EVALUATION OF ALLELOPATHY IN CROTALARIA BY USING A SEED PACK GROWTH POUCH

Allelopathic effect of aqueous extracts of six Crotalania species on w heat root growth at early growing stage was examined by using a seed p ack growth pouch. There was a significant difference in total root len gth of wheat with application of the extract of each species compared with control at 21 days after planting. C. juncea and C. pallida suppr essed the length by approximately 40% based on the control. Remarkable suppression of root growth could be clarified by image-processing of the root system which appeared on the surface of the pouch. A signific ant reduction in the length of the longest root was also observed, and C. juncea and C. spectabilis showed severe reduction. Definite inhibi tion was observed with the leaf extract compared with the stem extract in C. spertabilis, and the inhibition was remarkable as the concentra tion of the extracts increased. Dry weights of both top and root of wh eat were not influenced by application of C. brevidens, C. juncea, C. lanceolata and C. pallida. With application of C. spectabilis, however , top dry weight was restricted to a low value compared with the contr ol. Fractal dimension of the profile of root system ranged in value fr om 1.27 to 1.35, and it was not necessarily influenced by the applicat ion of extract of each species. These results indicated that wheat roo t growth was inhibited by application of the aqueous extract of Crotal atia, and the seed pack growth pouch techique might be applied to the evaluation of allelopathy.