Estádio de maturação dos frutos, tratamentos pré-germinativos e variabilidade da emergência de plântulas de morototó (Schefflera morototoni)

Abstract

The objective of this work was to evaluate the influence of the fruit maturation stage in the physical attributes and germination of Schefflera morototoni pyrenes subjected to pre-germination treatments. Fruits with green and purplish green coloration were collected from 14 individuals, pulped in running water, the hollow pyrenes were discarded after counting, together with those presenting retracted and oxidized endosperm, using the uniforms (with the greenish endosperm occupying the whole cavity of the pyrene). The experiment was conducted in completely randomized design in a 2 x 5 factorial (stages of fruit maturation and pre-germination treatments), with four repetitions in plots containing 25 pyrenes. For greater capacity and germination speed of the pyrenes, fruits should be harvested when they present a purplish green coloration, discarding those with hollow pyrenes, with retracted or oxidized endosperm. The germination capacity of the pyrenes with uniform endosperm varied between 50 and 60%, with the beginning of the process at about 40 days after sowing and extending for up to 60 days in vermiculite. Pulped pyrenes, dried and soaked in water at 60ºC for 5 minutes, followed by soaking in water at room temperature for 12 hours begin the germination process in less time, in relation to those pulped, dried, scarified and soaked for 6 hours. The fruit endocarp is permeable and rigid; however, it presents a natural opening when soaked. The objective was to evaluate the variability in seedling emergence measures of Schefflera morototoni from pyrenes of different individuals. Fruits of 14 individuals were pulped and pyrenes with uniform endosperm were selected. The experiment was conducted in completely randomized design with 14 treatments (individuals) and 11 repetitions in parcels containing 50 pyrenes with uniform endosperm treated by immersion in water at 60 ºC for 5 minutes and then soaked at room temperature for 12 hours. The substrate used was a mixture in proportion 2:1:1:1/2 (v/v) soil, commercial substrate Bioplant®, coarse sand and vermicompost, with pyrenes sown at 1 cm depth in expanded polystyrene trays, maintained in a nursery with 50% reduction in luminosity at average temperatures of 19.3ºC minimum and 30.2 ºC maximum and daily irrigation. Daily counting of seedlings evaluated capacity, time, rate, uniformity and synchrony of emergence, besides the distribution of frequency of emergence in relation to time. The emergence of seedlings is slow, irregular and asynchronous, taking more than 80 days for stabilization of the emergence. The percentage of seedlings can reach up to 57%, but even when the endosperm occupies the whole cavity of the pyrene and is greenish, the emergence of seedlings may not occur. There is variability in seedling emergence measurements from pyrenes of different Schefflera morototoni individuals.