Mustafa, Adeel: Morphology, Ontogeny, and Biomineralization of Trichomes of Selected Higher Plants. - Bonn, 2018. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-50062
@phdthesis{handle:20.500.11811/7518,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-50062,
author = {{Adeel Mustafa}},
title = {Morphology, Ontogeny, and Biomineralization of Trichomes of Selected Higher Plants},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2018,
month = mar,

note = {This thesis describes the morphology and biomineralization of trichomes, which occur in different plant orders investigating: (i) The morphology and overall ontogenetic development stages of stinging hairs and scabrid-glochidiate trichomes in 14 representative species of Loasaceae, and the process of biomineralization; (ii) Patterns of multiple-biomineralization with calcium phosphate, silica and calcium carbonate in stinging trichomes and scabrid-glochidiate trichomes in 31 species of Loasaceae; (iii) Comparison of stinging trichomes biomineralization in 17 representative species from five different plant families; (iv) Distribution of the three biominerals in 42 species from nine families of the order Boraginales; (v) A broader survey of the distribution of the biomineral calcium phosphate, in combination with calcium carbonate and silica, in the walls of single-celled trichomes of several common and widespread plant species of different plant groups, extending to the total number of species analyzed up to 94.
Most of the SEM studies were performed on fresh plant materials from of the Botanical Garden of the University of Bonn, Germany, herbarium specimens were used only in few cases. SEMs equipped with an EDX element analysis system were used for the detection and localization of the mineral elements. Different SEM preparation methods were used, including cryo-SEM, critical point drying (CPD) and cryo-harvesting of trichomes. Further methods include Raman spectroscopy for the identification of biominerals and light microscopy for transmission views of isolated stinging trichomes.
It was revealed that trichomes of Loasaceae were mineralized with up to three different biominerals: calcium phosphate, calcium carbonate and silica. Very early stages of the different types of trichomes (stinging and scabrid-glochidiate) showed no mineralization. Trichome development initiated very early in organ development, and the different trichome types started developing their distinctive morphology at a very early stage. The process of biomineralization starts with the deposition of calcium phosphate or silica in the apex and then proceeds irregularly in the shaft and base. Typically, up to three biominerals – calcium phosphate, calcium carbonate and silica – are deposited at three different zones of the trichomes. The tips contained either silica or calcium phosphate; shafts usually contained calcium carbonate, or calcium phosphate in few cases; and bases often had additional silica deposits. Surprisingly, the biomineral calcium phosphate was found in the trichomes of many species in the orders Boraginales, Brassicales, Cornales, Malpighiales and Rosales. Boraginales (Boraginales I and Boraginales II) trichomes displayed either triple-mineralization (calcium phosphate, calcium carbonate and silica) or silica replacing calcium phosphate. Stinging trichome tips of Urticaceae were generally mineralized with silica; Caricaceae and Namaceae with calcium phosphate; and Loasaceae deposit with both minerals. Only the stinging trichomes of the genus Cnidoscolus (Euphorbiaceae) were found to be unmineralized.
Overall, the studies have greatly expanded our knowledge and understanding of the biomineralization diversity in plants, among different genera, different trichome types and even in various parts of the same trichome. Disparate biomineralization of the parts of individual, unicellular trichomes clearly indicates an extraordinary degree of physiological control over this process.},

url = {https://hdl.handle.net/20.500.11811/7518}
}

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