Data from: Demographic senescence in the aquatic plant Lemna gibba L. (Araceae)

Senescence is progressive, age-related bodily deterioration, accompanied
at the population level by declines in average survival and fecundity
(i.e., ‘demographic senescence’). Demographic senescence of plants has
been investigated in only a few species, including small, floating
macrophytes in the genus Lemna (family Araceae, subfamily Lemnoideae – the
‘duckweeds’). Unlike most plant species, Lemna ramets exhibit determinate
growth, potentially rendering them more likely to experience demographic
senescence. Here, our objective was to investigate senescence in a Lemna
species not previously studied in this context, L. gibba L., toward the
long-term goal of conducting cross-species comparative analyses. In a
longitudinal lab study, we investigated a cohort of 334 individual L.
gibba fronds, whose survival and reproduction we followed daily from birth
(defined by the date a focal frond detached from its parent) to death
(defined by the date a focal frond’s last daughter detached). We fit
survival data to exponential, Weibull, Gompertz, and logistic models, the
first of which represents ‘no senescence’. The logistic model was found to
have the greatest support (AICC weight >0.99), indicating strong
age-related declines in survival. We fit reproduction data using a
generalized estimating equation approach, which showed a significant
age-related decline in the predicted probability of daily reproduction –
from 0.61 at age 3 days to 0.23 at age 52 days (i.e., after excluding the
first two days of reproduction data to account for the initial,
pre-reproductive phase of the L. gibba lifecycle). These age-related
declines provide strong evidence that L. gibba does exhibit demographic
senescence, consistent with evidence from congeneric species.