RELATIVE SENSITIVITY OF CONGRESS GRASS (PARTHENIUM-HYSTEROPHORUS), FINGER MILLET (ELEUSINE-CORACANA) AND WHEAT (TRITICUM-AESTIVUM) SEEDS TOINHIBITORY EFFECT OF DIAMMONIUM PHOSPHATE DURING GERMINATION

Effect of diammonium phosphate on germination of the seeds of congress grass (Parthenium hysterophorus L.). finger miller [Eleusine coracana (L.) Gaertn.] and wheat (Triticum aestivum L. emend. Fiori & Paol.) w as investigated. The sensitivity of the seeds to diammonium phosphate (18% N, 46% P + inert material) during germination was in the order: c ongress grass > finger millet > wheat. The germination of these seeds was completely inhibited by diammonium phosphate (w/v) respectively at 0.25, 2.5 and 5.0% concentrations; and by 50% at 0.1, 2.4 and 4.2%. T he dehydrogenase activity in the seeds of congress grass appeared more sensitive to diammonium phosphate concentration than in those of fing er miller and wheat. A major reason for relative tolerance of the latt er 2 crops to higher concentrations of diammonium phosphate appears to be the retention of higher levels of dehydrogenase activity and thus higher level of mitochondrial functions.