Abstract

Solid lipid nanoparticles (SLN) are characterized by their biodegradability, low toxicity, and great effectiveness to apply bioactive compounds, potentiating their application in agricultural systems to decrease the use of agrochemicals. The objective was to evaluate the effect of doses of 2-ketones released from SLN on seedling growth in Lactuca sativa and Solanum lycopersicum. SLN-21 was formulated to encapsulate 125, 375, and 500 mg L−1 of 2-nonanone, 2-undecanone, or 2-tridecanone by high shear homogenization followed by ultrasonication. Four-day-old seedlings of L. sativa and S. lycopersicum grown under controlled conditions were exposed to 2-ketones released from SLN-21 for 9 days. SLN-21 had a spherical shape and size from 25 to 50 nm in the solid state. The rheological analysis showed a solid structure of SLN-21 up to 30 °C. Differential release of 2-ketones was evidenced depending on the dose encapsulated in SLN-21. The foliar length of L. sativa was increased by 2-nonanone (500 mg Lc1) and 2-tridecanone (125 mg L−1) (3.14 and 3.02 cm versus 2.53 cm). Similarly, foliar growth of S. lycopersicum was increased by 2-nonanone (350 mg L−1) (5.43 cm versus 4.58 cm). Root length was increased by 2-tridecanone (125 and 375 mg L−1) and 2-nonanone (375 and 500 mg L−1) in L. sativa and S. lycopersicum respectively. It was observed that 2-tridecanone (500 mg L−1) released from SLN-21 increased the number of lateral roots (1.58 versus 0.5) in L. sativa. Furthermore, 375 mg L−1 of 2-undecanone and 2-tridecanone increased lateral root length in S. lycopersicum, while 2-nonanone (375 and 500 mg L−1) and 2-undecanone (125 and 375 mg L−1) increased the number of lateral roots. Interestingly, 2-ketones increased the nitrogen content (~ 8%) in both species. SLN-21 is an effective nanocarrier for the application of 2-ketones to increase L. sativa and S. lycopersicum growth during the seedling stage.