plant develop 
        a new plant via development of adventitious axillary buds

     B. Tissue culture = Individual cells, or tissues can form new 
        plants given the right nutrients and phytohormones in some 
        species (Totipotency)
Sexual Reproduction

I. Diplobiontic, D+h, Sporic Meiosis Life Cycle

     A. Sporophyte (2N) -> Meiosis -> Spores (N)

     B. Spores (N) -> Mitosis -> Gametophyte (N)

     C. Gametophyte (N) -> Differentiation via Mitosis
        -> Gametes (N)

     D. Gamete (N) + Gamete (N) -> Fertilization
        -> Zygote (2N)

     E. Zygote (2N) -> Mitosis -> Sporophyte (2N)

     F. Variations in Plant Kingdom 

          1. Bryophytes: Sporophyte is dependent on Gametophyte

          2. Lower Vascular Plants (Lycopods, Horsetails, Ferns):
               Both Sporophyte and Gametophyte independent

          3. Higher Vascular Plants (Gymnosperms, Angiosperms):
               Gametophyte dependent on Sporophyte
II. Higher Vascular Plant Life Cycle

     A. Duration (Seed to Seed)

          1. Gymnosperms(G): 2,3 years
          2. Angiosperms(A): months

     B. Male reproductive structure of sporophyte

          1. G: = male cone 
          2. A: = stamen (filament + anther)

          3. Microsporocytes -> Meiosis -> Microspores 
               -> Mitosis -> Male Gametophyte (pollen grain)

     C. Female reproductive structure of sporophyte

          1. G: = ovule on ovuliferous scale of female cone
          2. A: = ovule in ovary portion of carpel (Stigma +
               Style + Ovary)

          3. Megasporocytes -> Meiosis -> Megaspores
               -> Mitosis -> Female Gametophyte (Body Cells + Egg)

     D. Pollination = Transfer of pollen from male reproductive   
        structure to female reproductive structure

          1. G: Wind from male cone to ovules on female cone

          2. A: Wind/Animals from anther to stigma of carpel

          3. Pollen grain germinates to form pollen tube
                + Mitosis of gametophyte cell to form sperm

     E.  Fertilization = Fusion of sperm with egg to form zygote

          1. G: Zygote nutrition provided by vegetative female
               gametophyte tissue

          2. A: Zygote nutrition provided by endosperm that is
               created by fusion of other sperm + polar cells

          3. A: "Double Fertilization" = 
                    sperm+egg -> zygote
                    sperm+polar cells -> endosperm

     F. Seed Formation

          1. G: Naked 
                Integument of ovule (2N) -> Seed Coat
                Female gametophyte (N) -> Stored nutrient for
                                        Embryo
                Zygote (2N) -> Embryo with multiple cotyledons

          2. A: Enclosed in Fruit = Ripened Ovary
                Integuments of ovule (2N) -> Seed Coat
                Endosperm (various ploidy levels) 
                    -> stored nutrient for Embryo, or
                    -> nutrients absorbed & incorporated into
                         fleshy cotyledons
                Zygote (2N) -> Embryo with 1 or 2 cotyledons

          3. Embryo enters dormancy within protective seed coat
               until conditions are right for 

     G. Germination

          1. Uptake of water
          2. Mobilization of stored nutrients
          3. Activation of cell division and cell expansion of 
               Root & Shoot Apical Meristems -> New Sporophyte