Red foliage is often associated with autumn. Yet the same pigments, anthocyanin, which makes for spectacular leaf peeping in autumn is also present during spring, although short lived and more subtle.
However, although still debated, it’s two primary functions are the same during both seasons, mainly photo-inhibition and a visual deterrent for herbivores. The colour red seems to repel aphids and at the same time it absorbs excessive incoming light which might damage the fragile photosynthetic machinery of a young leaf. As the leaves mature they lose their red tint as more chlorophyll starts to make up the bulk of the leaf pigments. This is what is illustrated in the attached image series. More interesting literature on the topic is listed below.
Some suggested reads on the topic:
- Hoch, W. a, Singsaas, E. L. & McCown, B. H. Resorption protection. Anthocyanins facilitate nutrient recovery in autumn by shielding leaves from potentially damaging light levels. Plant Physiol. 133, 1296–1305 (2003).
- Lee, D. W., O’Keefe, J., Holbrook, N. M. & Feild, T. S. Pigment dynamics and autumn leaf senescence in a New England deciduous forest, eastern USA. Ecol. Res. 18, 677–694 (2003).
- Lev-Yadun, S. & Holopainen, J. K. Why red-dominated autumn leaves in America and yellow-dominated autumn leaves in Northern Europe? New Phytol. 183, 506–512 (2009).
- Schaberg, P. G., Murakami, P. F., Turner, M. R., Heitz, H. K. & Hawley, G. J. Association of red coloration with senescence of sugar maple leaves in autumn. Trees - Struct. Funct. 22, 573–578 (2008).
- Archetti, M. et al. Unravelling the evolution of autumn colours: an interdisciplinary approach. Trends Ecol. Evol. 24, 166–173 (2009).