ARE FACTORS INFLUENCING ADVENTITIOUS BUD FORMATION IN LILIUM SCALE EXPLANTS WORKING ON ONE BIOCHEMICAL PROCESS?

Adventitious bud formation in bulb-scale explants of Lilium speciosum Thunb. is influenced by, e.g. exogenous NAA and TIBA, temperature and wounding. The number of adventitious buds formed per scale explant is linearly correlated with the culture temperature in the range 15–25°C. The effects of wounding and NAA on the mean number of buds are additional to the observed effect of the culture temperature. The regression lines obtained from these experiments intersect the abscissa roughly at 3°C, indicating that wounding, NAA and temperature influence a single biochemical process, that is inactive below 3°C. Because ethylene biosynthesis is known to be influenced by these factors the production of ethylene by cultured scale explants was investigated in relation to adventitioys bud formation. During the first days of culture the ethylene production is negatively correlated with the ethane production. The slope of these ethylene-ethane regression lines is highly correlated with the number of adventitious buds formed per scale explant. Our interpretation of these results is that the number of adventitious plantlets is related to the speed of recovery, marked by ethylene production, from initial membrane damage, marked by ethane production. Because ethylene production is dependent on calcium we think that the internal calcium concentration may controll the recovery process. To investigate this hypothesis we started experiments, in which we observe the effect of substances that influence the intracellular calcium concentration on ethylene production in correlation with plantlet regeneration on bulb-scale explants, in order to see wether these substances mimic the observed effects of NAA and wounding.