Improved Shoot Organogenesis from Leaves of Grape

Abstract

Adventitious shoots developed within 3 weeks from the petiolar stub and, less often, from wounded lamina tissues when leaves excised from nodal cultures of Vitis vinifera L. cvs. French Colombard and Thompson Seedless were cultured on solid Nitsch and Nitsch medium containing BAP at 2 mg·liter-1. The youngest leaf that could be excised, from 1 to 8 mm long, was the most responsive (90% of explants producing shoots compared to 16% for leaf 6). Removal of the lamina from the petiolar stub within the first 3 weeks of culture reduced shoot production. Increase in nodal culture age, without transfer to fresh medium, had no effect on subsequent regeneration from the youngest leaves but did reduce the regeneration frequency of leaves at the next position from 43% to 20%. In regularly subculture nodal cultures, the number of transfers had no effect on subsequent regeneration. Leaves from recently established shoot tip cultures were more responsive than leaves from nodal cultures. The frequency of shoot production was higher in laterally bisected than intact leaves (70% vs. 43%) due to additional regeneration from the distal leaf half at the sites of severed veins. Shoot outgrowth was promoted by the isolation and subculture of regenerating tissue to fresh regeneration medium. Petiolar stub removal promoted de novo shoot organogenesis from the resulting lamina wound. Shoots rooted at a high frequency on Murashige and Skoog medium with 1 mg IA-A/liter and produced morphologically normal plants. Chemical names used: 6-benzylaminopurine (BAP); indole-3-acetic acid (IAA).