EFFECTS OF DESICCATION ON EXCISED EMBRYONIC AXES OF 3 RECALCITRANT SEEDS AND STUDIES ON CRYOPRESERVATION

The drying of excised embryonic axes of lychee (Litchi chinensis Sonn. ), longan (Euphoria longan Lour.) and jackfruit (Artocarpus heterophyl lus Lam.) seeds was investigated. The effect of different drying metho ds on survival and growth of embryonic axes are somewhat different. By use of the silica gel and aseptic air current method, the moisture co ntents of axes of jackfruit seeds were reduced to a lower safe level a nd critical moisture content (16% and 26%) than that achieved by the v acuum method. There was no significant difference between the two diff erent levels of air pressure (760 and 140 mm Hg/cm2) , during silica g el dehydration in the survival of excised axes of longan and lychee se eds. Excised embryonic axes of longan seeds can be dried down to a rel atively low moisture content (13%) for maintaining viability, lower th an that for lychee seeds. Only embryonic axes of longan seeds with moi sture content of 18% can survive after 24 h storage in liquid nitrogen .