Germinação das sementes e análise citogenética em duas espécies de palmeiras

Abstract

Germination of the seeds and cytogenetic analysis in two species of palmsEuterpe edulis and Archontophoenix alexandrae are palm trees used for ornamentation purpose and palm heart extraction. Seed germination and VGI, mitotic and meiotic chromosome behavior and quantification of pollen were assessed. For each species in each location and in each substracts, 60 seeds were used. Mitotic chromosome analyses and identification of differential nucleoli were made in meristem zone of primary root. Giemsa 2% (m/v) and AgNO 3 50% (m/v) were used as dyes, respectively. Chromosomes analysis in microsporogenesis and pollen viability were made on anthers of buds and stained with carmine propionic 2% (m/v). The greatest index of germination and VGI of the seeds, in two species, were observed in samples from Maquiné in a substract containing vermiculite. A. alexandrae is a diploid with 2n=2x=32 chromosomes with karyotype m+12sm+4st+2t. E. edulis is a diploid with 2n=2x=36 chromosomes with karyotype 16m + 12sm + 8t. Both have a submetacentric pair of chromosomes with intermediate secondary constriction containing nucleoli with active ribosome genes. In these two species microsporogenesis and pollen analyses showed high percentage of normal cells at all stages of meiosis I and II resulting a high meiotic index (normal tetrads) and pollen viability, indicating that in these species the genes are expressed normally in environmental conditions in which they live and do not present problems in the formation of male reproductive cells.

Interphase nuclei, karyotypes and nuclear DNA amounts in five species of Oenocarpus (Arecaceae)

“…The number of chromosomes found for the Oenocarpus species was the same as that found for other species of the tribe Euterpeae ( Battistin et al 2012 ; Oliveira et al 2016 ). The constancy in the number of chromosomes among closely related species is quite common among groups of Arecaceae ( Röser 1994 , 1995 ; Dransfield et al 2008 ; Corrêa et al 2009 ).…”

“…Other chromosome numbers have been reported for species of the subfamily Arecoideae , to which the genus Oenocarpus belongs. Castilho et al (2000) , Corrêa et al (2009) , Battistin et al (2012) , and Pereira et al (2017) found 2n = 32 chromosomes for Elaeis guineensis (Jacquin, 1763), five species of Butia (Beccari, 1916), Archontophoenix alexandrae ((F. Muell.)…”

“…The determination of chromosome number and karyotype are the easiest and cheapest activities among all cytogenetic techniques available, and constitute important information for cytotaxonomic studies ( Guerra 2008 ). There are numerous studies of palm cytogenetics, some including karyotypes, banding patterns and comparison of interphase nuclei morphology, based on chromatin distribution and arrangement ( Röser 1993 , 1994 , 1995 , 1999 , 2000 ; Röser et al 1997 ; Castilho et al 2000 ; Corrêa et al 2009 ; Abreu et al 2011 ; Battistin et al 2012 ; Gaiero et al 2012 ; Oliveira et al 2016 ; Pereira et al 2017 ; Kadam et al 2023 ; Witono et al 2024 ). However, among the five subfamilies of Arecaceae , the one that has the least cytogenetic information for its species is Arecoideae , which includes Oenocarpus , with at least five tribes with no information even on the chromosome number ( Dransfield et al 2008 ).…”