A. Soukup | Charles University, Prague (original) (raw)

Papers by A. Soukup

The International journal of developmental biology, 1998

Although hyperthermia is an established teratogen in all species studied and the cellular heat sh... more Although hyperthermia is an established teratogen in all species studied and the cellular heat shock response is well known, the mechanisms of developmental deviation remain obscure. We have used a chick model system in which fertilized eggs containing embryos at presomite and/or early somite stages (HH 4-10) were exposed to 45 degrees C for 180 min. Six hours following treatment we did not observe any overt morphological disturbance, but at twelve hours following exposure (when controls reached HH 11-13) embryos exposed at late streak stages (HH 4-6) exhibited severe malformation of the head. Embryos exposed later (HH 6-9) manifested spina bifida at the thoracic and lumbosacral levels. Mirror image heart looping was also observed in 20% of these embryos. Paraxial mesoderm was apparently unaffected. Changes in cell proliferation and induced cell death preceded morphological changes. We used acridine orange and confocal laser microscopy to demonstrate that hyperthermia induced cell d...

Frontiers in plant science, 2017

The origin of the agriculture was one of the turning points in human history, and a central part ... more The origin of the agriculture was one of the turning points in human history, and a central part of this was the evolution of new plant forms, domesticated crops. Seed dispersal and germination are two key traits which have been selected to facilitate cultivation and harvesting of crops. The objective of this study was to analyze anatomical structure of seed coat and pod, identify metabolic compounds associated with water-impermeable seed coat and differentially expressed genes involved in pea seed dormancy and pod dehiscence. Comparative anatomical, metabolomics, and transcriptomic analyses were carried out on wild dormant, dehiscent Pisum elatius (JI64, VIR320) and cultivated, indehiscent Pisum sativum non-dormant (JI92, Cameor) and recombinant inbred lines (RILs). Considerable differences were found in texture of testa surface, length of macrosclereids, and seed coat thickness. Histochemical and biochemical analyses indicated genotype related variation in composition and heteroge...

Methods in molecular biology (Clifton, N.J.), 2014

This chapter gives examples of basic procedures of quantification of plant structures with the us... more This chapter gives examples of basic procedures of quantification of plant structures with the use of image analysis, which are commonly employed to describe differences among experimental treatments or phenotypes of plant material. Tasks are demonstrated with the use of ImageJ, a widely used public domain Java image processing program. Principles of sampling design based on systematic uniform random sampling for quantitative studies of anatomical parameters are given to obtain their unbiased estimations and simplified "rules of thumb" are presented. The basic procedures mentioned in the text are (1) sampling, (2) calibration, (3) manual length measurement, (4) leaf surface area measurement, (5) estimation of particle density demonstrated on an example of stomatal density, and (6) analysis of epidermal cell shape.

Methods in molecular biology (Clifton, N.J.), 2014

Histochemical methods allow for identification and localization of various components within the ... more Histochemical methods allow for identification and localization of various components within the tissue. Such information on the spatial heterogeneity is not available with biochemical methods. However, there is limitation of the specificity of such detection in context of complex tissue, which is important to consider, and interpretations of the results should regard suitable control treatments if possible. Hereby we present set of selected simple staining and histochemical methods with comments based on our laboratory experience.

Frontiers in Plant Science, 2014

Annals of Botany, 2013

† Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of... more † Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. † Methods Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. † Key Results The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. † Conclusions The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem structure and maintenance; however, development of the epidermis and cortex are impaired.

Planta, 2011

An indeterminate developmental program allows plant organs to grow continuously by maintaining fu... more An indeterminate developmental program allows plant organs to grow continuously by maintaining functional meristems over time. The molecular mechanisms involved in the maintenance of the root apical meristem are not completely understood. We have identified a new Arabidopsis thaliana mutant named moots koom 1 (mko1) that showed complete root apical meristem exhaustion of the primary root by 9 days post-germination. MKO1 is essential for maintenance of root cell proliferation. In the mutant, cell division is uncoupled from cell growth in the region corresponding to the root apical meristem. We established the sequence of cellular events that lead to meristem exhaustion in this mutant. Interestingly, the SCR and WOX5 promoters were active in the mko1 quiescent center at all developmental stages. However, during meristem exhaustion, the mutant root tip showed defects in starch accumulation in the columella and changes in auxin response pattern. Therefore, contrary to many described mutants, the determinate growth in mko1 seedlings does not appear to be a consequence of incorrect establishment or affected maintenance of the quiescent center but rather of cell proliferation defects both in stem cell niche and in the rest of the apical meristem. Our results support a model whereby the MKO1 gene plays an important role in the maintenance of the root apical meristem proliferative capacity and indeterminate root growth, which apparently acts independently of the SCR/SHR and WOX5 regulatory pathways.

Different algal species that may have germination inducing activity of holoparasitic broomrape we... more Different algal species that may have germination inducing activity of holoparasitic broomrape weeds Phelipanche aegyptiaca and P. ramosa seeds were screened through germination bioassay. Green alga produce SL-related compounds. Applied extracts of biomass obtained from the culture of green alga Trebouxia arboricola increased seeds germination of both parasites. An optimatization of the alga extraction led to an increase of P. aegyptiaca germination. Exhausted medium also contained SL-related compounds. The crude extract stimulated the roots length of Arabidopsis thaliana tested in vitro. A similar effect had the algae and GR24 aplications on expression levels of the SL-related genes in Physcomitrella patens. The novel analytical method DESI-MSI detected production of carlactone in the algae. The Trebouxia sp. culture applications in pot experiments had positive effect on growth characteristics of pea plants.

Functional Plant Biology, 2016

Traits influencing plant water use eventually define the fitness of genotypes for specific rainfa... more Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89–33 (terminal drought-adapted parent), H 77/833–2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89–33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (g H2O cm–2 h–1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per therma...

Biologia plantarum, 2016

Root epidermis and apoplastic barriers (endodermis and exodermis) are the critical root structure... more Root epidermis and apoplastic barriers (endodermis and exodermis) are the critical root structures involved in setting up plant-soil interface by regulating free apoplastic movement of solutes within root tissues. Probing root apoplast permeability with "apoplastic tracers" presents one of scarce tools available for detection of "apoplastic leakage" sites and evaluation of their role in overall root uptake of water, nutrients, or pollutants. Although the tracers are used for many decades, there is still not an ideal apoplastic tracer and flawless procedure with straightforward interpretation. In this article, we present our experience with the most frequently used tracers representing various types of chemicals with different characteristics. We examine their behaviour, characteristics, and limitations. Here, we show that results gained with an apoplastic tracer assay technique are reliable but depend on many parameters-chemical properties of a selected tracer, plant species, cell wall properties, exposure time, or sample processing.

Methods in molecular biology (Clifton, N.J.), 2014

There are various preparatory techniques for light microscopy permitting access to the inner stru... more There are various preparatory techniques for light microscopy permitting access to the inner structure of plant body and its development. Minute objects might be processed as whole-mount preparations, while voluminous ones should be separated into smaller pieces. Hereby we summarize some of the "classical" techniques to cut more voluminous objects into slices and access their inner structure either for simple anatomical analysis or for further processing (e.g., histochemistry, immunohistochemistry, in situ hybridization, enzyme histochemistry).

Annals of botany, 2005

The anatomical structure and development of adventitious roots were analysed in the basal monocot... more The anatomical structure and development of adventitious roots were analysed in the basal monocotyledon, Acorus calamus, to determine to what extent those features are related to phylogenetic position. Root specimens were harvested and sectioned, either with a hand microtome or freehand, at varying distances from the root tip and examined under the microscope using a variety of staining techniques. Roots of Acorus calamus possess a unique set of developmental characteristics that produce some traits similar to those of another basal angiosperm group, Nymphaeales. The root apical meristem organization seems to be intermediate between that of a closed and an open monocotyledonous root apical meristem organization. The open-type root apical meristem consists of a curved zone of cortical initials and epidermal initials overlying the vascular cylinder initials; the epidermal part of the meristem varies in its association with the cortical initials and columellar initials of the promerist...

New Phytologist, 2006

Few studies have examined exodermal development in relation to the formation of barriers to both ... more Few studies have examined exodermal development in relation to the formation of barriers to both radial oxygen loss (ROL) and solute penetration along growing roots. Here, we report on the structural development, chemical composition and functional properties of the exodermis in two diverse wetland grasses, Glyceria maxima and Phragmites australis. Anatomical features, development, the biochemical composition of exodermal suberin and the penetration of apoplastic tracers and oxygen were examined. Striking interspecific differences in exodermal structure, suberin composition and quantity per unit surface area, and developmental changes along the roots were recorded. Towards the root base, ROL and periodic acid (H(5)IO(6)) penetration were virtually stopped in P. australis; in G. maxima, a tight ROL barrier restricted but did not stop H(5)IO(6) penetration and the exodermis failed to stain with lipidic dyes. Cultivation in stagnant deep hypoxia conditions or oxygenated circulating solution affected the longitudinal pattern of ROL profiles in G. maxima but statistically significant changes in exodermal suberin composition or content were not detected. Interspecific differences in barrier performance were found to be related to hypodermal structure and probably to qualitative as well as quantitative variations in suberin composition and distribution within exodermal cell walls. Implications for root system function are discussed, and it is emphasized that sufficient spatial resolution to identify the effects of developmental changes along roots is crucial for realistic evaluation of exodermal barrier properties.

In Vitro Cellular & Developmental Biology - Plant, 2011

Plant regeneration was obtained from cultured anthers and hypocotyl segments of caraway (Carum ca... more Plant regeneration was obtained from cultured anthers and hypocotyl segments of caraway (Carum carvi L.). Microspore- and somatic tissue-derived embryos were compared by observation of the regeneration process under identical induction conditions. Fluorescent microscopy with DAPI staining showed initiation of cell divisions and formation of embryogenic callus and somatic embryos from anther sacs, with production of embryos of both microspore

Environmental and Experimental Botany, 2006

Performance of Typha angustifolia, a species common in European wetlands, was studied in connecti... more Performance of Typha angustifolia, a species common in European wetlands, was studied in connection with wetlands eutrophication. Cultivation in a sand culture was used to follow the effect of nutrient availability per se and to study, in detail, both aboveground as well as belowground organs (rhizomes and roots) of the plant in contrast to the possibilities of field study. A complex study of growth, carbohydrate, and nitrogen metabolic relationships, with respect to tissue age, was done in plants growing in nutrient solutions that differed in their levels of N and P (oligotrophic: 0.026 mM N and 0.001 mM P; eutrophic: 2.635 mM N and 0.0999 mM P; hypertrophic treatment: 9.539 mM N and 0.999 mM P). In contrast to the poor growth of Typha plants under the oligotrophic treatment, Typha coped best under the eutrophic treatment. Further increase in nutrient availability to the hypertrophic treatment did not result in additional stimulation of growth, but instead some negative reactions appeared. Changes in the growth and allocation of biomass, in favour of shoots and including rhizomes (as compared with roots) with increasing nutrient availability, were accompanied by an increase in N allocation and content of non-structural carbohydrates in these tissues. Detailed biochemical analysis revealed significant differences between tissues of different ages. These characteristics probably reflect the physiological potential of this species for their successful spreading in natural eutrophic habitats. Moreover, a decrease in the C/N ratio, decreasing proportion of starch/soluble sugars ratio, increasing proportion of hexoses/sucrose ratio (taking into account the type and tissue age of plant organs), with increasing nutrient availability, indicate high metabolic activity of the tissues at the stage of maximum growth.

Biologia plantarum, 2004

The lignin contents and anatomical structure of roots of wild cherry (Prunus avium L.) and pedunc... more The lignin contents and anatomical structure of roots of wild cherry (Prunus avium L.) and pedunculate oak (Quercus robur L.) plantlets were compared to explain differences in response during transfer from in vitro to ex vitro conditions. Lignification of cell walls increased significantly in both oak and cherry roots during the period of acclimation and finally lignin content of root tissues of in vitro propagated plantlets reached the levels not significantly different from seedlings grown in soil. Later on when secondary tissues appeared, lignified secondary xylem constituted most of the tissues of both species. The most conspicuous interspecific difference in root structure was the presence of phithickenings in cortical layers just outer to endodermis in cherry roots cultivated ex vitro. Formation of phi-thickenings was avoided in vitro and their presence thus seems to be under environmental control. Suberised well established exodermis was present in roots of oak but not detected in those of cherry. Very early development of exodermis in oak roots, preceding suberisation of endodermis, was recorded in vitro but not in well aerated soil. While multilayered and well-developed cork occurred in oak, only thin walled and less suberised secondary dermal tissues were found in cherry.

Biologia plantarum, 2009

Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by ... more Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by environmental conditions. In our study, young maize plants, cultivated in various ways in order to minimise the stressing effect of hypoxia, flooding, mechanical impedance or nutrient starvation, were examined for the presence of aerenchyma in their primary roots. The area of aerenchyma in the root cortex was correlated with the root length. Although 12 different maize accessions were used, no plants without aerenchyma were acquired until an ethylene synthesis inhibitor was employed. Using an ACC-synthase inhibitor, it was confirmed that the aerenchyma formation is ethylene-regulated and dependent on irradiance. The presence of TUNEL-positive nuclei and ultrastructural changes in cortical cells suggest a connection between ethylene-dependent aerenchyma formation and programmed cell death. Position of cells with TUNEL-positive nuclei in relation to aerenchyma-channels was described.

Annals of botany, 2005

We review literature and present new observations on the differences among three general patterns... more We review literature and present new observations on the differences among three general patterns of aerenchyma origin and their systematic distributions among the flowering plants, and we clarify terminology on root aerenchyma. From our own previous works and some new observations, we have analysed the root cortex in 85 species of 41 families in 21 orders of flowering plants that typically grow in wetlands to determine the characteristic patterns of aerenchyma. A developmental and structural pattern that we term expansigeny, as manifested by honeycomb aerenchyma, is characteristic of all aquatic basal angiosperms (the Nymphaeales) and basal monocots (the Acorales). Expansigenous aerenchyma develops by expansion of intercellular spaces into lacunae by cell division and cell expansion. Schizogeny and lysigeny, so often characterized in recent reviews as the only patterns of root cortex lacunar formation, are present in most wetland plants, but are clearly not present in the most basa...

The International journal of developmental biology, 1998

Although hyperthermia is an established teratogen in all species studied and the cellular heat sh... more Although hyperthermia is an established teratogen in all species studied and the cellular heat shock response is well known, the mechanisms of developmental deviation remain obscure. We have used a chick model system in which fertilized eggs containing embryos at presomite and/or early somite stages (HH 4-10) were exposed to 45 degrees C for 180 min. Six hours following treatment we did not observe any overt morphological disturbance, but at twelve hours following exposure (when controls reached HH 11-13) embryos exposed at late streak stages (HH 4-6) exhibited severe malformation of the head. Embryos exposed later (HH 6-9) manifested spina bifida at the thoracic and lumbosacral levels. Mirror image heart looping was also observed in 20% of these embryos. Paraxial mesoderm was apparently unaffected. Changes in cell proliferation and induced cell death preceded morphological changes. We used acridine orange and confocal laser microscopy to demonstrate that hyperthermia induced cell d...

Frontiers in plant science, 2017

The origin of the agriculture was one of the turning points in human history, and a central part ... more The origin of the agriculture was one of the turning points in human history, and a central part of this was the evolution of new plant forms, domesticated crops. Seed dispersal and germination are two key traits which have been selected to facilitate cultivation and harvesting of crops. The objective of this study was to analyze anatomical structure of seed coat and pod, identify metabolic compounds associated with water-impermeable seed coat and differentially expressed genes involved in pea seed dormancy and pod dehiscence. Comparative anatomical, metabolomics, and transcriptomic analyses were carried out on wild dormant, dehiscent Pisum elatius (JI64, VIR320) and cultivated, indehiscent Pisum sativum non-dormant (JI92, Cameor) and recombinant inbred lines (RILs). Considerable differences were found in texture of testa surface, length of macrosclereids, and seed coat thickness. Histochemical and biochemical analyses indicated genotype related variation in composition and heteroge...

Methods in molecular biology (Clifton, N.J.), 2014

This chapter gives examples of basic procedures of quantification of plant structures with the us... more This chapter gives examples of basic procedures of quantification of plant structures with the use of image analysis, which are commonly employed to describe differences among experimental treatments or phenotypes of plant material. Tasks are demonstrated with the use of ImageJ, a widely used public domain Java image processing program. Principles of sampling design based on systematic uniform random sampling for quantitative studies of anatomical parameters are given to obtain their unbiased estimations and simplified "rules of thumb" are presented. The basic procedures mentioned in the text are (1) sampling, (2) calibration, (3) manual length measurement, (4) leaf surface area measurement, (5) estimation of particle density demonstrated on an example of stomatal density, and (6) analysis of epidermal cell shape.

Methods in molecular biology (Clifton, N.J.), 2014

Histochemical methods allow for identification and localization of various components within the ... more Histochemical methods allow for identification and localization of various components within the tissue. Such information on the spatial heterogeneity is not available with biochemical methods. However, there is limitation of the specificity of such detection in context of complex tissue, which is important to consider, and interpretations of the results should regard suitable control treatments if possible. Hereby we present set of selected simple staining and histochemical methods with comments based on our laboratory experience.

Frontiers in Plant Science, 2014

Annals of Botany, 2013

† Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of... more † Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. † Methods Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. † Key Results The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. † Conclusions The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem structure and maintenance; however, development of the epidermis and cortex are impaired.

Planta, 2011

An indeterminate developmental program allows plant organs to grow continuously by maintaining fu... more An indeterminate developmental program allows plant organs to grow continuously by maintaining functional meristems over time. The molecular mechanisms involved in the maintenance of the root apical meristem are not completely understood. We have identified a new Arabidopsis thaliana mutant named moots koom 1 (mko1) that showed complete root apical meristem exhaustion of the primary root by 9 days post-germination. MKO1 is essential for maintenance of root cell proliferation. In the mutant, cell division is uncoupled from cell growth in the region corresponding to the root apical meristem. We established the sequence of cellular events that lead to meristem exhaustion in this mutant. Interestingly, the SCR and WOX5 promoters were active in the mko1 quiescent center at all developmental stages. However, during meristem exhaustion, the mutant root tip showed defects in starch accumulation in the columella and changes in auxin response pattern. Therefore, contrary to many described mutants, the determinate growth in mko1 seedlings does not appear to be a consequence of incorrect establishment or affected maintenance of the quiescent center but rather of cell proliferation defects both in stem cell niche and in the rest of the apical meristem. Our results support a model whereby the MKO1 gene plays an important role in the maintenance of the root apical meristem proliferative capacity and indeterminate root growth, which apparently acts independently of the SCR/SHR and WOX5 regulatory pathways.

Different algal species that may have germination inducing activity of holoparasitic broomrape we... more Different algal species that may have germination inducing activity of holoparasitic broomrape weeds Phelipanche aegyptiaca and P. ramosa seeds were screened through germination bioassay. Green alga produce SL-related compounds. Applied extracts of biomass obtained from the culture of green alga Trebouxia arboricola increased seeds germination of both parasites. An optimatization of the alga extraction led to an increase of P. aegyptiaca germination. Exhausted medium also contained SL-related compounds. The crude extract stimulated the roots length of Arabidopsis thaliana tested in vitro. A similar effect had the algae and GR24 aplications on expression levels of the SL-related genes in Physcomitrella patens. The novel analytical method DESI-MSI detected production of carlactone in the algae. The Trebouxia sp. culture applications in pot experiments had positive effect on growth characteristics of pea plants.

Functional Plant Biology, 2016

Traits influencing plant water use eventually define the fitness of genotypes for specific rainfa... more Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89–33 (terminal drought-adapted parent), H 77/833–2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89–33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (g H2O cm–2 h–1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per therma...

Biologia plantarum, 2016

Root epidermis and apoplastic barriers (endodermis and exodermis) are the critical root structure... more Root epidermis and apoplastic barriers (endodermis and exodermis) are the critical root structures involved in setting up plant-soil interface by regulating free apoplastic movement of solutes within root tissues. Probing root apoplast permeability with "apoplastic tracers" presents one of scarce tools available for detection of "apoplastic leakage" sites and evaluation of their role in overall root uptake of water, nutrients, or pollutants. Although the tracers are used for many decades, there is still not an ideal apoplastic tracer and flawless procedure with straightforward interpretation. In this article, we present our experience with the most frequently used tracers representing various types of chemicals with different characteristics. We examine their behaviour, characteristics, and limitations. Here, we show that results gained with an apoplastic tracer assay technique are reliable but depend on many parameters-chemical properties of a selected tracer, plant species, cell wall properties, exposure time, or sample processing.

Methods in molecular biology (Clifton, N.J.), 2014

There are various preparatory techniques for light microscopy permitting access to the inner stru... more There are various preparatory techniques for light microscopy permitting access to the inner structure of plant body and its development. Minute objects might be processed as whole-mount preparations, while voluminous ones should be separated into smaller pieces. Hereby we summarize some of the "classical" techniques to cut more voluminous objects into slices and access their inner structure either for simple anatomical analysis or for further processing (e.g., histochemistry, immunohistochemistry, in situ hybridization, enzyme histochemistry).

Annals of botany, 2005

The anatomical structure and development of adventitious roots were analysed in the basal monocot... more The anatomical structure and development of adventitious roots were analysed in the basal monocotyledon, Acorus calamus, to determine to what extent those features are related to phylogenetic position. Root specimens were harvested and sectioned, either with a hand microtome or freehand, at varying distances from the root tip and examined under the microscope using a variety of staining techniques. Roots of Acorus calamus possess a unique set of developmental characteristics that produce some traits similar to those of another basal angiosperm group, Nymphaeales. The root apical meristem organization seems to be intermediate between that of a closed and an open monocotyledonous root apical meristem organization. The open-type root apical meristem consists of a curved zone of cortical initials and epidermal initials overlying the vascular cylinder initials; the epidermal part of the meristem varies in its association with the cortical initials and columellar initials of the promerist...

New Phytologist, 2006

Few studies have examined exodermal development in relation to the formation of barriers to both ... more Few studies have examined exodermal development in relation to the formation of barriers to both radial oxygen loss (ROL) and solute penetration along growing roots. Here, we report on the structural development, chemical composition and functional properties of the exodermis in two diverse wetland grasses, Glyceria maxima and Phragmites australis. Anatomical features, development, the biochemical composition of exodermal suberin and the penetration of apoplastic tracers and oxygen were examined. Striking interspecific differences in exodermal structure, suberin composition and quantity per unit surface area, and developmental changes along the roots were recorded. Towards the root base, ROL and periodic acid (H(5)IO(6)) penetration were virtually stopped in P. australis; in G. maxima, a tight ROL barrier restricted but did not stop H(5)IO(6) penetration and the exodermis failed to stain with lipidic dyes. Cultivation in stagnant deep hypoxia conditions or oxygenated circulating solution affected the longitudinal pattern of ROL profiles in G. maxima but statistically significant changes in exodermal suberin composition or content were not detected. Interspecific differences in barrier performance were found to be related to hypodermal structure and probably to qualitative as well as quantitative variations in suberin composition and distribution within exodermal cell walls. Implications for root system function are discussed, and it is emphasized that sufficient spatial resolution to identify the effects of developmental changes along roots is crucial for realistic evaluation of exodermal barrier properties.

In Vitro Cellular & Developmental Biology - Plant, 2011

Plant regeneration was obtained from cultured anthers and hypocotyl segments of caraway (Carum ca... more Plant regeneration was obtained from cultured anthers and hypocotyl segments of caraway (Carum carvi L.). Microspore- and somatic tissue-derived embryos were compared by observation of the regeneration process under identical induction conditions. Fluorescent microscopy with DAPI staining showed initiation of cell divisions and formation of embryogenic callus and somatic embryos from anther sacs, with production of embryos of both microspore

Environmental and Experimental Botany, 2006

Performance of Typha angustifolia, a species common in European wetlands, was studied in connecti... more Performance of Typha angustifolia, a species common in European wetlands, was studied in connection with wetlands eutrophication. Cultivation in a sand culture was used to follow the effect of nutrient availability per se and to study, in detail, both aboveground as well as belowground organs (rhizomes and roots) of the plant in contrast to the possibilities of field study. A complex study of growth, carbohydrate, and nitrogen metabolic relationships, with respect to tissue age, was done in plants growing in nutrient solutions that differed in their levels of N and P (oligotrophic: 0.026 mM N and 0.001 mM P; eutrophic: 2.635 mM N and 0.0999 mM P; hypertrophic treatment: 9.539 mM N and 0.999 mM P). In contrast to the poor growth of Typha plants under the oligotrophic treatment, Typha coped best under the eutrophic treatment. Further increase in nutrient availability to the hypertrophic treatment did not result in additional stimulation of growth, but instead some negative reactions appeared. Changes in the growth and allocation of biomass, in favour of shoots and including rhizomes (as compared with roots) with increasing nutrient availability, were accompanied by an increase in N allocation and content of non-structural carbohydrates in these tissues. Detailed biochemical analysis revealed significant differences between tissues of different ages. These characteristics probably reflect the physiological potential of this species for their successful spreading in natural eutrophic habitats. Moreover, a decrease in the C/N ratio, decreasing proportion of starch/soluble sugars ratio, increasing proportion of hexoses/sucrose ratio (taking into account the type and tissue age of plant organs), with increasing nutrient availability, indicate high metabolic activity of the tissues at the stage of maximum growth.

Biologia plantarum, 2004

The lignin contents and anatomical structure of roots of wild cherry (Prunus avium L.) and pedunc... more The lignin contents and anatomical structure of roots of wild cherry (Prunus avium L.) and pedunculate oak (Quercus robur L.) plantlets were compared to explain differences in response during transfer from in vitro to ex vitro conditions. Lignification of cell walls increased significantly in both oak and cherry roots during the period of acclimation and finally lignin content of root tissues of in vitro propagated plantlets reached the levels not significantly different from seedlings grown in soil. Later on when secondary tissues appeared, lignified secondary xylem constituted most of the tissues of both species. The most conspicuous interspecific difference in root structure was the presence of phithickenings in cortical layers just outer to endodermis in cherry roots cultivated ex vitro. Formation of phi-thickenings was avoided in vitro and their presence thus seems to be under environmental control. Suberised well established exodermis was present in roots of oak but not detected in those of cherry. Very early development of exodermis in oak roots, preceding suberisation of endodermis, was recorded in vitro but not in well aerated soil. While multilayered and well-developed cork occurred in oak, only thin walled and less suberised secondary dermal tissues were found in cherry.

Biologia plantarum, 2009

Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by ... more Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by environmental conditions. In our study, young maize plants, cultivated in various ways in order to minimise the stressing effect of hypoxia, flooding, mechanical impedance or nutrient starvation, were examined for the presence of aerenchyma in their primary roots. The area of aerenchyma in the root cortex was correlated with the root length. Although 12 different maize accessions were used, no plants without aerenchyma were acquired until an ethylene synthesis inhibitor was employed. Using an ACC-synthase inhibitor, it was confirmed that the aerenchyma formation is ethylene-regulated and dependent on irradiance. The presence of TUNEL-positive nuclei and ultrastructural changes in cortical cells suggest a connection between ethylene-dependent aerenchyma formation and programmed cell death. Position of cells with TUNEL-positive nuclei in relation to aerenchyma-channels was described.

Annals of botany, 2005

We review literature and present new observations on the differences among three general patterns... more We review literature and present new observations on the differences among three general patterns of aerenchyma origin and their systematic distributions among the flowering plants, and we clarify terminology on root aerenchyma. From our own previous works and some new observations, we have analysed the root cortex in 85 species of 41 families in 21 orders of flowering plants that typically grow in wetlands to determine the characteristic patterns of aerenchyma. A developmental and structural pattern that we term expansigeny, as manifested by honeycomb aerenchyma, is characteristic of all aquatic basal angiosperms (the Nymphaeales) and basal monocots (the Acorales). Expansigenous aerenchyma develops by expansion of intercellular spaces into lacunae by cell division and cell expansion. Schizogeny and lysigeny, so often characterized in recent reviews as the only patterns of root cortex lacunar formation, are present in most wetland plants, but are clearly not present in the most basa...