The fruit contain the baobab seeds important for the reproduction of the trees. The seeds are well protected. They are embedded in the fruit pulp and red-brown fibers within the hard pericarp. The seeds are about one centimeter tall, dark brown to reddish black and kidney-shaped. A hard shell, the testa, surrounds the seeds. It is about 1 millimeter thick. A seed weighs 300 milligrams on average.
Seeds remain germinable for many years
Baobabs develop their fruit and seeds after flowering, which begins shortly after the onset of the rainy season.The fruit hang pendulous off the branches on long pedicels. During the dry season, about 6 to 8 months after the rainy season, the fruits are ripe and fall from the trees to the ground. As the drop height may be high, the outer shell bursts upon hitting the ground. Termites for example take advantage and enter the fruit through cracks. They feed on the fruit pulp and thereby set the seeds free. These remain in the shell and wait for the next rainy season and ideal growing conditions. Baobab seeds retain their germination capacity for many years. However, their germination probability is low – it is only about 20%.
Animals love Baobab Pulp
Not only termites benefit from the fruit. Elephants and baboons crack the fruit capsules and thus reach the nutrient-rich fruit pulp, eat it and swallow the seeds. These travel through the digestive tract and are often transported to remote locations by the animals. They sometimes cover large distances and therefore contribute to the spreading of baobabs. The seeds soak in digestive juices in the animals’ stomachs which opens up the hard shells. Together with other digestive end products the seeds are excreted along the way. This provides them with necessary fertilizer for a good start in life on earth. Other animals such as antelopes, squirrels, rats, monkeys and birds swallow the fruit pulp with the seeds and contribute to the dissemination, too.
Rain is important for germination
With the onset of the rainy season, the germination of baobab seeds starts. In order to grow they need warm temperatures and sufficient water on a regular basis. Small baobabs are susceptible to fungal attack. With too little water the shoots waste away and with too much water they are likely to catch fungus.
The conditions for the survival of sprouts from seeds are not yet fully explored. It is believed that ideal conditions for natural baobab reproduction occur only every 50 to 100 years. This might have consequences for their natural long term survival. If commercial harvesting of baobab fruit does not leave enough seeds for natural reproduction, the old baobab stocks could be at risk in the future. Baobabs need a very long time to gain their adult form. Depending on their regional occurrence they grow their first fruit between 10 – 25 years.