Summary1 Dispersal of endozoochorous seed involves uptake by a herbivore and exposure to different kinds of digestive fluids during passage through the gastrointestinal tract. Assessment of the ecological significance of endozoochory therefore requires examination of the survival rate of seeds during this phase. 2 A feeding experiment was conducted with seeds of 19 plant species that are important constituents of temperate semi-natural grasslands and five animal species (two ruminants, two colon fermenters and a caecum fermenter). Mean retention time of germinable seeds was determined and seed characteristics that might affect germination success were examined. 3 Gut-passed seeds had a much lower germination success (0 -26%) than non-gut-passed seeds either sown directly on dung (2-79%) or bare soil (7-89%). 4 Relative germination success differed considerably between both plant and animal species. This may result from complex, herbivore-specific interactions between animal behaviour (chewing, digestion) and seed characteristics. 5 Germination success was positively related to seed longevity and, remarkably, also to seed mass and seed shape. Retention time of germinable seeds varied from c . 12 hours (rabbit) to 72 hours (ungulates), potentially allowing long-distance seed dispersal. This study highlights both the complex interaction between animal species and seed characteristics and the considerable differences in germination success of gut-passed seeds, which exist between plant species. The loss of seed germinability after gut passage calls into question the ecological significance of endozoochory, although the costs of other dispersal mechanisms remain to be tested.

In the last decade, a new class of low abundant plant l ectins was identified. These proteins are expressed after exposure of the plant to different stress factors and changing environmental conditions, and therefore are referred to as "inducible" lectins. Interestingly, these lectins accumulate in the nucleocytoplasmic compartment of plant cells. At present at least six carbohydrate recognition domains have been identified within the group of nucleocytoplasmic plant lectins. This review will focus on a group of proteins that show homology to the Nicotiana tabacum (tobacco) agglutinin or Nictaba. The tobacco lectin is a 38 kDa nucleocytoplasmic protein which is only expressed upon treatment with jasmonate-related compounds or after insect herbivory. The lectin exhibits specificity towards GlcNAc, but also reacts with N-glycan structures. Extensive searches revealed that Nictaba-related sequences are widespread in the plant kingdom. Analyses of the different transcriptome databases showed that the Nictaba domain is often part of chimeric proteins comprising one or more Nictaba domain(s) fused to unrelated N- and C-terminal domains with (un)known function. At present only few proteins of these Nictaba-related proteins have been studied and characterized for their biological properties and physiological role. Despite the sequence similarity and the conserved amino acids constituting the binding site, the Nictaba domain has a promiscuous carbohydrate binding site capable of interacting with different carbohydrate motifs, suggesting that subtle changes in the vicinity of the binding site can alter its sugar specificity.

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