In a recent thread Mr B pointed me in the direction of some interesting material on seed germination. Dr. Norman Deno, long associated with Penn State and now recently deceased who did much work on the topic of seed germination. I'm starting this topic to give it a bit more exposure plus everyone likes free stuff. His principal work "Seed Germination Theory and Practice" along with two later supplements to the same work are now in the public domain. They can be downloaded in the form of pdf files from the USDA but are a bit hard to find there. Here are some alternate links to the same files:
http://www.gardenfundamentals.com/wp-content/uploads/2018/06/Deno-Seed-G...
http://www.gardenfundamentals.com/wp-content/uploads/2018/06/Deno-Seed-G...
http://www.gardenfundamentals.com/wp-content/uploads/2018/06/Deno-Seed-G...
I haven't had time to study these in detail yet but from a first viewing it appears that there is more here than you ever wanted to know about seed germination.