Endoreduplication in the germinating embryo and young seedling is related to the type of seedling establishment but is not coupled with superoxide radical accumulation

Abstract

During germination, the embryo axis elongates and the radicle emerges through the surrounding structures of the seed. However, this elongation is not even along the axis, and it has been suggested that the region responsible for radicle protrusion is related to the type of subsequent seedling establishment. Eleven epigeal- and five hypogeal-type species were selected to study endoreduplication, a process coupled with cell elongation, in the radicle, hypocotyl-radicle transition zone, hypocotyl, and cotyledons of dry and germinating seeds, and in seedlings after radicle protrusion. Flow cytometry was used to establish the proportions of nuclei with different DNA contents, the mean C-value, and the (Σ>2C)/2C ratio. Additionally, a nitroblue tetrazolium chloride test was applied to the embryos/seedlings in the dry state and during and after germination to localize superoxide radical (O2(•-)) accumulation, which has been suggested to play a role in cell elongation. Endoreduplication intensity varied in different species, in the embryo/seedling regions, and with the type of seedling establishment. In most of the cases, it was highest in the transition zone of epigeal species and in the hypocotyl in hypogeal species. O2(•-) was invariably produced during germination in the radicle, and additionally in the transition zone at the time of radicle protrusion; thus, it was not coupled with endoreduplication, and most probably played a role in defence against biotic and abiotic environmental stresses. These results provide information to aid in the selection of the most suitable plant material for molecular research on germination and for monitoring seed priming.

Plant material selection, collection, preservation, and storage for nuclear DNA content estimation

“…Alternatively, these problems may be reduced during sample tissue selection. Even within individual, endopolyploidy is usually expressed to different degrees in particular organs and tissues ([10], Figure 1), and this is apparent from the earliest developmental stages (germinating seeds, seedlings; [11]).…”

Nucleoside Metabolism Is Induced in Common Bean During Early Seedling Development

“…This could be particularly relevant for species with large genomes or with high DNA content in seeds as result of endoreduplication. Interestingly, cotyledons and embryonic axes of P. vulgaris seeds contain endopolyploid nuclei (Rewers and Sliwinska, 2014).…”

ERF4 interacts with and antagonizes TCP15 in regulating endoreduplication and cell growth in Arabidopsis

“…Endoreduplication (consisting of two phases: G and S) is a modification of the mitotic cell cycle (consisting of four phases: G1, S, G2, and M), during which cells replicate their nuclear genome in multiple rounds of DNA replication without subsequent chromosome separation and cytokinesis, resulting in cellular polyploidy (Edgar and Orr‐Weaver, 2001; Francis, 2007; Lee et al, 2009). Moreover, endoreduplication intensity varies between plant species, organs, and regions of an organ (Powell and Lenhard, 2012); for instance, it is highest in the transition zone of epigeal species and in the hypocotyl of hypogeal species in most cases (Rewers and Sliwinska, 2014). Endoreduplication typically enlarges cells, which is one of the mechanisms by which plants regulate organ growth through the integration of endogenous signals and various environmental cues (Lee et al, 2009; De Veylder et al, 2011; Fox and Duronio, 2013; Shu et al, 2018; Xu et al, 2020).…”