Adansonia digitata germination tests. Elephants or heat: what causes scarification of seed to facilitate germination?

Botanical Studies

Table 5 Heat treatment: Relative germination rate of Adansonia digitata seeds in percentage

Treatment	0–2 weeks	3–4 weeks	5–6 weeks	7–8 weeks	9–10 weeks
Short-time heat treatment
In oven for 5 min 75°C	0	26	21	4	0
In oven for 5 min 100°C	0	35	42	1	0
In oven for 5 min 125°C	0	5	4	2	0
In oven for 5 min 150°C	0	0	3	0	0
Long-time heat treatment
In oven for 40 min 50°C	0	6	6	1	0
In oven for 40 min 75°C	0	19	45	0	0
In oven for 40 min 100°C	0	0	0	0	0
In oven for 40 min 125°C	0	0	0	0	0
In wet sand in oven for 40 min 50°C	0	2	6	0	0
In wet sand in oven for 40 min 75°C	5	46	21	0	0
In wet sand in oven for 40 min 100°C	0	0	0	0	0
In wet sand in oven for 40 min 125°C	0	0	0	0	0
Combination of elephants´ digestion and heat treatment
Elephants´ digestion + in oven 5 min 75°C	2	12	10	0	0
Elephants´ digestion + in oven 5 min 100°C	0	18	10	0	0
Elephants´ digestion + in oven 5 min 125°C	0	8	8	0	0
Elephants´ digestion + in oven 5 min 150°C	2	2	0	0	0

Numbers marked with ^aare the average of the germination tests (2017, 2018, 2019) the remaining numbers are obtained in the test sets in 2018 or 2019