caa a22 4500 475806743 CHVBK 20180406123749.0 cr unu---uuuuu 170329e20000301xx s 000 0 eng 10.1007/BF00984094 doi (NATIONALLICENCE)springer-10.1007/BF00984094 Pacini E. Dipartimento di Scienze Ambientali, via P. A. Mattioli 4, I-53100, Siena, Italy aut From anther and pollen ripening to pollen presentation [Elektronische Daten] [E. Pacini] The events and processes occurring between pollen maturation, opening of the anther and presentation of pollen to dispersing agents are described. In the final phases of pollen development, starch is always stored; this occurs before the anther opens. Depending on the species, this starch may be totally or partially transformed into: (a) other types of polysaccharides (fructans and rarely callose); (b) disaccharides (sucrose); (c) monosaccharides (glucose and fructose, all situated in the cytoplasm. While awaiting dispersing agents and during dispersal, polysaccharides, especially fructans, and sucrose may be interconverted to control osmotic pressure and prevent loss and uptake of water. Opening of the anther is preceded by disappearance of the locular fluid and in many cases by partial dehydration of the pollen. Pollen generally has a water content between 5 and 50%. Pollen with a high water content may or may not be able to control water retention during pollen exposure and dispersal. Pollen may be dispersed in monads or grouped in pollen dispersing units by the following mechanisms: (i). tangling of filamentous pollen; (ii). adhesion by viscous substances (pollenkitt, tryphine, elastoviscin) derived from the tapetum; (iii). common walls. When the anther opens, the pollen may be dispersed immediately, remain until dispersed (primary presentation), or be presented to pollinators in another part of the flower (secondary presentation). Springer-Verlag, 2000 Anther nationallicence pollen nationallicence dispersing units nationallicence dehydration state nationallicence carbohydrate reserves nationallicence pollen presentation nationallicence Plant Systematics and Evolution Springer-Verlag 222/1-4(2000-03-01), 19-43 0378-2697 222:1-4<19 2000 222 606 https://doi.org/10.1007/BF00984094 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00984094 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Pacini E. Dipartimento di Scienze Ambientali, via P. A. Mattioli 4, I-53100, Siena, Italy aut NATIONALLICENCE 773 0- Plant Systematics and Evolution Springer-Verlag 222/1-4(2000-03-01), 19-43 0378-2697 222:1-4<19 2000 222 606 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer