Probably not. Plants have a relatively small "sweet spot", and greenhouses try quite hard to prevent overheating. The glass panes can be raised to let hot air e

Probably not. Plants have a relatively small "sweet spot", and greenhouses try quite hard to prevent overheating. The glass panes can be raised to let hot air escape, and they'll even have blinds. 25C (77F) is about ideal, with 20-30C (68-86F) being somewhat acceptable before seeing a huge reduction in crop yield. Higher temperatures will also significantly increase water consumption. Temperature in a solar updraft tower is about 20-30C above ambient. That pretty much immediately rules out dual use in all but the coldest environments.