Amygdalin content in four stone fruit species at different developmental stages

The amygdalin content of four species of stone fruit trees (apricot, peach, plum, and bitter apricot trees) during different stages was investigated by thin-layer chromatography. The results showed that the amygdalin content in the kernel was much higher than in pulps, roots, shoots, or leaves, and the highest amygdalin occurred in bitter apricot kernels. The patterns of amygdalin content in leaves of the four species consisted of a single peak curve, which increased from 30 April to 30 July, then started to decline reaching a lower level in October. In shoot and root, amygdalin decreased dramatically from 15 March to 15 May, then increased slightly until 15 December and maintained a relatively stable value. The tendency of amygdalin in xylem of stem and root was similarly a double peak curve, originally increasing from 15 March to 15 May, then decreasing to a low level, after that increasing slightly until December. However, the patterns of amygdalin content in shoots phloem was distinct from that of the xylem. The amygdalin decreased in shoot phloem whereas it increased in the stem xylem during the stage from 15 March to 15 July. The amygdalin content in root phloem and root xylem showed a similar trend with stem. Results demonstrated that amygdalin content in pulps and kernels was increased with the increasing in the leaves; the decrease in amygdalin in the phloem is connected with the increased in the xylem in early growth period.