**5.1 Impermeability of seed-coats to water**

The seed coats of many species are completely impermeable to water at the time of their maturity. This condition is very common in the seeds of many legumes, (example, clovers, alfalfa) of the water lotus, and of the morning glory. Germination fails to occur until water penetrates through the seed coats [28–32, 34].
