Biochemical Status of Stock Plants and Their Annual Sprouts as a Crucial Key for Successful Adventitious Root Formation

Leafy cuttings of Prunus subhirtella Miq. ‘Autumnalis’ were harvested from mature, semi-mature and juvenile stock plants at four dates during the vegetative period 2011 (on 16th of May, on 30th of May, on 20th of June and on 11th of July) and their auxin levels (IAA, IAA-Asp) and sugar content (glucose, sucrose, sorbitol) were quantified. The IAA and IAA-Asp contents in cutting bases increased over the vegetative period, whereby aspartate values were higher than IAA values. The IAA-Asp values ranged from 6.3 µg g-1 to 22.7 µg g-1 FW and reached two great peaks on 30th of May and on 11th of July. The IAA values ranged from 0.29 µg g-1 to 4.51 µg g-1 FW, reaching a small fall on 20th of June. Significantly higher levels of IAA and IAA-Asp were measured at the base of mature cuttings compared to cuttings of semi-mature and juvenile origin, when the cuttings were harvested on 30th of May and on 11th of July. On the other hand, mature leafy cuttings accumulated significantly less fructose and glucose in their root emergence zone (16.3 g kg-1 DW, 45.2 g kg-1 DW) compared to semi-mature cuttings (26.4 g kg-1 DW, 62.5 g kg-1 DW) and juvenile cuttings (27.3 g kg-1 DW, 73.9 g kg-1 DW). All measured rooting parameters (rooting success, number of main roots and root length) were significantly improved when cuttings of a more juvenile origin (semi-mature and juvenile) were used.