Introduction

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Introduction

Monocots: A monocot is a plant that produces one seed leaf, as opposed to a dicot which is a plant that produces two leaf seeds. A plant that is a monocot may be a flowering plant, or may include some food plants as well.

Other names for monocots:

- monocotyledons

- liliopsida

Monocotyledons & dicotyledons are the two main groups of flowering plants.

One-quarter of all flowering plants species are made up by monocots.

Economically monocots are perhaps the most important organisms on earth.

Corn, rice, wheat and barley are our four more important food and they all come from monocots.

Introduction (cont…)

Monocots evolved

100-120 million years ago

• Numerous vegetation types are dominated by monocots including: palm savannas, cattail marshes and grassland.

 Many tropical fruits such as bananas, pineapple, coconuts and dates come from monocots.

Characteristics of

Monocot Flowers

Flowers

· The petals, stamens, and other flower parts of monocots are usually found in threes or multiples of three.

Leaf

· The leaf veins in monocots typically run parallel to the length of the leaf.

Pollen

· In monocots, the pollen spores feature a single furrow or pore through the monosulcate, or outer layer.

Stem

· The vascular structure of monocots is grouped in long strands of vascular bundles. These bundles form a cylinder and appear as small dots when the stem is cut.

The vascular bundles are scattered throughout the stem, often appearing more towards the edges than the middle.

Roots

· Instead of sprouting from the bottom of the seed, roots in monocots develop from nodes in the stem. When the roots are grouped near the bottom of the stem, they're known as prop roots.

Types of Monocot Flowers

Grasses

The grasses comprise one of the largest groups. Also called poaceaes, there are over 9,000 species in this family of plants.

Although we may not typically think of grasses as flowers, these plants actually have small flowers at the tips. A number of plants that we may not actually realize are grasses also belong to this group, including corn, wheat and rice.

Types of Monocot

Orchids

Flowers

Orchids and other members of the orchidaceae family are also monocots, with the 20,000 to

25,000 species making up about

30 percent of all monocots.

Orchids are distinctive because of their stamens and pistils, which are responsible for reproduction for the flower. Like most monocots, they have petals in groups of three. The pollen of orchids is usually found in masses called pollinia, and one of the petals on the flower usually forms a "lip" to make the flower symmetrical.

Types of Monocot Flowers

Asparagales

There are around 5,000 species that are part of the asparagales family, all of which are types of monocots. This family of flowering plants includes aloe, onion, asparagus, garlic, daffodils and daylilies. Most of these plants have a cluster of leaves at either the base or tip of their truck, and their seeds are coated with phytomelanin, which is a sooty black substance

Types of Monocot Flowers

True Lilies

The lilales familiy, also called "true lilies," is a group of flowers with about 1,200 species. Many flowers that we call lilies, including water lilies and arum lilies, are actually not a part of this group. Instead, members of this group include tulips, bomareas (a type of tropical vine), wake robins and mariposa lilies. All members of the true lily family grow from bulbs or corms, which keep the flower alive during the winter.

Structure

Monocots are plants whose seeds have one cotyledon, a food-storing structure. Seeds of dicots have two cotyledons.

In addition to the number of cotyledons per seed, monocots and dicots differ in other ways. In monocots, vascular bundles, groups of conductive tissue, are scattered throughout the stem, but in dicots, they are arranged in an outer circle.

Monocots have long, narrow leaves with parallel veins. Dicot leaves are broad with branched veins. Flower parts of monocots are arranged in threes or multiples of three, but flower parts of dicots are arranged in fours or fives or mulitples of four or five.

Common monocots include plants of great value to humans, such as bananas, and cereals such as corn, wheat, rice, and barley. Ornamental flowers that are monocots include tulips, orchids, and lilies. Beans, carrots, peas, and potatoes are dicots.

The number of species of dicots is much greater than number of species of monocots.

Facts

 monocots  Sexual Reproduction

 There are approximately 50,000 species of monocots

 Monocots tend to grow quickly and their stems stay soft and pliable, except for bamboos and palms. Most are herbaceous.

 The flower parts of monocots, such as petals, tend to be set in threes or multiples of three

Question # 1

T/F monocots are plants whose seeds have two cotyledon.

Answer # 1

False

Question # 2

What are the other two names for monocots?

Answer # 2

- monocotyledons

- liliopsida

Question # 3

Floral parts of monocots are often in multiples of ________ .

Answer # 3

vocabulary

Flower - In an angiosperm, a short stem with up to four sets of modified leaves, bearing structures that function in sexual reproduction.

Carpel - The ovule –producing reproductive organ of a flower, consisting of the stigma, style, and ovary.

Style -

The stalk of a flower’s carpel, with the ovary at the base and the stigma at the top.

Fruit - A mature ovary of a flower that protects dormant seeds and aids in their dispersal.

Embryo sac - The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure with eight haploid nuclei.

Endosperm - A nutrient

–rich tissue formed by the union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds.

Monocots - A clade consisting of flowering plants that have one embryonic seed leaf, or cotyledon.

Dicots - A term traditionally used to refer to flowering plants that have two embryonic seed leaves, or cotyledons. Recent molecular evidence indicates that dicots do not form a clade (see eudicots).

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