Enraizamento e rustificação in vitro de mandioquinha-salsa (Arracacia xanthorrhiza bancroft)

Abstract

Micropropagation and in vitro cultivation have great potential within plant biotechnology, as they contribute to the improvement of plant cultivation conditions. For mandioquinha-salsa (Arracacia xanthorrhiza Bancroft), which is vegetatively propagated through shoots and seedlings, micropropagation offers suitable characteristics to meet the needs for plant quality and health. Therefore, the objective of this study was to evaluate the performance of in vitro-rooted and acclimatized mandioquinha-salsa seedlings. The parent plants were introduced from explants previously introduced in B5 culture medium and in the third subculture of the ASA cultivar. For the development of this study, mandioquinha-salsa seedlings were introduced into a basal culture medium with saline formulation and B5 vitamins, maintaining full concentration (1 B5) and half concentration (½ B5), with different types of sealing (T1: 1B5 + parafilm; T2: 1B5 + gauze; T3: 1B5 + PVC; T4: ½ B5 + parafilm; T5: ½ B5 + gauze; T6: ½ B5 + PVC). Additionally, they were supplemented with 3% (w/v) sucrose, gelified with 0.7% (w/v) agar, and pH adjusted to 5.8. After four weeks in the growth room, the seedlings were removed from their culture bottles and placed in plastic cups containing substrate + coconut fiber. Thus, in vitro parameters were evaluated, including survival rate, root length, number of roots, plant height, number of shoots, and petiole length. Ex vitro parameters were also assessed, including plant survival percentage (after 30 days in substrate + coconut fiber), plant height, number of leaves, petiole size, as well as root length and number. The parameters were measured using a ruler. The data obtained were subjected to analysis of variance (ANOVA) and multiple mean comparison test using the Tukey test (5%) when assumptions were met; otherwise, a non-parametric analysis was performed using the Kruskal-Wallis test. A cultura medium and sealing that best demonstrated rooting and rustification of mandioquinha-salsa in vitro was the combination of ½B5+PVC for the length of the longest root (4.67 cm), plant height (9.25 cm), and petiole length (4.45 cm). For the number of shoots, the combination of ½B5+para-film was the most effective (2.72). Regarding plant height, length of the longest root, and number of leaves, the best combination found ex vitro was ½B5+PVC with averages of 23.015 cm, 11.90 cm, and 4.50, respectively. For petiole length and number of roots, the best result was the combination 1B5+PVC, with averages of 11.81 cm and 7.85, respectively. Therefore, the use of the PVC sealing method can be highlighted as a more cost-effective and efficient approach for the rooting and rustification of mandioquinha-salsa plants.