Decrease of the DXR-induced genotoxicity and nongenotoxic effects of Theobroma cacao revealed by micronucleus assay

Regeneration of cocoa (Theobroma cacao L.) via somatic embryogenesis: Key aspects in the in vitro conversion stage and in the ex vitro adaptation of plantlets

Adapting plantlets to ex vitro conditions is a decisive step in the micropropagation process via organogenesis or somatic embryogenesis (ES). The percentage of success in this stage determines the quality of the product, an example of which is found in cocoa plantlets regenerated by ES, which require specific conditions to overcome the stress of the new environment. Considering the quality of the in vitro plantlets largely determines the survival and growth in ex vitro conditions, the effect of two culture media between the embryo maturation stage and the initial stage of conversion to plantlet was evaluated (EM2 - MM6 and EM2 – MF medium), achieving with the latter greater stem height, root length and the number of true leaves. In the final stage of the conversion and growth of the plantlet, the effect of five culture media was evaluated (ENR6, MF, ENR8, EDL, PR), achieving better results in stem height, root length, and the number of true leaves on MF medium. In addition, it was found that the transition of the EM2-MF had a significant development in the presence of the desired pivoting root and fibrous roots. Under nursery conditions, the growth and development of the plantlets was tested through the inoculation of beneficial microorganisms to promote survival. The plantlets that met the minimum morphological parameters for acclimation were planted in a substrate of coconut palm and sand (3:1 v/v) previously selected in the laboratory (BS). The effect of Pseudomonas ACC deaminase (PAACd), Trichoderma asperellum (Ta) and arbuscular mycorrhiza forming fungus (AMF) and different concentrations of phosphorus (PC) (0%, 50% and 100%) in the Hoagland nutrient solution (1:10) was evaluated. First, for CCN5, 62.5% of survival was obtained with PAACd + AMF. Second, the largest leaf size and survival were obtained with PAACd + Ta for CNCh12 and CCN51; likewise, for CNCh13, the best result was obtained with PAACd. Keywords: Cacao, Clonal propagation, Mycorrhiza, Pseudomonas, Trichoderma.

Reproductive Toxicity of Theobroma cacao: Increase in Survival Index, Nongenotoxic, and Proimplantation Potential

Unsweetened natural cocoa (UNCP) was evaluated for reproductive toxicity in rats. A preliminary genotoxic potential was evaluated by the DNA comet assay test using C57Bl/6 mice. Both therapeutic dose (TD; 900 mg/kg) and high dose (HD; 9000 mg/kg) of UNCP were used. White Wistar rats were used in two experimental groups. The females received UNCP 15 days before crossing with untreated males. The males received UNCP for 48 days before mating with untreated females. Subacute toxicity was observed during a 14-day oral administration of UNCP. Results show that a high tail DNA% was observed with methyl mesylate administration in all tissues analysed. The lowest tail DNA% value was observed in the liver (1.64 ± 0.26) and kidney (1.63 ± 0.30) during UNCP (TD) administration. UNCP did not induce observable physical congenital malformations on the pubs of treated female and male rats, lacks genotoxic potential, and did not adversely affect pregnancy index, pub weights, and survival index, but UNCP exhibited proimplantation potential (p > 0.05).