This is a queary of mine and I am wondering if anyone has info. on subject. While watching plants grow, there are many effects shown on the leaves. With my Rhodo's. The leaves in winter months will close or role. I understand it to prevent desiccation. Rolling to expose less of leaf surface to cold. I have noticed on my Brugmansia's in summer that the leaves are horizontal, but at dusk the leaves will stand up vertically, in a "v" shape. Is this to conserve moisture? Do the leaves stay horizontal when light levels are low, to take in as much sunlight as possible? Do they go vertical when light levels are intense? Leaves will drop to save water in summers months in now. I realize these questions may be trivial, but are things I have thought about and sought out the reasons. Your insight is welcomed. CR
Hi, It is fascinating how the leaf is the vital organ for capturing energy and for regulating the metabolism of the plant. Amongst the very extensive list of study material I've been through I found excellent basic information about the structure and function of the elements of plants, the leaf in particular, in the following book: Botany: An introduction to plant biology 3rd Ed. by Mauseth, James D. Year/Format: 2003, Book, xvii, 848, [42] p. : It is well written and very well illustrated.
When a plant gets a lot of sunlight (in the summer time) they go through the light cycle quite a bit. When there is two much oxygen from the oxidation of water in the light cycle, it inhibits Rubisco in the calvin cycle. Therefore the plant does not need any more sun. That's why you'll find you're Brugmansia stands up at dusk, it has collected all the sunlight it needs and then some.
