• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month


Extracts from this document...


PROJECT A: FACTORS WHICH MIGHT AFFECT STOMATAL OPENING (LIGHT) How light affects the stomatal opening in a leaf Abstract My aim of this investigation was to check the affect of environmental factors affecting stomatal opening. My experiment was designed to check the stomata opening in light. Plants move in ways that may not seem obvious. The opening and closing of stomata is one example of this movement. There are a large amount of growth conditions that can affect a plant. One of the most important of these conditions concerns the type of availability of light present for photosynthesis. By controlling the type of light that a plant receives, its growth can be affected. I chose to measure this growth by observing the number of stomata present on the underside of leaves exposed to the dark and to sunlight. Based on the idea that there are more open stomata present on leaves exposed to the sun, my hypothesis that 'Factors which might affect stomatal opening' (Light) there will be more stomata on the plants exposed to the light. Hypothesis I believe the results of my investigations will show that the more the light source the more the stomata will open. ...read more.


The rate of gas exchange for the entire leaf is determined by the responses of all the stomatal pores on a leaf to ambient environmental conditions. Many researchers have noticed that stomatal response to seemingly identical treatments can vary considerably. Stomata, then, seem to function as separate entities which respond individually to the same environmental stimuli. The ecological implications of this "patchy stomatal response" are the focus of a great deal of current research. Knowledge of stomatal response increases our understanding of carbon dioxide assimilation and transpiration rates, as well as the nature of ecophysiological adaptations of plants to their environments. (1) The usual response of stomata to environmental factors is shown in Fig. 1.2. Closed stomata begin to open in a few minutes after exposure to light and they start to close when returned to the dark. When plants are put in CO2-free air, stomata tend to open even in the dark. Conversely, an increase in CO2 concentration above the normal level (330-340 ppm) causes stomata to close in the light. Within range of about 5-25 ? C the effect of temperature is mainly on the rate of opening and closing reactions rather than on aperture size. ...read more.


The container was labelled with this plant "DARK." 4. Both plants were placed in front of the light. Time was recorded that the plants were placed in the light on the data sheet (Table 1). Temperature was monitored next to the uncovered leaves by placing a thermometer on the leaf surface. Do not let the temperature of the plant rise above 30oC. 5. Every 15 minutes for 90 minutes, one covered leaf was removed and one uncovered leaf from each plant. The appropriate surface was painted with nail polish. The nail polish was left to dry, then cast was remove. 6. Microscope slides were prepared as before. For the easiest comparison, both casts were placed from the "LIGHT" plant side by side on one slide; both casts were placed from leaves off the "DARK" plant side by side on a second slide. Results 1. According to my observations and calculations abaxial surface of the leaf has more stomata than the adaxial surface of the leaf. This is to aid in preventing dehydration. 2. The leaves which were placed in the dark there stomata were closed while the leaves which were placed in the light there stomata were opened. 3. Bright light, leaf temperature less than 30oC, low wind speeds, and wet soil all lead to stomatal opening. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Compare stomatal densities of the upper and lower epidermis of a leaf.

    Now the average stomata count of both sides of the leaf have been calculated, I can now calculate the stomata density as numbers of stomata per cm2. To do this I first needed to calculate the area of the field view in cm2.

  2. The investigation is aiming to look at transpiration.

    will be obtaining wrong results, which will also lead to a wrong conclusion. We have to: {1} make sure that there are no air bubbles in the photometer as this could lead to us obtaining wrong results. The reason for this will be explained later in this coursework.

  1. Poikilohydry in mosses: an ecological limitation or opportunity?

    However, the homoiohydric system has success within certain limits defined by temperature and the availability of water 5,7. Mosses are the successors of ecological niches characterised by intermittent water availability due to their ability suspend metabolism during periods of drought (escaping the need for metabolic function)

  2. Investigating the abiotic factors that affect the size of Ivy leaves in shaded and ...

    Light energy can then excite an electron from photosystem I, and this excited electron passes to another electron acceptor - nicotinamide adenine dinucleotide phosphate (NADP). NADP also takes up a hydrogen ion from water and is thus reduced, forming NADPH.

  1. The aim of my particular experiment was to investigate into the possible existence of ...

    In most broad leaved plants, a greater number of stomata are found on the cooler, lower surface. This ensures that sufficient carbon dioxide can enter while at the same time cutting down the amount of water lost by transpiration. In this scenario water-uptake can also be preceded by an uptake of potassium ions.

  2. "A comparison of soils (e.g. garden/ school / park / woodland) linked to controlling ...

    (sedimentation of soil analysis) Apparatus: * Soil sieves * Air-tight containers * Measuring scales * Measuring cups * Nutrient soil testing kit * Bunsen burner * Tripod stand * Test tubes * Wire gauze * Crucible pot * Tongs (test-tube holder) * Forceps * Ethanol * Lamps * Graduated cylinder * Retort stands * Timer * Gloves * Beaker * Fireproof slate Method 1.

  1. Three separate experiments which are to be carried out to investigate a plant's unique ...

    These are explained on page 5 under the heading 'The factors affecting transpiration'. The Set-up: We must be very careful when setting up this experiment. If when we insert the plant into the potometer, we get a little air bubble just below the stem, our results will be very wrong,

  2. The aim of this science investigation is to find out where the stomata are ...

    In the morning the resumption of photosynthesis lowers the concentration of carbon dioxide. As a result the level of carbonic acid falls, the pH rises, starch is converted to sugar, the osmotic pressure of the guard cells increases, and the stoma opens. This theory leaves a number of facts unexplained.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work