Question

YES Photosynthesis Lab: Plant Growth and Light Colors Spinach Avg. Height Radish Avg. Height Lettuce Avg. Height Filter Color (cm) (cm) (cm) Red Orange Green Blue Violet Directions: Using the Glencoe virtual lab, use the interface to determine average plant growth under different colors from the light spectrum. Record your data below. Answer the questions below. Make a hypothesis about which color in the visible spectrum causes the most plant growth and which color results in the least plant growth. • How did you test your hypothesis? Which variables did you control in your experiments and which variable did you change in order to compare your growth results? • Analyze the results of your experiment. Did your results support your hypothesis? Explain. • What conclusions can you draw about which color in the visible light spectrum causes the most plant growth? Given that white light contains all colors of the spectrum, what growth results would you expect under white light? 1

Answer 1

ANSWER

A. HYPOTHESIS: Average length of spinach, raddish and lettuce increases in blue light

Spinach, raddish and lettuce are exposed to different wavelenth of the visible light (red, orange, green, blue and voilet). As we all aware that Photosynthesis is important physiologicalpathway of the plants that generate food for them and affect plant growth. it is a light dependent process. Maximum photosynthesis occur when plant recieves low intensity light mainly in blue light and in case of high intensity light (red) the process of photosynthesis is lowered. Hence, the average length of the spinach, raddish and lettuce are obtained when these are exposed to blue light.

B. We will check our hypothesis by keeping these plants under same conditions. These plants can be exposed to different light (wavelenths) at same temperature and atmospheric conditions for the same duration. The avg length will be measured for all plants at the same time. The mangement of photoperiod is very much important in photomorphogenesis experiment. The variables which we use to change during the assessment of photomorphogenesis or for the assessment of avg growth of the spinach, raddish and lettuce plants are the light wavelengths (high intensity to low intensity). We can also design an experiment in whichthese plants are exposed to combinations of lights. White light which is mixture of all wavelenths of visible region can be used as a control.

C. After analysis after certain duration we can observe that the maximum average length is obtained when the plants are exposed to blue light and it substantiate our hypothesis by getting enhanced plant lengths.

D. We conclude that the low intensity color (blue) light very much affected plant growth as it support maximum pgotosynthesis while high light exposure toplants can cause quenching reaction.

E. White light contains all the wavelength of visible light. When plant is exposed to white light it shows intermediate growth lesser that than obtained in blue light and higher than that obtained in red light.