EFFECTS OF NONDESTRUCTIVE TISSUE EXTRACTION ON THE VIABILITY OF CORN,SOYBEAN, AND BEAN-SEEDS

Extraction of tissue from seeds of bean (Phaseolus vulgaris L.), soybe an (Glycine max L. [Merr.]), and corn (Zea mays L.) was accomplished w ith minimal adverse effects on the viability of seeds stored for up to one year at 12-degrees-C and 50% relative humidity. To avoid loss in seed viability, consideration must be given to the seed species, the s eed structure from which the tissue is removed and conditions for hydr ating and drying seeds. Corn seed germination was unaffected by extrac tion of tissue from the endosperm. Removal of cores of tissue from cot yledons of soybeans and beans resulted in significant reduction of ger mination in seeds dried at 22-degrees-C and 24% relative humidity afte r coring but this did not occur in seeds dried at 12-degrees-C and 50% relative humidity. The adverse effects of coring on soybean or bean s eeds was evidenced by increased numbers of dead seeds and abnormalitie s in the radicles and hypocotyls of germinated seedlings. There was no advantage to hydrating soybean and bean seeds before tissue extractio n to minimize germination loss. Moisture loss in cored seeds could be reduced by coating the extracted area with paraffin wax, but this did not improve germination. Effects on seed viability resulting from tiss ue extraction from embryos depended upon seed type and embryo part ext racted. For corn, there was minimal germination loss when the coleopti le, scutellum or radicle was cored, but germination was drastically re duced (>90%) when tissue was removed from the mesocotyl. For soybeans, germination was reduced by 25-35% when hypocotyls and radicles were c ored and by approximately 45% when tissue was removed from the epicoty l. For beans, no significant germination loss occurred when cores were taken from the hypocotyl and radicle, but a considerable (ca. 25%) de pression in germination occurred when they were removed from the epico tyl.