Effects of 2-Chloroethylphosphonic Acid on Growth, Plastid Pigments, and Sucrose Translocation in Radish

Abstract

2-Chloroethylphosphonic acid (CEPA) caused a significant decline in chlorophyll content of radish plant within 5 d of treatment. Such effects were greater when plants were treated at the two- than at the four-leaf stage. In early treated plants, concentration of CEPA increasing from 20 mg/1 progressively increased leaf weight, while decreasing root (radish) weight. A concentration of 10 mg/1, applied at the three-leaf stage, increased leaf and root weights by 27 and 30 per cent respectively in the cultivar ‘Cavalier’. Similar responses were obtained with the cultivar ‘Cherry Belle’. While Cavalier showed a discrete 10 mg/1 optimum, ‘Cherry Belle’ exhibited a range of concentrations (10-40 mg/1) optimal for growth. At relatively high concentrations, early application of CEPA caused inverse changes in sucrose-14C in the leaves and the root, so that decreased retention by leaves was accompanied by increased transport to roots. Low concentrations of CEPA appear promising for growth stimulation in root-crop plants.