Methylamine treatment changes the allocation of carbohydrate to roots in rice plants

Methylamine (MA), an ammonia analogue, has been used to investigate ammonia uptake. This compound competes with ammonia to be taken up and also inhibits the nitrate assimilation pathway. However, the effect of MA on plant growth is unknown. In this paper, we describe the responses of the rice plant to MA. The growth of MA-treated plants was inhibited in the aerial parts and stimulated in the roots. MA-treatment also induced a decrease of starch and hexose in shoots whereas hexose, sucrose and starch contents are increased in MA-treated roots. These results indicate that MA can change the mass allocation of biomass to the roots. The properties of MA suggest that a plant alters its growth via a change in the distribution of carbohydrate in resposes to the nitrogen status.