Bio-stimulatory properties of a Lupinus albus L. seed suspension

[摘要] English: The sustainable increase in crop yields on available land, in light of an ever growing worldpopulation, remains an issue of importance for agronomists and plant physiologists alike. Withthis in mind, the underlying study was aimed at investigating the bio-stimulatory properties ofa Lupinus albus L. seed suspension (SS) as well as its potential to be applied as a natural plantgrowth regulator in the horticultural and agricultural industries. Preliminary bio-tests,including the respiration rate of monoculture yeast cells, seed germination and seedlinggrowth, strongly indicated that the rather crude seed suspension possessed the ability tomanipulate these aspects when applied exogenously. SS significantly increased the respirationrate of monoculture yeast cells and, although it did not have a significant effect on seedgermination, stimulated seedling growth in terms of coleoptile and root length in a number ofcrops at an optimal concentration of 5 mg L-1. Subsequently, the effect of SS on the yields ofa variety of vegetable crops, flowers and cash crops was tested under field conditions at aconcentration of 5 mg L-1. This concentration proved to be optimal for most vegetables,flowers, maize and wheat as either flower formation or yield of different crops weresignificantly enhanced. The most significant yield increases, after a foliar spray treatmentwith SS at an early growth stage, was observed in beetroot, lettuce and carrots under dripirrigation by increasing the yield with 9.3, 20.0 and 24.3 ton ha-1 respectively. This suppliedthe rationale for activity directed isolation and purification of the active bio-stimulatorycompounds involved using standard chromatography techniques. By means of NMRspectroscopy and mass spectrometry the active compound was identified as a triglyceride,glycerol trilinoleate, and its structural formula elucidated. It was concluded from this studythat the development of a natural product with growth regulating and yield enhancingproperties should be considered strongly from a commercial perspective.

[发布机构] University of the Free State