液氮保存疫霉属菌种存活期检测

对Phytophthora和Peronophythora所属12个种29株菌在液氮中保存5年零8个月至6年零3个月后检测证明有68.9％的菌种存活下来。但有些种未能存活,这些种有Phytophthora colocasiae(XH30),P.drechsleri(ATCC15428),P.erythroseptica(ATCC36302)与Peronophythora litchii(ATCC 34595)。即使存活的菌种也不一定每个保存的菌株与菌块都存活。说明在液氮中也有存活力下降的现象。除菌种本身耐深冻贮藏特性不同外,贮藏前菌种培养的旺盛程度明显影响存活。对一些菌的致病性测定证明长期保存后致病力维持不变。液氮保藏不失为保持菌种长期不变的良好方法,只是要严格按要求掌握,并对菌的耐冻力先行了解。

DETERMINATION OF THE VIABILITY OF PHYTOPHTHOR CULTURES STORED IN LIQUID NITROGEN

The duration of 29 isolates of 12 species belonging to Phytophthora and Peronophythora stored in liquid nitrogen was tested. Results show that after long-term cryopreservation (68—75 months) about 68.9% isolates remain viable. Some species, such as Phytophthora colorcasiae (XH30), P. drechsleri(ATCC 15428), P. erythroseptica (ATCC 36302) and Peronophythora litchii (ATCC 34595) lose their viability. Even in the survived species, not all isolates or mycelial discs preserved are viable. It implies that decrease of viability may also occur in long-term cryopreservation. In addition to the indigenous difference of viability of fungal species, the prosperity of growth in culture medium before cryopreservation also influences the duration of longivity. The pathogenicity of some isolates was tested and proved to be stable after long-term cryopreservation. Preservation under liquid nitrogen is a good method for long-term preservation with least variation of cultures provided that the requirements of cryopreservation are fulfilled.