Morphological and Histological Effects of Sethoxydim on Corn (Zea mays) Seedlings

Abstract

The herbicidal action of sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} on corn (Zea maysL. ‘Goldencrossbantam’) was investigated in preemergence and postemergence experiments and hydroponic culture. Soil-applied sethoxydim did not inhibit corn germination. Leaves failed to emerge through the coleoptile with a high herbicide rate (1.6 kg ai/ha), but chlorotic leaves emerged at a lower rate (0.8 kg ai/ha). Growth of corn seedlings treated with a foliar application of 0.2 kg ai/ha was inhibited within 1 day after treatment, but at a lower application rate (0.05 kg ai/ha) growth continued with chlorotic zones on newly expanding leaves. Over the concentration range 3 × 10-5to 1 × 10-6M, sethoxydim inhibited the growth of primary roots of corn in hydroponic culture within 24 h. Cytological investigation showed that sethoxydim inhibited cell division but did not interfere with mitosis.