Fig. 5 Seed survival in the soil; (a) Probability of finding
seeds in 2021 that were sown in 2019 and 2020 according to burial-depth
and accession; (b) viability of seeds found in 2021 using a germination
test in an incubator (IN) and the tetrazolium chloride test (TTC), with
reference to viability at the start of the experiment using embryo
rescue techniques (ER), and maximum germination achieved in a
Simulated-NH; p values show contrasts (Dunnett test) against original
viability (ER) for each year.
Seeds that were removed from
storage and incubated under suitable conditions (20/35°C), displayed
dormancy i.e., they did not germinate at all. However, if they were
buried in the soil at 7 cm for up to three months, germination
significantly increased to probability 0.4 (t=2.518, p=0.021, Fig. 6).