Short Communication: Analysis of the chromosome numbers of Zinnia elegans Jacq. in single, double, and pom-pom flowers

Saifudin, Shafira S, Dwiranti A, Salamah A. 2021. Short Communication: Analysis of the chromosome numbers of Zinnia elegans Jacq. in single, double, and pom-pom flowers. Biodiversitas 22: 2771-2777. Zinnia elegans Jacq. is highly valued as an ornamental plant with a variety of flower colors, sizes, and shapes. Polyploidization has been reported in Z. elegans with pom-pom flowers, nevertheless, the variation in chromosome numbers of various flower shapes has yet to be investigated. This study aimed to analyze the chromosome numbers of Z. elegans Jacq. cultivar “California Giant,” “Lilliput,” and “Cactus Flowered Mix” with single, double, and pom-pom flowers to determine their variations and identify the morphology of the flowers. Chromosomes were prepared using the squashing method, and images were analyzed using the Chromosome Image Analyzing System (CHIAS) IV. The minimum of 5 slides was prepared for each flower type from each cultivar. The results show that the three cultivars are diploid plants (2n = 24) with varying flower morphology. The single and double flowers of Z. elegans “Lilliput” and the single flower of “Cactus Flowered Mix” showed no variation in chromosome numbers. In contrast, chromosome number variation was found in the pom-pom flower of Z. elegans “California Giant” (2n = 22, 24, 48) and the double flower of “Cactus Flowered Mix” (2n = 9, 13, 15, 24). Two cultivars, Z. elegans “California Giant” and Z. elegans “Cactus Flowered Mix,” were successfully analyzed using CHIAS IV. Statistical analysis using a t-test (? = 0.05) showed that the total chromosome length of Z. elegans “California Giant” (2n = 24) was significantly greater than that of Z. elegans “Cactus Flowered Mix” (2n = 24). Chromosome satellites were found in both cultivars.

Molecular Phylogenetics and Micromorphology of Australasian Stipeae (Poaceae, Subfamily Pooideae), and the Interrelation of Whole-Genome Duplication and Evolutionary Radiations in This Grass Tribe

The mainly Australian grass genus Austrostipa (tribe Stipeae) comprising approximately 64 species represents a remarkable example of an evolutionary radiation. To investigate aspects of diversification, macro- and micromorphological variation in this genus, we conducted molecular phylogenetic and scanning electron microscopy (SEM) analyses including representatives from most of Austrostipa’s currently accepted subgenera. Because of its taxonomic significance in Stipeae, we studied the lemma epidermal pattern (LEP) in 34 representatives of Austrostipa. Plastid DNA variation within Austrostipa was low and only few lineages were resolved. Nuclear ITS and Acc1 yielded comparable groupings of taxa and resolved subgenera Arbuscula, Petaurista, and Bambusina in a common clade and as monophyletic. In most of the Austrostipa species studied, the LEP was relatively uniform (typical maize-like), but six species had a modified cellular structure. The species representing subgenera Lobatae, Petaurista, Bambusina as well as A. muelleri from subg. Tuberculatae were well-separated from all the other species included in the analysis. We suggest recognizing nine subgenera in Austrostipa (with number of species): Arbuscula (4), Aulax (2), Austrostipa (36), Bambusina (2), Falcatae (10), Lobatae (5), Longiaristatae (2), Petaurista (2) and the new subgenus Paucispiculatae (1) encompassing A. muelleri. Two paralogous sequence copies of Acc1, forming two distinct clades, were found in polyploid Austrostipa and Anemanthele. We found analogous patterns for our samples of Stipa s.str. with their Acc1 clades strongly separated from those of Austrostipa and Anemanthele. This underlines a previous hypothesis of Tzvelev (1977) that most extant Stipeae are of hybrid origin. We also prepared an up-to-date survey and reviewed the chromosome number variation for our molecularly studied taxa and the whole tribe Stipeae. The chromosome base number patterns as well as dysploidy and whole-genome duplication events were interpreted in a phylogenetic framework. The rather coherent picture of chromosome number variation underlines the enormous phylogenetic and evolutionary significance of this frequently ignored character.

CHROMOSOME NUMBER VARIATION IN PART OF THE FLORA OF PROTECTED WILD AREAS IN THE ARAUCANiA REGION OF SOUTHERN CHILE

An analysis was made of the correspondence between species diversity and chromosome number (CN) diversity across 13 Protected Wild Areas (PWA) in the Araucanía Region of southern Chile, encompassing 84 plant species with available cytogenetic data. Our aim was to establish whether higher species diversity within a PWA entails higher CN variation as based on the index of chromosome number heterogeneity (ICNH). The CN data were extracted from databases for Chilean plants, and the ICNH for the flora of each PWA was calculated. Results showed that in nine PWA the species diversity clearly correlates with CN diversity. However, four PWA do not fit this trend. The percentage of species with CN data varied between 9.6% and 24.5% among PWA, with 11 PWA presenting percentages higher than 11%. A 27.3% of the Chilean vascular plant species with available cytogenetic data were studied here for the 13 PWA. The results obtained by studying one part of the flora with available CN data suggest that the PWA could be an important reservoir of genetic diversity at a chromosome level, thus justifying the protective role of the PWA as biodiversity conservation sites. Key words: Chromosome number heterogeneity; floristic diversity; Chilean flora.

Molecular phylogenetics and micromorphology of Australasian Stipeae (Poaceae), and the interrelation of whole-genome duplication and evolutionary radiations in this grass tribe

ABSTRACTThe mainly Australian grass genus Austrostipa with ca. 64 species represents a remarkable example of an evolutionary radiation. To investigate aspects of diversification, macro- and micromorphological variation in this genus we conducted a molecular phylogenetic and scanning electron microscopy (SEM) analysis including representatives from all of its accepted subgenera.Plastid DNA variation within Austrostipa was low and only few lineages were resolved. Nuclear ITS and Acc1 yielded comparable groupings of taxa and resolved subgenera Arbuscula, Petaurista, Bambusina in a common clade and as monophyletic. In summary, we suggest recognizing nine subgenera in Austrostipa.Because of its taxonomic significance in Stipeae, we studied the lemma epidermal structure in 34 representatives of Austrostipa. In most species, the lemma epidermal pattern (LEP) was relatively uniform (maize-like LEP), but in six species it was more similar to that of Stipa s.str., Neotrinia, Ptilagrostis and Orthoraphium. The species representing subgenera Lobatae, Petaurista, Bambusina and A. muelleri from subg. Tuberculatae were well-separated from all the other species included in the analysis.Two different sequence copies of Acc1 were found in polyploid Austrostipa and Anemanthele. Each of the copy types formed a single clade. This was also true of the sampled species of Stipa s.str., but their clades were strongly separated from those of Austrostipa and Anemanthele. This underlines the statement of Tzvelev (1977) that most if not all contemporary Stipeae are of hybrid origin and demonstrates it for the first time unambiguously on the molecular level.Chromosome number variation is surveyed and reviewed for the whole tribe Stipeae and interpreted in a molecular phylogenetic framework. The rather coherent picture of chromosome number variation underlines the phylogenetic and evolutionary significance of this character.The closest extant relatives of Austrostipa and Anemanthele are in the clade of Achnatherum s.str., Celtica, Oloptum and Stipellula. These genera are most abundant in Central and Eastern Asia, which makes a colonization of Australian and New Zealand from this region more likely, perhaps via long-distance dispersal, than colonization of Australia from southern South America via Antarctica as previously invoked.Supporting Information may be found online in the Supporting Information section at the end of the article.