SEED DISPERSAL OF DENDROMECON: ITS ECOLOGIC, EVOLUTIONARY, AND TAXONOMIC SIGNIFICANCE
1966; Wiley; Volume: 53; Issue: 1 Linguagem: Inglês
10.1002/j.1537-2197.1966.tb07298.x
ISSN1537-2197
Autores Tópico(s)Plant Parasitism and Resistance
ResumoBoth species of Dendromecon are diplochorous, that is, the seeds are first scattered from the mother plant by violently dehiscing capsules and then transported further away by ants, which are strongly attracted to the elaiosome at the micropylar end of the seed. The tensions that cause the capsule to explode develop between the two carpels and also between lateral and central fiber strands in the capsular valves. The elaiosome is unusual in that it contains large quntities of starch in addition to the commonly present fatty oils and that it is more drought resistant than most known elaiosomes. Seed dispersal is very efficient over short distances, but migration barriers a few hundred meters or more cannot be crossed except by chance dispersal. Dendromecon differs strikingly from most ant‐dispersed plants in being woody and xerophytic; so far, D. rigida is the only chaparral plant known to be habitually dispersed by ants. The presence of an auto‐chorous‐myrmecochorous type of seed dispersal in D. rigida may partly explain the polymorphism of this species, since this type of seed dispersal tends to keep local populations isolated. The nearly complete correspondence, anatomically, morphologically, and functionally, between the fruit of Dendromecon and that of Eschscholzia strongly supports the idea of a close taxonomic relationship between these two genera. The seed appendage is believed to be a “recent” specialization in Dendromecon , phylogenetically independent from seed appendages facilitating dispersal by ants in other genera of the Papaveraceae.
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