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Weed Science > Weed Test 1 > Flashcards

Weed Test 1 Flashcards

(46 cards)

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1
Q

weed

A

any plant out of place or growing where it is not wanted WSSA definition: any plant that is objectionable or interferes with the welfare of man or natural systems

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2
Q

ligule

A

tissue clasping the stem inside the leaf at the junction of the blade with the sheath. (present when you pull back the leaf)

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3
Q

auricle

A

appendages projecting from either side of the collar (look like fingers)

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4
Q

collar

A

a thickened, often apparently vein-less, shelf-like band marking the junction of the blade and sheath (unfold and keeps coming down)

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5
Q

flower

A

stem or branch bearing highly modified leaves concerned with sexual reproduction

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6
Q

fruit

A

a mature ovary plus attached floral or vegetative structures that become enlarged and ripen with it

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7
Q

seed

A

a mature ripened ovule

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8
Q

safe site

A

safe place where seed is allowed to germinate without competition or predators and has the right resources needed

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9
Q

carrying capacity

A

max population size of a species that the environment can sustain

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10
Q

dormancy

A

state of suspended development even though conditions are environmentally conductive for germination

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11
Q

quiescence

A

inhibition of germination when complete requirements are not met

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12
Q

persistence

A

the ability of a community to remain relatively unchanged over time

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13
Q

resistance

A

the ability of a community to remain unchanged during a period of stress

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14
Q

resilience

A

the ability of a community to return to its original state following stress or disturbance

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15
Q

elasticity

A

the speed at which the system returns to its former state following a disturbance

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16
Q

losses caused by weeds

A

reduction of crop yields

increased cost of operations

reduction in quality or quantity

increased processing costs

depreciated land values

reduced crop choice

allergies and poisoning

aesthetics

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17
Q

ideal characteristics of weeds

A

ability to germinate in many environments

discontinuous germination and seed longevity

rapid growth

continuous seed production

self pollination

cross pollination

high seed output in adverse conditions

adaptions for dispersal

ability to compete interspecifically by special means

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18
Q

most important general characteristics of problem weeds

A

number of individuals produced

range of habitats

ability to continue

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19
Q

monocot

Study These Flashcards
A

one cotyledon

parallel leaf veins

hollow stems with vascular bundles scattered throughout

underground: bulbs, corms, rhizomes

flower parts in 3’s

ex: grasses

20
Q

dicot

Study These Flashcards
A

2 cotyledon

net veination of leaves

stems with vascular bundles in a ring around pith or woody stems surrounded by bark

no scaly bulbs

flower parts in multiples of 2 or 5

ex: broadleaf plants

21
Q

weed crop ecosystem components

Study These Flashcards
A

weeds

crops

humans

natural environment

22
Q

weed crop ecosystem concepts

Study These Flashcards
A

understanding aids in developing weed management programs

traditional concepts focused only on weed and crop

now geared more toward specific weeds in a given crop in a single year

species have changed in response to weed control and other practices

23
Q

weed species shifts

Study These Flashcards
A

changed in response to weed control and other production practices

24
Q

environmental factors

Study These Flashcards
A

climate

physiographic

biotic

25
climate factors
light temp water wind atmosphere
26
physiographic factors
soil factors: pH, fertility, texture, structure, organic matter, CO2, O2, water drainage topographic: altitude, slope, exposure to the sun
27
biotic factors
plants (competion, toxins/stimulants, diseases, parasites, soil flora) animals (insects, grazers, soil fauna, man)
28
population
group of individuals that occupy an area within an environment which permits interbreeding among the group
29
population characteristics
density age distribution growth form adaptiveness persistance reproductive fitness birth and death rates dispersion
30
what gives population structure
variation of individuals within population such as age, size, stage of development, and other physical and genetic features
31
niche
a species place and role in a community
32
niche separation
refers to the process by which natural selection drives competing species into different patterns of resource use or different niches
33
plant succession
an orderly change in species resulting from modification of the physical environment by the plant community
34
resource allocation
ability to accommodate and maximize growth over a wide range of light and temperature interactions
35
weeds are dispersed over
time (dormancy) space (physical movement)
36
reasons for dispersal of weeds
avoid competition between parents and siblings increase colonization opportunities reduce predation chances
37
special adaption of weed seeds for dispersal
saccate fruits (floats) winged fruits and seeds (expanded wings or margins) comate seeds (long hairs or bristles) parachute fruits (spreading tufts or bristles) plumed fruits (long branched plume) clinging fruits (prickles, barbs, burs)
38
dispersal of weed seed by man
seeds on clothes or shoes ballast/trash from boats hay and feedstuff digestive tract spreading manure equipment packing materials mixed in crop seed
39
federal seed act
1939 provides for regulation of transport and sale of seeds in both foreign and interstate commerce seed label include: kind, variety, type of seed exceeding 5% origin of lot % by weight of seed kinds of noxious weed seeds and occurrence % other seeds and inert matter %germination and % hard seed with test date name and address of shipper or receiver
40
types of dormancy
innate (genetic) induced (environmental) enforced (environmental)
41
innate dormancy
impermeable or resistant seed coat chemical inhibitor (delays germination) rudimentary embryo (not fully developed)
42
induced dormancy
conditions cause seed to go into secondary dormancy, don't germinate at first with favorable conditions, but do eventually causes: excessive light, lack of moisture, high CO2, low O2, high temp
43
enforced dormancy
conditions cause seed not to germinate but when favorable conditions arise, germination occurs
44
seed bank
seeds of different ages and dormancy levels that make up the seeds which could germinate in a given land area
45
transient seed bank
seeds persist for a short period of time (1 yr or less) and remain near soil surface
46
persistent seed bank
seeds remain dormant and become incorporated into the soil, persisting for long periods and stabilizing area

Weed Science (6 decks)

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