| Abstrakt: |
During an extended screening program of plant extracts for bio-stimulatory activity, a seed suspension (SS) of Lupinus albusL. cv. Betsuhana White was identified as most promising. By testing a concentration range of SS using three in vitrobio-assays [i.e. respiration rate of monoculture yeast (Saccharomyces cerevisiae) cells, germination rate of seeds from selected crops, and subsequent seedling growth], 5mg/L was identified as the optimal concentration in terms of in vitrobio-stimulatory activity. A commercially available bio-stimulant, ComCat®, was used as a positive control, while a glucose solution for respiration tests and distilled water for germination tests served as negative controls. Compared with the controls, significant (P<0.05) increases in the respiration rate of monoculture yeast cells and seedling root growth in the majority of test crops after treatment with SS confirmed its in vitrobio-stimulatory potential. Seedling root growth compared favourably with results obtained with the commercial bio-stimulant. Subsequently, the in vivoyield response of selected crops to foliar treatment with SS was investigated under field conditions using ComCat®as a positive control. All trials were laid out in a complete randomised block design. Foliar applications of SS at 5mg/L under a drip irrigation system contributed to significant (P<0.05) yield increases in lettuce (by 20.0t/ha) and carrots (by 22.2t/ha), which compared favourably with the positive control, but not in beetroot and cabbage. Beetroot yield was enhanced whereas cabbage yield was decreased markedly, but not significantly, by the SS treatment, compared with the negative control. The results confirmed both the in vitroand in vivobio-stimulatory potential of a seed suspension of L. albuscv. Betsuhana White in terms of its ability to manipulate early seedling growth and enhance the yield of selected vegetable crops. |
