Exudation of amino acids and sugars from imbibing seeds of several leguminous crops

Exudation from imbibing seeds is an indicator of seed vigor and influences seedling emergence. The objective of this report was to determine the subst ance of exudation from the seeds and its differences among crops and cultiv ars. The amounts of amino acids and sugars exuded from the imbibing seeds o f 66 cultivars in 8 leguminous crops were measured by HPLC. Sixteen amino a cids were detected from the seeds in soybean, and 14 in kidney bean. Only t wo were detected from the seeds in rice bean. The amount of exudates was gr eatest in soybean (1020 mug per gram seed), and least in rice Lean (7 mug p er gram seed). Arginin exuded in high frequency, however, it accounted for 32% (kidney bean) to 80% (rice bean) of total amino acid exudation. The sug ars exuded from the seeds were mostly fructose and glucose. The frequency o f sugar exudation was high in soybean and kidney bean, but low in mung bean and rice bean, and no detection in black gram. A great deal of exudates wa s found in soybean (2065 mug per gram seed) and kidney bean (1297 mug per g ram seed). It doubled the amount of amino acids exuded in these two crops. No correlation between the exudation of full seeds and crushed seeds indica ted that the exudation is independent of the contents of exudates in the se ed. Dramatic difference was found among 29 cultivars in soybean, since the exudation presented from no detection to the greatest deal of exudation in some cultivars. Furthermore, the large seeds were very likely easy to exude , but no significant correlation was found between exudation and thickness of seedcoat.