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23 Cards in this Set
- Front
- Back
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What are the 5 roles of the seed?
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1) multiplication of the species
2) provide dispersal 3) food for embryo 4) protects embryo from adverse conditions 5) maintain diversity |
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What is weeds'production potential when compared to crops?
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the crop will ususally outcompete but weeds make up for it by producing a lot
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What is in a weed seed bank?
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1) lots of species
2) tremendous numbers of seeds 3) different levels of dormancy |
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What influences the size of the weed seed bank?
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tillage, crops/rotation, management
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What is the safe-site concept and what influences it?
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only a fraction of seeds are goin to come up at one time
Influenced by: Dormancy Survivability Number of seeds |
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What is dormancy?
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the ability of seed to sit in a resting state waiting for the right conditions to germinate
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What is vivipary?
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when innate dormancy doesn't work and causes germination on the mother plant
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What are the 3 types of dormancy and their mechanism?
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1) Innate--keeps seeds from germ. while forming due to a chem. inhibitor
2) Enforced--env. conditions have to ideal to germ. 3) Induced--enforced + chem. inhibitor or some other mech that prevents germ. even under ideal conditions |
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Name 2 mechanisms of maintaining dormancy.
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1)physical--hard seed coat
2)morphological--not fully mature 3)physiological--chem. inhibitor that has to be leached out |
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What is going to have a greater influence on weed presence--seed bank dynamics or influx of external seed?
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influx of external seed b/c if weeds with induced dormancy go to seed they can be in there for years compared to innate which come up every season.
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What is the plant pigment that is involved in light responses in plant (red-far-red ratio)?
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phytochrome
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What factors affect germination?
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1) depth of burial
2) soil factors 3) seed shape 4) moisture 5) temperature 6) oxygen 7) light 8) pH and minerals |
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What are the (dis)advantages of using burial for management?
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Adv: most grasses and small seeded can be controlled
Disadv: will work the 1st year but the 2nd year the soil is flipped back over and can germinate if it has dormancy |
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What soil factors affect germination?
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microtopography-surface of soil
compression/compaction soil type |
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How does the seed shape affect germination?
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small and smooth seed slides down into a crack
large and rough seed increases surface area |
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How can knowing a weed's osmotic potential affect management?
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know if you can use saltwater as a management technique
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Why is rice grown in water?
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to eliminate weeds b/c most weeds need O2
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What type of light does dogfennel need and why?
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red b/c it is so small that it needs to be near the surface
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The weed seed bank contains various numbers of weed species and includes dormant seeds. TRUE or FALSE
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true
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What factors influences how long a seed can last in the soil and still be viable?
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composition of seed coat
metabolism, microorganisms and env. factors |
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Name 2 specialized vegetative structures.
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Tubers, turions
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Explain about vegetative structures.
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Usually stem tissue
k strategy perennials structure for maintaining bud/meristem asexual reprod. only |
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What nutrient will stimulate germination?
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Nitrogen
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