An investigation of the use of exogenous Glycine Betaine and Seaweed Extract to ameliorate drought stress in cutting propagation of Griselinia littoralis and Lavatera x Clementii

Abstract

The exogenous application of Glycine Betaine (GB) and seaweed extract (SWE) has been suggested as a possibly effective approach for improving the drought tolerance of cuttings. The aim of this study were to test the feasibility of GB and GB+SWE helping cuttings fight drought stress during cutting propagation in glasshouses. The research first examined whether exogenous spray application (GB and GB+SWE) alleviates the detrimental effect of drought stress on the root growth of Griselinia littoralis in fertilized and unfertilized potting mix. Then GB and GB+SWE were evaluated in terms of their agronomic values in fighting drought stress during cutting propagation was considered, through the use of a series of experiments. From analyzing the data of all the experiments, the different times when the cuttings were taken, the frequency of the exogenous application and the environmental conditions were investigated to whether they may be factors affecting the cuttings’ growth under drought stress. During cutting propagation, the drought conditions experienced by the cuttings were caused by high temperature and strong sunlight. Experiments showed that GB and GB+SWE can be effective to fight drought stress. The use of GB gave better improvements in cutting growth, compared with the GB and fertilizer in the potting mix together, but these results were opposite to those of GB+SWE in the potting mix while this result was significantly different between cuttings in potting mix and in the soil with three month mix fertilizer. The effects of GB and GB+SWE were various in different treatments and inconclusive because of variations in high temperature, strong sunlight, and types of soil. However, further research is required to investigate ways of using GB and GB+SWE in the most efficient manner, while taking care to eliminate random variables which affect cutting growth.