A MATHEMATICAL-MODEL TO PREDICT THE TISSUE-RESPONSE TO PARTHENIN - ANALLELOCHEMICAL

Parthenin - a sesquiterpene lactone from Parthenium hysterophorus L. i s an allelochemical that prevents the germination of Phaseolus aureus Roxb cv. ML-5 seeds. The response of the seed has been attributed to t he inhibition of the respiratory electron transport ability of its emb ryo. It has been shown to depend directly not only upon concentration of parthenin, but simultaneously on the duration of exposure of the se eds to the chemical as well. A strong correlation exists between the q uantum of the response and the product of the period of exposure and t he concentration of parthenin. In order to predict the maximum possibl e germination ability of the seed exposed for a given period to a give n concentration of parthenin, an expression X = 10 000 Y3/[e(Y/0.31-1) ] was formulated from the equation X = AY3/[e(Y/Y0-1)], where X repres ents values of maximum respiratory activity, Y represents the product of concentration and time in units mg cm-3 h, A represents a dimension al constant. The trend and nature of response that is calculated on th e basis of formulation coincides with that of measured response throug h spectrophotometry.