A1: Plant Reproduction
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What are the two types of plant reproduction?
sexual and asexual reproduction
Explain the life cycle of a plant.
1) germination 2) growing plant 3) flowering plant 4) pollination 5) fertilization 6) dispersal of seeds
Explain asexual reproduction in plants.
VEGETATIVE GROWTH - portion of plant is taken - result: genetically identical progeny
When is asexual reproduction in plants an advantage?
When the plant shows superior qualities.
Why is asexual reproduction in plants a disadvantage?
Because there is no genetic variability –> crucial for the health of the plant as a species.
What is sexual reproduction?
The production of sex gametes followed by their fusion and development into an embryo.
Explain the plants reproductive organs. What two types are there?
Male reproductive organs: STAMEN: - fillament - anther Female reproductive organs: CARPEL: - stigma - style - ovary - ovule (forms within ovary)
What does pollination lead to?
the generation of a pollen tube: - discharge of sperm - fertilization of the egg - formation of an embryo
What is pollination?
The transfer of pollen from an anther to a stigma.
What does the process of polination require?
pollinators
What are “pollination syndromes”?
flower traits that attract different pollinators.
What are some examples through which pollination can take place?
• wind • water • insect • animal
What is biotic pollination?
Pollination by organisms. - ENTOMOPHILY: pollination by insects - ZOOPHILY: pollination by animals
How does the majority of pollination occur?
Through biotic pollination (80%).
What is abiotic pollination?
Pollination by non-organism factors. ANEMOPHILY: pollination by wind (98%) HYDROPHYLY: pollination by water
What is a pollinator?
The agent which moves the pollen.
What is a pollenizer?
The plant that provides the pollen.
What are the two ways for pollination to occur?
• cross pollination • self pollination
What factors prevent self fertilization? What do they insure?
RECOGNITION factors. - ensure genetic variability - acts as a plants immune system - recognizes and rejects ‘self pollen’ DEVELOPMENT OF STAMENS AND CARPELS AT DIFFERENT TIMES. - pin (female) vs thrum (male)
What is meant by “self-incompatability”?
The ability of a plant to reject its own pollen and the pollen of closely related individuals.
What are dioecious plants unable to do?
self fertilize. - they only posess one type of reproductive structure on each individual plant.
What is cross-pollination? What is its other name?
• occurs between a pollinator and an externam pollenizer, • “SYNGAMY” • pollen is delivered to a flower of a different plant
What is self-pollination? What is its other name?
• pollen moves to th efemale part of the same flower or to another flower on the same plant. • AUTOGAMY • accomplish pollination without an external pollinator
What is CLEISTOGAMY?
• autogamy pollination • occurs inside the glower, before the flower opens