Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Department name when degree awarded

Plant Science

Committee Chair(s)

J. LaMar Anderson


J. LaMar Anderson


Alvin R. Hamson


M. Coburn Wiliams


Using radioautography 14C simazine, 14C EPTC, 14C 2,4-D, 1414 DCPA and 14C pyrazon absorption by seeds of bean (Phaseolus vulgaris L.), squash (Cucurbita maxima), corn (Zea mays), onion (Allium cepa) and oat (Avena sativa) was studied. Simazine, EPTC, 2,4-D and pyrazon were absorbed through the seed coat of bean, squash, corn and onion, the amount increasing with time. Little DCPA was absorbed by seeds of bean, squash, onion and oat. Distribution and translocation of 14C simazine, 14C EPTC and 14C pyrazon occurred in the young plants of bean, squash, corn and onion. Simazine and pyrazon accumulated in the leaf margins of bean, EPTC and pyrazon were found in the cotyledon margins of squash, and pyrazon was found in the coleoptile tips and leaf tips of corn. The translocation of 14C 2,4-D in bean, onion and squash showed a characteristic fixation along the path of the translocation. Very little translocation or distribution of 14C DCPA were found in bean, squash, onion or oat.

In bean leaf, 14C pyrazon was absorbed and moved acropetally in the apoplast. Basipetal movement of 14C pyrazon was limited.

Microadioautography was used to determine the tissues involved in the translocation of 14C simazine, 14C EPTC, 14C 2,4-D and 14C pyrazon. Simazine and EPTC were found in the vascular bundle tissues of bean leaf. EPTC was found in the cortex of squash root. 2,4-D was found in the vascular tissues and surrounding the vascular bundle of squash cotyledon and onion hypocotyl. Pyrazon was found intercellularly and intracellularly in bean cotyledon.