BIOL1309 Evolutionary Diversity - (7) Angiosperm

Phylum: Anthophyta, i.e. flowering plants / angiosperms

Compare dicots and monocots. What is the difference in terms of the arrangement of their flower parts?

Dicots: usually in 4s (sets of 4) or 5s (sets of 5)

Monocots: usually in 3s (sets of 3)

Compare dicots and monocots. What is the difference in terms of the pollen appearance?

Dicots: with 3 apertures / furrows

Monocots: with only 1 aperture / furrow

Compare dicots and monocots. Suggest 3 differences in terms of the structure of cotyledons.

Dicots: 2 cotyledons, embryo takes up the size of the whole seed

Monocots: 1 cotyledon, embryo takes up part of the seed

What is the ploidy level of the endosperm?

3n (triploid)

Compare dicots and monocots. What is the difference in terms of the leaf venation?

Dicots: net-like

Monocots: parallel

Compare dicots and monocots. What is the difference in terms of the arrangement of primary vascular bundles in stem?

Dicots: in a ring

Monocots: scattered arrangement

Compare dicots and monocots. What is the difference in terms of secondary growth?

Dicots: secondary growth is often present

Monocots: secondary growth is typically absent

Compare dicots and monocots. What is the difference in terms of the root appearance?

Dicots: taproot with lateral roots

Monocots: fibrous roots

There are 4 whorls (circle of 1 kind of flower part) of flower parts. Label the structures of flower.

Which structures does perianth consist of?

Petal, sepal

T or F: Petals and sepals are always distinguishable.

F. Sometimes petals and sepals are fused.

T or F: Individual parts in each whorl is always free.

F. Individual parts in each whorl can be free or fused.

What is the definition of complete flowers?

Flowers that possess all flower parts (sepal, petal, stamen, carpel).

What is the definition of perfect flowers?

Flowers that possess both stamen and carpel, i.e. perfect flowers are bisexual, imperfect flowers are unisexual.

T or F: Incomplete flowers are always imperfect.

F. An incomplete flower is perfect if it lacks sepal and/or petal.

Which structures is stamen composed of?

Anther, filament.

Label the cross-section structure of anther.

Fill in the blanks: Anther is a modified (a) bearing (b).

a: microsporophyll

b: microsporangia

What is the ploidy level of microsporocyte?

2n (diploid)

What is the ploidy level of microspore?

n (haploid)

Fill in the blank: Microsporocyte is the mother cell of (a).

a: microspore

Fill in the blanks: Microsporocyte inside (a) undergoes (b) to produce microspore.

a: microsporangium

b: meiosis

What is the ploidy level of microsporophyll?

2n (diploid)

What is the ploidy level of microsporangium?

2n (diploid)

What does microspore develop into? What is the process undergone?

Pollen grain. Mitosis.

What is the ploidy level of pollen grain?

n (haploid)

Conclusion: Microsporophyll (2n) contains microsporangia (2n). Microsporangium contains microsporocytes (2n). Microsporocyte undergoes meiosis to produce microspores (n). Microspores undergo mitosis to develop into pollen grains (i.e. male gametophytes) (n).

Identify the whorl and label the structures.

Carpel.

Identify the ovary arrangement.

Superior ovary.

Identify the ovary arrangement.

Inferior ovary.

Identify the ovary arrangement.

Inferior ovary.

Identify the ovary arrangement.

Half-inferior ovary.

Identify the ovary arrangement.

Superior ovary.

Identify the ovary arrangement.

Superior ovary.

For half-inferior ovary, what is the name of the modified receptacle?

Hypanthium.

Fill in the blanks: Carpel is a modified (a) bearing (b) inside ovules.

a: megasporophyll

b: megasporangium

What is the ploidy level of megasporophyll?

2n (diploid)

What is the ploidy level of megasporangium?

2n (diploid)

T or F: Some flowers may contain separate ovaries and carpels.

T, and some flowers contain single ovary and single carpel

T or F: Single ovary and multiple fused carpels cannot exist in flowers.

F. Some flowers have single ovary and multiple fused carpels.

T or F: Styles cannot be fused in flowers.

F. Flowers with single ovary and multiple fused carpels may have either fused or separate styles.

Identify the ovule placentation (i.e. arrangement of ovule attachment inside ovary).

Marginal.

Identify the ovule placentation.

Axile.

Identify the ovule placentation.

Parietal.

Identify the ovule placentation.

Parietal.

Identify the ovule placentation.

Axile.

Identify the ovule placentation.

Free central.

What is the definition of inflorescence?

Clusters of flowers arranged in a specific manner.

What is the definition of bract?

Modified leaf associated with flowers.

T or F: Sunflower is a single flower.

F. Sunflower possesses inflorescence.

Label the structures of sunflower’s inflorescence.

Label the structures of a disc floret of a sunflower. (Hint: disc floret has an inferior ovary.)

*Filaments are separate and surrounded by petals, while anthers are fused and exposed. There are 5 stamens (5 anthers and 5 filaments).

The disc floret of sunflowers have 1 ovary, 1 style, and 2 stigma lobes. Fill in the blanks: Disk floret has (a) ovary and 2 (b) carpels, with (c) styles.

a: single

b: fused

c: fused

Label the structures of a ray floret of a sunflower. (Hint: disc floret has an inferior ovary.)

*Ligule = 3 or 5 fused petals

Suggest a group in the sunflower family (Asteraceae) that has only disc florets.

Thistle inflorescence.

Suggest a group in the sunflower family (Asteraceae) that has only ray florets.

Chrysanthemum inflorescence.

What is the type of the inflorescence in plants of the Araceae family?

Spadix inflorescence, i.e. flowers borne on fleshy stalk.

What is the name of the bract in Araceae plants?

Spathe.

Label the structures of the Araceae plant.

Label the structures of the Araceae plant.

Label the structures of the Araceae plant.

What is the function of spathe?

To protect spadix.

T or F: All flowers are unisexual in the inflorescence of Araceae plants.

F. Some flowers are bisexual.

Suggest a feature of sepals and petals in Araceae plants.

There are no or reduced sepals and petals.

T or F: Sterile regions may be present in the inflorescence of Araceae plants.

T.

What is the relationship between fruit and carpel?

Fruit is a matured carpel / ovary.

In fruits, what does the ovule and ovary wall develop into?

Ovule develops into seeds. Ovary wall develops into pericarp, i.e. outer wall of fruit.

What is the function of pericarp?

To surround and protect the seeds.

What are the 3 layers of pericarp (from outer to inner)?

Exocarp, mesocarp, endocarp.

In simple fruits, which layer is usually edible?

Mesocarp.

Identify the pericarp layers.

Fill in the blanks: Simple fruits arise from a (a) flower containing (b) ovary.

a: single

b: one

Citrus fruit is a type of simple fruit. Identify the layers of pericarp of a citrus fruit.

Fill in the blanks: Each segment of a citrus fruit is the (a). The segment in the photo shows the membranous (b) removed.

a: carpel

b: endosperm

Fill in the blanks: In citrus fruits, (a) is the edible tissue. (a) is derived from juice-filled (b) inside a carpel.

a: pulp

b: hair

T or F: Accessory floral tissues do not form part of the fruit.

F. Accessory floral tissues may become united with the ovary

during its maturation and form part of the fruit.

What is the apple / pear flesh derived from?

Hypanthium (modified receptacle).

Fill in the blanks: Aggregate fruits arise from (a) flower with many (b) ovaries.

a: one / single

b: separate

Fill in the blank: In aggregate fruits, each fruit comes from (a) ovary / ovaries.

a: one

Which part of the flower develops into the edible, fleshy part of strawberry?

Receptacle.

Suggest 2 flower structures that become remnant in aggregate fruits.

Stamen and style.

Suggest 3 examples of aggregate fruits.

Raspberry, blackberry, strawberry.

What is the visible remnant of strawberry that is a reproductive structure?

Stamen.

Identify the structures in strawberry.

Describe the pericarp / fruit wall of strawberry fruits.

Thin, reduced.

T or F: In strawberry, each individual ovary is pollinated and becomes a fruit.

T.

Fill in the blanks: Multiple fruits arise from (a) flower / flowers in an (b).

a: multiple

b: inflorescence

In multiple fruits, how many ovary / ovaries per flower is / are there?

1.

What is an example of multiple fruits?

Mulberries.

T or F: Mulberries have bisexual flowers.

F. Mulberries have unisexual flowers.

How many sepals and stamens do each flower in male inflorescence have?

4 sepals, 4 stamens.

How many sepals and stigma, style and ovary do each flower in female inflorescence have?

4 sepals, 1 stigma, style and ovary.

Identify the structure in pineapple, a multiple fruit.

Identify the structures in pineapple, a multiple fruit.

Identify the structures in pineapple, a multiple fruit.

T or F: Figs are flower-less multiple fruits.

F. Fruits cannot form in plants without flowers. Figs have flowers which develop inside the receptacle.

What is the definition of syconium?

Type of inflorescence formed by enlarged, fleshy, hollow receptacle with individual flowers / fruits borne inside it.

Identify the structures of grain, the fruit of cereals.

Fill in the blank: Grain is a one-(a) fruit.

a: seeded

Identify the structure in the ovary.

Identify the structures in the ovary.