you are here->home->Biology->Class 10->Study of Phototropism and Geotropism in Plants
Study of Phototropism and Geotropism in Plants

Materials Required

  • Two un-branched plants   
  • Adhesive tape. 
  • Cotton 
  • Two boiling tubes marked as A and B  
  • Water 
  • Two laboratory stands with clamps 

Real Lab Procedure

  • Take two boiling tubes labelled as A and B. 
  • Fill up both the tubes with water until they are two-thirds full. 
  • Insert the plants one by one into each boiling tube. 
  • Introduce the cotton swabs in such a way that roots dip in water and the stem with leaves project out of the boiling tubes. 
  • Seal the mouth of two boiling tubes using adhesive tape such that no water trickles out of the boiling tube even when they are inverted.  
  • Fix tube A vertically upright in a laboratory stand.  
  • Fix the other boiling tube B upside down in another laboratory stand.  
  • Ensure that the water in second tube (B) does not trickle down. 
  • Place the two laboratory stands near a window such that direct sunlight falls on the two plants. 
  • Observe the plants in each boiling tube on Day 1, Day 2, Day 3, and Day 4. 

Simulator Procedure (as performed through the Online Labs)

  • Drag and drop one plant to the marked boiling tubes (A) containing water (roots dip in water and the stem with leaves project out of the boiling tubes). 
  • Drag an drop the next plant to the marked boiling tubes (B) containing water. 
  • Drag and drop two cotton swabs into top of the corresponding two boiling tubes.  
  • Drag and drop adhesive tape onto the mouth of two boiling tubes for sealing. 
  • Drag and drop boiling tube A vertically upright in the laboratory stand. 
  • Drag and drop boiling tube B upside down in another laboratory stand. 
  • Click on the next button to go to the next screen of simulator. 
  • You can see the observation of Day 1, Day 2, Day3 and Day 4 on screen. Corresponding to each day, movement of clock will be shown along with the movement of Plants A and B towards sunlight. 
  • After Day 4 observation click on the next button. 
  • Drag and drop the correct answers from the control panel to appropriate places towards the empty boxes. 
  • If the option dragged is wrong, then it will go back to its original place. 
  • Click on the information icon to see the inference. 
  • You can redo the experiment anytime by clicking on the ‘Reset’ button. 

Observation

The stem in test tube A grows vertically upwards and bends towards the light. The stem in test tube B shows a curvature and bends upwards towards the light and away from the gravitational force, thus showing +ve phototropism and –ve geotropism.

The roots in both the test tubes grow towards the gravitational force and grow away from sunlight thus exhibiting -ve phototropism and +ve geotropism. While roots in test tube B curve and grow towards the gravitational force.