Category: Plants

 

Detergent & Seed Germination

Introduction:

Seeds come in different sizes, shapes, and colors. Some are edible and some are not. Some seeds germinate readily while others need specific conditions to be met before they will germinate. Within every seed lives a tiny plant or embryo.The outer covering of a seed is called the seed coat. Seed coasts help protect the embryo from injury and also from drying out. Seed coats can be quite thin and soft as in beans or very thick and hard as in locust or coconut seeds. Endosperm, which is a temporary food supply, is packed around the embryo in the form of special leaves called cotyledons or seed leaves. These generally are the first parts visible when the seed germinates. Plants are classified based upon the number of seed leaves (cotyledons) in the seed. Plants such as grasses and grass relatives can be monocots, containing one cotyledon. Dicots are plants that have two cotyledons.

 Seeds remain dormant or inactive until conditions are right for germination. All seeds need water, oxygen, and proper temperature in order to germinate. Some seeds require proper light also. Some germinate better in full light while other require darkness to germinate.When a seed is exposed to the proper conditions, water and oxygen are taken in through the seed coat. The embryo’s cells start to enlarge and the seed coat breaks open and root or radicle emerges first, followed by the shoot or plumule which contains the leaves and stem.

Many factors contribute to poor germination. Over-watering results in a lack of proper oxygen levels. Planting seeds to too deep results in the seed using up all of its stored energy before reaching the soil surface, and dry conditions result in the lack of sufficient moisture to start and sustain the germination process.

Objective:

The students will be able to describe how some environmental factors affect seed germination.

Materials:

Masking tape, Scissors, 3 ziplock bags, Marker, Forceps, Paper Towels, Metric Ruler, 3 colored pencils, 25 seeds, distilled water, 50 ml graduated, 1% detergent solution, 10% detergent solution, graph paper

Procedure:

1. Label the 3 zip lock bags: Control, 1% Solution and, 10% Solution.
2. Cut 6 square pieces of paper toweling to fit each bag.
3. Place 2 squares in each bag.
4. Distribute 6 seeds on each side of the paper towel between the plastic and towel.
5. In the control bag add 25 ml of distilled water completely moistening the paper towel.
6. In the 1% solution bag add 25 ml of 1% detergent solution making sure to completely moisten the towel.
7. Do the same to the 10% solution bag by adding 25 ml of 10% detergent solution.
8. Make sure all bags are sealed tightly.
9. Place the bags in a dark warm place designated by the instructor.
10. Write a hypothesis predicting the results of the experiment.
11. Examine the bags daily for 5 days. Record any changes that might have occurred. If the roots is visible the seed is considered germinated.
12. Record your date in the table below.
13. Do not allow your towels to dry out. Moisten each bag with the appropriate solutions in equal amounts.
14. Measure the root growth of each seed daily from the time it appeared.
15. Graph the data from the table using the colored pencils to represent each of the zip lock bags.

Number of Seeds Germinated

Average Growth of Germinating Seeds(mm)

Graph Title: ________________________________________

Analysis:

1. How many of the seeds germinated after 5 days in distilled water? ________. In 1% solution? _______ in 10% solution? ________.

2. Was there a difference in the number of seeds germinated?

3. In which of the three bags did seeds germinate faster?

4. What was the purpose of the control?

5. Did the detergent strength have an effect on the seed’s germination? If so What was it?

6. Was your hypothesis correct? Why or why not?

7. If it was not, what will you do now?

 

Moss & Fern Puzzle Solution

Plants that lack tubes to carry food and water are called nonvascular plants. These plants are also known as bryophytes. Most bryophytes are terrestrial and live in moist environments. Water is required so that the sperm can swim to the egg during fertilization. Bryophytes do not produce seeds, but instead produce spores to reproduce. These plants exhibit alternation of generations in their life cycle. Because these plants lack vascular tissue, they are small in  height. Moss is one example of a bryophyte that grows like a lush, green carpet. The dominant stage in the moss life cycle is the gametophyte. Root like rhizoids attach each gametophyte to the soil but do not absorb water. Both male and female gametophytes exist. The sporophyte generation is attached to the top of the gametophyte. Mosses are called pioneer plants because they often are the first plants to re-enter a barren area. Mosses also help prevent soil erosion. Sphagnum, or peat moss, is harvested and burned as fuel in some countries. Liverworts and hornworts are nonvascular plants that also grow in moist, shady places. Liverworts have leaflike structures along a stem and lay close to the ground. Hornworts, like algae, have a single large chloroplast in each cell. Ferns are simple, vascular plants that also lack seeds and reproduce by spores. Tree ferns are the largest ferns. Most ferns have an underground stem called a rhizomes. New leaves of ferns are tightly coiled and are called fiddleheads. Mature fern leaves are called fronds. Spores are produced on the underside of fern fronds.

 

Photosynthesis Answer Key:

All organisms use energy to carry out their life functions. Some organisms obtain this energy from sunlight. The process by which this energy transfer takes place is called photosynthesis. Photosynthesis involves a biochemical pathway in which the product of one reaction is consumed in the next reaction. Autotrophs are organisms that carry on photosynthesis and includes plants and other organisms containing the green pigment chlorophyll. Autotrophs use carbon dioxide and water to make oxygen and the simple sugar glucose. The pigment chlorophyll absorbs light energy from the sun during the light reactions. Accessory pigments also in the chloroplast absorb other wavelengths of light that chlorophyll does not absorb. These accessory pigments are responsible for other colors we see in plants such as red, orange, and yellow. Chloroplasts are surrounded by a double membrane. Inside chloroplasts is a system of membranes arranged as stacks of flattened sacs called granum. Each sac in the stack is called a thylakoid. The thylakoids are surrounded by a solution called the stroma. The dark reactions of photosynthesis take place in the stroma. Most chloroplasts are found in the leaves of plants. The underside of a leaf contains openings called stomata where gases such as oxygen and carbon dioxide enter and leave. These openings or stomata are closed during the hottest times of the day by cells called guard cells.