Abstract
Environmental conditions encountered in arid ecosystems differ vastly from those in more mesic ecosystems. Dispersal strategies in arid environments reflect these differences and many mechanisms have evolved that restrict or hinder dispersal. Myxospermy is a trait developed by plant species from arid regions to restrict diaspore dispersal by means of an anchorage mechanism. Several of the abundant plant species in Namaqualand, within the arid Succulent Karoo Biome, display myxospermy. Diaspores of these species produce copious amounts of mucilage when they are moistened and are anchored to the soil once the mucilage dries out again. This study investigated the origin of the mucilaginous layer of 12 species anatomically, using both light and scanning electron microscopy. The mucilage production of the species investigated could best be grouped into three types: 1, epidermal and sub-epidermal cells of seeds and achenes; 2, specialized tissue in wings or the pappus of achenes; and 3, mucilage excreting hairs. Previous systems for classifying the different types of mucilage production did not recognize the mucilaginous nature of wings or a pappus. A short note on the composition of the mucilage is included.
Highlights
Plants have developed many functional traits that allow them to adapt and survive in different environments
Neither the classification systems of Zohary (1937) or Grubert (1974) accommodate diaspores where the mucilage production occurs on wings of achenes, as was reported in the present study
The presence of wings would allow anemochoric dispersal during phase I dispersal (Chambers & MacMahon 1994), but further anemochoric dispersal would be prevented once the achenes were moistened and remained attached to soil particles
Summary
Plants have developed many functional traits that allow them to adapt and survive in different environments. Seed dispersal is an important functional trait that influences the population structure and the spatial and temporal turnover of species within a plant community. The original explanation for the prevalence of antitelechory in desert environments was that these mechanisms were adaptive responses to the high mortality of dispersed seeds in deserts and that they had evolved as mechanisms to reclaim the mother site (Murbeck 1919; Zohary 1937; Stopp 1958; Ellner & Shmida 1981; Van Rooyen et al 1990). Ellner & Shmida (1981) argued that antitelechory was a side effect of characters whose adaptive value was not directly related to dispersal. Among the benefits derived from antitelechory are the spreading of germination over time and the provision of suitable conditions for germination and subsequent seedling establishment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
