Aclimatização e desenvolvimento ex vitro de abacaxizeiro cv. Pérola

Abstract

In Brazil, cv. Pérola is the most produced among the cultivars, which guarantees the country the 3rd place in world production. To guarantee this production, seedlings from micropropagation are used in commercial crops, as in addition to guaranteeing the standardization of the seedlings, it offers a greater quantity of seedlings in a reduced time. The objective of this work was to evaluate the development of pineapple cv. Pearl in the acclimatization phase from different in vitro conditions on different substrates. The experimental design was completely randomized (DIC), with 5 replications, with a plant in a cup with substrate or soil considered as an experimental unit. The factorial scheme was 2x2+1, with two types of substrate (school farm soil and Quixabá® commercial compost) and the types of cultivation in which the seedlings were previously established in the in vitro phase: the photomixotrophic (10g L-1 sucrose and 30 g L-1 of sucrose) and a conventional one, used as a control. Plants from in vitro photomixotrophic cultivation system showed greater adaptation to the acclimatization phase, which led to more expressive numbers of aerial part height and root dry mass. The Quixabá® substrate provided the plants with a greater capacity to develop the number of leaves and stem diameter, as well as contributing the most to the intensity of the green color of the plants. As for the gas exchange variables, it was observed that the sucrose dosages were determinant for the efficiency of the variables in the pineapple plants, since the plants coming from the system with lower sucrose in the establishment (10 g L-1) showed greater control of stomatal conductance. Pineapple plants cv. Pérola, when coming from photomixotrophic culture systems, present superior development in the acclimatization phase, however, it is the smaller amount of sucrose in the culture media, which determines the better adaptability of the photosynthetic apparatus, thus promoting greater stomatal resistance to gas flows and sweating. Thus, using seedlings from a photomixotrophic system, with a lower dose of sucrose (10 g L-1) in the in vitro phase, in a commercial Quixabá® substrate provides greater development of pineapple cv. Pérola in the acclimatization phase