Growth and Development of Resting Buds of Conifers InVitro

Publisher Website
Google Scholar
Abstract
Resting, vegetative buds of white spruce, black spruce, Norway spruce, balsam fir, and Douglas-fir were grown under aseptic conditions on agar with various supplements. While an inorganic source of nitrogen was sufficient for the rapid growth of buds, the addition of organic nitrogen to the medium consistently promoted growth, but changes in weight and axis length were not always significant. For white spruce, all levels of growth regulators inhibited bud development. Coconut milk supported organized growth. Malt extract and casein hydrolysate were not beneficial. Levels of sugar above 2% (w/v) greatly improved the weight and length of the emerging shoot.The extent of shoot formation depended on the portion of dormant bud which was used as starting material. Buds isolated with an attached crown and intact embryonic shoot grew faster than those excised above this nodal diaphragm. By 40 days, the fresh weight of isolated buds increased 15–20 times, and their axes elongated 5–6 fold. Needles of some species (Douglas-fir) were well-developed. Changes in the free amino acids of developing white spruce shoots in culture corresponded in kind, and sequence to changes found during late winter, and spring in growing buds on trees under field conditions. Initially, buds contained low levels of total soluble N, and high percentages of proline N. Subsequently both invitro and in the field, the total soluble N increased and the content of proline N decreased. Amides now dominated the composition of the soluble N. Reduced growth and axis length usually reflected high percentages of arginine N and increased scale development in a way that resembled bud formation during late summer under field conditions.

This publication has 0 references indexed in Scilit: