Evidência da atuação do sistema de auto-incompatibilidade tardia em Acca Sellowiana (berg) burret. (Myrtaceae)

Abstract

RESUMO-Acca sellowiana (Myrtaceae) é uma frutífera nativa da região Sul do Brasil e nordeste do Uruguai, que vem despertando grande interesse devido ao alto potencial organoléptico de seus frutos. Neste trabalho, teve-se como objetivo a caracterização do tipo de sistema de incompatibilidade atuante em A. sellowiana, através da avaliação do desenvolvimento dos tubos polínicos. Utilizaramse dois acessos: 458, sendo autocompatível, e 101, auto-incompatível. A maior porcentagem de germinação de grãos de pólen foi observada no acesso 101, com 68,8% de grãos de pólen germinados. Não foram observadas diferenças no crescimento dos tubos polínicos em pistilos autopolinizados ou de polinização cruzada, em ambos os acessos. O crescimento completo do tubo polínico até o ovário ocorreu em pistilos coletados 96 horas após a polinização, independentemente do tratamento aplicado. Sugere-se a ocorrência de auto-esterilidade ou auto-incompatibilidade tardia ou pós-zigótica, considerando que o abortamento dos frutos de A. sellowiana é uniforme e ocorre num prazo curto, por volta de 20 a 30 dias após a fertilização das flores. Termos para indexação: sistema reprodutivo, auto-incompatibilidade, polinização, fluorescência. EVIDENCE OF THE LATE-ACTING SELF-INCOMPATIBILITY SYSTEM IN ACCA SELLOWIANA (BERG) BURRET. (MYRTACEAE)ABSTRACT -Acca sellowiana (Myrtaceae) is a native fruit species from the South Brazil and northeast Uruguay which is attracting great interest due to the high organoleptic potential of its fruits. In this study we aimed to characterize the type of incompatibility system which occurs in A. sellowiana, through the evaluation of the polinic tube development. Two accesses were used: being 458 self-compatible and 101 self-incompatible. The highest percentage of pollen grains germination, 68,8%, was observed in the access 101. It was not observed differences in the growth of the polinic tubes between self-pollinated pistils and cross-pollinated ones in both accesses. The complete growth of the polinic tube until reaching the ovary occurred only in pistils collected 96 hours after the polinization, independent of the treatment. The data suggests the occurrence of self-sterility, or a delayed or post-zygotic selfincompatibility in the species, considering that the abortion of A. sellowiana fruits is uniform and occurs in a short period of time, around 20 to 30 days, after the fertilization of the flowers.

Reproductive Biology and Flowering of Feijoa (Acca sellowiana (Berg) Burret) in Areas of Marginal Occurrence

“…In areas where the species naturally occurs, pollen germination has been observed, by several studies, to always be greater than 69% (Franzon et al, 2005;Santos et al, 2007), although a wide variation of pollen germination was observed in the review conducted by Ramírez and Kallarackal (2017). In the present study, the low pollen germination (Table 1) may be evidence that the climatic conditions of the regions (Pato Branco and Dois Vizinhos) are not adequate for the studied genotypes.…”

Genetic parameters of pollen viability in guava (Psidium guajava L.)

“…Knowledge about pollen viability is important for taxonomy, ecology and palynology, providing information on the reproductive biology and conservation of the species (Alexander, 1980;Souza et al, 2002;Usman et al, 2013). It is also critical in genetic breeding, in the routine use of artificial pollination (Nascimento et al, 2003;Munhoz et al, 2008); in pollen monitoring during storage; in evaluation of pollen germination after exposure to stresses; in analyses of dispersion and gene flow; and in studies of genetics and pollen-stigma interactions, incompatibility and fertility (Santos et al, 2007;Bauermann et al, 2009;Almeida et al, 2011;Soares et al, 2011;Cuchiara et al, 2012 ).…”