Plant reproduction

Cards (22)

  • Plant Reproduction - Flowering plants reproduce sexually, asexually, or both.
  • ASEXUAL REPRODUCTION
    ► Offspring are derived from a single parent without any fusion of egg and sperm
    ► Result is a clone that is genetically identical to its parent
  • Vegetative reproduction
    Asexual plant reproduction based on the vegetative growth of stems, leaves, or roots is known as vegetative reproduction.
  • Agamospermy
    ► The production of seeds without fertilization
    ► Embryos of agamospermy seeds are genetically identical to the parent plant
  • SEXUAL REPRODUCTION
    ► involves the transfer of male gametophytes, the pollen grains, either to the micropyle of an ovule or to the stigma of a pistil
    ► two major processes in sexual reproduction of seed plants are pollination and fertilization
  • POLLINATION
    • transfer of pollen to the part of a seed plant containing the ovule
    • can give an insight into the function, homology, and evolution of associated floral features
    • can occur by wind, water, or animals and insects
  • wind pollination (anemophily) - release of enormous quantities of smaller-sized pollen compensates for the randomness of dispersal by the wind.
  • water pollination (hydrophily) - may occur in aquatic plants with flowers either at or under the water surface • rely on water to disperse pollen.
  • insect pollination (entomophily) is when insects transfer pollen from one flower to another.
  • bees - melittophily or hymenopterophilybee-pollinated flowers have a delicate, sweet fragrance — often have specialized color patterns called nectar guidesultraviolet markings that help insects locate the nectaries — bees are attracted to bright colors, primarily yellow and blue
  • moths - phalaenophilymoths detect odors, flowers they pollinate are often sweetly fragrant — usually white or yellow, which stand out at night when they are active — tend to have long, nectar-filled tubes or spur
  • butterflies - psychophily — butterflies detect odors, flowers they pollinate are often sweetly fragrant — usually bright-colored — tend to have long, nectar-filled tubes or spurs
  • flies - sapromyiophily — many fly-pollinated flowers are reddish, maroon or brown in color and fleshy — emit an odor like rotten meat or flesh
  • bats - cheiropterophily — like moth-pollinated flowers, are lightcolored and aromatic, attracting their nocturnal pollinators — stamens tend to be numerous
  • birds - ornithophily — usually large and bright red or yellow, but have little odor — flowers produce sugary nectar that helps meet the high energy demands of the pollinating birdspetals are often fused, forming a bent floral tube that fits the curved beak of the bird
  • GAMETOGENESIS - formation and development of gametes • occurs in anther and ovules
    • in anther, meiosis occurs in microsporocytes to form microspores
    • in ovules, meiosis occurs in megasporocytes to produce megaspores
  • ovule - immature seeds, technically consisting of a megasproangium enveloped by one or more integuments
  • identify
    A) chalazal end
    B) nucellus
    C) micropyle
    D) funiculus
    E) micropylar region
    F) integument
  • microsporangia - sites of production of pollen grain
  • FERTILIZATION • fusion of gametes • occurs after the two sperm reach the female gametophyte
  • double fertilization
    ► One sperm fertilizes the egg, forming the zygote.
    ► The other sperm combines with the two polar nuclei, forming a triploid (3n) nucleus
  • EMBRYOLOGY • Process of initiation and development of an embryo from a zygote which is a product of double fertilization