Silva et al. 2015 (Conference Paper) Ananas

Growth and carbohydrate content of the bromeliad Ananas comosus var. ananassoides cultivated in different N concentrations

Author(s):—P. Silva P., V. Carvalho, C. Carvalho, M.R. Braga, M. Gaspar & V. Tamaki in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—Ananas comosus var. ananassoides (Baker) Coppens & F. Leal is a terricolous bromeliad with high ornamental value. It is endemic to the Cerrado biome, which has soil with low nutrient content. Despite being tolerant to such conditions, studies have shown that this bromeliad has optimum growth when cultured in vitro in nutrient medium containing sucrose and high nitrogen concentrations. It is known that carbohydrate metabolism in plants is influenced by the amount of nitrogen available in the nutrient medium. Indeed, the carbon/nitrogen ratio is determinant for plant growth. The aim of this study was to evaluate the growth and content of soluble carbohydrates and starch in A. comosus var. ananassoides plants cultured in vitro at different concentrations of nitrogen. Seeds were grown on Murashige and Skoog (MS) with 50% of the original macronutrient composition for two months in culture room at 26 °C, 12 h photoperiod and PAR of 30 µmol. m-2 .s-1. The obtained plants had the leaves cut 1 cm above the stem base, followed by transfer to fresh MS media with nitrogen concentrations of 15 (T1), 30 (T2) and 60 mM (T3). Plants were kept in the dark for 3 months to induce etiolation. Nodal segments were isolated and placed in MS media containing the respective nitrogen concentrations of each treatment (T1, T2 and T3), then kept for 11 months in the culture room. The limited availability of nitrogen led to lower growth in T1 and T2 plants in comparison with T3 plants. Leaves in T3 were longer, although root growth did not differ among treatments. Total carbohydrate content in T1 plants was 5 and 9 times greater than T2 and T3 plants, respectively. Therefore, nitrogen shortage led to reduced shoot growth and high content of soluble sugars in leaves, although it did not influence the root system. In contrast, the starch content increased in plants under higher nitrogen concentrations (T2 and T3). It was concluded that nitrogen deficiency affected the metabolism of carbohydrates reserve in leaves of A. comosus var. ananassoides, favoring the accumulation of soluble sugars to the detriment of starch.

Keywords:—Bromeliaceae; Micropropagation; In vitro.