Akira Kuriyama

Micropropagation of Passion fruit from Subcultured Multiple Shoot Primordia

Summary A technique for long-term micropropagation of Passiflora edulis from subcultured multiple shoot primordia is described. Excised tissues from leaves cultured on Murashige and Skoog medium (MS medium) supplemented with 3 % (w/v) sucrose, 1 μmol L -1 6-benzylaminopurine (BA) and 1 μmol L -1 indole-3-butyric acid (IBA) formed multiple shoot primordia. These shoot primordia were transferred to a medium containing 10 μM BA and subcultured repeatedly at 3-week intervals. When subcultured shoot primordia were transferred to a medium containing lower concentrations (0.1 or 1.0 μmol L -1 ) of BA, shoots were formed. Subcultured shoot primordia have continued to regenerate plants for more than 3 years. Shoots developed and rooted on MS medium lacking growth regulators. Rooted plants were transferred to pots and grown in a greenhouse. According to the morphology of leaves of regenerated plants, rejuvenation was obtained by this method of in vitro culture.

Inhibitory Effect of Jasmonic Acid on Gametophytic Growth, Initiation and Development of Sporophytic Shoots in Equisetum arvense

Summary An in vitro culture system of Equisetum arvense L. was used to analyze the effects of jasmonic acid (JA) on gametophytic growth and initiation and development of sporophytic shoots. The growth of gametophytic and sporophytic tissues was inhibited by JA if the culture medium contained permanently this growth regulator; preincubation of these tissues with JA and subsequent cultivation on a JA-free medium were nearly inefficient. JA inhibited effectively the initiation of sporophytic shoots, if applied simultaneously with cytokinin (benzyl adenine), which is absolutely required for this initiation process. The interaction between JA and cytokinin in sporophytic shoot initiation in E. arvense may be an important control for the regulation of this physiological process.

Histological and morphological observation of sporophytic shoot of Equisetum arvense produced from gametophytic cells by exogenously supplied cytokinin.

Summary Histological and morphological analysis were carried out during the sequence of sporophytic shoot formation of Equisetum arvense which was induced by exogenously supplied cytokinin. Internal histological observation revealed that meristemoid from the division of small and cytoplasmic dense cells formed on the marginal or surface part of gametophyte tissue and subsequently developed to a sporophytic shoot bud with an apical cell and leaf primordia. These result suggest that sporophytic shoot is produced by cytokinin apogamously. Using a low-temperature SEM method, we could obtained three-dimensional information during the morphogenesis of an apogamous shoot bud. The single apical cell, which is characteristic of the genus Equisetum , was recognized with high resolution of cellular dynamics by the SEM.

Influence of the Herbicide Oryzalin on the Sporophytic Morphogenesis of Equisetum arvense

Summary Sporophytic shoot primordia are initiated on gametophyte tissue of Equisetum arvense when cultured in a medium supplemented with cytokinin. The initiated shoots can develop on a cytokinin-free medium. Oryzalin, a dinitroaniline herbicide, inhibited the initiation and development of sporophytic shoots. But gametophytic growth with normal morphogenesis was not inhibited by oryzalin. These results suggest that some alteration induced by oryzalin is fatal to sporophytic, but not to gametophytic morphogenesis. Histological features in relation to the inhibition of sporophytic morphogenesis by oryzalin are discussed.