Technique to Obtain Mitotic Chromosomes of <i>Conyza bonariensis</i> L. Cronquist (Asteraceae)

Abstract

Cytogenetic analysis requires cytological preparations that unequivocally reveal the chromosome number and permit optimal visualizations of chromosome morphology for the construction of karyotypes and ideograms. Chromosomal characterization is possible only by establishing these two parameters. To cytogenetically characterize the weed Conyza bonariensis (L.) Cronquist (Asteraceae), it was necessary to improve cytological analysis techniques to obtain optimal results. This species belongs to a genus whose plants have wide phenotypic plasticity. These plants can be morphologically differentiated by other types of analysis, and thus the application of this technique will serve as a reference for cytogenetical analysis of other groups of plants that have cytogenetic characteristics similar to those of C. bonariensis. The methodology described here highlights three main protocol steps: 1) root tip collection from newly germinated seed radicles and from young root tips of mature plants, 2) pretreatment of meristems with antimitotic agents, both isolated and combined, and 3) acid and enzymatic hydrolytic processes.

In vitro and in vivo evaluation of enzymatic and antioxidant activity, cytotoxicity and genotoxicity of curcumin-loaded solid dispersions

“…In the same way, for the two controls, roots were collected at 0, 24 and 48 h. Roots were fixed in Carnoy 3:1 (ethanol: acetic acid) for 24 h (three roots per bulb were taken). On average, 03 slides per onion bulb were mounted (Paula and Pinto-Maglio, 2015) and analyzed under an optical microscope at 400x magnification. For each onion bulb 1000 cells were analyzed at a given exposure time.…”

Gene expression in response to glyphosate treatment in fleabane (Conyza bonariensis) – glyphosate death response and candidate resistance genes

“…This gene dosage effect and dilution of target‐site mutations in polyploids could favour non‐target site mechanisms over target site mechanisms in the evolution of herbicide resistance in polyploid weeds. The genus Conyza is ploidy variable, with C. canadensis being a diploid with 2 n = 2 x = 18, and C. bonariensis being allohexaploid with a chromosome count of 2 n = 6 x = 54 . The copy number of the EPSPS gene is further complicated by there being three copies in the diploid C. canadensis …”

“…The genus Conyza is ploidy variable, with C. canadensis being a diploid with 2n = 2x = 18, and C. bonariensis being allohexaploid with a chromosome count of 2n = 6x = 54. [30][31][32] The copy number of the EPSPS gene is further complicated by there being three copies in the diploid C. canadensis. 14,17 This experiment was established to explore the gene expression changes induced by glyphosate treatment in susceptible and resistant lines of Australian C. bonariensis.…”

Complete chloroplast genome of glyphosate resistant Conyza bonariensis (L.) Cronquist from Australia

“…This species has evolved glyphosate resistance in at least nine different countries (Heap 2017 ) and several species in the genus have evolved glyphosate resistance. Conyza bonariensis is allohexaploid with a chromosome count of 2 n = 6 x = 54 (Thebaud and Abbott 1995 ; Paula and Pinto-Maglio 2015 ). Several species in this genus are polyploid but their ancestry and evolutionary relationships are not clear.…”