Chapter 25- Plant Responses + adaptations

true or false? Plant growth follows patterns that are the same for all species

False

what is a target cell?

The portion of an organism affected by a particular hormone

what is a hormone?

a substance that is produced in one part of an organism and affects another part of the same individual

What are gibberellins?

another group of plant hormones and are important in initiating seed germination

the closer a bud is to the stem's tip the more it is inhibited. What is this phenomenon called.

apical dominance

the venus fly trap is an example of what kind of nutritional specialist

carnivorous

the folding together of mimosa leaflets when touched is the result of what changes in cells at the base of each leaflet

change of osmotic pressure

what are herbicides

compounds that are toxic to the plant

what are xerophytes

desert plants

what do fruit tissues do in response to auxins

initiate early growth or release hormone ethylene, which stimulates plant to ripen

how does the venus fly trap obtain the nutrient it needs from and insect?

it receives nitrogen directly from the insect from the protein inside of the bug

why do cacti have small leaves or no leaves at all?

it reduces the rate of transpiration and allows the plant to store the most water

how does nicotine protect a tobacco plant from potential predators

its a natural insecticide that disrupts the nervous system of bugs

what is a lateral bud

meristemic area on the side of a tem that gives rise to side branches

what common plant grows as a parasite on conifers in the western US?

mistletoe

why do the roots of xerophytes have many hairs

so they can quickly absorb rainfall before water sinks too deep into soil

what adaptations do the leaves of salt-tolerant plants have that protects them against high salt concentrations?

specialized cells that pump salt out of the tissues and onto leaf structures

what are three plant adaptations to a desert climate?

1. Extensive roots 2. Reduced leaves 3. thick stems that can store water

When light hits one side of stem, a higher concentration of auxins develops on the ______ side. the concentration of auxins stimulates cells on the shaded side to_________ as a result, the stemp bend towards the ____________

1. shade 2. elongate 3. light

what is true about hormones and plant growth? A. Plant hormones are produced in growing flowers and fruits B. Single hormones may affect two different tissues in different ways c. hormones can activate the transcription of certain genes d. All plant cells are affected by all plant hormones

A, B, C

Phototropism

A growth response to light

what is dormancy?

A period when an organism's growth or activity stops

which are true about plant growth? A. chemicals direct, control, and regulate plant growth. B. Meristems are found at places where plants grow rapidly C. Plants stop growing when they reach maturity D. Even very old plants continue to grow

A, B, D

which are true about auxins A. Auxins cause roots to grow downward B. Auxins regulate cell division in meristem C. Snipping off the tip of a plant removes the source of auxins D. in roots, auxins stimulate cell elongation

A. Auxins... B.Auxins... C.Snipping...

what are two examples of how cytokinins produce effects opposite to those of auxins

A. Cytokinins inhibit the growth of lateral and cause cells to grow thicker B.stimulate lateral bud growth

which is true about the effects of thigmotropism A.the tendrils of a grapevine wrap tightly around any object they encounter B. a plant that is touched regularly may be stunted in growth C. the stems of climbing plants don't grow straight up d. when the tip of a vine encounters an object, it breaks off

A. the... B.A... C.The

what are two ways in which plant hormones control plant growth?

A. they control; patterns of development b. they control plant responses to the environment

which are true about cytokinins A. they delay the aging of leaves B. the stop cell division and growth of lateral buds C. They often produce effects opposite of those of auxins

A. they... C.they... D. They...

what is true about the adaptations of aquatic plants? A. all aquatic plants grow very slowly after germination B. in waterlilies, oxygen diffuses from open spaces in petioles to roots C.the knees of mangrove trees bring oxygen rich air down to roots D. the seeds of some aquatic plants can float in water

B, C, D

what nutrient do carnivorous plants need to obtain from insects that they can't other get?

nitrogen

how do waterlilies get oxygen to their roots?

oxygen diffuses from open spaces in petioles to the roots

What plant pigment is responsible for photoperiodism?

phytochrome

how does phytochrome control photoperiodism?

phytochrome absorbs red light and activates a number of signaling pathways within plant cells

what are cytokinins

plant hormones that are produced in growing roots and in developing fruits and seeds

What are long-day plants?

plants that flower when the days are long

what are epiphytes?

plants that grow directly on the body's of other plants

how do shorter days and lower temps. affect photosynthesis?

reduce efficiency because, auxin production drops, ethylene increases, less chlorophyll being produced. an abscission layers seals the leaf off and leaf falls off

Gravitropism

response of plant growth to the force of gravity

what is photoperiodism?

response to changing lengths of day and night

Thigmotropism

response to touch

ethylene is a plant hormone that caused fruit to ___

ripen

what does a trigger in venus' flytrap that causes the leaf to snap shut?

sensory cells

particularly in stems and fruits, gibberellins produce dramatic increases in _____

size

when days shorten at summer's end, what changes start a series of events that gradually shut down the leaves of flowering plants?

the change in the amount of auxin and ethylene

what adaptations do aquatic plants have that allow them to grow in mud that is saturated with water and nearly devoid of oxygen?

the contain air filled spaces in their tissues

abscission layer

the layer of cells at the petiole that seals off a leaf from the vascular system

what do tropisms demonstrate about plants

the plants ability to respond to the conditions the live in

what is gravitropism

the response of a plant to the pull of gravity

what are tropisms

the response of plants to environmental stimuli

What is photoropism?

the tendency of a plant to grow towards light

what is photoperiodism responsible for?

the timing of seasonal activitie such as flowering and growth

from their experiment with oak seedlings, what did the Darwin suspect about the seedlings

the top of each seedling produced substances that regulate cell growth

where are auxins produced and how are they distributed in a plant

they are produced in the apical meristem and are transported downward to the rest of the plant

what is the advantage for many desert plants that have seeds that can remain dormant for years?

they can survive long droughts because they germinate when sufficient moisture guarantees them a chance for survival

why are plants such as chrysanthemums and poinsettias called short day plants?

they flower when days are short

why aren't epiphytes considered to be plant parasites?

they gather their own moisture and produce their own food

how do many plants defend themselves against insect attack?

they produce antimicrobial chemicals.

how do auxins affect plant cells

they stimulate cell elongation

as cold weather approaches, what happens to deciduous plants?

they turn off photosynthetic pathways, transports materials from leaves to roots, an seals off seed

where is most of a desert plant's photosynthesis carried out?

thick green stems

why doesn't a tree's sap freeze during a cold winter?

xylem and phloem tissues pump themselves full of ions and organic compounds.