Article: leafless orchid and carbon assimilation

[markr]

Just thought I'd post a link to an interesting (though fairly technical) article on carbon assimilation by Chiloschista usneoides, a leafless orchid species.

Photosynthetic Carbon Assimilation in a Shootless Orchid, Chiloschista usneoides (DON) LDL: A Variant on Crassulacean Acid Metabolism -- Cockburn et al. 77 (1): 83 -- PLANT PHYSIOLOGY

If the conclusions of this article are true, there might be an interesting practical consequence for those of us who grow leafless orchids, such as the Chiloschistas, Microcoelia, or Ghost orchids. Being without leaves, C. usneoides relies on its root for *both* water absorbtion and CO2 absorbtion. It appears that this orchid cannot absorb CO2 through its roots very well when the roots are engorged with water. Although not mentioned by this particular article, that likely applies to other leafless species too. Like many orchids (CAM plants), CO2 absorbtion only occurs at night (in darkness). Perhaps a consequence for growers is that we should be sure that our leafless orchids are dry by night in order to maximize their opportunity to absorb sufficient carbon.

It's a special problem for leafless orchids, and obviously isn't such a concern for regular leafy orchids, since they can absorb CO2 through the leaves while their roots are wet.

Anyway, bored at work today and thought I'd share. I've read one more recent article on this topic with related conclusions, but it's not available online.