Nitric oxide enhances development of lateral roots in tomato (Solanum lycopersicum L.) under elevated carbon dioxide.

ABSTRACT

Elevated carbon dioxide (CO2) has been shown to enhance the growth and development of plants, especially of roots. Amongst them, lateral roots play an important role in nutrient uptake, and thus alleviate the nutrient limitation to plant growth under elevated CO2. This paper examined the mechanism underlying CO2 elevation-induced lateral root formation in tomato. The endogenous nitric oxide (NO) in roots was detected by the specific probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA). We suggest that CO2 elevation-induced NO accumulation was important for lateral root formation. Elevated CO2 significantly increased the activity of nitric oxide synthase in roots, but not nitrate reductase activity. Moreover, the pharmacological evidence showed that nitric oxide synthase rather than nitrate reductase was responsible for CO2 elevation-induced NO accumulation. Elevated CO2 enhanced the activity of nitric oxide synthase and promoted production of NO, which was involved in lateral root formation in tomato under elevated CO2.