Germinação, desenvolvimento de plântula, variabilidade genética, morfoanatomia e mobilização de reservas em sementes de Jarina (Phytelephas Macrocarpa Ruíz & Pavón)

Abstract

The jarina palm (Phytelephas macrocarpa Ruiz & Pavón), also known as "vegetable ivory", is a naturally occurring palm in western Amazonia and its seeds are used for making buttons, handicrafts and biojoias. Its exploitation is essentially extractive, and to date only a few studies related to the biology and silviculture aspects of it have been carried out. Its seed germination is slow, irregular and sometimes very low. This work has been divided into two chapters. In the first one, the objective was to evaluate the morphophysiological characteristics of the seeds and seedlings from different progenies of jarina to infer about its genetic variation. Seeds of fifteen progenies were used and the degree of moisture, seeds biometric, and aspects of germination and seedling development were evaluated using thirty-one variables. From the twenty four variables that presented significant differences, a grouping study (UPGMA) and principal component analysis (PCA) were carried out. In the second chapter, the objective was to investigate morphoanatomic, histochemical and mobilization of organic reserves (lipids, proteins, starch and soluble sugars) in seeds and seedlings of the jarina palm. The evaluated progenies presented significant differences for twenty four characteristics related to the biometry, germination and development of the seedling, indicating genetic variation between them. Three progenies stood out (P04, P11 and P12) for they highest percentages of germination and the different stages of seedling development, as well as higher speed indexes and shorter times to reach these percentages. From the fifteen progenies of jarina and twenty-four characters related to the morphophysiology of seed, germination and seedling, four distinct genetic groups were found. The jarina palm presented particular morphoanatomic characteristics and differences in the mobilization dynamics of the primary metabolites, with the starch as the major reserve, followed by lipids, proteins and total soluble sugars. Histochemical tests on the haustory and endosperm tissues, with seedlings at different stages, confirmed the presence of primary reserves (starch, lipids and proteins), as well as pectins, mucilages and phenolic compounds.