Allelopathic Effect of Calotropis procera Leaves Extract on Seed Germination of Some Plants

The effect of dry leaf water extraction (5, 10, 20, 40 and60%) of calotropis procera decne. plants on the germination ofbarley (hordeum vulgare l.), wheat (triticum aestivum l.),cucumber (cucumis satirus) l., fenugreek (trigonella foenum graecuml.) and alssana (senna occidentalis l. link) was investigated.the results showed that the germination delayed at the higherconcentrations, and the final germination percentage was decreasedby increasing leaf extract concentration. the most affected seeds ofthe tested plants were senna occidentalis seeds, which were inhibitedat the last two treatments (40 and 60%). generally, the radicle andplumule growth was sensitive to different levels of leaf extractionwhereas, the radicle length was decreased by increasing the extractconcentration; it died at the higher concentrations (40 and 60%) foralssana seeds. plumule emergence and growth stimulated by the lowerconcentration (5%) for alssana cucumber and fenugreek morethan control treatment, and then the plumule length decreased withincreasing the concentration in leaf extracted of c. procera plants.introduction