Environment Influences Anatomy of Stomata and Epidermal Cells in Tissue-cultured Rosa multiflora

The surface structure of rose (Rosa multiflora L. cv . Montse) leaves formed in vitro under several environmental conditions (light level, relative humidity) and with various growth regulator treatments was studied by light and scanning electron microscopy. The epidermis from leaves developed in cultures grown under a higher light level and a lower relative humidity (80 μmol·s -1 ·m -2 and 75% RH) than the conditions used in commercial laboratories (25 μmol·s -1 ·m -2 and 100% RH) showed anatomical modifications of the epicuticular wax, stomata, and epidermal cells similar to that of greenhouse-grown plant leaves. These results indicate that cultured plantlets can resemble greenhouse-grown plants under modified environmental conditions. In vitro pretreatment will reduce transplant losses and shorten the acclimatization period in the greenhouse.