Function and variation of the beta-glucosidase linamarase in natural populations of Trifolium repens
1993
Kakes, P.
Cyanogenesis is the production of HCN by plants, and in some cases, by animals. Cyanogenesis is only apparent after damage of the cyanogenic organs or tissues of the plant. The mechanism responsible for cyanogenesis is hydrolysis of one or more cyanogenic substrates by a beta-glucosidase. The function of cyanogenesis is best studied in species that are polymorphic for cyanogenesis. Trifolium repens (white clover) is polymorphic for both the cyanogenic substrates and the beta-glucosidase linamarase. This situation makes it possible to study the function of linamarase in plants with and without the natural substrates. The most obvious function of cyanogenesis is defense against herbivores. However I was able to show that linamarase has no function in the deterrence of slugs and snails by the cyanogenic glucosides present in white clover. It is possible that linamarase has a function in the deterrence of other herbivores, but the evidence for this is weak. There is much variation in linamarase content in natural populations of white clover. The significance of this variation is discussed within the framework of the cost-benefit hypothesis.
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