We measured nuclear genome size of aroids, collected in La Gamba (Costa Rica),
using DNA image cytometry. We aimed to establish whether plants with the same life form
have similar genome size, whether closely related species have similar genome sizes and
whether polyploidy is present in any of the studied samples. We measured 46 species from
12 genera, in which we found a wide range in 2C-values. 39 species and 3 genera were
measured for the first time. We determined that life form is not correlated with genome size,
while life cycle is. Closely related species had similar genome sizes only in genera
Philodendron and Pistia. Polyploidy was disproved for taxon Philodendron sp. (sample Etl
#9), while additional research is necessary for Philodendron cf. sulcatum. We also counted
the chromosome number for an unidentified species of genus Adelonema (2n = 10), which
is the first data for this genus. Due to methodological flaws, we recommend additional
measurements for 5 species, while other measurements could be included into the online C-
value database by Royal Botanic Gardens, Kew (Great Britain). Our measurements were
compared with known data of aroids, monocots, and angiosperms in general. We found
angiosperms have on average a smaller genome size than aroids, despite being the clade that
includes both aroids and monocots.
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