Chromosome, ploidy analysis, and flow cytometric genome size estimation of Datura stramonium and D. innoxia medicinal plant

Datura stramonium and D. innoxia are among the important species of Datura genus. They have many uses in traditional and modern medicine. Since Iran is located in the origin area of Datura, it is expected that Iranian germplasms are factors of global genetic diversity of Datura. Ploidy level, chromosome number and length, and genome size estimation were studied on 15 populations of both Datura species mostly collected from different parts of Iran and a few from abroad. For chromosomal preparations, root tip was squashed and stained with 1% (w/v) aceto-orcein. For genome size estimation, flow cytometric analysis was conducted on fresh developed leaves of Datura samples along with those of internal standard reference (Solanum lycopersicum cv. Stupick, 2C = 1.96 pg DNA), using PI fluorochrome. All the studied populations were diploids (2n = 2x = 24). The mean chromosome length in D. stramonium and D. innoxia was determined as 1.97 µm and 2.39 µm, respectively; the latter had 21% larger chromosomes. The mean monoploid genome size was determined as 3.80 pg in D. stramonium (ranged 3.65 pg to 3.93 pg) and 3.91 pg in D. innoxia (ranged 3.68 pg to 4.30 pg). The present study provides completely new information about cytogenetics in D. stramonium and D. innoxia populations from Iran for the first time, which is useful for whole genome sequencing and the construction of genetic and physical maps in the future.