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Plantlets were recovered from axillary bud cultures of muscadine grape (Vitis rotundifolia, `Summit'). Nodal segments 0.5 to 1.0 cm long were cultured in Murashige and Skoog (MS) basal medium supplemented with 5, 10, 20, or 40 μm BA. Best total shoot production was obtained with 10 μm BA; with higher BA levels, shoots were unexpanded and exhibited high mortalities. MS medium supplemented with IBA enhanced rooting by increasing rooting percentage and number per plantlet. Shoots previously proliferated on medium with 5 μm BA rooted significantly better than those multiplied on 10 μM BA. Shoot vigor during rooting was greater in shoots proliferated on 5 vs. 10 μm BA. Root development was not significantly affected by liquid vs. agar-solidifted medium or shoot length. Chemical names used: N-(phenylmethyl) -1H-purin-6-amine (BA), 1H-indole-3-butyric acid (IBA).
Abstract
It is increasingly evident that the concentration and type of matrix used in nutrient media can profoundly influence the response of tissues cultured in vitro. Picea abies shoot cultures exhibited increased dry weight yields (4) and increased shoot growth (9) with decreasing agar concentrations. Singha (5) compared shoot proliferation of crabapple and pear in Phytagar concentrations ranging from 0% to 1.2%. Optimal proliferation and growth occurred in crabapple on 0.3% agar, with higher concentrations decreasing these growth characteristics. In pear, increasing agar concentration also decreased shoot growth, but shoot proliferation was greatest at 0.6% or higher agar concentrations. Rooting has been promoted without or with lower agar concentrations in grape (1), Norway spruce (9), and apple (10). However, vitrification (glassiness or waterlogging) has been shown to increase with lower agar concentrations (9) and limits the use of liquid culture in some species.
Abstract
The anatomy of in vitro- and in vivo-developed leaves of sweetgum, Liquidambar styraciflua L., grown under three quantum fluxes (PPF), was evaluated using light and scanning electron microscopy. Leaf characteristics of both in vitro- and in vivo-developed plants were modified by light: high irradiance was associated with more compact mesophyll and larger cells than low irradiance. However, when compared to plants grown in vivo under corresponding irradiance levels, all plants grown in vitro had smaller, thinner leaves and smaller mesophyll cells lacking extensive vacuolar components. Leaves developed in vitro had larger, raised stomata regardless of light level and, except at the highest irradiance, exhibited significantly greater stomatal densities than in vivo-developed leaves.