Studies on sporopollenin biosynthesis in Tulipa anthers

Abstract

Extensive tracer experiments were carried out on Tulipa with the aim of determining the structure and biosynthesis of sporopollenin. The radiolabeled precursors were applied using an improved technique previously selected. The sporopollenin fraction was purified using either a gentle method -hydrolyzing enzymes (pronase, amylase, amyloglucosidase, cellulase, pectinase and lipase) and alkaline hydrolysis (method A) -or by a conventional aggressive procedure, where the material was enriched by alkaline hydrolysis and treated several days with 80% phosphoric acid (method B). The 14C-labeled precursors applied were mevalonate, glucose, acetate, malonic acid, phenylalanine, tyrosine, p-coumaric acid. Regardless of the method of enrichment, a higher level of incorporation into the sporopollenin fraction was always seen with [U-14C]-phenylalanine. The level of radioactivity found in sporopollenin labeled by phenylalanine or malonate was sufficiently high for the labeled polymer to be degraded and the products released analyzed for the first time. In the case of phenylalanine-labeled sporopollenin, the main degradation component, p-hydroxybenzoic acid, was also the most heavily labeled substance. This result was not dependent on the procedure used for sporopollenin enrichment. These findings are interpreted as meaning that phenylpropane metabolism via phenylalanine-ammonia lyase is involved in sporopollenin biosynthesis.

Hollow Pollen Shells to Enhance Drug Delivery

“…FTIR (Fourier transform infrared) studies by Kawase et al agreed with a high proportion of aliphatic units and suggested that possibly the aliphatic core of sporopollenin shares a common biosynthesis among all different taxa and vascular plants in particular [ 52 , 53 ]. This means that each type of plant produces different aromatic side chains, which could differentiate pollen grain and spores at a microscopic level by both morphology and chemical structure [ 43 , 54 , 55 , 56 , 57 , 58 ]. Further solid-state NMR studies provided more data with more detail on the structure showing that the core comprises of tetra-, hexa-, and octa-cosanes.…”

“…The presence of phenolic groups in sporopollenin was showed using FTIR spectroscopy [ 69 ]. There are indications that phenols (particularly p -coumaric and ferulic acids) are not just involved as side chains within the core [ 52 , 70 ] but also in the cross-linking of the polymer [ 43 , 46 , 47 , 57 , 58 , 66 , 67 ].…”

Pollen-Mimetic Multiphase Polymer Microparticles

“…It is not soluble in any known solvent. Elemental analysis [3], ozonolytic oxidation [4], solid state NMR [5], IR [6] and fluorescence spectroscopy [7], as well as isotope labelling [8,9] hint to a crosslinked aromatic-aliphatic polyether-ester compound, * This paper was presented at the 15th Chitose International Forum "Nanotechnology -From Synthesis to Devices," Chitose Institute of Science and Technology, Chitose, Japan, October 2-3, 2014. † Corresponding author: kart@photon.chitose.ac.jp which is formed during pollen morphogenesis while the tapetum wall around the pollen tetrad dissolves [10,11].…”