Selected perennial plants do provide convenient standards for the determination of genome sizes with flow cytometry

Abstract

Flow cytometry delivers a key value to detect differences between species and hybrids and to determine ploidy. In addition, DNA weight per nucleus appears to be related to various properties, such as the size of the cell and the nucleus, the duration of mitosis and meiosis and the generation time. The variation in DNA weight is also useful to analyze biodiversity, genome evolution and relationships between related taxa and recognizing ploidy-chimeras. Moreover, it is essential to know the size of a genome before one starts to determine the base sequences of DNA of a plant. To be able to measure the amount of DNA per nucleus, a standard that is genetically stable with constant genome size, easy to use and commonly available is recommended for flow cytometry. In this study, standards from selected perennial plants instead of annuals are recommended as these are more stable than individual seedlings and don’t need greenhouse facilities. Four different methods are used here to determine genome sizes or 2C-value (the amount of DNA per nucleus) for the standard values of perennial plants: 1. Eight selected standards are measured separately against four primary standards 2. Starting with the lowest two standards, each result is used cascade-wise as a standard for the next plant. 3/4. Combining six to nine standard plants in a single chopping event: 3. Calculating all standards against a single standard and 4. Calculate all plants cascade-wise. The last combination 3/4 was also used to compare the results from buffers of Bharathan, Galbraith, Otto and Doležel. The aim of this study was to present selected perennial plants to be useful in flow cytometry. Selected perennial plants have several advantages like permanent availability, surviving for weeks without watering and the absence of variation as is possible in seedlings of annuals. The obtained 2C-values of perennial plants, ranging from 2.7 to 70.5 pg, are presented as a valuable tool in the determination of genome sizes. Agave americana’Aureomarginata’ is presented as the preferred reference standard.