Question

Would you expect the absorption spectra to look the same for green leaves collected during the summer and red leaves collected in autumn? Explain your answer?

Answer 1

The absorption spectra for green leaves collected during the summer and red leaves collected in autumn will be different. The absorption spectrum of green leaves lies in the blue and red parts of spectrum corresponding to the wavelength of 430-640 nm. Grren leaves absorbs light to manufacture chlorophyll pigment which gives green color to the plants and in autumn leaves these chlorophyll are broken down and are degraded to protect leaves from harsh sunlight before falling down. Anthocyanins present in autumn leaves has a absorption spectrum of blue green wavelengths hence they scatter light in plants making them red in colour. So yes there is difference in their absorption spectrum as well as absorbance of wavelengths by the pigments of both the leaves.Green leaves have a absorption spectrum having 2 peaks while in the autumn leaves it is onlu one near the blue green region. So this why there is difference in each of these leaves.