Investigating of a wide range of concentrations of multi-walled carbon nanotubes on germination and growth of castor seeds (Ricinus communis L.)

Abstract

Abstract Carbon nanotubes act as regulators of plant germination and growth and are able to change the morphology and physiology of plant cells. The castor plant (Ricinus communis L.) belongs to the Euphorbiaceae family and is a very important medicinal plant. The aim of this study was to investigate the effect of 10 different concentrations of multi-walled carbon nanotubes (MWCNTs) (2, 5, 10, 20, 50, 75, 100, 125, 250 and 500 μg · ml−1) alongside the control under laboratory conditions on the germination and growth of castor seedlings. The results demonstrated that the maximum percentage of germination (96.7%) and relative germination percentage (100%) were found in the concentrations of 50 and 100 μg · ml−1, respectively, and the highest germination rate (53.3%) and the mean germination time (4.6 days) was seen in the concentration of 75 μg · ml−1. However, no statistically significant differences were found between the different concentrations in any of the germination factors. In the concentration of 100 μg · ml−1, there was a significant increase in the seedling vigor index I (400) when compared with the concentrations of 5 and 10 μg · ml−1. The maximum seedling vigor index II (11.3) was found in the concentration of 100 μg · ml−1 and was significantly different from the control and all applied concentrations. The length of radicle in the 100 and 125 μg · ml−1 had a significant increase when compared with the control and the concentrations of 10 and 50 μg · ml−1. The maximum seedling length (4.6 cm) was seen in the concentration of 100 μg · ml−1 where there was a significant increase with 10 μg · ml−1. Moreover, in the 100 μg · ml−1 concentration, the largest number of rootlets (8.6) was seen and when compared with the control and concentrations of 5, 10 and 50 μg · ml−1, there was a statistically significant increase. The maximum wet weight (0.3 g) and dry weight (0.1 g) of seedlings were obtained in the concentration of 100 μg · ml−1 and when compared with the control, there was a significant increase. It was found that in all factors related to the growth of seedlings, the concentrations of 10 and 50 MWCNTs had an inhibitory effect on the response index. The MWCNTs concentration of 100 μg · ml−1 was considered as the optimum concentration in the growth stage of castor seedlings.