Fig. 4 Segmented GLMs of binomial germination outcomes
back-transformed to the response probability scale as response to
microclimate variables in simulated-NHs, dashed lines are breakpoints
and pink shading is standard error (0.95), residuals are red circles.
Survival and dormancy loss in the soil
Overall, 40% of seeds that were buried in the soil for two years and
68% for one year were successfully exhumed from the soil. The
probability of finding seeds was modelled against year, burial-depth,
and accession (Fig. 5a). Seed burial-depth was the most important
factor, deep-buried seeds were more likely to be successfully exhumed
(z=16.722, p<0.001), followed by year (z=13.379,
<0.001). Surprisingly, seeds with low viability when sown had
high probability of being exhumed (bur60 z=7.242, p<0.001,
sia61 z=7.025, p<0.001).
Viability of exhumed seeds were tested by TTC and incubation. Viability
tests from these, original ER and maximum in Simulated-NHs, was modelled
in a GLM. In contrast to the results of the above, accession was
excluded from the MAM, year remained. Contrasts were made per year
against original ER. Viability from the incubator test was not lost
during one year in the soil. After two years in the soil, viability was
reduced in both incubator and TTC tests. The TTC test consistently
underestimated viability.