|
Abstract: It has been reported that in several Hymenomycetes the hyphal bridge is formed after fusion between two monocaryotic hjphae with a minor role of their mating types (Ahmad and Miles, 1970; Smythe, 1973). In the crosses of sexually compatible combination, the exchange of nuclei occurs reciprocally between mycelia through the hyphal bridge followed by cellto- cell migration of introduced nuclei. This nucleus divides repeatedly to leave daughter nuclei in the transverse cells during migration. Thus, the cell having both of acceptor and donor nuclei may develop to form dicaryon with clamp connections in all or some of hyphal septa Thus both parental homocaryons become dicaryotic, respectively. Each component of this "reciprocal dicaryon pair" should have an identical genotype, then identical phenotypic expression to the other. However, phenotypically assymmetric dicaryotization occurred frequently in the reciprocal cross between mycelia from different origins (Kinugawa, unpublished data). This may be due to the controls of different cytoplasms (Fig 1). The present study revealed that even in crosses between homocaryotic mycelia originated from a single fruit-body, there occurred some reciprocal dicaryon pairs exhibiting different phenotypes between components, though they possess identical combination of nuclei and cytoplasms.
Full text download: ISMS subscribers
ISHS members & pay-per-view
Translate:
   |