RNA metabolism in senescing detached betel (Piper betle L.) leaves.

This study aimed to examine the changes in the metabolism of RNA taking place in the detached petiolated betel leaf and to compare them with those occurring in depetiolated/ demidribbed leaves. While RNA level declined continuously, the activity of RNases increased manifold as the leaf senesced. These events were, however, slowed down due to depetiolation/demidribbing treatments. Pulse feeding experiments showed that the ability of the tissue to synthesise RNA declined during senescence. Precursor incorporation in fast senescing petiolated leaves was poorer than in treated slow senescing ones. It is concluded that depetiolation/demidribbing-induced delay in the onset of senescence is accompanied by relatively higher synthesis and lower degradation of RNA.