Pore Development and Seed Coat Permeability in Soybean1
- R. W. Yaklich,
- E. L. Vigil and
- W. P. Wergin2
The development of pores and permeability of the seed coat in soybean [Glycine max (L.) Merr.] was examined to determine the Name of their formation after desiccation in the pod and their functional relationship. Two replicates of four genotypes were grown in the field at Beltsville, MD. When plants reached growth stage R5 (seeds could be felt when the pods were squeezed), 50 pods were removed from Node 4 of different plants. Subsequently, a similar number was picked at 3 to 4 day intervals until harvest maturity. The pods were dried at room temperature and shelled. Pore formation in 50 seeds from each sampling interval was examined by observation with a dissecting microscope. Permeability of seed coats was determined by placing seeds in wet paper towels for 1 h. When seeds attained the mature shape, weekly samples of 15 seeds from each replicate were separated into seed coat and embryo, weighed, and the seed coat/embryo ratio determined. Seeds from the different harvest dates were also observed by scanning electron microscopy. After desiccation in the pod, soybean seed development progressed through three shapes; transversely narrowly elliptic, depressed ovate, and transversely broadly elliptic. Desiccation presumably caused pores and the impermeable seed coat to form during the depressed ovate stage. Prior to formation of pores and presumably the impermeable seed coat, the mature surface structure of the soybean seed coat developed. The seed coat surface elevated and the surface cells gathered closer together. Pores formed first around the hilum, encircled the seed parallel with the axis, and then formed on the abaxial surface (area covering the round face of the cotyledon). Surface deposits were observed on all seed coats. The amount of deposit, which varied on the surface of the seed coat, was derived from the endocarp of the pod wall. After attaining the mature shape, the seed coat/embryo ratio decreased as the seeds became larger. At maturity, genotypes with permeable seed coats had seed coat/embryo ratios <0.1. Seed coat/embryo ratios may be related to seed coat permeability.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .