Translocation of 2,4‐D, asulam and amitrole in water hyacinth

Abstract

Summary:In glasshouse experiments foliar application or 14C‐labelled herbicides to water hyacinth plants at the 4‐leaf stage indicated that amilroie transport from the treated leaf blade was faster and greater than 2.4‐D. but a little less than asulam. From the treated leaf 14·2, 25·9. 39·7. 44·5 and 51·8% of the recovered 14CNamitrole was translocated at intervals of 6 h. and 1. 3. 6 and 12 day., respectively. Both xylem and phloem transport of asulam and amitrole was evident, whereas 2.4‐D moved only from ‘source to sink’.Movement of the herbicides from the mother to the connected daughter plant or vice versa was dependent upon the size of the latter. Maximum transport of these herbicides in either direction took place at the 2‐leaf stage of daughter plants. With any increase or decrease in the number of leaves on daughter plants, the transport of herbicides was reduced. As an exception, daughter plant to mother plant movement of amilroie was maximum at the 1‐leaf stage.After extraction, fractionation and TLC separation of foliage applied 14C‐2.4‐D 76–4 and 72·1% of the radioactivity was detected in the chloroform phase of the leaf extract at 3 and 6 day intervals, respectively.In another pot culture experiment, it was observed that after spraying the mother plants with 2.4‐D‐amine at 0–75 kg/ha the connected daughter plants at 1 to 4‐leaf stages werckilled if the culture solution was contaminated while spraying, or by dying leaves. When contamination was totally avoided, the connected but unsprayed daughter plants at 3 to 4‐feaf stages survived.