Plant trichomes and the biomechanics of defense in various systems, with Solanaceae as a model

Botany ◽  
2019 ◽  
Vol 97 (12) ◽  
pp. 651-660 ◽  
Author(s):  
Maya Bar ◽  
Ilana Shtein

Plant trichomes are epidermal outgrowths of varying size and form. While the chemical defensive function of the secretory trichomes is well established, the biomechanical function of the non-glandular trichomes emerges as another major defensive strategy of plants. In particular, trichomes impede the locomotion of insect herbivores both by serving as a physical barrier and by wounding them. Solanaceous trichomes are often viewed as a model for the trichome development and defensive function. In particular, trichomes in tomato and relative species have been extensively examined, with different trichome types being precisely described. This review attempts to summarize the knowledge on trichomal defense and biomechanics, with a special emphasis on Solanaceae species, and suggests several avenues for future research.

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4166
Author(s):  
Agata Konarska ◽  
Elżbieta Weryszko-Chmielewska ◽  
Anna Matysik-Woźniak ◽  
Aneta Sulborska ◽  
Beata Polak ◽  
...  

The aim of this study was to conduct a histochemical analysis to localize lipids, terpenes, essential oil, and iridoids in the trichomes of the L. album subsp. album corolla. Morphometric examinations of individual trichome types were performed. Light and scanning electron microscopy techniques were used to show the micromorphology and localization of lipophilic compounds and iridoids in secretory trichomes with the use of histochemical tests. Additionally, the content of essential oil and its components were determined using gas chromatography-mass spectrometry (GC-MS). Qualitative analyses of triterpenes carried out using high-performance thin-layer chromatography (HPTLC) coupled with densitometric detection, and the iridoid content expressed as aucubin was examined with spectrophotometric techniques. We showed the presence of iridoids and different lipophilic compounds in papillae and glandular and non-glandular trichomes. On average, the flowers of L. album subsp. album yielded 0.04 mL/kg of essential oil, which was dominated by aldehydes, sesquiterpenes, and alkanes. The extract of the L. album subsp. album corolla contained 1.5 × 10−3 ± 4.3 × 10−4 mg/mL of iridoid aucubin and three triterpenes: oleanolic acid, β-amyrin, and β-amyrin acetate. Aucubin and β-amyrin acetate were detected for the first time. We suggest the use of L. album subsp. album flowers as supplements in human nutrition.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Peina Zhou ◽  
Mengjiao Yin ◽  
Shilin Dai ◽  
Ke Bao ◽  
Chenglin Song ◽  
...  

Abstract Background Perilla frutescens (L.) Britt is a medicinal and edible plant widely cultivated in Asia. Terpenoids, flavonoids and phenolic acids are the primary source of medicinal ingredients. Glandular trichomes with multicellular structures are known as biochemical cell factories which synthesized specialized metabolites. However, there is currently limited information regarding the site and mechanism of biosynthesis of these constituents in P. frutescens. Herein, we studied morphological features of glandular trichomes, metabolic profiling and transcriptomes through different tissues. Results Observation of light microscopy and scanning electron microscopy indicated the presence of three distinct glandular trichome types based on their morphological features: peltate, capitate, and digitiform glandular trichomes. The oil of peltate glandular trichomes, collected by custom-made micropipettes and analyzed by LC–MS and GC–MS, contained perillaketone, isoegomaketone, and egomaketone as the major constituents which are consistent with the components of leaves. Metabolomics and transcriptomics were applied to explore the bioactive constituent biosynthesis in the leaves, stem, and root of P. frutescens. Transcriptome sequencing profiles revealed differential regulation of genes related to terpenoids, flavonoids, and phenylpropanoid biosynthesis, respectively with most genes expressed highly in leaves. The genes affecting the development of trichomes were preliminarily predicted and discussed. Conclusions The current study established the morphological and chemical characteristics of glandular trichome types of P. frutescens implying the bioactive constituents were mainly synthesized in peltate glandular trichomes. The genes related to bioactive constituents biosynthesis were explored via transcriptomes, which provided the basis for unraveling the biosynthesis of bioactive constituents in this popular medicinal plant.


2012 ◽  
Vol 40 (1) ◽  
pp. 35 ◽  
Author(s):  
Hüseyin CILDIR ◽  
Ahmet KAHRAMAN ◽  
Musa DOGAN

In this study, the epidermal types and their distribution on dorsal and lateral petals, the trichome types and their density on sepals of Lathyrus chloranthus, L. digitatus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, L. sativus, and L. tuberosus, belonging to sections Lathyrus, Lathyrostylis, Pratensis, and Orobon of the genus Lathyrus in Turkey were investigated using light microscopy (LM) and scanning electron microscopy (SEM), and the systematic significance of these characters was evaluated. These taxa, except L. sativus, are studied for the first time under aspects of the petal and sepal micromorphology. Three major epidermal types were recognized on the petal: tabular rugose striate cells (TRS), areolate cells with more or less striations (AS), and papillose conical striate cells (PCS). TRS and AS were further subdivided into three subtypes. TRS was found on the dorsal and lateral petals of L. chloranthus, L. sativus, and L. tuberosus: the dorsal petals of L. roseus subsp. roseus and the lateral petals of L. laxiflorus subsp. laxiflorus, while AS was present on the dorsal and lateral petals of L. digitatus and the lateral petals of L. roseus subsp. roseus. PCS was found only on the dorsal petals of L. digitatus. Three main types of trichomes on the sepal were observed: peltate glandular, capitate glandular, and nonglandular trichomes. The capitate glandular and nonglandular trichomes were further subdivided into three subtypes. The peltate glandular trichomes were present only in L. chloranthus, but absent in the others. The capitate glandular trichomes were found in L. chloranthus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, and L. tuberosus. The nonglandular trichomes were always present in L. chloranthus and L. laxiflorus subsp. laxiflorus. The present results show that the petal and sepal micromorphology can be used in delimitation of the taxa based on petal and sepal micromorphology.


2004 ◽  
Vol 31 (3) ◽  
pp. 267 ◽  
Author(s):  
James L. Smith II ◽  
J. Daniel Hare

Plant trichomes commonly serve a role in mechanical and chemical defence against herbivores, but may also have the potential to alter physiology by reducing the amount of light absorbed by leaves, lowering temperatures, and reducing water loss. Populations of Datura wrightii Regel in southern California produce 'sticky' plants with glandular trichomes and 'velvety' plants bearing non-glandular trichomes. Because stickiness is inherited as a dominant Mendelian trait, and the proportions of sticky plants vary among populations with the moisture availability of their environment, there may be some ecophysiological differences between trichome types that contribute to their ability to survive in a particular geographic location. To examine the possible physiological significance of trichome variation, we measured the spectral properties, midday gas-exchange rates, and water potentials of D. wrightii leaves from sticky and velvety plants growing in a field experiment. The differences in leaf reflectance (0.9%) and absorptance (1.3%) of photosynthetically active radiation (PAR) between trichome types are too small to have any direct physiologically significant effect. Simulations of leaf temperatures based on the difference in leaf absorptances reveal that leaf temperature would be no more than 1°C lower in velvety compared to sticky plants. Gas-exchange measurements revealed no significant difference between types in their transpiration rates or stomatal conductances. In this case, trichome variation may be more important to plant defenses than to physiology.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1686 ◽  
Author(s):  
Shinji Sugiura

Some animals have evolved the use of environmental materials as “portable armour” against natural enemies. Portable bags that bagworm larvae (Lepidoptera: Psychidae) construct using their own silk and plant parts are generally believed to play an important role as a physical barrier against natural enemies. However, no experimental studies have tested the importance of bags as portable armour against predators. To clarify the defensive function, I studied the bagwormEumeta minusculaand a potential predatorCalosoma maximoviczi(Coleoptera: Carabidae). Under laboratory conditions, all bagworm larvae were attacked by carabid adults, but successfully defended themselves against the predators’ mandibles using their own bags. The portable bags, which are composed mainly of host plant twigs, may function as a physical barrier against predator mandibles. To test this hypothesis, I removed the twig bags and replaced some with herb leaf bags; all bag-removed larvae were easily caught and predated by carabids, while all bag-replaced larvae could successfully defend themselves against carabid attacks. Therefore, various types of portable bags can protect bagworm larvae from carabid attacks. This is the first study to test the defensive function of bagworm portable bags against invertebrate predators.


Author(s):  
V Trivellone ◽  
C H Dietrich

Abstract The association between insect herbivores and vascular plants represents one of the greatest success stories in terrestrial evolution. Specific mechanisms generating diversity in the association remain poorly understood, but it has become increasingly clear that microbes play important roles in mediating plant–insect interactions. Previous research on phytoplasmas (Acholeplasmatales: Acholeplasmataceae), a diverse group of plant-pathogenic bacteria, and their hemipteran insect vectors suggests that this system provides a new model for understanding how interactions among distantly related but ecologically associated groups of organisms can drive evolutionary diversification. Phytoplasma infections affect the phenotypes of both plants and vectors, altering functional traits (e.g., diet breadth) and mediating host shifts which may, in turn, alter genetic and phylogenetic patterns. This review highlights previous research on the functional ecology and phylogenetic components of phytoplasma-plant-vector (PPV) associations relevant to the evolutionary diversification of this system. Although phytoplasmas and their hosts occur in most terrestrial biomes and have evolved together over the past 300+ million years, major gaps in knowledge of PPV associations remain because most prior research on the system focused on strategies for mitigating effects of phytoplasma diseases in agroecosystems. Study of this system within a broader evolutionary context could help elucidate mechanisms by which interactions between insect herbivores, microbes, and plants drive biological diversification and also help predict the emergence of diseases affecting agriculture. Future research should more thoroughly document PPV associations in natural habitats, examine the relative prevalence of cospeciation versus host shifts in this system, and test possible macroevolutionary consequences of host manipulation by phytoplasmas.


Symmetry ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 13 ◽  
Author(s):  
Jiansheng Guo ◽  
Cheng Zhou

Pogostemon auricularius, an aromatic plant in Lamiaceae, has wide application in pharmaceutical preparations. However, little is known about the secretory structures that contain the medicinal compounds. In this study, two kinds of glandular trichome types, including peltate glandular trichomes and short-stalked capitate trichomes, were identified in the leaves and stems by cryo-scanning electron microscope. Oil secretion from the glands contained lipids, flavones, and terpenes, and the progresses of secretion were different in the two glands types. The investigation by transmission electron microscope indicated that the endoplasmic reticulum system and plastids were involved in the biosynthesis of oils in the two glandular trichomes. The vacuoles showed a new role in the oil preparations and storage. The synthesized oil could be transported from the head cell to the sub-cuticular space by different way in the two glands. Comparative analysis of the development, distribution, histochemistry and ultrastructures of the secretory structures in Pogostemon auricularius led us to propose that the two glands may make different contribution to the collection of medicinal compounds. Furthermore, the characteristics of two glands in the secretory stage probably indicated the synthesizing site of metabolite.


2021 ◽  
Vol 106 ◽  
pp. 271-291
Author(s):  
Mariana C. Grohar ◽  
Sonia Rosenfeldt ◽  
Renée H. Fortunato ◽  
Matías Morales

The genus Mimosa L. is well known for its high morphological variability and the presence of taxonomic complexes—groups of taxa that are not adequately circumscribed and are therefore in continuous revision. For this study, we analyzed flowers from 28 different taxa in Mimosa sect. Calothamnos Barneby and five vegetatively similar taxa from Mimosa sect. Mimosa. We observed three calyx shapes and four (glabrous or pubescent) calyx border types, as well as describe glandular trichomes on the calyx border for the first time in section Calothamnos. While the corolla exhibits only two shape types, trichomes on the corolla are much more diverse, as we found one simple and 11 branched trichome types in diverse orientations and dispositions. Given the taxonomic value of trichomes and profuse terminology in different families, we focused on the detailed description of their micromorphology, type, and shape, finding morphological differences between trichome types, which is an easy way to adequately compare them between even unrelated taxa. Our results using trichome types on the corolla are consistent with the original differentiation of sections Calothamnos and Mimosa. Flower micromorphology also provides characters to distinguish species, groups of species, and varieties within section Calothamnos and could be useful in a future taxonomic treatment of the section. We also found that some floral features, such as inflorescence color and stamen fusion, are associated with the characters used in this study.


2007 ◽  
Vol 85 (8) ◽  
pp. 712-721 ◽  
Author(s):  
Julio Antonio Lombardi

In South America, the family Vitaceae is represented by 65 species divided into 2 genera: Cissus contains 64 species, whereas Vitis consists of only 1 species. Recent studies on the Neotropical Cissus reveal that with regard to species delimitation, trichome types and the morphology of fruits and seeds are more important than the traditionally used trichome density and leaf shape. Fifteen provisional species groups are recognized for South America, excluding one species whose grouping is uncertain. Future research in this area should incorporate other data (e.g., anatomical, histological, and molecular) to identify a subgeneric division in Cissus.


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