[Studies on the effects of fungi on the course of seed germination of Dendrobium lohohens and Dendrobium candidum].

This paper reports the results of studies on the effects of fungi isolated from the protocorms of Orchidaceae on the course of seed germination of D. lohohens and D. candidum. The experiments revealed that these fungi could promote seed germination: the seed germination rate of D. lohohens was 20%, that of D. candidum was 64%, and that of control was zero. The changes of cell ultrastructure in the course of fungus-infected seed germination of D. candidum was also studied. After hyphae of M. osmundicola penetrate the embryo from the suspensor, organelles of embryonic cells infected with fungi will disappear. When the hyphae wall is thickened and enclosed by the embryo's, the hyphae will be digested and used as the source of nutrition for seed germination. Also, the metabolism of cells without infection, but adjacent to those cells penetrated by hyphae is enhanced.