CARACTERIZAÇÃO MORFOLÓGICA DE SEMENTES E FRUTOS E ESTUDOS DA GERMINAÇÃO DA ESPÉCIE Ziziphus joazeiro Mart (Rhamnaceae)

Abstract

The Ziziphus joazeiro Mart. is an endemic species from the caatinga which belongs to the Rhamnaceae family. Among the Brazilian species of the blind, it is the most known for its economical and medicinal potential, especially in the semi-arid regions of the Brazilian Northeast, where there is enormous distribution in all the states of the this region. Although it produces big quantities of the feasible seeds every year, it is known a little by its germinative process and its seeds behaviour during the storage. The aims of this work consists of determining the morphological characteristics of the fruit and seeds and chemical characteristics of the fruit; defining a simple and efficient methodology to accelerate and uniform the germination; testing different ways of storage, aiming to establish criterions to keep the germinative power of the seeds for a long time and identify the substrate which fits better to the development of the seedling. To the morphological characterization were determinated the length, width, weight and the external and internal morphology of the fruit, pits and seeds. It was still analized the kind of the germination and the external morphology of the seedling. The initial viability of the seeds was calculated through the tetrazolium test. For the germination and the storage test, the experiments es the seeds, making a barrier to the development of the seedling. The chemical scarification with sulfhuric acid for 20 and 30 minutes showed itself efficient to shorten and uniform the germination, due to the wear that happened in the endocarp, becoming it more permeable by water and becoming easier the development of the radicle. The mechanic scarification with sandpaper showed efficient as well, speaking about reducing the necessary time to finish the germinative process, this result comes from the overcoming of the endocarp hardness created by the scarification. Although the application of the Gibberellic acid hadn t helped to the increasing of the germination porcentage and Speed Germination index, the usage of that purposed the increasing of the seedling vigor since we could see the increasing of the aerial part and the length of roots. The work of the storage showed that the germination capacity of the species wasn t affected by the time. Considering the different blinds of the storage, it noted that the storage in natural conditions and in silica-gel were more efficient to accelerate the germination. The analysis of the substrates showed that the mixture vegetal soil + vermiculite showed itself more efficient in all the ways tested when compared with the other treatments.