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

Botanical Studies

Table 3 Heat treatment: Relative germination rate of Adansonia digitata seeds after 10 weeks [%]

Treatment	2017a	2017b	2018	2019b/2020	Average
Cold water for 3 days	0	1	0		0.3
In hot water for 40 min 70°C	70	73	42	63	62**
Short-time heat treatment
In oven for 5 min 75°C				51	51**
In oven for 5 min 100°C				78	78**
In oven for 5 min 125°C				11	11**
In oven for 5 min 150°C				3	3
Long-time heat treatment
In oven for 40 min 50°C			13		13**
In oven for 40 min 75°C			64		64**
In oven for 40 min 100°C			0		0
In oven for 40 min 125°C			0		0
In wet sand in oven for 40 min 50°C			8		8**
In wet sand in oven for 40 min 75°C			72		72**
In wet sand in oven for 40 min 100°C			0		0
In wet sand in oven for 40 min 125°C			0		0
Combination of elephants´ digestion and heat treatment
Elephants´ digestion + in oven 5 min 75°C				24	24**
Elephants´ digestion + in oven 5 min 100°C				28	28**
Elephants´ digestion + in oven 5 min 125°C				16	16**
Elephants´ digestion + in oven 5 min 150°C				4	4*

Results obtained in three test setups with 100 seeds per treatment each, except 50 seeds for combination of elephant’s digestion and heat treatment: 2017a, 2017b, 2018 and 2019b. Significant increase of GR compared to the control without treatment are indicated with *P<0.05, **P<0.01