Cold-induced dwarfism

An increase in the rate of exocytosis has been put forth as one hypothesis to explain how plants maintain their growth rate in cold weather, in work from Jian Hua (now at Cornell University, New York, NY), Gerald Fink (Whitehead Institute, Cambridge, MA) and colleagues. They base their suspicion on a plant mutant that is a midget only in the cold.The mutant, bonzai1 (bon1), was isolated by Hua. “In the beginning I was just looking for something that would affect cell division and expansion,” she says. But she ended up with bon1, which at 2°C is almost normal but at 22°C is a real shrimp, with epidermal cells and stems that are seven and eight times shorter than normal, respectively. The mutant also has fewer cells when grown in the cold, although...