Efeitos do 2.4-D sobre a anatomia do epicótilo, cotilédones e folhas primarias de plântulas de Stizolobium aterrimum Piper et Tracy

Abstract

The effects of the 2,4-D upon tiie anatomy and the morphology of the epicotyl, cotyledon and primary leaves of seedlings of Stizofobium aterrimum Piper et Tracy, were studied under laboratory conditions. On the sixth day after sowing, the seeds were transferred to glass bottles containing distilled water, 0.01; 0.10; 1.00; 10.00 or 100.00 mg/l solutions of the 2,4-D. The seedlings were collected for analyses 15 days after sowing, inhibition in the development of the epicotyl ocurred above the dosage of 0.10 mg/l, with concomitant anatomical alterations of the stern lips when treated with the dosages of 10.00 or 100.00 mg/t. In the middle region, only the dosage of 10.00 mg/l induced anatomical modifications. The herbicide inhibited the development of the epicotyl, in the treatment of 100.00 mg/L The 2,4-D did not alter the size and structure of the cotyledons but inhibited the consumption of reserve material when at the greatest dosages. Above the level of 0.10 mg/l, it began a progressive reduction in Vie development of the primary leaves, which provoked a compaction of the mesophyll.