Roots and Growth

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Roots and Growth
2011-10-30 15:41:52
Zobot Roots Growth

Botany Unit #3 Notes
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  1. What are the three MAJOR functions of roots?
    • 1. Storage
    • 2. Anchorage
    • 3. Absorption
  2. Detailed summary of Storage.
    • Starch
    • Carbohydrates (for next season or "hard times")
    • Some store water
  3. Detailed summary of Anchorage.
    So plants can withstand the force of gravity and wind (upper part of the plant is much larger).
  4. Detailed summary of Absorption.
    • Water
    • Minerals
    • General nutrients (Phosphorus, Nitrogen)
  5. Roots form an extensive branching network that constitutes what percent of the total dry weight of the plant?
    About 1/3; 31-33%.
  6. How far can roots penetrate the soil?
    At depths from 10-100 feet.
  7. What are the different kind of specialized roots?
    • 1. Food Storage Roots
    • 2. Adventitious Roots
    • 3. Pneumatophores
    • 4. Contractile Roots
    • 5. Parasitic Roots
  8. What are fleshy and thick for the storage of carbohydrates needed in the next season?
    Food Storage Roots
  9. What are examples of food storage roots?
    Sweet potatoes, yams, carrots, beets, turnips, radishes.
  10. What are Adventitious Roots?
    Roots that develop from the stem.
  11. What are the three types of Adventitious Roots?
    • 1. Prop Roots
    • 2. Buttress Roots
    • 3. Aerial Roots
  12. What are roots that are found near the base of the stem in order to provide additional support for the plant?
    Prop Roots
  13. What is an example of a Prop Root?
  14. Corn plants are monocots, why are prop roots a necessary adaptive advantage?
    Because monocots do not have wood or bark, so it provides structure.
  15. Found in tropical areas, these adventitious roots are much larger. They help plants that are found in areas with very thin soil. What are they?
    Buttress Roots
  16. What is an example of a Buttress Root?
  17. What are roots that emerge above ground from branches, that will directly support the weight of large branches?
    Aerial Roots
  18. What is an example of an Aerial Root? (These are the highest in the air!)
    Banyan Tree
  19. What are special roots that grow from the soil UPWARD into the air?
  20. What are found at the top of pneumatophores?
    Lenticels, along with a mass of spongy, air filled tissue directly beneath them.
  21. Why do pneumatophores need more ATP (energy) to absorb their nutrients than most plants?
    Because these trees live in areas where it is difficult to absorb the nutrients from the soil necessary for survival.
  22. Why do the spongy pneumatophore roots directly supply oxygen to root tissues?
    For cell respiration and ATP production.
  23. What is an example of pneumatophores?
    Mangrove Trees (they live in swamps with variable tides).
  24. Pneuma = ?
  25. Phores = ?
  26. What kind of specialized root pulls the plant deeper into the soil until stable temperatures are met (warmer during cold conditions)?
    Contractile Roots
  27. What are examples of Contractile Roots?
    Lilies, Tulips, and Dandelions.
  28. What are roots that invade another plants vascular system and steal their nutrients and sugars?
    Parasitic Roots
  29. What are examples of Parasitic Roots?
    Mistletoe and Dodder.
  30. What are the human relevance of roots?
    • A. Source of Food
    • B. Source of Spices
    • C. Source of Medicines/Drugs
  31. What does are Biennial root crops?
    They complete life cycle in two seasons.
  32. What are non-biennials?
    Annuals or perennials.
  33. What are examples of biennials?
    Carrots, Beats, and Turnips.
  34. What are examples of Non-biennials?
    Sweet potatoes, Yams, Tapioca.
  35. What are examples of Spices?
    Sassafrass, Sasparilla, and Licorice.
  36. What are examples of Medicines/Drugs?
    Ginseng, Gentian, and Ipecac.
  37. What are General Root Types?
    • 1. Radicle (Baby Roots)
    • 2. Taproots
    • 3. Fibrous Roots
    • 4. Feeder Roots
  38. What is the embryonic root, located in the seed? It develops into the first root after germination (the seed beginning to grow, hatching...if you will).
    Radicle Root
  39. As it grows downward into the soil and matures, what will the Radicle Root eventually be referred to as?
    A Primary Root
  40. After germination, one of the two types of root systems usually develops...what are they?
    Taproots or Fibrous Roots
  41. Usually one large primary root develops. Many smaller secondary roots develop off to the side of the primary root. The primary root usually remains very large throughout its life.
  42. This root system is mostly found in dicots.
  43. What are examples of plants with taproots?
    Carrots, Turnips, Radishes, and Dandelions.
  44. What function are taproots specialized for?
    Additional Storage
  45. Many smaller roots are present without an obviously larger primary root detectable. This root system has more surface area.
    Fibrous Roots
  46. This root system is mostly found in Monocots.
    Fibrous Roots
  47. What are examples of plants with fibrous roots?
    Grass and Corn.
  48. What function are fibrous roots specialized for?
    Absorption and anchorage.
  49. These roots are produced by both taproot and fibrous root systems, these are very small roots that are found near the surface of the soil.
    Feeder Roots
  50. What is the function of feeder roots?
    This is where most of the absorption takes place.
  51. What specialized epidermal cells must these feeder roots have many of?
    Root Hairs
  52. Root systems have great absorptive ability, which is aided by root hairs that increase a root's what?
    Suface area
  53. What is an example of how root hairs increase a root's surface area?
    A single rye plant, growin in a 12" x 22" box produces roots 387 miles long if laid end to end (644 kilometers).
  54. What is the root structure of the longitudinal section of the end of a root?
    • A. Root Cap
    • B. Region of Cell Division
    • C. Region of Elongation
    • D. Region of Maturation
  55. What is a thimble-shaped mass of parenchyma, found ONLY in roots?
    Root Cap
  56. What are the functions of the root cap?
    • a) Protection of the apical meristem.
    • b) Parenchyma cells of the root cap secretes mucilage for lubrication.
    • c) Detects which direction gravity is coming from.
  57. Root cap cells are being constantly lost and replaced. The average life span of root cap cells is less than a week. What does this sloughing off aid in?
  58. What is region of cell division also called?
    The apical meristem (Meristematic region).
  59. What is an inverted, cup-shaped dome?
    The region of cell division.
  60. Where does cell division take place at in the region of cell division?
    At the edges.
  61. How often do cells divide in the region of cell division?
    Every 12-36 hours.
  62. What has a quiescent center (infrequent cell divisions here)?
    Region of cell division
  63. What kind of cells are produced in the region of cell division?
    A large nucleus, and few, if any, small vacuoles.
  64. What does the apical meristem in the region of cell division subdivide into?
    3 primary meristems.
  65. What are the three primary meristems?
    • 1. Protoderm.
    • 2. Ground Meristem
    • 3. Promcambium
  66. What gives rise to epidermis?
  67. What produces parenchyma of to the cortex?
    Ground Meristem
  68. What produces primary xylem and phloem; In dicots there is a solid core of xylem and phloem in dicot roots; In monocots pith is present and surrounded by xylem and phloem?
  69. Where do cells become loner as cell differentiation proceeds?
    Region of elongation
  70. Where do cells assume their mature size and shape?
    Region of elongation
  71. What happens to the tiny vacuoles in the region of elongation?
    They merge and grow into one or two large vacuoles, occupying up to 90% of the volume.
  72. Where do cells fully mature?
    Region of maturation
  73. What is the region of maturation also sometimes called?
    Region of differntiation, or root-hair region.
  74. Where do root hairs emerge?
    Region of maturation
  75. Root hairs are extremely fragile, so how long are their life spans usually?
    Usually not more than 4-5 days.
  76. On an average plant how many root hairs are found per cm2 of root?
    38,000 root hairs
  77. What is an example of a plant with a large amount of root hairs?
    A single rye plant has 14 billion root hairs which combined have the surface area the size of a football field.
  78. Root hairs are only 10 micrometers in diameter. How many cells thick are they?
    Only one cell.
  79. What is the advantage of root hairs being so narrow?
    They have larger surface area which allow them to absorb more nutrients and water.
  80. As root hairs develop, their cell membranes become richly embedded with proteins that use ATP to do what?
    Selectively transport materials from the environment into the root hair's cytoplasm.
  81. Why is it important that the the proteins of root hairs are selective?
    To keep harmful substances out of the cell. For example toxins, poison, aluminum...and they are also the first line of defense.
  82. What is the root structure of a cross section throughout monocot and dicot roots consist of?
    • A. Epidermis
    • B. Cortex
    • C. Endodermis
    • D. Pericycle
    • E. Primary Xylem and Phloem
  83. What has a VERY thin cuticle or none at all?
  84. Why is it important that the cuticle of the epidermis is thin or missing?
    Because the root's primary function is absorption.
  85. What is the tissue found in the cortex?
    Parnechyma tissue
  86. What is the cortex's function?
    Storing starch (amyloplasts).
  87. What is a single layer of compact cells surrounding the vascular cylinder (where the xylem and phloem are found in roots)?
  88. What are the endodermis cells partially coated with?
    Suberin in the primary walls.
  89. What are the suberin bands in the endodermis called?
    Casparian Strips
  90. What do the Casparian Strips in the endodermis essentially coat?
    The top, bottom, and sides of the cells, leaving the front and back uncoated.
  91. Casparian bands (strips) create a barrier around the vascular cylinder that prevents what?
    Molecules from slipping between cells, into the vascular cylinder.
  92. Water, nutrients, and minerals need to gain access to the cascular cylinder. What does the Casparian Strip barrier force molecules to do?
    It forces molecues to pass directly through the plasmodesmata of the cell walls, and then cell's plasma membranes which regulate which types of minerals can enter the vascular cylinder. Remember, cell membranes are selective.
  93. Eventually the vascular cambium appears as what?
    Concentric cylinders
  94. Eventually the vascular cambium produces what?
    The secondary phloem to the outside and the secondary xylem to the inside.
  95. What are vascular tissues that are found in the vasuclar cylinder?
    Primary Xylem and Phloem
  96. In dicots, what pattern do xylem and phloem form in between the arms?
    An "X" pattern.
  97. In monocots, where is the xylem and phloem?
    There is patch of pith in the center of the vascular cylinder and it is surrounded by xylem (inner) and then phloem (outer).
  98. What are some beneficial minerals to roots?
    Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur, Magnesium, Iron
  99. What are some harmful minerals to roots?
  100. Unfortunately, xylem cannot simply "make the decision" of what should enter, and what should stay out of roots. Why not?
    Because it is dead.
  101. What are the three plant strategies for reducing the impact of alminum ions in the soil?
    • 1. Release negatively charged organic acids that will bind aluminum ions in the soil.
    • 2. Aluminum ions can be actively trapped in cell walls.
    • 3. Produce more specific transporter proteins for other essential materials (Ex. phosphates).
  102. How does acid rain affect the amount of aluminum ions present in soil water?
    • 1. Soil PH goes DOWN when acid rain comes.
    • 2. Concentration of H+(hydrogen) goes UP
    • 3. Free H+ binds to soil. (overtakes aluminum's spot)
    • 4. Releases Al3+ which is now absorbed into the plant.
  103. What is it called when organisms can live with members of a completely different species in our world?
  104. What are the three different trypes of symbiotic relationships?
    • 1. Mutualism
    • 2. Parasitism
    • 3. Commensalism
  105. What is it called when both members benefit from the relationship?
  106. What is it called when one member benfits, the other is harmed?
  107. What is it called when one member benefits, the other is not affected in any way?
  108. Specific mutualistic bond where roots and fungus live together. The fungues allows the root to absorb phosphorous which gives the plant sugar. What is this?
  109. Mutualistic relationship where the root nodules that contain bacteria provide nitrogen.
    Root nodules with Nitrogen Fixing Bacteria
  110. Summary of Absorption Process.
    Soil particles are negatively charged particles, while minerals are positively charged ions in the soil that are attracted to soil because they have opposite charges. Aluminum is a harmful mineral that essentially disrupts membranes, causing them to lose the ability to transfer materials. The most pertinent effect of aluminum is it causes the region of elongation to lose the ability to absorb water, disenabling the plant to grow. In order to try and keep aluminum out, root hairs, which selectively absorb minerals based on their shape, size, or charge contain transporter proteins that have a specifically shaped protein that matches all the beneficial minerals a plant can absorb. After this first check point in a plant the plasmodesmata also is selective to make sure that what is going through is beneficial, preventing aluminum from reaching the vascular cylinder. Just before the vascular cylinder lies the endodermis, the ultimate blocking point, which is made of suberin and prevents molecules from squeezing through the cells and forces them to go through the "face". Although aluminum can still squeeze between two cells through intercellular spaces, it cannot penetrate through the endoermis unless there is a large concentration of it.
  111. What are plant growth and development regulated by?
  112. What are chemical compounds produced in one part of an organism that infulences development and functions in another part?
  113. Summary of Hormone Driven Communication.
    Hormones are chemical messengers that are produced in one cell but sent to another. The location where the hormone gets sent (the cell that receives the message) are called target cells. This message is carried through the xylem or phloem. Essentially the receptors actually receive the message, and then they transmit the message to the nucleus through a series of chemical reactions called signal transduction. Signal transduction sends across a signal from the recepter to the nucleus, like a dominoe effect. The nucleus then picks up the chemical reaction from the delivery of compounds, then realizes it needs to turn a gene off or on, and comples the hormone driven communication process.
  114. What are the plant hormones?
    • 1. Auxin
    • 2. Cytokinin
    • 3. Ethylene
    • 4. Gibberellins
    • 5. Abscisic Acid (ABA's)
    • 6. Brassinosteroids
    • 7. Systemin
    • 8. Salicylic Acid
  115. What is the location of auxins?
    • 1. Primary meristems
    • 2. Buds
    • 3. Young leaves
  116. What are the primary effects of auxin?
    • 1. Promotes cell elongation and enlargement
    • 2. Promotes apical dominance.
  117. What is growth in response to a particular stimulus? (Auxins are produced in reaction to different stimuli.)
  118. What can tropism be?
    Postive (towards) or negative (away).
  119. What are examples of tropism?
    • 1. Light: Phototropism
    • 2. Water: Hydrotropism
    • 3. Gravity: Gravitropism
    • 4. Touch: Thigmotropism
    • 5. Temperature: Thermotropism
  120. What type of tropism(s) does a root exhibit?
    • + gravitropism
    • + hydrotropism
    • - phototropism
  121. What type of tropism(s) does a stem(s) exhibit?
    • + phototropism
    • - gravitropism
    • + thigmotropism?
  122. What are auxins produced at the tips of plants that inhibit the growth of lateral buds?
    Apical Dominance
  123. If you are a gardener, how can you encourage a plant to appear thicker/bushier? Why does this work?
    Remove the apical meristem, which lets the lateral buds grow that produce branches and leaves, therefore making the plant appear bushier/thicker.
  124. What is Agent Orange, and what was it used for?
    2, 4-D (a type of auxin) mixed with 2, 4, 5-T makes up Agent Orange. It was contaminated with dioxin which made it a carcinogen. It was used in the Vietnam War to remove leaves from trees, little did the soldiers know it was extremely deadly.
  125. Where is cytokinin located?
    • 1. Root tips
    • 2. Germinating seeds
  126. What is the primary function of cytokinin?
    Stimulates cell division.
  127. What are the specific names for forming root partnerships with nitrogen fixing bacteria and fungi?
    • Bacteria: Mycorrhize
    • Fungi: Root nodules
  128. Where is ethylene located?
    Everywhere, but especially in fruits.
  129. What are the primary functions of ethylene?
    • 1. Fruit ripening
    • 2. Leaf/fruit dropping
  130. What is the basis for the idea that one bad apple can spoil the others?
    Because fruits give off ethylene to ripen, the ripened fruit being surrounded by the ripening fruits can become rotten due to the ethylene being produced by all the others still ripening, spoiling the single ripe fruit.
  131. What is the location for gibberellins?
    • 1. Roots
    • 2. Young leaves
    • 3. Embryos
    • 4. Apical buds
  132. What are the functions of gibberellins?
    • 1. Promote cell division of the shoot.
    • 2. Promote cell elongation of the shoot.
    • 3. Promote seed germination (the starches and proteins stoed in seeds gets broken down).
    • 4. Stimulates flowering in some plants.
  133. Where are ABA's (abscisic acid) located?
    • 1. Buds
    • 2. Seeds
  134. What are the functions of ABA's?
    • 2. Stop plant metabolism
    • 2. Promotes dormancy (especially in seeds)
  135. Where are brassinosteroids located?
    • 1. Leaves
    • 2. Shoots
    • 3. Fruits
    • 4. Seeds
    • 5. Flowers
  136. What are the functions of brassinosteroids?
    • 1. Cell elongation
    • 2. Protection from temperature changes, salts, and herbicides.
  137. Where is systemin located?
    Wounded leaves.
  138. What is the function of systemin?
    Send defensive alerts to neighboring plant structures/tissues.
  139. Where is salicylic acid located?
    • 1. Bark
    • 2. Flowers
  140. What are the functions of salicylic acid?
    • 1. Delay flower aging.
    • 2. Defense against invading microbes (bacteria, fungi, etc...).
  141. Aspirin is made from large quantities of Salicylic Acid, why might it be beneficial to drop an aspirin into a vase of freshly cut flowers?
    It will let the flower last longer.
  142. Which hormones promote growth?
    • 1. Auxin
    • 2. Cytokinin
    • 3. Gibberellins
    • 4. Brassinosteroids
  143. Which hormones promote senescence?
    • 1. Ethylene
    • 2. Systemin...? (triggers production of ethylene)
  144. Which hormones are defensive?
    • 1. Brassinosteroids
    • 2. Systemin
    • 3. Salicylic acid
    • 4. ABA'S
  145. What do light sensing pigments control?
    Plant responses to light stimuli.
  146. What are cryptochrome and phytocrome?
    Light sensitive pigments that act like switches controlled by light.
  147. When cryptochrome are turned OFF, what happens?
    The plant grows taller.
  148. When cryptochrome is tured ON (in response to blue light), what happens?
    The plant produces leaves for photosynthesis.
  149. How does cryptochrome provide an adaptive advantage for plants?
    It maximizes its resources so it can detect when light is present.
  150. When phytochrome is turned OFF, what happens?
    The seed remains dormant.
  151. When phytochrome is turned ON (in response to red light), what happens?
    The seed will germinate.
  152. How does phytochrome provide an adaptive advantage for plants?
    It lets the plant know that it has enough light to survive and begin growing.
  153. What are short-day plants?
    They flower when the day is shorter then their critical period.
  154. What are examples of short-day plants?
    Strawberries, dahlias, soybeans, potatoes.
  155. What are long-day plants?
    Flower when the day is longer than their critical period.
  156. What are examples of long-day plants?
    Clover, carnation, spinach.
  157. What are day-neutral plants?
    Need daylight, but it doesn't matter how much.
  158. What are examples of day-neutral plants?
    Sunflowers, cucumbers, tomatoes.
  159. What is a critical period of a flower?
    How long they need to flower.
  160. What is a root that has a beneficial symbiosis with a fungus where the fungus increases water and mineral uptake for the plant and, in turn, receives food from the plant?
  161. As you walk through a forest, you stop and smell some flowers, as well as hearlessly puncture, stab, and tear some leaves. What plant hormone is going to be produced as a result of your rampage?
  162. What hormone is the most important to the germination of seeds?
  163. Is there a possible scenario where all three plants could flower at the same time?
    Yes! It all depends on critical periods.