Studies On Changes In Anatomy And Origin Of Calli In Strawberry (Fragaria Ananassa Duch.)Anther Culture

Obtaining haploid plantlet was the initial aim of anther culture. For many crops, haploid plantlets have been induced by this way. But most of the plantlets regenerated in strawberry anther culture were diploid, because most of the callus was induced from anther wall or connective tissue not from microspore. In the experiments, the factors that affect callus production, the changes of anther's morphology and where the callus was origin in in vitro anther culture of strawberry were investigated with three cultivars (Jixin, Siji, Baojiaozaosheng). The results are as follow: (1) Genotype, concentration of growth regulators and Fe-EDTA in media, cold pretreatment before inoculation all affected callus production in strawberry anther culture. The callus-inducing rate of Jixin and Baojiaozaosheng reached to 8 9.02% and 95.4% respectively, which were higher than Siji's. More callus were induced when the proportion of cytokinin and auxin was higher (a -naphthaleneacetic acid combined with kinetin (KT) for Jixin and Baojiaozaosheng, NAA combined with KT and 6-benzylaminopurine (BA) for Siji). Cold pretreatment at 40C for 4 days increased callus production in Jixin and Siji. The highest rate of callus inducing was obtained from the media with basal concentration of Fe-EDTA. No callus was produced when there were no Fe-EDTA in media. (2) Most of the calli were origin from anther wall in our experiments with Jixin. Calli induced from connective tissue were not founded by microscope investigation after 20 days of inoculation. Growth regulators affected callus production of anther wall tissue, higher proportion of NAA and BA inhibited its produce in some degree. Calli were appearing from anther wall from 5 to 20 days after inoculation. (3) Significant changes have be&n occurred in anther's morphology during the course of culture. Most of the cells of middle layer were disintegrated. But the cells of fibrous layer and cutex swelled and became rounded at the stimulation of culture condition. The connective structure also changed greatly during the early stage of in vitro culture, the cell especially the cell of vascular tissue swelled and the connective structure became compacted. But there were no deep changes in connective tissue, except for a few of them disintegrated as culture continued. Only a few microspores swelled and few of them divided when the anthers were incubated for 20 days.