POTENTIALLY DEFENSIVE PROTEINS IN MATURE SEEDS OF 59 SPECIES OF TROPICAL LEGUMINOSAE

Abstract

A survey of 59 species of tropical legume seeds revealed high interspecific variation in pTOlcinaccous capacity to inhibit bovine trypsin (a digesli"e enzyme) and 10 agglutinate human (type B. Rh positive) and laoorawry rabbit red blood cells. The legume subfamily Mimosoideae was conspicuous for the absence of seeds with vcry weak trypsin inhibilion. Congenerics sometimes differed strongly from each OIher with ~spect to both trypsin inh ibition and phytohemagglutination. Half the species of seeds d isplayed no hemagglutinating capacity with one or the OIher kinds of red blood cell s. and in only 27\11. of the 30 case.~ whe~ there was some activity did the same species of seed aclh'ely agglutinate both species of red blood cells. A species of seed that had hemagglutinating capacity was almost invariably associated witll moderate 10 high levels of trypsin inactiyation . Wllile it lias been long known that a g~at diyersity of small toxic and potemiaJly defensive molecules occur in legume seeds and that one species of seed often contains sevcral of them. we now feel that il is ~asonable to consider legume seeds as also COn13ining a hi gll diver.>ily of potentially toxic protein molecules. A single seed is likely to contain. al the least. thm: to four classes of defe nsiye compounds, any or all of which. or somc in combination, may be the cause of a seed being ~jected by a potential seed predator.