Crescimento e acúmulo de nutrientes em curauá Ananas comosus var. erectifolius (L. B. Smith), em casa de vegetação

Abstract

The species Ananas comosus exhibits a range of morphotypes, including curauá, which is utilized for industrial purposes. However, there is limited knowledge regarding the phenological and nutritional characteristics of this species. This study aimed to determine the phenophases, growth patterns, and nutrient accumulation of two types of curauá (Ananas comosus var. erectifolius (L. B. Smith)) in a controlled greenhouse environment. The experiment employed a completely randomized design with a factorial arrangement of 9 x 3, encompassing nine evaluation periods [60, 120, 180, 240, 300, 360, 420, 480, 540 days after transplanting (DAT) the seedlings] and three plant parts (root, stem, and leaves), with four replications. Each plant constituted an experimental unit, cultivated in 12 L pots, resulting in a total of 40 experimental units for each type of curauá. All plants received an identical nutrient dosage. Morphological characteristics were assessed, including plant height, stem diameter, leaf count, leaf area, and nutrient content in each plant part. Three phenophases were identified for both types of curauá: the vegetative phase for white curauá (420 DAT) and purple curauá (480 DAT), the flowering phase for white curauá (420 to 430 DAT) and purple curauá (480 to 490 DAT), and the fruit production phase for white curauá (430 to 540 DAT) and purple curauá (490 to 540 DAT). The plants demonstrated linear growth, with the highest growth rates for white curauá between 300 and 360 DAT and for purple curauá between 360 and 420 DAT. Nutrient accumulation increased progressively, with the highest values recorded for potassium and nitrogen among macronutrients, and iron and manganese among micronutrients in both curauá types. Notably, the greatest nutrient accumulation occurred in the leaves. The growth and nutrient accumulation in both curauá types were correlated with cultivation duration and the productive phenological period, during which there was a marked increase in nutrient accumulation relative to other phenophases. The preferential sequence of nutrient accumulation was K > N > Ca > Mg > S > P > Fe > Mn > B > Zn > Cu for both curauá types at the conclusion of the experiment. Logistic equations proved most suitable for characterizing curauá growth, while the sigmoid equation more accurately represented nutrient accumulation in the plants.