Adjustment of mineral elements in the culture medium for the micropropagation of three Vriesea Bromeliads from the Brazilian Atlantic Forest: the importance of calcium - Aranda-Peres, Alice Noemí; Martinelli, Adriana Pinheiro; Peres, Lázaro Eustáquio Pereira; Higashi, Edson Namita (HortScience, 2009)