Ellen G. Sutter, V. Novello, K. Shackel
Acclimatization remains a problematic area in the production of plants by in vitro methods. Differences in the environmental conditions between the culture environment and in vitro culture impose significant stress on the plants and result in acute water stress, wilting, desiccation, and death if the plants are not properly handled. We have studied several possible factors that might account for the sensitivity of the plants when they are removed from culture. In many plants, particularly those that are glaucous, water loss after removal from culture has been shown to be due to reduced epicuticular wax compared with plants grown in a growth chamber, greenhouse, or the field. Reduced epicuticular wax cannot explain all water loss, however, since some plants such as strawberry and maranta have extensive deposits of epicuticular wax in vitro. Another possible cause of water stress is the inability of stomata to close under reduced relative humidity. We have shown that limited stomatal functioning does occur in cultured plants of apple, cherry, and sweetgum, but it is not sufficient to prevent wilting when the plants are severely stressed. In addition, cuticular transpiration, although low, may contribute significantly to water loss of the transferred plants when they are removed from culture. Loss of integrity of cellular structure may occur under severe stress, leading to rapid and uncontrolled desiccation. After acclimatization, stomatal conductance of all three species decreases significantly. Recent studies on apple shoots grown in vitro indicate that when relative humidity is closely controlled at levels above 90%, stomatal conductance decreases in a predictable manner, indicating that the stomata are functional.
Sutter, Ellen G., Novello, V. and Shackel, K. (1988). PHYSIOLOGICAL AND ANATOMICAL ASPECTS OF WATER STRESS OF CULTURED PLANTS. Acta Hortic. 230, 113-120
DOI: 10.17660/ActaHortic.1988.230.11

Acta Horticulturae