You have two really good, informative examples (one as an answer, one in the comments) of real-world scenarios. So here is a really wild, out-there but plausible answer.
The fruit has formed a really good symbiotic relationship with a particular strain of bacteria. The plant provides these bacteria (located in the fruit pod) with nutrients, and the bacteria produces methane gas as a byproduct.
The fruit pod outer membrane is made of a tough, elastic protein (similar to intestines) that constrains this methane under pressure.
When the seed pod (fruit) falls, the nutrients to the bacteria are cut off, and this signals the bacteria to start consuming the enveloping membrane of the pod. This forms a hole, and the external membrane collapses like a balloon. The guts of the pod are expelled.
The exposure of the bacteria to air causes them to create high voltage sparks, that ignite the methane, creating an even larger explosion, that propels the seeds far and wide, along with the bacteria. Thus, the seeds and the symbiotic bacteria are equally dispersed.
Very recently, it has been discovered that, indeed, certain human gut bacteria do produce electricity in sufficient quantities to be usable for this purpose.
The Bacteria in Your Gut Produce Electricity
The electricity could be stored in biological capacitors until it becomes sufficient enough to cause ignition.
Biological capacitance studies of anodes in microbial fuel cells using electrochemical impedance spectroscopy.
The physics textbook, along with the Chemistry and Biology textbooks, are recently getting very thick indeed. Knowing this makes sci-fi writing all that much easier, without calling on magic.