Photosynthetic Responses of Seedlings of two Indigenous Plants inside Exotic Tree Plantations and adjacent Natural Forest in Munessa–Shashemene Forest, SouthernEthiopia

Abstract

The potential role of exotic tree plantations in facilitating successional processes on degraded areas was evaluated in southern Ethiopia, Munessa-Shashemene forest, by examining photosynthetic responses of Bersamaabyssinica Fres. and Croton macrostachyusDel. seedlings naturally grown inside plantations of Eucalyptussaligna and Pinuspatula and adjacent natural forest. Photosynthetic responses of the seedlings were recorded using modulated photosynthesis yield analyzer, Mini-PAM. Analysis of fluorescence parameters in the leaves showed no significant differences in the level of dark-adapted and light-adapted fluorescence yield (Fv/Fm and ÄF/Fm,, respectively) among seedlings grown inside plantations and adjacent natural forest indicating similar photosynthetic performance. The light response curves of electron transport rate (ETR), light-adapted fluorescence yield (ÄF/Fm,) and non-photochemical quenching (NPQ)showed similar light saturation behavior among the seedlings grown inside plantations and natural forest and suggested a shade-adapted behavior of Bersamaabyssinica as compared to Croton macrostachyus. The results suggest the role of exotic tree plantationsin facilitating restoration processes on degraded areas by improving light conditions for photosynthesis.