What does photosythesis outside leaves look like?
What does photosynthesis outside leaves look like?
Dr. Christos Chondrogiannis is a co-author of two recently published papers on the understudied and less understood non-foliar photosynthesis. Foliar photosynthesis occurs in organs other than leaves, such as stems, fruits, and cortex. The microenvironment where non-foliar photosynthesis occurs may differ significantly from that of leaves due to physiological and anatomical differences between the organs, and its contribution to the total carbon budget of the plant varies greatly.
The first paper on stem photosynthesis, titled “Reduced diffusional limitations in carnation stems facilitate higher photosynthetic rates and reduced photorespiratory losses compared with leaves” was published in Physiologia Plantarum (Link). Stem photosynthesis is an ancient mechanism, as stems were the sole photosynthetic organs in the early land plants. In this paper, the photosynthetic activity of carnation stems was studied compared to leaves. It was shown that the vertically oriented stems can readily attain higher CO2 assimilation rates than leaves, owing to higher CO2 conductance. In contrast, leaves showed photoprotective and water-conserving adaptations that help them cope with the high incident light intensities they naturally experience.
The second paper on fruit photosynthesis, titled “Photosynthetic traits of Quercus coccifera green fruits: A comparison with corresponding leaves during Mediterranean summer” was published in Plants Journal (Link). Fruit photosynthesis occurs in an internal microenvironment seldom encountered by a leaf due to its metabolic and anatomical features. In this study, the anatomical and photosynthetic traits of green fruits of Quercus coccifera L. were assessed during the period of fruit production and compared to their leaf counterparts. It is suggested that during summer, when leaves suffer from high temperatures and drought, acorns could contribute to the overall carbon balance, through the re-assimilation of the CO2 produced from their respiration, thereby reducing the reproductive cost.
Christos Chondrogiannis