REGULATION OF CADAVERINE AND PUTRESCINE LEVELS IN DIFFERENT ORGANS OFCHICKPEA SEED AND SEEDLINGS DURING GERMINATION

In chick-pea (Cicer arietinum L.) seed germinated in the presence of C -14-lysine, the latter is taken up and partly metabolised to cadaverin e and TCA-precipitable molecules. Labelled cadaverine is detectable in seedlings only after 3 days, on a labelled lysine-containing medium, as confirmed also by the presence of lysine decarboxylase (LDC) activi ty, measured in the embryo axis and cotyledons of the seed and in the epicotyl, cotyledons, hypocotyl and roots of the seedling on the basis of (CO2)-C-14 evolution from the labelled precursor. Putrescine biosy nthesis occurred only via arginine decarboxylase (ADC) activity in soa ked seeds and via both ADC and ornithine decarboxylase (ODC) activitie s in seedlings. Both putrescine and cadaverine were present in soaked seed, and accumulated in very large amounts in the different portions of both 3- and 8-day-old seedlings, while spermidine and spermine tite rs were maintained at similar levels with respect to the seed. Diamine oxidase activity, measured by evaluating oxygen consumption in the pr esence of putrescine, was absent in ungerminated seed and appeared in 3- and 8-day-old seedlings. In order to clarify the metabolic relation ships between cadaverine and tile more common polyamines, gradients of biosynthesis, accumulation and degradation of putrescine and cadaveri ne along the seedling axis were compared, indicating that (he two diam ines behave similarly during seed germination and seedling development . Their conspicuous accumulation (up to 6 mM for putrescine) seems to be regulated mainly via oxidation rather than biosynthesis.