70 likes | 229 Views
Reproduction In Plants. Pollination Nation: Plant Sex. Pollination the mixing of male gametes ( pollen grains ) with female gametes ( ovule ) to reproduce sexually Two Styles of Pollination:
E N D
Pollination Nation: Plant Sex • Pollination the mixing of male gametes (pollen grains) with female gametes (ovule) to reproduce sexually • Two Styles of Pollination: • Insect-pollination plant grows flowers and releases scents to attract pollinators (insects/birds) • Symbiosis both groups gain something • Flower has pollen mixed with ovule of different plants • Insect gets nectar (glucose energy drink) • Wind-pollination plant is designed for pollen to be carried by the wind • No energy wasted on nectar/scents • Pollination success rate is lower
Structure of a Flower (Insect) Stigma Carpel Stamen Anther Style • Petals display bright colors, patterns, and scents to attract pollinators • Stamen male organ made of a filament holding up an anther (produces pollen grain) • Sepal protective layer around carpel • Carpel female sex organ made of the… • Stigma entrance where pollen grains must land • Style narrow tube leading to ovary • Ovary container for ovules (eggs) • Ovule female gametes kept inside two different ovaries; 6 ovules per ovary • Nectary produced nectar for insect Filament Ovary Nectary Petal Sepal Ovule
Structure of a Flower (Wind) Inflorescence Spikelet • Inflorescence groups of spikelets on a branch • Spikelet group of flowers • Stamen male organ made of filaments and anthers; millions are pollen grain are produced, but most are wasted • Feathery Stigma long filament with net-like fibers designed for catching pollen grains in the air • Style tube leading to plant ovary • Ovary contains the female gametes (ovules) Anther Filament Filament Stigma Style Ovary
Insect vs. Wind • Compare the structural differences between the two pollination styles: Absent; no need for them Present; colorful and scented Absent; no need for them Present; rewards for insect Attached to short filaments inside the flower Attached to long filaments and hang outside the flower Small quantities and sticky; attach to insects easily Large quantities, smooth, and very light so to be carried by the wind Sticky, small stigmas inside the flower Large and feathery for catching pollen; extend outside flower
Self and Cross Pollination • Depending on environmental factors, flowering plants can be pollinated by another plant or by themselves • Cross-Pollination mixing of gametes from two different plants of the same species • Produces more variation in offspring’s DNA • Requires pollen from genetically different partner, that might not be available • Most plants hope for this style • Self-Pollination Plan B; plant mixes is own gametes together to become fertilized • Because of Meiosis, some variation is made • If plant is not pollinated by a certain point, the plant will self-pollinate so the gametes are not wasted