Imbibition and Germination Properties of Wrinkled Soybean Seeds

Wrinkled seeds of soybean (cv. Enrei), known as “chirimen-jiwa” in Japan have transverse wrinkles on their dorsal side. Here, imbibition properties, susceptibility to flooding injury and vigor of wrinkled seeds were investigated in comparison with those of normal seeds (no visible wrinkles). Although both wrinkled and normal seeds imbibed similarly when submerged in water, a marked difference was observed after submergence. The wrinkled seeds had conspicuous depressions and distortions on the surface, which were indicative of unequal swelling, whereas the normal seeds were smooth. The rate of imbibition from the ventral (hilum) side exhibited no difference between wrinkled and normal seeds during the first 3 hr, but after 3 hr, it was higher in the wrinkled seeds than in the normal seeds resulting in a 40% larger amount of absorbed water. On the contrary, the wrinkled seeds absorbed 12% and 16% less water than the normal seeds when imbibed through the abaxial and the dorsal side, respectively. In the seeds submerged for 24 hr, seedling emergence and growth were poorer, and cotyledon disruption was significantly greater in the wrinkled seeds than in the normal seeds. Seed vigor of the wrinkled seeds estimated by the accelerated aging test was lower than that of the normal seeds. In the wrinkled seeds, unequal swelling and/or some factors responsible for their low seed vigor may aggravate the susceptibility to flooding injury.