Phytotoxic Effects of Apple of Sodom [Calotropis procera (Aiton) W.T.] Leaves Aqueous Extract on Seed Germination of some Solanaceous Crops Using Probit Analysis

Abstract

Several plants are phytotoxic in nature as they produce and release many chemical compounds into the environment. This study was carried out to investigate the phytotoxic effects of the leaves aqueous extract of Apple of Sodom [Calotropis procera (Aiton) W.T.] on seed germination of sweet paper (Capsicum annuum L.), tomato (Lycopersicon esculentum Mill.), eggplant (Solanum melongena L.) and hot paper (Capsicum frutescens L.) using probit analysis. A laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in 2017. Ten concentrations (2.11, 4.21, 6.34, 8.42, 10.53, 12.63, 14.13, 16.84, 18.94 and 21.05 g/l) of the leaves aqueous extract of apple of Sodom were prepared from the stock solution (50 g / l). A control with sterilized-distilled water was included for comparison. Treatments were arranged in completely randomized design with four replicates. Inhibition of seeds germination was examined at consecutive three days after initial germination. Collected data were transformed using Abbott’s formula and subjected to probit analysis procedure (P  0.5). The leaves aqueous extract of Apple of Sodom inhibited the seed germination of tested solanaceous crops. The results displayed direct positive relationship between concentration (g/l) and inhibition (%). Also, the result revealed that the leaves aqueous extract of Apple of Sodom was more toxic to the seeds of the hot pepper compared to the seeds of the other tested solanaceous crops. There were no differences in inhibition of seed germination among the rest of tested crops. The LC50 for sweet pepper, tomato, eggplant and hot pepper was 14.88, 13.52, 13.46 and 5.35 g/l, respectively. It was concluded that that the leaves aqueous extract of Apple of Sodom had toxic effects to the seeds of the tested solanaceous crops.