The effect of cobalt and silver nanoparticles on overcoming leaf abscission and enhanced growth of rose (Rosa hybrida L. ‘Baby Love’) plantlets cultured in vitro

Abstract

Leaf abscission of rose (Rosa hybrida L. ‘Baby Love’) cultured in vitro due to ethylene gas accumulation and enzymatic hydrolytic activity, is one of the abnormal phenomena affecting the shoots quality. In this study, silver nanoparticles (AgNPs) and cobalt nanoparticles (CoNPs) were used to overcome leaves abscission as well as, the effect of shoot mass propagation, rooting and acclimatization at the nursery stage. The results showed that shoots cultured on MS (Murashige and Skoog, in Physiol Plantarum 15(3):473–497, 10.1111/j.1399-3054.1962.tb08052.x, 1962) medium supplemented with 2 mg/L AgNPs gave the highest shoot multiplication coefficient, shoot height, fresh weight, dry weight and chlorophyll index (5.33 shoots; 3.06 cm; 451.00 mg; 58.33 mg; 32.28; respectively) than CoNPs (replace CoCl2 in the MS medium) and basal MS medium. Meanwhile in the rooting stage, MS medium added of 4.65 µg/L CoNPs was the most optimal with dry mass ratio (10.28%), number of roots (5.67 roots), root length (2.17 cm) and SPAD (41.07 nmol/cm2) as well as reduced the ethylene gas content (0.11 ppm) and enzymes activity such as pectinase (0.07 UI/mL) and cellulase (0.25 UI/mL) in comparision to the other treatments after 4 weeks culture. The plantlets derived from in vitro culture on medium added 4.65 µg/L CoNPs gave the highest survival rate (96.67%) as well as growth and development at the nursery stage. Cobalt and silver nanoparticles (CoNPs, AgNPs) were used to overcome leaf abscission, enhance growth and increase the survival rate of plantlets at the nursery stage. CoNPs helps reduce the ethylene gas content, enzymatic hydrolytic activity such as pectinase and cellulase. AgNPs was the most suitable factor for shoots mass propagation.