While the basic functions of both plant cells and the animal cells are similar to each other, the one function that is exclusive to plant cells is photosynthesis: the synthesis of food using water and carbon dioxide, in the presence of sunlight.
-Separate pigments and calculate their Rf values.
-Learn a technique to determine photosynthesis rates
-Compare photosynthesis rates under various conditions.
-Explain why the rate of photosynthesis varies under different environmental conditions.
The bottle garden is a close relative of the biosphere: a tiny garden growing inside abottle, a glass sphere, or a demijohn. The main difference is that soil is the maincomponent not water. The container can be kept sealed or opened like a terrarium. Ourswill be more for just plants whereas the terrarium may have animals. These gardens in abottle, can be cured and perfected as a system, they are also very decorative, in fact youcan treat them as a bonsai with not only a single tree, but whole landscapes. A carefullychosen stone becomes a rock, a small plot of moss represents a great prairie. A contorted,little plant is now a hundred year old tree. Maybe a marsh wetlands with peat moss,mushrooms and ferns is more to your liking. Maybe appropriate succulent plants with sandand rocks for a vast desert landscape. The choice is yours. There is no rigid rule aboutbeing either an open or a closed garden. It maybe useful to keep the lid on to retainwater. Or eventually, the plants grow up and need to hang down the outside.
If the container is always sealed, the challenge becomes quite demanding. In fact, it thenis necessary to obtain an equilibrium between plants and animals in order to keep aneffective cycle of substances and energy, but if this is difficult in a predominantlywater environment, it is even more difficult in a just moist environment. So, the gardenhas to contain a moist soil, plants, little animals like terrestrial isopods (i.e.: sowbug, pill bug), earthworms, etc. Plants have to be resistant to high moisture and have asmall size and limited growth. To avoid roots rotten, you can also try to refer tohydroponics and substitute the ground with small sized expanded clay or with gravel. Inthis case you will have more difficulties in hosting animal species, so it will have to beleft open. It is important you place your garden in a cool and well illuminated place, butaway from direct sunlight. Open or closed, a bottle garden is a fascinating thing, and theidea itself of a little and self-sufficient world is fascinating as well. There are peopleso fond of bottle gardens they work at them a long time, taking care of them using longand thin tools and to observe these environments till they imagine to be one of theirinhabitants.
Then choose among these main options:
1 - Opened bottle garden, containing moist ground, plants and possible little animals. Itis suited for people who love taking care of gardens and who have a flair for
the architecture of little wide spaces.
2 - Opened bottle garden, prepared in hydroponics and containing plants. It is suited forthose who tend to forget to water their plants.
3 - Sealed bottle garden, holding moist soil, plants, and some little animals. Thisexercise is suitable for people who are keen on biology and scientific research. They willhave to find appropriate plants and animals suitable for a sealed ecosystem and will haveto achieve the necessary conditions for a long survival. This research, bibliographic inpart and experimental, will keep students happily busy for long time.
The educational value of these little ecosystems is evident. They can be carried out evenin a school, where the teacher will be allowed to illustrate their characteristics topupils and encourage interesting discussions. In the web sites below, you will findimportant practical information in building your bottle gardens.
Terrariums : Miniature Worlds in a Bottle!
BBC online, how to gardening, bottle garden
Un jardin en bouteille
Le terrarium : Un monde miniature dans une bouteille!
Internet keywords: garden bottle jar, jardin bouteille bonbonne.
Hydroponics is a method of growing plants without soil. Plants are simply placed in water with the necessary chemicals. As plants are deprived of support from the ground, they will fall down. To support the plants, an inert material like expanded clay pebbles is used in a pot in the tank (figure 5). Before inserting a plant in a hydroponic system, you must carefully remove all soil from the roots otherwise bacteria will putrefy them.
For many houseplants you can use tap water. Though, particularly for vegetables, it is advised to add appropriate nutrients. This cultivation method has the advantages of both requiring less frequent waterings and using very little water. With this system you can grow nearly any houseplant or vegetable. Hydroponics is useful also to show what nutrition plants need.
1 - Place some houseplants in hydroponics.
2 - Try hydroponics with vegetables and find the suitable nutrients.
Hydroponics in the Classroom
Growing plants without soil
To teach orphaned children how to grow their own food with hydroponics (gardening that uses very little water).
Organic Greenhouse Vegetable Production
Internet keywords: hydroponics classroom.
An ecosystem consists of the whole community of living organisms (biocenosis), the abioticcomponent of a certain environment (biotope) and their relationships.
The relationships essentially consist in a flux of substances which pass from thenon-living components to living ones and in a flux of energy which passes from thephotosynthetic organisms (plants) to the herbivorous animals, then to carnivores. Thewastes and the dead organisms are then decomposed by the micro-organisms which brake downthe substances back to simple components, in a full cycle.
1 - With a shovel in a field or in a wood, dig a square hole of about half a meter (1 1/2feet) square and about 40 cm (18") deep. Describe the non-living components of thesoil and all forms of life you find: roots, earthworms, snails, centipedes, spiders,crickets, etc. To complete the description of the ecosystem of the soil, look forinformation on the role of each of these organisms and the relationships with the otherforms of life of this environment.
2 - In similar way you have studied the soil ecosystem, you can analyze other ecosystemssuch as the ones in a forest, pond, shore, or desert.
G. and L. Durrell (2) can be useful, or there are many other books on this matter.
An Illustration of a Soil Ecosystem
Protocols for a Soil Ecosystem Approach for Characterizing Soil Biodiversity
Internet keywords: soil ecosystem.
If placed in a suitable nutrient environment, cells and tissues of many organisms are ableto reproduce and form new plants or animals. Now, we will deal with vegetable tissues,whose culture is simpler than that of animal cellules and tissues. It is necessary toprepare a nutritive and sterilized culture medium for the piece of plant tissue. Keep theculture in the suitable conditions of light and temperature and which vary from plant toplant. Over many days, you will observe the growth of a callus or roots or shoots. In thisway you can obtain even whole plants (cloning). These experiments show that special cellskeep all the information necessary to generate the whole plant.
As we have mentioned, it is necessary avoid bacteria and moulds in the cultures. For thisyou will need sterilize tools, vials, tubes, and nutrient medium. Place each in anautoclave for a ten minutes or, lacking an autoclave, a pressure cooker. The tissues aswell have to be free from microorganisms and they have to be sterilized with bleach (40%solution for 15 min) or with alcohol.
The transfer of the tissues into the test tubes has to be made in aseptic conditions,using a sterile box. Lacking that, make your first trials in a quiet place, as devoid ofwind and dust as possible. The culture medium should contain water, vitamins (particularlythose of the B-complex. For this, use yeast extract), sugars, mineral salts. To enrich thewater with mineral salts, boil some water with a handful of soil, then let settle andfilter it. Usually, people also insert 0.5-0.8% of agar-agar to "solidify" themedium. As culture medium, coconut milk has been used. It contains mineral salts, sugars,vitamins and growth hormones.
1 - For yours first tests of micropropagation, use strawberries tissues.
2 - If this simple experiment interests you, you can continue on the way of the invitro culture of vegetable tissues. In fact you can propagate a lot of plants in thisway. Plants easy to culture are the following: tomato, potato, strawberry, chrysanthemum,geranium, sunflower, tobacco, carrot and onion. You can use tissues obtained from seeds,such as the embryo, but you can use also tissues taken from adult plants, such as tissuesof roots, stems, apical buds, shoots, leaves, even single cells. Each plant and tissue hasits own needs. They are different from each other. You can try the influence of thevegetable hormones, special nutrients, etc.
This field is very broad and complex so, if you are interested in continuing with theseexperiments, you can buy special books and you should build a sterile box.
Plant Tissue Culture for the Gardener
Basic Principle in Plant Tissue Culture Technique
Plant Tissue Culture Kit Manual
Plant Micropropagation Using African Violet Leaves
Plant Tissue Culture (links)
Internet keywords: in vitro culture plant tissue micropropagation.
Students extract pigments from spinach leaves for analysis using chromatography and colorimetry. Paper chromatography separates the pigments present in the extract so they can be identified. Analysis of the extract with a colorimeter allows students to determine the relative absorbance of four different colors of light (blue, green, orange, and red). They relate the chromatography results to the colorimeter measurements to refine their understanding of how plants capture light for photosynthesis. If available, a spectrometer allows students to view the full absorbance spectrum for spinach leaves.
Students analyze spinach pigments and chloroplasts using paper chromatography, a colorimeter, and a spectrometer to understand how plants capture light for photosynthesis.
The colorimeter is used again in Part 2 to measure photosynthesis using DPIP (2,6-dichloropheno-lindophenol), an electron acceptor that experiences a color change if photosynthesis is occurring. For student-designed experiments, students can analyze factors such as the effect of different light sources, distance from a light source, and comparison of pigments in the leaves of different plants using chromatography, DPIP analysis, or both.