Introduction to the Symposium

Abstract

Abstract The influence of the stock plant (mother plant, donor plant) has long been known to exert a profound effect on subsequent propagation capability of its propagules. Both treatments applied to the stock plant and the environment under which the stock plant is grown have a strong influence on subsequent propagation. These effects may include an increase in size or number of cuttings and improved root regeneration by cuttings taken from such stock plants. Nutrition, light, temperature, genotype, plant growth regulator applications, physical manipulations, and season of the year have all been reported to influence macropropagation efforts. Similarly, the influence of these same factors often has been reported to have a strong effect on the performance of propagated explants taken from stock plants so treated. From the early work of Kraus and Kraybill (18) in 1918, we can see that the carbohydrate: nitrogen ratio was shown to be an important factor in the rooting of tomato cuttings. Micronutrition of stock plants also has been given some attention, as exemplified by the work of Weiser and Blaney (25). Dhillon (5) also has pointed out that nutrient effects often are modified by light. Reduced light intensity has been reported to enhance the rooting of dahlia, forsythia, and weigelia (3, 19). Etiolation, or extreme light reduction, frequently has been reported to also improve rooting (9. 17). Other authors have reported that reduced stock plant light intensities can lead to better rooting of the cuttings of several species (1, 11, 21). Increases in endogenous auxin level generally are believed to occur under reduced light, thus enhancing rooting (20). Whally (26) has reviewed literature on photoperiod effects on rooting of numerous ornamental species. Keeping stock plants in a vegetative condition by the use of night interruption or day extension has enabled researchers to provide a continuous supply of cuttings (14, 15, 24). Bachelard and Stowe (2) and von Hentig (16) have reported direct effects of stock plant photoperiod on the rooting of cuttings.