ABSTRACT
It was recently reported that a novel allelopathic substance, which has potent stimulating activity for the growth of other plant species was isolated from the exudates of germinating cress seeds. The substance was identified and its absolute configuration was determined to be 2-O-[(1 S,2R,3S)-4-deoxy-enopyranosyluronic acid sodium salt]-L-rhamnopyranose (lepidimoide, LM), and the structure-activity relationship of LM was also studied. LM has shown multiple physiological functions for the growth and development of plants. It promotes leaf development, frequency of flowering and seed production, as well as shoot growth in Arabidopsis plants. It inhibits the loss of total chlorophyll (Chl) in excised oat leaf segments during leaf senescence, and delays abscission in bean petiole explants. LM also promotes Chl accumulation by affecting the level of 5-aminolevulinic acid (ALA) in sunflower seedlings. In addition, the free carboxylic acid form of LM 124(lepidimoic acid, LMA) affects glycolytic metabolism in Amaranthus seedlings by affecting the activity of pyrophosphate-dependent phosphofructokinase (PFP) due to increasing levels of fructose 2,6-bisphosphate. These observations suggest that LM and LMA may play the role of a natural hormone-like substance that controls various aspects of physiological growth and development in plants.
