Plantlet Formation by Anther Culture of Citrus aurantium L.

Abstract

An anther culture technique was employed in Citrus aurantiuln L.; 'Sour Orange', 'Bouquet', and two varieties grown in Japan, 'Kabusu (Shu-to)' and 'Choshu-to'. Anthers collected from immature flower buds were cultured on the MURASHIGE and SKOOG's (19692) medium supplemented with or without indole-3-acetic acid (IAA) and kinetin at 28°C in darkness. Embryoid formation vvas generally evident 14 weeks after inoculation of anthers of 'Sour Orange' and 'Choshu-to'. Anthers containing pollen grains at the late uninucleate stage formed embryoids effectively on media with 0.02mg/l of kinetin. Nuclear divisions of pollen grains and multinucleate pollen grains were observed in the 'Sour Orange' an-thers, while embryoids from pollen grains were not observed microscopically so far. After the incubation in light with a 16-hour photoperiod, some of these embryoids differentiated into shoots, developing into plantlets, while some of the other embryoids produced more embryoids mainly from the hypocotyl region. Induction of roots and shoots was stimulated by transfer from the embryoid induction media containing growth regulators to a medium eliminated growth regulators. Root tip cells of some of the differentiated plantlets had the diploid chromosome number.