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Angiosperm Reproduction and biotechnology . Alex Grzadzielewski. The Importance of Pollination. Diploid plants are saprophytes , because they produce haploid spores by meiosis. GAMETOPHYTE DEVELOPMENT: Microspores are the haploid male gametophytes,
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Angiosperm Reproduction and biotechnology Alex Grzadzielewski
The Importance of Pollination • Diploid plants are saprophytes, because they produce haploid spores by meiosis. • GAMETOPHYTE DEVELOPMENT: Microspores are the haploid male gametophytes, Megaspores are the female gametophytes.
Flower Structure Floral distribution: individual flowers or clusters (inflorescence) Petals are modified leaves, brightly colored to attract pollinators. Stamen has the Anther and filament. Anther has the pollen sacs. Filament holds up the anther. Carpelsin the receptacle, contains the ovary, the style, and the stigma. OVARY LOCATION refers to their position relative to the stamens, petals, and sepals; superior if attached below it, semi-inferior if attached alongside it, inferior if attached above it. SYMMETRY: Bilateral or Radial
Mechanisms that prevent self-fertilization: • Self-incompatibility: the ability of a plant to reject its own pollen and the pollen of those similar to it (like an immune system).
MATURE SEED STRUCTURE: • Seed coat protects the embryo • Hypocotyl & Epicotyl are the embryonic axis • Radical is the embryonic root • Endosperm surrounds the embryo and provides nutrition In the form of starch • Cotyledons are the embryonic leaves. • In monocots there is only one cotyledon, the scutellum. Monocots have a coleoptile which Covers the shoot, and a coleorhiza Which covers the root.
Fruits Seeds develop from ovules, but fruits develop from the ovary • Simple fruits: A single fruit on single carpel. • Aggregate fruits: multiple carpels in a flower produce clusters of “fluitlets” on a single receptacle • Multiple fruits: The result of inflorescence; when the ovaries of multiple flowers fuse together into one fruit. Simple Fruit Aggregate Fruit Multiple Fruit
Seed Germination • As the seed matures, it dehydrates, entering a phase called Dormancy. • Dormancy is initiated and maintained through extremely low metabolic rates and the suspension of growth and development. • Seed dormancy is important because it increases the chance that the seed will eventually find itself in a suitable place to germinate • The seed finally germinates through a process called imbibition, the uptake of water due to low water potential of the dry seed.
Asexual Reproduction(Vegetative reproduction) • Fragmentation: separation of parent plant into parts develop into whole plants (clones from cuttings). • Apomixix is the asexual reproduction of seed when a diploid cell in the ovule creates a seed embryo without the joining of sperm and egg. • Grafting: If compatible, two plants can be mushed together and grown into one strange hybrid. The plant that provides the root system is the Stock. The plant that’s grafted onto the stock is the Scion.
Plant Biotechnology • Artificial Selection; evolutionary process by which [humans] intervene in the process of plant reproduction. • Issues of environmental effect. • Issues on human health. • The problem of Transgene escape, the hybridization between genetically modified organisms (GMOs) and their wild relatives. If the GMO is invasive then the original species could become endangered or extinct.
