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

The effect of light on plant activities

Extracts from this document...


The effect of light on plant activities In this essay I will look at the different effects that light has on plant activities, in particular the effect it has on the flowering of plants. I will discuss the role of phytochrome in plants and how the two different types are dependant on the length of day. Light affects plant activities in various ways, but in order for these activities to take place, the plant must first have a method of absorbing and then utilizing the light - this is where phytochrome comes into play. Phytochrome is a blue-green pigment that is present in very small amounts throughout the plant, particularly at the growing tips. There are two types: phytochrome red (Pr) and phytochrome far-red (Pfr), with phytochrome red absorbing red light and phytochrome far-red absorbing far-red light. ...read more.


Therefore, in SDP's Pfr inhibits flowering. In order to decipher which wavelength of light has greatest effect on the plant's activites, one must first use an action spectrum. An action spectrum simply shows which wavelength of light is most effectively used in a given reaction. In the case of phytochrome, the red light and far-red light parts of the spectrum are used much more efficiently than any other. Therefore, the action spectrum graph would show spikes above the wavelengths representing the colors red and far-red. An absorption spectrum shows which part of the spectrum is most effectively absorbed, in this case, by a plant. The absorption peak of the red-absorbing form of phytochrome is 660nm and the absorption peak for the far-red form is 730nm. ...read more.


However, these findings did not account for the fact that SDP's grown under non-inducing conditions (thus producing gibberellin) will not cause flowering of grafted LDP's that are also under non-inductive conditions (thus producing anthesin). It is argued that florigen does not exist but instead, a particular ratio of other hormones must be achieved for the plant to flower. However, there are also strong arguments to suggest that it does exist. Recent experiments suggest that florigen does exist. Its existence is substantiated by experiments that indicate that the substance that triggers blooming is produced or activated in the leaves of the plant, and must be given time to pass out of the leaves before the plant can flower. In conclusion, light affects a plant activites in a number of ways. This is reinforced by the fact that that a plants level of activity changes depending on the time of day and therefore the intensity of light. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

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

Here's what a star student thought of this essay

3 star(s)

Response to the question

Overall essay structure okay, but does not stick to the main point of the question and the title needs to be adjusted to reflect this.
Introduction is good, and sets out what the main body of the text will be ...

Read full review

Response to the question

Overall essay structure okay, but does not stick to the main point of the question and the title needs to be adjusted to reflect this.
Introduction is good, and sets out what the main body of the text will be about without going into too much depth, sets out the main investigations of the essay well, apart from the second half of the essay which should be introduced in the introduction as a point that is examined. Does not answer directly the question of the effect of light on plant activities but more investigates the effect of light, hormones and phytochrome on flowering plants. However, the essay itself is very clear. The conclusion is adequate, but needs to include the hormonal aspect as does the introduction.

Level of analysis

Explains accurately the need for Phytochrome. Clearly describes the link between phytochrome and how light affects flowering plants well, and the role of the two different types of phytrochrome and why there is two different types without me having to have any previous knowledge of the subject, therefore good links and analysis of research seen. Explains the use of an action spectrum which is not introduced in the introduction and should have been as it makes up the second half of the main body of text. Argues the different theories for plant hormones and their affects on flowering plants well but this is not related to the main aim of describing phytochrome and the different effects that light has, therefore the introduction should be expanded to include this as the point seems relevant of the control of flowering in plants which seems the main investigation here, rather than the effect of light on plant activities as the title suggests.

Quality of writing

Lack of paragraphs makes the main body of the text quite hard to read and does not split the paragraphs up into relevant topics and discussions. Spelling, grammar and punctuation all good.

Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by skatealexia 01/03/2012

Read less
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 AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    sucrose breaks down into glucose and fructose, and maltose breaks down into two glucose molecules. Both glucose and fructose have fast rates of reaction but it will again depend on which enzymes are more abundant in the yeast. Sucrose and maltose will have a slower rate than fructose and glucose

  2. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    Tap water also has a high PH, which affects and encourages the nutrient uptake by plants. Therefore it is important that I use tap water and not distilled water, as it ensures that other minerals do not become a limiting factor on plant growth.

  1. Marked by a teacher

    Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant ...

    5 star(s)

    A similar factor to fatigue is alcohol, a substance which society believes to be the biggest factor influencing accidents. A recent reaction time study in Stanford University (8) has shown that subjects deprived of sleep had longer average reaction times than that of the intoxicated subjects, this research sheds

  2. Marked by a teacher

    Biology coursework investigation: Comparing the length of ivy leaves (Hedera helix) in areas of ...

    4 star(s)

    This test will prove whether the results of the investigation are significant, in this case, that the ivy leaves in the shade will be longer than the ivy leaves in the sun. If the final value is larger than the critical value, the results will be significant.

  1. Marked by a teacher

    To make sure we have plenty of energy in the future, it's up to ...

    4 star(s)

    These include solar, wind, geothermal and hydro. These types of energy are constantly being renewed or restored. But many of the other forms of energy we use in our homes and cars are not being replenished. Fossil fuels took millions of years to create. They cannot be made over night.

  2. the effect of bile concentration on the activity of the enzyme lipase during the ...

    The body neutralises the acidic conditions produced by stomach to this pH by secreting bile into the duodenum of the small intestine which contain hydrogencarbonate ions. This is important for this investigation as to maintain lipases optimum working conditions not only do we have to monitor and control the temperature

  1. The basic factors that effect human comfort

    The displaced particles pass on their extra energy and a pattern of compressions and rarefactions travels out from the source, while the individual particles return to their original positions. While the particles return to their original positions, the energy they pass on to neighbouring particles does not; this energy travels forward in a wave.

  2. Energy absorbed by a bouncing ball.

    This can be worked out by using the following equation: PE = Mass x Gravity x Height PE = mgh * where g = 9.8 The Experiment This is a diagram showing how I am going to take my experimental results.

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