Experiment on Transpiration in plants with dicot leaves


Transpiration is a physiological activity of plants where the plant looses water in the form of water through the aerial parts of the plant. In this resource I have described an experiment to prove that more transpiration occurs from lower (ventral) surface of a dicot leaf than upper (dorsal) surface. Along with the experiment some important questions related to the experiment are given below and are helpful to the students who are appearing for practical as well as various Board's final theory exams.

Introduction

Transpiration is the evaporative loss of water through the aerial parts of the plants especially through the leaves. In all green plants transpiration occurs mostly through the stomata of the leaves. In dicot plants leaves will have more stomata on the lower surface than the upper surface. So more transpiration occurs through the lower surface of the leaves of this plant. Stomatal pores get widely opened when the leaf get exposed to bright sunlight. To avoid excessive loss of water through transpiration dicot leaves possess more stomata on the lower surface as this surface is not much exposed to sunlight.

Aim of the experiment

To prove more transpiration occurs from the lower (ventral) surface of a dicot leaf than upper (dorsal) surface. (OR) To prove unequal transpiration from the two surfaces of a dorsiventral leaf.

Requirements

A well watered potted dicot plant, strips of dry cobalt chloride paper, glass slides, clips.

Procedure for the experiment

A well watered dicot plant has to be selected for this experiment. Now two strips of filter paper are soaked in 2% solution of cobalt chloride and are perfectly dried under sunlight. Cobalt chloride paper will be blue in color when it is dry and become pink when it absorbs moisture. Due to this characteristic feature it acts as a chemical indicator in this experiment. One strip of this dry blue cobalt chloride paper is kept on either surface of a healthy dorsiventral leaf and are covered by glass slides with the help of clips. Now the whole experimental setup is kept under bright sunlight. Observe closely the changes which occur in cobalt chloride papers placed on both the surfaces.

Experiment to show more transpiration occurs from lower surface of a dicot leaf than upper
Courtesy:-dev.elearn.punjab.gov.pk

Result

Within few minutes we observe the cobalt chloride paper kept on the lower or ventral surface of the leaf turns into deep pink color but the strip of cobalt chloride paper kept at the upper surface remains unchanged or it takes longer time to change into pale pink color. The reason for this is more stomata are present on the ventral or lower surface of a dicot leaf than the upper or dorsal surface. Due to this more water vapor from the ventral surface is released than dorsal surface and hence cobalt chloride paper kept at the lower surface changes into pink color immediately.

Here is anExperiment on Photosynthesis-Sunlight is necessary for Photosynthesis

Questions and answers related to the experiment

  • What is the aim of above experimental setup?
    Ans. To prove that more transpiration occurs from the ventral (lower) surface of a dicot leaf than dorsal (upper) surface.

  • Write the characteristic feature of the cobalt chloride paper used to serve the purpose of this experiment?
    Ans. Cobalt chloride paper is blue in color when it is dry but turns into pink color when it absorbs moisture and thus it acts as a chemical indicator in this experiment.

  • Why glass slides were attached above the cobalt chloride papers placed above below the surface of leaves?
    Ans. Glass slides were covered over the cobalt chloride papers to prevent the atmospheric moisture to react with them so that the aim of our experiment may be failed.

  • After some time of the experiment what change you expect to find on the dorsal and ventral side of the experimental leaf? Give a reason in support of your answer.
    Ans. The cobalt chloride paper kept on the dorsal surface would not show any change much because the number of stomata on the dorsal surface of dicot leaf are less. But the cobalt chloride paper kept on the ventral surface immediately changes into pink color because more stomata are present on the ventral surface of a dicot leaf.

  • Is the leaf used in the above experimental setup is dicot or monocot? Give a reason in support of your answer.
    Ans. The leaf used in the experimental setup is dicot leaf. The reason for saying it is a dicot leaf is showing reticulate venation.

  • Why this experiment should be conducted with an intact leaf only?
    Ans. The leaf should be intact with the plant so that there will be continuous supply of water to it to carry transpiration otherwise we may not get the desired result.

Here is a video on Transpiration in a dicot leaf:-

Courtesy:- OLabs - Amrita University


Related Articles

Which are the Popular Indoor plants

In this article, I would like to share the information regarding the most popular Indoor plants. Now days we people are living in most congested and tidy houses at where we have not particular space for growing plants. This article will furnish the information about the popular Indoor plants, which can be grown up in our homes.

Return of the elephant seal

Aside from man and elephant seals only enemies are large sharks, parasites, and particularly killer whales. Although the birth rate of the species is white low, the seal was always in balance with its natural predators. The operations of modern man, how ever, but disastrous.

What is the Role of Water in a Plant's Life?

In this article I discussed about the importance of water in a plant's life. In this article I explained the role played by water in maintaining the posture of plant body and also its role in its life activities like photosynthesis, germination of seeds, transport of food within in the plant body, opening and closing of stomata for transpiration, transport of minerals from the soil into plant body, metabolic activities of the plant cells etc.

How Oxygen is evolved by green plants in an experiment on Photosynthesis

Photosynthesis is an anabolic chemical process of green plants and it is a food synthesizing process. In this resource I have explained in detail how an experiment can be conducted to prove oxygen is evolved during photosynthesis process. Along with the experiment I gave some important questions as well as answers related to the experiment which will be useful for those preparing for final practical or theory exams of various Boards.

More articles: Science experiment Plants

Comments

No responses found. Be the first to comment...


  • Do not include your name, "with regards" etc in the comment. Write detailed comment, relevant to the topic.
  • No HTML formatting and links to other web sites are allowed.
  • This is a strictly moderated site. Absolutely no spam allowed.
  • Name:
    Email: