Dispersal, seeds

In the natural world, carotenoid oxidation products are important mediators presenting different properties. Volatile carotenoid-derived compounds such as noriso-prenoids are well known for their aroma properties. Examples include the cyclic norisoprenoid P-ionone and the non-cyclic pseudoionone or Neral. Carotenoid oxidation products are also important bioactive mediators for plant development, the best-known example being abscisic acid. Apo-carotenoids act as visual and volatile signals to attract pollination and seed dispersal agents in the same way as carotenoids do, but they are also plant defense factors and signaling molecules for the regulation of plant architecture. 

Apocarotenoids also act as chemoattractants, repellants, and growth effectors in plants and cyanobacteria. They attract pollinators to plants through the use of color similar to full-length carotenoids. Their aromas are thought to be attractants for animals and insects to facilitate in seed dispersal and pollination. Small volatile apocarotenoids lure pollinators and levels of apocarotenoids... 

Another chemically mediated transaction between plants and ants that is more complicated and much less common than seed-dispersal appears to be limited to a few species of tropical treedwelling ants and several small plants adapted to growing in trees rather than in the soil. The ants collect the plants seeds, and the plants grow on, or really as part of, the ants arboreal nests. 

Secondary compounds produced by plants may have other significant survival roles, such as signals to attract insects, birds, or other animals to enhance pollination or seed dispersal. In addition to any potential functions, secondary compounds may concomitantly serve a physiologic function, such as protection against ultraviolet (UV) light or frost, or provide a function in nitrogen transport and storage. In several instances, compounds can serve multiple functions in the same plant. Anthocyanins or monoterpenes can be... 

Seeded dispersion polymerization was extensively investigated for radical systems [17]. Much less is known about seeded dispersion polymerizations with propagation on ionic and/or pseudoionic active centers. Awan et al. reported seeded ionic polymerization of styrene, which at certain conditions produced particles with narrow diameter size dispersity [18,19]. We presented the first data on the seeded ring-opening polymerization with constant number of microspheres. 

Fruit flavor, consumption and seed dispersal by birds... 

Dorcas gazelle Acacia (3 spp.) t to 13% (C 1%) fto21%(C 4%) 4- Acceleration 7%/5 days 13% /10 days Bruchid beetle opens seed Dispersal adaptation to desert rain pattern Or and Ward, 2003... 

Cipollini, M. L. and Levey, D. J. (1997). Antifungal activity ofSolanum fruit glycoalkaloids implications for frugivory and seed dispersal. Ecology 78,799-809. 

Enterolobium cyclocarpum seed passage rate and survival in horses, Costa Rican Pleistocene seed dispersal agents. Ecology 61,593-601. 

The flavonoids are a remarkable group of plant metabolites. No other class of secondary product has been credited with so many — or such diverse — key functions in plant growth and development. Many of these tasks are critical for survival, such as attraction of animal vectors for pollination and seed dispersal, stimulation of Rhizobium bacteria for nitrogen fixation. 

Chemical Signals as Attractants for Pollination and Seed Dispersal... 

Flavonoids in fruit probably serve to attract frugivores that assist in seed dispersal. This is especially important for larger plants such as trees, for which seeds need to be transported some critical distance away from the parent to ensure germination. 

The widest diversity in the manner of seed dispersal is exhibited by the dry fruits. These include the windborne types such as dandelion parachutes or sycamore keys . Mechanical scattering is exhibited by many of the legumes, whose seed pods, when fully ripened and dried out, can split with explosive force to scatter their contents in readiness for a follow-on crop. Another type is made up of those fruits, such as cleavers or dock-buns , that possess small hooks whereby the fruit is caught up in the fur of animals for transportation. 

Baumann TW, Schulthess BH and Hanni K (1995) Guarana (Paullinia cupana) rewards seed dispersers without intoxicating them by caffeine. Phytochemistry 39, 1063-1070. 

Stallings, G.P., D.C. Thill, C.A. Mallory-Smith, and L.W. Lass (1995a). Plant movement and seed dispersal of Russian thistle (Salsola iberica). Weed Sci., 43 63-69. 

Signal compounds to attract pollinating and seed dispersing animals... 

In practice, so-called overspray occurs this characterizes the non-deposited liquid drops. In the model, a factor kos considers the overspray, as a ratio of the mass flux of the overspray and the injected solid mass flux. The efficiency of the separator (filter, cyclone) is considered by a factor ksep, which describes the ratio of the re-fed mass flux to the granulator to the fed mass flux into the separator. The factor kgrowth describes the ratio of the mass flux which comes from the separator and is used for the layering and growth (continuous phase) and the mass flux which comes from the separator (dust) and is used as new internal seeds (disperse phase). 

This dust separated by pneumatic filters or cyclones can be recycled and used as internal seeds (disperse phase) for the production of new particles or for the layered growth (continuous phase) of existing particles. One effect of the production of internal seeds is the formation of a wide particle size distribution, while the deposition of the re-fed dust yields to growth of particles. 

Few researchers have concerned themselves with the role of chemicals in directing community succession. In the Piedmont area of North Carolina, Keever (27) began her work on succession in the hope of finding a chemical basis. However, she concluded that succession there was mainly directed by growth form of the plants involved (annual, biennial, perennial), time of germination, amount of shade cast, or efficiency of seed dispersal. She found little or no evidence for chemical control. 

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