Developmental changes in Sitka spruce as indices of physiological age: II. Rooting of cuttings and callusing of needle explants.

摘要: SUMMARY the lowest whorls of 3- and 4-year-old trees. Needles were sampled for measurement length, width, length/width ratio, projected total surface areas, dry weight specific leaf area. For explants uppermost whorl origin, there decreases in rooting ability cuttings callusing response needles with increasing age tree. Associated loss was an increase production a black exudate. The changes rooiing, exudation could each be adequately described by Gompertz growth function which showed their rates change to similar. observed are closely associated needle area, Euclidean distances (using mean values selected characteristics class) computed as measure physiological age. shoots basal more juvenile character than those taken from same