Influence of the Hybrid Compound La(NO₃)₃@Zn-MOF on the In Vitro Growth of Sugarcane (Saccharum spp. L.)

In agriculture, the use of Porous Coordination Polymers (PCPs), also known as Metal-Organic Frameworks (MOFs), has emerged as a promising area of research for biological applications, particularly as long-lasting delivery systems for biostimulant chemical compounds. The objective of this study was to evaluate the effect of different concentrations of the hybrid compound La(NO₃)₃@Zn-MOF and La(NO₃)₃·6H₂O on the in vitro growth of sugarcane cv. Mex 69-290. To assess the effect on sugarcane (Saccharum spp. L.), plantlets were grown in flasks containing Murashige and Skoog (MS) liquid medium without growth regulators. Each treatment consisted of three independent culture flasks, each containing three sugarcane plantlets, and different concentrations (0, 2.5, 5, 10, and 20 mg L^-1) of La(NO₃)₃@Zn-MOF and La(NO₃)₃·6H₂O were added separately. After 30 days of culture, various growth variables were evaluated, including explant length, number of leaves, number and length of shoots, fresh matter, dry matter, and chlorophyll content (a, b, and total). The 5 mg L^-1 concentration of La(NO₃)₃@Zn-MOF increased the number of shoots and leaves in the sugarcane plantlets, and significant increases in fresh and dry matter were observed, while no statistically significant differences were detected in explant length, shoot length, or chlorophyll a, b, and total chlorophyll. However, inhibitory effects were observed at concentrations of 10 and 20 mg L^-1 of La(NO₃)₃@Zn-MOF and La(NO₃)₃·6H₂O, respectively. In conclusion, the hybrid compound La(NO₃)₃@Zn-MOF exhibited biostimulatory effects on sugarcane growth and physiology under in vitro conditions, whereas high concentrations of the lanthanum(III) salt caused toxicity symptoms in the sugarcane plantlets.