Reproduction In Plants
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Transcript of Reproduction In Plants
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:• 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)• 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
Stamen Anther
Filament
StigmaCarpel
Style
Ovary
Petal
Sepal
Ovule
Nectary
Structure of a Flower (Wind)• 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)
Filament
Filament
Anther
Stigma
Style
Ovary
Inflorescence
Spikelet
Insect vs. Wind• Compare the structural differences between the two pollination styles:
Structure Insect-Pollination Wind-Pollination
Petals
Nectaries
Stamens
Pollen
Carpels
Present; colorful and scented Absent; no need for them
Present; rewards for insect Absent; no need for them
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