Lecture 8 Flashcards
Is the stamen the male of female reproductive parts
Male reproductive parts
Is Carpel the male or female reproductive parts
Female reproductive parts
Name the parts of the stamen
•Anther (Pollen,Sperm)
•Filament
Name the parts of the carpel
•Stigma
•Style
•Ovary
Write a short note on SEXUAL reproduction
•produces offspring by the fusion of egg and sperm
•resulting in offspring that are genetically different to the parents and each other
Write a short note on ASEXUAL reproduction
•produces offspring without the fusion of egg and sperm
•the offspring are genetically identical to the parent plant and to each other (aka clones)
What is CROSS pollination
pollen from one flower pollinates flowers on a different plant
What percentage of cross pollination is BIOTIC
80%
What percentage of cross pollination is ABIOTIC
20%
Example of BIOTIC pollinators
•birds, bats and mammals
•but most biotic pollination is by insects (c.65%)
Name the two modes of ABIOTIC pollination
•98% wind
•2% water
Example of cross pollinated species
•maize
•rye
•carrot
•cauliflower
•onion
What is SELF pollination
pollen from one flower pollinates the same flower or other flowers on the same plant
Example of self pollinated species
•wheat
•rice
•barley
•mung bean
•cowpea
What type of species is SELF pollination mostly seen in
short-lived annual species and plants that colonize new locations
Name the most important pollinators
Bees
What kind of characteristics are bees attracted to
•Bright colours
•Sweet fragrance
What do honey bees feed on for food
•Nectar
•Pollen
What kind of characteristics are moths attracted to
•Light coloured or dull flowers to be seen in low light
•sweetly fragrant flowers
What kind of characteristics are bats attracted to
•Flowers that are light coloured or dull to be seen in low light
•flowers that smell musty
What kind of characteristics are birds attracted to
•Flowers with bright red,orange,yellow flowers
•Flowers that have very little scent
What is special about Soybeans(Glycine max)
•flowers open and remain receptive to insect cross pollination during the day.
•If this is not accomplished, the flowers self-pollinate as they are closing in the evening.
What does sexual reproduction result in
Seeds
Example of important crops grown from seed
• Grass, cereals (rice, wheat, maize, barley, oat, rye)
• Legumes (pea, bean, soybean, clover, mung bean, cowpea)
• Vegetables, fruits, flower seeds (for humans/animals) • Commercial crops e.g. sugarcane, oilseed
If asexual reproduction doesn’t produce seeds how does reproduction occur
• Fragmentation (stolons, runners e.g. strawberry,kikuyu grass (Pennisetum clandestinum)
• Tubers (potatoes,crocus corm,lily,dahlia)
• Bulbs (onions, daffodils)
• Cuttings (stem, leaf, root)
• Grafting or budding (fruit trees, roses)
What is Apomixis
Asexual reproduction that produces seeds without the fusion of egg and sperm i.e. it is clonal
reproduction through seeds
What are the two ways Apomixis can occur
• embryo arises from an unfertilized egg cell
• embryo is formed directly from some part of egg cell
Advantages of sexual reproduction
• Introduces variation
• Adaptability to new
environments
• Adverse conditions less likely to affect everyone
• Seed dispersal reduces competition
• Dormant seeds can survive unfavourable conditions in soil
Disadvantages of sexual reproduction
• Needs two parents
• Fertilisation is random so
harmful variations can occur
• Flowers and seeds are energetically expensive
• Can lead to extinction e.g. Encephalartos woodii
(only males left but reproduces by basal offsets)
Is sexual or asexual reproduction good in unstable environments
Sexual reproduction
Advantages of asexual reproduction
• Only one parent needed
• Rapid colonisation of favourable
environments
• Any part of plant can become a new plant
• Reproduction is faster
• No genetic variation can be an advantage in commercial horticulture
Disadvantages of asexual reproduction
• No genetic variation so adverse conditions, pests and diseases are likely to affect all individuals
• Cannot adapt
• May be prone to extinction
• No seeds so no dormancy mechanism
• Overcrowding and competition for resources
Is sexual or asexual reproduction good in stable environments
Asexual reproduction
Name the oldest creosote bush in the Mojave desert
King Clone
11,700 years old
Single colony of Larrea tridentata reaches up to 20 meters in diameter
Is metabolic rate low or high during seed dormancy
Extremely low metabolic rate
When does Germination occur seed dormancy
When seedling is likely to survive
What happens to growth and development during seed dormancy
Both are suspended
What is certified seed
Seed that is handled so as to satisfactorily maintain genetic identity and purity, and that has been approved and certified by the certifying agency
What does certification involve
field inspection, pre- and post-control tests, and seed quality tests.
What do football pitches use
Best quality certified seed
Seed for golf greens must be certified free of what
Annual meadow grass
Principles of seed storage
• Seed storage conditions should be dry and cool
• Effective storage pest control
• Proper sanitation in seed stores
• Before placing seeds into storage they should be dried to required moisture limits
• Store high quality seed only i.e. well-cleaned and treated, as well as of high germination and vigour
What does Seed germination begin with
Imbibition
Write a short note on the stages of seed germination after Imbibition
• Serotiny: fire required to release seeds from plant • Stratification: cold period to break dormancy
• Scarification: seed coat damage
• Acid digestion: seed coat breakdown
• Substantial rainfall: desert plants • Dark (most seeds)
• Light (lettuce, celery)
How long are most seeds viable for after seed germination
1-2 yeaes
Who proposed descent with modification
Darwin in 1859
What is descent with modification
• Natural adjustment of genetic make-up through generations over time
• Based on adaptations that enhance survival and reproduction in specific environments
• Individuals with certain inherited traits leave more offspring
• Over time, these traits become more prevalent in the population
What is Modern maize derived from
Teosinte
Why would modern maize become extinct without human propagation
Modern maize cannot spread its seeds
What is micropropagation also know
In vitro tissue culture
What does genetic engineering involve
the creation of recombinant DNA, which is inserted into the genetic material of a cell or virus
