9.02 Lab: Flowers, Fruits and Seeds, biology homework help

Lab: Flowers, Fruits and Seeds

The goal of this lab is to learn about the structure and function of flowers, fruits and seeds. You will also study the reproductive processes in flowering plants and discover the value of fruits to humans.

FRUITS:

A fruit is the mature ovary of a flower containing the fertilized ovules. Ethylene, a plant hormone, promotes the ripening of fruit. The structure of many fruits aids in the dispersal of the seeds. For example, colorful, fleshy, aromatic fruits tend to be eaten by animals. The seeds generally pass through the digestive system undamaged and are stimulated to germinate by the abrasive action of enzymes and extreme pH. Other fruits dry as they mature and “shoot” the seeds away from the mother plant. Still others are modified with wings or parachutes whose large surface area catches air currents.

The parts of the fruit are derived from the parts of the ovary. The wall of the ovary becomes the pericarp of the fruit. The pericarp may be fleshy, may be dry or may be only partially fleshy. Fruits can be classified based on, among other things, the kind of pericarp they have. Remember that the fertilized ovules become the seeds.

Objectives:

1. You will learn about the structure of flowers, fruits and seeds.
2. You should be able to identify the various parts of a typical flower and give their functions.
3. You will learn what represents the male gametophyte and female gametophyte in flowering plants, and what is meant by the term “alternation of generations”.
4. You will  learn about the processes of microsporogenesis, megasporogenesis, and pollination.
5. You should be able to describe the “double fertilization” that is unique to flowering plants.
6. You will learn the function/value of fruits to both the plant as well as humans.
7. You will learn about the major types of asexual reproduction among flowering plants.

Time Requirements:

This lab should take three hours to complete.

Recording Your Observations:

Click here to download the lab report for this lab.

Procedures:

1. Obtain a flower (preferably a large gladiolus or lily, but NOT a sunflower, carnation, or daisy) you have bought from your local grocery store or from your own garden. You will need to know the identity of the flower. If possible, take several digital photos of the flower as you dissect it.
2. Make a sketch of the flower you have and identify its parts. If you could not get a flower, use the flower in the image below.

• • How many petals does this flower have?
  • How many stamens does this flower have?
  • How many stigmas does this flower have?
  • Is this the flower of a monocot or a dicot?
  • How can you tell?
  • Is this consistent with the structure of the leaves of this plant? Explain.

Perfect flowers have both stamens and pistils, while flowers lacking either stamens or pistils are termedimperfect (i.e., there are separate male and female flowers in imperfect plants while perfect flowers are bisexual).

• • Is this flower perfect or imperfect?