Effect of Various Concentrations of 2,4-D and 2,4,5-T on Seed Germination, Dry Matter Yield and Transpiration Rate of Some Economic Plants

The role played by the two applied herbicidal auxins, namely; 2,4-D and 2,4,5-T, when supplied in various concentration on germination, radicle and plumule lengths, dry matter and transpiration of Zea mays, Helianthus annuus, and Vicia faba were studied. The two herbicidal auxins were significantly effective in producing inhibition of germination, radicle and plumule lengths, dry matter and transpiration of the tested plants when supplied in high concentrations (10-4 and 10-3 M). However, no inhibitory effect on the germination of the treated seeds was displayed in the presence of 10-7M. Moreover a significant stimulatory effect on radicle and plumule growth of sunflower and bean germinating seeds was displayed at 10-7 M of any of the two compounds used. At low concentrations the transpiration rate values either approached that of the control or increased it.