Potencial de inibição da regeneração de raízes e plântulas em sementes germinantes de Eugenia pyriformis

Abstract

Resumo -O objetivo deste trabalho foi avaliar o potencial de inibição da formação de raízes e plântulas, em sementes germinantes de uvaieira (Eugenia pyriformis), fragmentadas e fissuradas. As sementes foram separadas por tamanho em dois grupos. Cada grupo foi separado em dois subgrupos, um dos quais foi submetido a teste de germinação. As sementes de cada subgrupo foram submetidas a dois tipos de incisão (total ou parcial) e, em seguida, foram avaliadas quanto à produção de raízes e plântulas. Em sementes com incisão parcial, que apresentavam apenas uma plântula desenvolvida, completou-se a incisão até que as metades fossem separadas. A metade com a raiz foi descartada, e sua complementar foi colocada para germinar, para avaliação da produção de raízes e plântulas nessas frações sem raízes. Em todos os experimentos, utilizou-se o delineamento inteiramente casualizado, em arranjo fatorial 2x2 (tamanho das sementes x germinação visível) e 2x4 (tamanho das sementes x tipo de incisão). As sementes fracionadas de uvaieira apresentam potencial para regeneração de raízes e plântulas, e podem produzir mais de uma muda por semente. A germinação inicia processos de inibição da regeneração de novas raízes e plântulas na semente, e a incisão dos cotilédones pode bloquear essa inibição.Termos para indexação: fracionamento, inibidores, produção de mudas, regenerabilidade, uvaieira. Potential for regeneration inhibition of roots and seedlings in germinating Eugenia pyriformis seedsAbstract -The objective of this work was to evaluate the potential for inhibiting the formation of new roots and seedlings from germinating seeds of "uvaieira" (Eugenia pyriformis), fragmented and fissured. Seeds were separated by size into two groups. Each group was separated into two subgroups, one of which was subjected to germination test. Seeds of each subgroup were subjected to two types of incision (total or partial) and, then, evaluated as for the production of roots and seedlings. Seeds with partial incision, which had only one developed plantlet, had the incision completed until the halves were separated. The half fragment containing the root was discarded, and its complementary part was placed to germinate, in order to evaluate the production of roots and seedlings in these fractions without the roots. The design in all the experiments was completely randomized, in a 2x2 factorial arrangement (length x seed visible germination) or 2x4 (seed size x incision type). Fragmented seeds of "uvaieira" shows potential for root and seedling regeneration and can produce more than one seedling per seed. Germination starts inhibition processes of formation of new roots and plantlets, and the incision of cotyledons can block this inhibition.

Germination inhibits the growth of new roots and seedlings in Eugenia uniflora and Eugenia brasiliensis

“…Seeds subjected to fractionation (Tables 2 and 3 fractionated) have shown again the potential of the species of the genus Eugenia to form roots and seedlings, even when half of the reserve tissue is removed from these seeds (Silva et al, 2003;Amador and Barbedo, 2011), and even when still unripe (Teixeira and Barbedo, 2012).…”

“…(uvaia) and E. uniflora L. (pitanga). They are species that produce fleshy fruits that are suitable for fresh consumption or for industrialization and usually have few seeds (Delgado and Barbedo, 2007;Amador and Barbedo, 2011). These show a recalcitrant behavior, with different levels of tolerance to desiccation (Delgado and Barbedo, 2007;Delgado and Barbedo, 2012).…”

“…Also, there is obvious interest in understanding the factors involved in this regenerative capacity that allows the formation of new seedlings when fractionated; Eugenia embryo anatomy, for example, has been studied (Justo et al, 2007;Delgado et al, 2010). Interestingly, however, the formation of new roots and seedlings rarely occurs spontaneously: some kind of injury apparently is necessary for them to be formed (Silva et al, 2005;Amador and Barbedo, 2011).…”

“…However, in the seed complementary fraction, seedlings were formed on the cut surface, which shows some polarity in mobilizing hormones. This may also be related to the fact that only after spliting the halves a second seedling can be regenerated, as shown in seeds of E. pyriformis (Amador and Barbedo, 2011). It is possible, therefore, that once initiated the germination, the seed produce substances that are inhibitory to the differentiation of new embryonic tissues by the migration of such substances from the germinating area to the others.…”

Tratamentos osmóticos e térmicos para controle de fungos em sementes de grumixameira (Eugenia brasiliensis Lam.) e pitangueira (Eugenia uniflora L.)

“…Além de potencialidades de uso alimentício e farmacêutico, espécies do gênero Eugenia (Myrtaceae) foram recentemente incluídas na cadeia de produção de cosméticos (Schmeda-Hirschmann et al 1987, Delgado et al 2010, Amador & Barbedo 2011, Delgado & Barbedo 2012. Contudo, o cultivo em larga escala dessas espécies depende do melhor conhecimento de diversos fatores, dentre os quais a conservação da viabilidade de suas sementes em armazenamento figura entre os principais.…”