Practical #2 - Gymnosperms and Angiosperms

Question 1

Angiosperm and Gymnosperm Taxonomic Classification

Answer 1

• Kingdom Plantae
  
  • Division Coniferophyta (Gymnosperms Pinus)
  • Division Anthophyta (angiosperms)
    
    • Class Monocots
    • Class Eudicots

Question 2

Desribe the general characteristics of the Gymnosperms

Answer 2

• Division Coniferophyta
• Produce naked seeds (their seeds are not enclosed in fruits
• wind pollinated trees or shrubs
• Plants are monoecious
  
  • ​have unisex male and femal reproductive structures on different parts of the same plant

Question 3

What is the difference between homospory and heterospory?

Answer 3

• Homospory
  
  • ​Producing 1 type of spore
  • Bryophytes and ferns do this
• Heterospory
  
  • ​2 different kinds of spores are produced by the sporophyte (they differ in size)
  • Megaspores - produce female gametophyte
  • Microspores - produce male gametophyte

Question 4

A few pine attributes

Answer 4

• Sporophyte - evergreen tree or shurb
• Leaves of a typical pinetree are usually needle-like and occur in fascicles (groups)
• Live in harsh environments

Question 5

What are the 2 types of cones produces by gymnosperm sporophytes

Answer 5

• Microsporangiate
  
  • ​Consists of a central axis with hunderd of microsporophylls (leaves that contain sporangia)
• Megasporangiate
  
  • ​Also called Ovulate cones, seed cones, or female strobili or just pine cones
  • found on upper branches
    *

Question 6

Where are microsporangia held and what do the develop into?

Answer 6

• Microsporangia - are located inside the microsporophylls on the microsporagniate cones
• Encloses the microspore mother cells
  
  • ​microsporocytes
• Microsporocytes undergo meiosis and produce 4 haploid microspores
• Each microspore develops into the microgametophyte
  
  • this develops 2 wings and is now a pollen grain

Question 7

Where is the megasporangium located and describe its features

Answer 7

• It is located in the megasporangiate cones
• Has a central axis covered with bract scales (leaves)
• the pine ovulate consists of an integument and nucellus
  
  • ​Integument - outer layer of diploid cells will eventually coat the mature pine seed
  • The integument encloses the megasporangium - also called the nucellus
  • The nucellus is composed of sporophyte tissue and a megaspore mother cell (megasporocyte)

Question 8

Describe the megasporocyte growth pathway to become a sporophyte (or embryo)

Answer 8

• Also called the megaspore mother cell
• undergoes meiosis resulting in a linear tetrad of megaspores
• 1 megaspore undergoes multiple rounds of mitosis to produce over 2,000 nuclei
• Then it will the femal gametophyte (megagametophyte)
• Archegonia are produced at the micropylar end of the megagametophyte and each archegonia as 1 egg.
• Pollen tube grows into it for fetilization

Question 9

What are the three distinct plant generation represented in a pine seed?

Answer 9

• the seed has an outer seed coat, derived from the integuments of parent sporophyte generation
• Inside the seed coat, remantns of the diploid nucellus and hapoloid gemale gametophyte
• The new diploid sporophyte embryo is within the remnants of the femal gametophyte

Question 10

What are the structures of a pine Seedling?

Answer 10

• Integument - outer layer of seed coat
• Micropyle - top of seed that leads inside
• Root primordium - area of the seed where the root will stem from
• Leaf Primordium - area of the seed where the leaf will stem form

Question 11

Angiosperm quick Info

Answer 11

• Flowering plants
• Division Anthophyta
• Classes: Monocot and Eudicot
• largest and most conspicuous group of plants

Question 12

Where do leaves attach to the stem in angiosperms?

Answer 12

Receptacle

Question 13

What is the outermost whorl of leaves on angiosperms?

Answer 13

• Sepals (collectively called the calyx)
• These enclose the other floral parts while the flower is still in the bud stage
  *

Question 14

Which leaves are found inside the sepals?

Answer 14

• Petals (Collectively called corolla)
• Highly collared and conspicuous
• All the petals and sepals are referred to as perianth

Question 15

What makes up the 3rd whorl and what are its structures?

Answer 15

• the 3rd whorl consists of stamens
  
  • ​highly modified microsporphylls
• 2 structures
  
  • Filament
    
    • ​Stalk of the stamen
  • Anther
    
    • ​pollen-producing part of the stamen
    • made of 4 fused microsporangia
• All stamens the stamens are collectively called androecium

Question 16

What is the 4th whorl called? What are its structures?

Answer 16

• Carpels
  
  • highly modified megasporophylls
  • Each carpel encloses on or more ovules
• All of the carpels are referred to as gynoecium
• Pistils - may contain one or more carpels​

Question 17

What are the 3 structures of the pistil?

Answer 17

• Stigma
  
  • Top - sticky part
• Style
  
  • Stalk - leads to ovary
• Ovary
  
  • contains the carple

Question 18

Complete vs Incomplete Flowers

Answer 18

• Complete Flowers
  
  • ​If all four whorls are present on a flower
• Incomplete Flower
  
  • ​If one or more of the 4 whorls is lacking

Question 19

Perfect vs Imperfect Flowers

Answer 19

• Perfect
  
  • ​Both stamens and carpels are present
• Imperfect
  
  • Flower that lacks either stamen or carpels
  • Staminate - have stamens, lack carpels
  • Carpellate - Have carpels but lack stamens

Question 20

Monoecious vs dioecious

Answer 20

• Monoecious
  
  • ​produces separate staminate and carpellate flowers on the same plant
• Dioecious
  
  • ​produces staminate flower on one individual plant and carpellate flowers on another individual

Question 21

What are the 2 types of Flower Symmetry?

Answer 21

• Regular, actinomorphic
  
  • ​can be bisected longitudinally such that the two halves are mirror images
• Irregular, zygomorphic
  
  • ​bilaterally symmetrical

Question 22

Why are angiosperms divided into classes Monocot and Eudicot?

Answer 22

• Angiosperm seeds contain either one or two cotyledons, or embyonic leaves

Question 23

Monocot Characteristics

Answer 23

• Seeds have one cotyledon
• Flower parts occur in multiple of threes
• Leaf vens are parallel
• Vascular bundles are scattered through stem
• Fibrous Root System

Question 24

Eudicot Characteristics

Answer 24

• two cotyledons
• lower parts occuring in multiples of fours and fives
• Leaf veins form a net-like pattern
• Vascular bundles are arranged in a ring in the stem
• Taproot system

Question 25

What was the structure of the Lily Anther?

Answer 25

• Made of 4 fused microsporangia
  
  • ​microspore mother cells undergo meiosis here forming tetrda of haploid microspores
• The microspores separarte making 2 celled pollen grains
  
  • 1 cell makes the tube cell nucleus
  • 1 cell makes the generative cell nuclues that becomes sperm later

Question 26

What is the structure of the Lily Ovary?

Answer 26

• megasporangia are found in the ovary of the pistil
• A megaspore mother cell divides meiotically and gives rise to four megaspores.
  
  • The lone survivor goes through 3 rounds of mitosis giving rise to an embryo sac containin 8 haploid nuclei
• The embryo sac is also called the female gametophyte or megagametophyte

Question 27

What is a fruit, what are the 2 types of fruits and what distinguishes the 2?

Answer 27

• Fruit is a ripened ovary
• 2 types of fruit are
  
  • Fleshy and Dry
• The wall of the fruit pericarp, can be dry or fleshy at maturity.

Question 28

What is a simple fruit, and what are some examples?

Answer 28

• Derived from a single ovary that may consists of a single carpel or anumber of fused carpels
• Drupes - 1 seed surrounded by hard outer covering
  
  • olives, cherries, peaches, plums, and cocnuts
• Berries - Ovary with many seeds and the flesh fruit is from the ovary
  
  • Ex: tomatoes, green peppers, bananas, grapes, lemons, limes, watermelon, cucumber, squash
• Pomes - develop in part from the surrounding flower and stem tissues, particularly the receptacle
  
  • Ex: Apples and pears

Question 29

What is an aggregate fruit?

Answer 29

• derived from a gynoecium consisting of a number of unfused carpels.
  
  • Ex: Strawberries, blackberries, and raspberries

Question 30

What is a Multiple Fruit?

Answer 30

• Derived from the fused ovaries and receptacles of many flowers.
  
  • Ex: Pineapple and Figs

Question 31

What is a Dry Fruit?

Answer 31

• Typically made of one ovary, with no fleshy materials around the seeds
• Can be lumped into two broad groups
  
  • Fruits that split when mature
  • Fruits that do not split when mature

Question 32

What are the 2 fruits that split when mature?

Answer 32

• legume (beans)
  
  • ​fruit with one cavity that splits along both sides of the ovary
• Capsule (lilies and irises)
  
  • ​fruit with an ovary consisting of several cavities containg seeds

Question 33

What are the 4 fruits that do not split when mature?

Answer 33

• Achene - thin pericap with one seed. The ovary wall and seed coat are fused together (sunflower).
• Caryopsis - fruits are single seeds that are fully attached to a think pericarp (wheat, rice, corn, other cereal grains)
• Samaras - winged seeds, thin pericarp forms a wing (maples, ashes and elms)
• A Nut - thick pericap that is hard or wood. Ovary wall is separated from the seed. (hickories, walnuts, oaks, pecans)

Question 34

What is Double Fertilization and why is it important?

Answer 34

• After pollination and germination of the pollen tube….one sperm nucleus migrates to ans fuses with the egg nucleus.
  
  • the resulting zygote develops into an embryo that will grow into the mature seed
• a 2nd sperm nucleus migrates to and fuses with two polar nuclei within the embryo sac
  
  • giving rise to the triploid endosperm tissue
• This allows the seed embyonic seed to survive even longer and harsher conditions due to having the endosperm as a back up supplier of nutrition.