Abaxial Epidermis Research Articles

Triacontanol Reverses Abscisic Acid Effects on Stomatal Regulation in Solanum lycopersicum L. under Drought Stress Conditions

When applied under abiotic stress conditions, triacontanol (TRIA) is effective in regulating the physicochemical processes in plants through mechanisms of defence such as abscisic acid (ABA) signalling. However, TRIA’s role in relation to ABA and stomatal opening is unclear. Therefore, the objective of this study was to evaluate the effects of TRIA and ABA and their combinations on different variables related to stomatal regulation in Solanum lycopersicum, which is subjected to drought stress, and on the leaf epidermis. The negative effects of stress and responses triggered by ABA were reversed in plants treated with TRIA. TRIA increased stomatal conductance and photosynthetic activity in the early hours, and it was determined that TRIA produced larger stomata than did the other treatments. Moreover, the chloroplasts of plants treated with TRIA were significantly smaller and more numerous than those of the control, which could improve CO2 diffusion efficiency and may be related to the regulation of stomatal opening and photosynthesis. Finally, the abaxial epidermis tests reaffirmed the inhibitory effects of TRIA on ABA on stomatal opening. These results confirm the important role of TRIA in regulating various processes in plants and processes triggered by ABA, such as those related to stomatal regulation.

Stomatal patterning is differently regulated in adaxial and abaxial epidermis in Arabidopsis.

Stomatal pores in leaves mediate CO2 uptake into the plant and water loss via transpiration. Most plants are hypostomatous with stomata present only in the lower leaf surface (abaxial epidermis). Many herbs, including the model plant Arabidopsis, have substantial numbers of stomata also on the upper (adaxial) leaf surface. Studies of stomatal development have mostly focused on abaxial stomata and very little is known of adaxial stomatal formation. We analysed the role of leaf number in determining stomatal density and stomatal ratio, and studied adaxial and abaxial stomatal patterns in Arabidopsis mutants deficient in known abaxial stomatal development regulators. We found that stomatal density in some genetic backgrounds varies between different fully expanded leaves, and thus we recommend using defined leaves for analyses of stomatal patterning. Our results indicate that stomatal development is at least partly independently regulated in adaxial and abaxial epidermis, as (i) plants deficient in ABA biosynthesis and perception have increased stomatal ratios, (ii) the epf1epf2, tmm, and sdd1 mutants have reduced stomatal ratios, (iii) erl2 mutants have increased adaxial but not abaxial stomatal index, and (iv) stomatal precursors preferentially occur in abaxial epidermis. Further studies of adaxial stomata can reveal new insights into stomatal form and function.

Quality Studies on Cynometra iripa Leaf and Bark as Herbal Medicines.

Cynometra iripa Kostel. is a Fabaceae species of mangrove used in traditional Ayurvedic medicine for treating inflammatory conditions. The present study aims to establish monographic botanical and chemical quality criteria for C. iripa leaf and bark as herbal substances and to evaluate their in vitro antioxidant potential. Macroscopic and microscopic qualitative and quantitative analyses, chemical LC-UV/DAD-ESI/MS profiling, and the quantification of key chemical classes were performed. Antioxidant activity was evaluated by DPPH and FRAP assays. Macroscopically, the leaf is asymmetrical with an emarginated apex and cuneate base. Microscopically, it shows features such as two-layered adaxial palisade parenchyma, vascular bundles surrounded by 3-6 layers of sclerenchyma, prismatic calcium oxalate crystals (5.89 ± 1.32 μm) along the fibers, paracytic stomata only on the abaxial epidermis (stomatal index-20.15), and non-glandular trichomes only on petiolules. The microscopic features of the bark include a broad cortex with large lignified sclereids, prismatic calcium oxalate crystals (8.24 ± 1.57 μm), and secondary phloem with distinct 2-5 seriated medullary rays without crystals. Chemical profile analysis revealed that phenolic derivatives, mainly condensed tannins and flavonoids, are the main classes identified. A total of 22 marker compounds were tentatively identified in both plant parts. The major compounds identified in the leaf were quercetin-3-O-glucoside and taxifolin pentoside and in the bark were B-type dimeric proanthocyanidins and taxifolin 3-O-rhamnoside. The total phenolics content was higher in the leaf (1521 ± 4.71 mg GAE/g dry weight), while the total flavonoids and condensed tannins content were higher in the bark (82 ± 0.58 mg CE/g and 1021 ± 5.51 mg CCE/g dry weight, respectively). A total of 70% of the hydroethanolic extracts of leaf and bark showed higher antioxidant activity than the ascorbic acid and concentration-dependent scavenging activity in the DPPH assay (IC50 23.95 ± 0.93 and 23.63 ± 1.37 µg/mL, respectively). A positive and statistically significant (p < 0.05) correlation between the phenol content and antioxidant activity was found. The results obtained will provide important clues for the quality control criteria of C. iripa leaf and bark, as well as for the knowledge of their pharmacological potential as possible anti-inflammatory agents with antioxidant activity.

MORPHO-ANATOMICAL PROFILE OF ELAEOCARPUS TUBERCULATUS ROXB

Objective: The anatomical studies of Elaeocarpus tuberculatus Roxb. (Elaeocarpaceae), an indigenous medicinal plant in the Indian pharmacopoeia. Methods: Fresh leaf and stem samples of E. tuberculatus were scrutinized macroscopic and microscopically by standard procedures. Results: Macroscopically, the leaves are simple, long, coriaceous, and rusty below, base obtuse, margin serrate, apex obtuse and petiole 3 cm long. Microscopically, the leaf showed the presence of four prominent collateral bundles. Paracytic stomata were distributed in the abaxial epidermis whereas the adaxial epidermis was apostomatic. The petiole was four-angled including wing bundles. The stem exhibited fissured periderm, wide secondary phloem, secondary xylem with incipient growth ring and abundant calcium oxalate crystals. Powdered microscopic study of the leaf revealed the presence of long whip-like epidermal trichomes, crystals, vessel elements showing pits and fiber-like sclereids. The stem powder showed thick-walled fibers with wide lumen, narrow fibers and a sclerenchyma cell showing wide pits. Conclusion: The results of the study can serve as a valuable source of information and provide suitable standards for the identification of E. tuberculatus in future investigations and applications

Anatomy of the saltgrass (Distichlis spicata L.) leaves with irrigation and without irrigation

Distichlis spicata is a gramineous halophyte species that grow around the coastal areas. The objective of the study was to identify the modifications in the anatomical structure of stomates of the D. spicata leaf epidermis, cultivated with irrigation and without irrigation conditions. Two populations were selected, 1) plants of D. spicata with irrigation and 2) plants of D. spicata without irrigation. Ten plants per replication were selected from each population, and from each selected plant, the fourth leaf was taken. Each leaf was cut longitudinally into four segments which were dried and analyzed using an Electronic Scanning Microscope. The variables measured were the stomatal density, length, and width of stomates and pores, the stomatal area, the proportion of the pore area concerning the size of the stomata, and the stomata proportion per surface. The results showed that D. spicata populations with irrigation and without irrigation showed anatomical modifications in the structure of stomates in the adaxial epidermis but not in the abaxial epidermis. In the adaxial epidermis, the plants with irrigation showed higher values of stoma length, stoma width, stoma area and pore length, while plants without irrigation showed higher values of proportion pore/stoma and stomatal density. The D. spicata plants without irrigation showed small stomates than plants with irrigation, also, the plants without irrigation, increased the accumulation of salt crystals in the abaxial epidermis.

Alterations induced by Colomerus vitis on the structural and physiological leaf features of two grape cultivars.

Vitis vinifera is cultivated worldwide for its high nutritional and commercial value. More than 60 grape cultivars are cultivated in Chile. Two of these, the país and the corinto cultivars, are the oldest known and widely used for the preparation of traditional homemade drinks and consumption as table grapes. These two grape cultivars are affected by Colomerus vitis, an eriophyid mite which establishes on their leaves and forms erinea, where the mite and its offspring obtain shelter and food. Although C. vitis has a cosmopolitan distribution, few studies of its impact on the structure and physiology of affected plants have been reported. Herein we aimed to evaluate the impact of C. vitis infection on the structural and physiological leaf performance of the two grape cultivars. The results showed tissue hyperplasia and cell hypertrophy in the epidermis, with an overproduction of trichomes and emergences in the abaxial epidermis in both cultivars. The anatomical changes were similar between the país and corinto cultivars, but they were proportionally greater in the país, where the area affected by the erinea were greater. No significant changes were detected in the photosynthetic pigment content; however, there was an increase in the total soluble sugars content in the erineum leaves of the país cultivar. Higher contents of anthocyanins and total phenols, as well as the presence of the pinocembrin in the corinto cultivar, which was less affected by C. vitis, could also indicate some resistance to mites' attack, which should be investigated in future studies.

AsHSP26.2, a creeping bentgrass chloroplast small heat shock protein positively regulates plant development.

The creeping bentgrass small heat shock protein AsHSP26.2 positively regulates plant growth and is a novel candidate for use in crop genetic engineering for enhanced biomass production and grain yield. Small heat shock proteins (sHSPs), a family of proteins with high level of diversity, significantly influence plant stress tolerance and plant development. We have cloned a creeping bentgrass chloroplast-localized sHSP gene, AsHSP26.2 responsive to IAA, GA and 6-BA stimulation. Transgenic creeping bentgrass overexpressing AsHSP26.2 exhibited significantly enhanced plant growth with increased stolon number and length as well as enlarged leaf blade width and leaf sheath diameters, but inhibited leaf trichomes initiation and development in the abaxial epidermis. These phenotypes are completely opposite to those displayed in the transgenic plants overexpressing AsHSP26.8, another chloroplast sHSP26 isoform that contains additional seven amino acids (AEGQGDG) between the consensus regions III and IV (Sun et al., Plant Cell Environ 44:1769-1787, 2021). Furthermore, AsHSP26.2 overexpression altered phytohormone biosynthesis and signaling transduction, resulting in elevated auxin and gibberellins (GA) accumulation. The results obtained provide novel insights implicating the sHSPs in plant growth and development regulation, and strongly suggest AsHSP26.2 to be a novel candidate for use in crop genetic engineering for enhanced plant biomass production and grain yield.

Estudos anatômicos, cariotípicos e de conteúdo de DNA nuclear em quatro morfotipos de alface silvestre

ABSTRACT Wild lettuce (Lactuca aff. canadensis L.), belonging to the Asteraceae family, occurs subspontaneously in Brazil and may originate from Africa, Asia, Europe and North America. Popularly known as Canada lettuce, it is an unconventional leafy vegetable. Studies on this species are scarce in Brazil, and its scientific name is debated among experts. It has high morphological variability and controversial botanical classification. This study characterized the stomata, organized the karyotype, and determined the nuclear DNA content of four morphotypes of wild lettuce to facilitate correct classification. The genetic material used was acquired from the non-conventional vegetable germplasm in UFLA. The leaves of wild lettuce morphotypes are hypoamphiestomatic with a greater number of stomata in the abaxial epidermis. There were similarities between the morphotypes (green and purple) and between the smooth purple types (narrow leaf and broad leaf) for the number and size of stomata. No variation was found in the number of chromosomes (2n = 18) or DNA content among the four morphotypes. The separation of the morphotypes of wild lettuce did not match the morphological classification or the karyological data. The four morphotypes evaluated were placed under the same species, and the results obtained when compared to other studies led us to infer that the four morphotypes of wild Lactuca belonged to the species L. indica and not L. canadensis as previously assumed. Further investigation may provide insights into the evolutionary history of this species.

Tolerance of Hymenaea stigonocarpa mart. Ex Hayne. To glyphosate.

Hymenaea stigonocarpa Mart. ex Hayne has leaves with adaxial and abaxial epidermis covered by a very thick cuticle, in addition to anatomical structures involved in reducing the amount of herbicide absorbed by plants. Thus, we tested the hypothesis that H. stigonocarpa is potentially resistant to the herbicide glyphosate, exposing the plants to different doses (0, 96, 240, 480, and 960 g a.e ha-1). We carried out assessments of the symptoms, anatomy, growth and physiology of the plants and found that exposure to glyphosate negatively affected the height and number of leaves of the plants. Leaf fall resulted in a reduction in the photosynthetic capacity of plants, which responded by investing in stem diameter. Despite this, no visual symptoms of glyphosate toxicity were observed at the concentrations evaluated and histochemical tests did not detect signs of oxidative stress in the leaves, nor starch accumulation, indicating that carbohydrate translocation was not impaired. These results confirm our hypothesis of tolerance of H. stigonocarpa to glyphosate. Furthermore, plants exposed to the lowest doses of glyphosate (96 and 240 g ha-1) showed good growth, photosynthesis, transpiration and photochemical potential responses, indicating a hormetic effect in this application range.

Tratamento foliar com metil jasmonato na restrição do crescimento e na anatomia de foliar de Begônia ‘Dragon Wing’

Abstract The application of plant growth regulators, primarily gibberellin inhibitors, is the main approach used for controlling the growth of ornamental plants. However, there is a growing interest in alternative products due to the risk of environmental toxicity associated with traditional methods. Methyl jasmonate (MeJa) is a natural substance found in plants and is considered to have low toxicity when used appropriately. Its use as a growth regulator has shown promise for controlling plant growth, but its effects have not been extensively explored in ornamental growth restriction. This study investigated the effects of foliar application of different concentrations of MeJa (0, 50, 100, and 150 µM) on the growth and leaf anatomy of Begonia ‘Dragon Wing’ Pink and Red. Plant growth parameters were evaluated, and qualitative-quantitative histological analyses of Begonia leaves were conducted. MeJa was efficient in compacting the plants, reducing height in 17.57% and diameter in 8.98% without compromising biomass, root growth, and flowering aspects. The average concentration studied also caused changes in leaf anatomy, increasing the thickness of the abaxial epidermis, reducing mesophyll thickness, the number of calcium oxalate crystals, and the size and number of stomata. The results demonstrated the promising effect of MeJa on controlling the growth of potted ornamental plants.

COMPARATIVE LEAF ANATOMY AND MICROMORPHOLOGY OF ASYSTASIA GANGETICA T.ANDERSON SUBSP. MICRANTHA (NEES) ENSERMU AND RHINACANTHUS NASUTUS (L.) KURZ (JUSTICIINAE, ACANTHACEAE) FROM PENINSULAR MALAYSIA

Acanthaceae family has been used traditionally for medicinal purposes, especially amongst the native communities in Peninsular Malaysia. Nowadays, many taxonomists have difficulties in the identification of the Acanthaceae species due to its morphological similarities and when there is an incomplete part of plants obtained from the field sampling. But until now, there is no comprehensive study that has been documented especially on the Acanthaceae family, specifically for A. gangetica subsp. micrantha and R. nasutus. To avoid incorrect species identification, a systematic study that involved the leaf anatomy and micromorphology parts is being used for the identification and classification of plants in the Acanthaceae. Therefore, the main objective of this present study is to identify the leaf anatomical and micromorphological characteristics that can be used in plant identification and for supportive data in plant classification. The leaf anatomical and micromorphological studies that are conducted on species studied involve several procedures such as cross-section using a sliding microtome, and observation under a light microscope and scanning electron microscope. The anatomical and micromorphological characteristics observed that have been used to identify each species studied include patterns of petiole and midrib vascular bundles, leaf margin, leaf lamina, presence of cuticular striae, and the presence of trichomes. The results of this study showed that the cystolith cells can be found only in midrib of A. gangetica subsp. micrantha while it also recorded in petiole, midrib, and the leaf lamina of R. nasutus. Observation under the light microscope revealed nine types of trichomes in R. nasutus meanwhile seven trichomes were recorded in A. gangetica subsp. micrantha. Other than that, the present of cuticular striae only recorded at the abaxial epidermis of A. gangetica subsp. micrantha. In conclusion, results showed that anatomical and micromorphological characteristics have taxonomic significance that can be used in the identification and classification, especially at the species level

Parallel auxin transport via PINs and plasmodesmata during the Arabidopsis leaf hyponasty response

Key messageThe leaf hyponasty response depends on tip-to-petiole auxin transport. This transport can happen through two parallel pathways: active trans-membrane transport mediated by PIN proteins and passive diffusion through plasmodesmata.A plant’s ability to counteract potential shading by neighboring plants depends on transport of the hormone auxin. Neighbor sensing at the leaf tip triggers auxin production. Once this auxin reaches the abaxial petiole epidermis, it causes cell elongation, which leads to leaf hyponasty. Two pathways are known to contribute to this intercellular tip-to-petiole auxin movement: (i) transport facilitated by plasma membrane-localized PIN auxin transporters and (ii) diffusion enabled by plasmodesmata. We tested if these two modes of transport are arranged sequentially or in parallel. Moreover, we investigated if they are functionally linked. Mutants in which one of the two pathways is disrupted indicated that both pathways are necessary for a full hyponasty response. Visualization of PIN3-GFP and PIN7-GFP localization indicated PIN-mediated transport in parallel to plasmodesmata-mediated transport along abaxial midrib epidermis cells. We found plasmodesmata-mediated cell coupling in the pin3pin4pin7 mutant to match wild-type levels, indicating no redundancy between pathways. Similarly, PIN3, PIN4 and PIN7 mRNA levels were unaffected in a mutant with disrupted plasmodesmata pathway. Our results provide mechanistic insight on leaf hyponasty, which might facilitate the manipulation of the shade avoidance response in crops.

The effect of heavy metal-containing wastewater sediment on the microanatomical characteristics of the leaves and stem of Salix viminalis L.

A comparative microanatomical study of Salix viminalis L. shoots was performed in order to get an idea of the effect of toxic elements stress on the microanatomical parameters of the shoot (leaves, stem). The examined Salix viminalis L. shoots originated from the Lovász-zug suburban area of Debrecen city, where a sewage settling pond was formerly operated as a secondary biological purification unit. The control Salix triandra x viminalis L. 'Inger' samples originated from the Nyíregyháza experiment with uncontaminated soil. As a result of our research, we can state the following in the case of the leaf samples grown on contaminated soil: the leaf lamina thickness decreased; the extent of the palisade parenchyma decreased; the extent of the intercellular spaced increased inside the spongy parenchyma; the width and the height of the main veins increased; the extent of the collenchyma bordering the main vein increased; the stomatal density increased both in the case of the adaxial and abaxial epidermis; the size of the stomas decreased. In the case of the stem samples, we observed the following: in the case of the samples grown on contaminated soil the extent of the primer cortex increased; the cell wall of the cells building the sclerenchimatic fibers thickened; the number of Ca-oxalate crystal rosettes and sclereids increased; the extent of secondary phloem increased; the lumen of the tracheas in the secondary xylem increased; the average width of the annual rings decreased; the extent of the central stele of the stem increased.

Foliar Pectins and Physiology of Diploid and Autotetraploid Mango Genotypes under Water Stress.

The cultivation of mango in Mediterranean-type climates is challenged by the depletion of freshwater. Polyploids are alternative genotypes with potential greater water use efficiency, but field evaluations of the anatomy and physiology of conspecific adult polyploid trees under water stress remain poorly explored. We combined field anatomical evaluations with measurements of leaf water potential (Ψl) and stomatal conductance (Gs) comparing one diploid and one autotetraploid tree per treatment with and without irrigation during dry summers (when fruits develop). Autotetraploid leaves displayed lower Ψl and Gs in both treatments, but the lack of irrigation only affected Gs. Foliar cells of the adaxial epidermis and the spongy mesophyll contained linear pectin epitopes, whereas branched pectins were localized in the abaxial epidermis, the chloroplast membrane, and the sieve tube elements of the phloem. Cell and fruit organ size was larger in autotetraploid than in diploid mango trees, but the sugar content in the fruits was similar between both cytotypes. Specific cell wall hygroscopic pectins correlate with more stable Ψl of autotetraploid leaves under soil water shortage, keeping lower Gs compared with diploids. These preliminary results point to diploids as more susceptible to water deficits than tetraploids.

Morphoanatomical leaf traits of herbaceous species raised in a cronosequence of naturally regenerated areas of tropical deciduous forest

ABSTRACT Plant survival in semi-arid climates depends on morphological, anatomical, and physiological adjustments that determine survival under limiting environmental conditions. In this study, anatomical and morphological characteristics of three herbaceous species with different growth habits were determined: a tall herb, Mesosphaerum suaveolens (tall), Stachytarpheta sanguinea (short), and Jacquemontia evolvuloides (climbing). Fully expanded leaves were collected from three sites in each of three different natural regeneration periods in a seasonally dry tropical forest. Leaf, specific leaf area, epidermis, cuticle, parenchyma, and mesophyll thicknesses; stomatal and trichome densities were measured. All three species have stomata and trichomes on both leaf surfaces and higher densities on the abaxial surface than the adaxial surface. M. suaveolens and S. sanguinea have unusual leaf morphological and anatomical adjustments, with a larger leaf area in the more open and youngest site, but thicker abaxial and adaxial epidermis and mesophyll in the oldest site which has the closest canopy stratum. J. evolvuloides has more usual adjustments, with a smaller specific leaf area and thinner epidermis and isobilateral parenchyma in the youngest site, being better acclimatized to low water availability and high light incidence. Therefore, M. suaveolens and S. sanguinea have unique acclimatization strategies for different environmental conditions.

Vegetative anatomy of five domesticated members of the genus Cucurbita (Linn.) in Southwestern Nigeria

The vegetative anatomy of five domesticated species of the genus Cucurbita L. found in South Western Nigeria was studied. The aim was to establish some useful diagnostic features that may be employed in combination with other characters as intra or inter-specific or generic tools for their delimitation. The study revealed exciting features that are helpful in the identification of each species. The genus can be divided into three groups based on the shape of the midrib. Those with a U-shape are C. pepo, C. argyrosperma and C. ficifolia. C. maximum has a round/flat shape while C. moschata has V shape. Those with a U-shape can further be classed into those with a wide and narrow neck. C. argyrosperma has narrow neck with two vascular bundles, four layers of palisade tissues and 6 layers of abaxial epidermis. C. pepo has a wide neck with three bicollateral bundles and two layers of palisade tissues while C. ficifolia has two bundles and three layers of palisade tissues. Overlaps and similarities in the number of vascular bundles, and layers of tissues showed generic affinity among the members.

An Accurate Phenotypic Study of The Foliar Epidermis for Some Species of Silene L. From Caryophyllaceae Family in Iraq

In the present research work, detailed micromorphological features study (investigated for foliar epidermal anatomy) for five species of the genus Silene L., belonging to the family Caryophyllaceae. One of the essential anatomical characteristics of the leaf in this genus observed two basic stomata types on both adaxial and abaxial epidermis, diacytic and anisocytic, from five species, three species have distinguished a diacytic type, exception two species S. chlorifolia and S. longipetala appeared to have both a diacytic and anisocytic, also has astrocytic crystals within epidermal cells. Also in the present work, 3 species out of 5 have trichomes on their both surfaces, observed having them multicellular uniseriate. All the taxa were the distinguished shape of the guard cells as reniform-like from a full short reniform in all species. So the general shape of ordinary epidermal cells, anticlinal wall of the epidermal cells, type of stomata cells, collar shape marginal of guard cells, and trichomes. Images enhanced the micromorphological characteristics under study. Information on the locations and dates of the collection was also confirmed. This study revealed that the micromorphological features of the family are taxonomically signi?cant in the accurate identi?cation of species.

Structural, developmental and functional analyses of leaf salt glands of mangrove recretohalophyte Aegiceras corniculatum.

Salt secretion is an important strategy used by the mangrove plant Aegiceras corniculatum to adapt to the coastal intertidal environment. However, the structural, developmental and functional analyses on the leaf salt glands, particularly the salt secretion mechanism, are not well documented. In this study, we investigated the structural, developmental and degenerative characteristics and the salt secretion mechanisms of salt glands to further elucidate the mechanisms of salt tolerance of A. corniculatum. The results showed that the salt gland cells have a large number of mitochondria and vesicles, and plenty of plasmodesmata as well, while chloroplasts were found in the collecting cells. The salt glands developed early and began to differentiate at the leaf primordium stage. We observed and defined three stages of salt gland degradation for the first time in A. corniculatum, where the secretory cells gradually twisted and wrinkled inward and collapsed downward as the salt gland degeneration increased and the intensity of salt gland autofluorescence gradually diminished. In addition, we found that the salt secretion rate of the salt glands increased when the treated concentration of NaCl increased, reaching the maximum at 400mM NaCl. The salt-secreting capacity of the salt glands of the adaxial epidermis is significantly greater than that of the abaxial epidermis. The real-time quantitative PCR results indicate that SAD2, TTG1, GL2 and RBR1 may be involved in regulating the development of the salt glands of A. corniculatum. Moreover, Na+/H+ antiporter, H+-ATPase, K+ channel and Cl- channel may play important roles in the salt secretion of salt glands. In sum mary, this study strengthens the understanding of the structural, developmental and degenerative patterns of salt glands and salt secretion mechanisms in mangrove recretohalophyte A. corniculatum, providing an important reference for further studies at the molecular level.

Assessment of the Drought-Tolerance Criteria for Screening Peach Cultivars

The article presents an analysis of the artificial dehydration effect of peach leaf tissues, simulating natural drought, on various physiological, morphological, and anatomical parameters described in the literature, associated with the trait of drought resistance. An investigation aimed to identify the most informative criteria for peach drought resistance which correlate with water loss during dehydration. The results present an assessment of the amount of water loss in 60 peach cultivars selected from different geographical areas and having different genetic origins. Four contrasting genotypes were identified, based on the results of the cluster analysis performed on the cultivar’s water regime. The influence of water regime parameters (leaf water content, water saturation deficit, dynamic of water loss), the morphological and anatomical structure of the leaf, the content of photosynthetic pigments, and the activity of the photosynthetic apparatus on drought resistance were investigated for selected peach cultivars. It was revealed that the most informative criteria for assessing drought resistance were dry and fresh leaf weight, leaf blade length, leaf width, and area (among morphometric parameters); stomatal pore length, stomata density, adaxial and abaxial epidermis thickness, and adaxial cuticle thickness (among anatomical parameters); and Fv/Fm—maximum photochemical quantum yield of PSII, Y(NO)—quantum yield of unregulated non-photochemical light energy dissipation in PS II and Y(NPQ)—controlled quantum losses (among indicators of photosynthetic activity).

Papillaephyllum, a new genus of angiosperm foliage from the Cenomanian of the Czech Republic

Angiosperm foliage Papillaephyllum labutae Čepičková et J. Kvaček, gen. et sp. nov. is described from the Cenomanian, Late Cretaceous of the Peruc-Korycany Formation in the Bohemian Cretaceous Basin, Czech Republic. Papillaephyllum labutae has been erected for rarely-found fossils with basal-angiosperm signs, characterized by serrate, sometimes double-serrate margins with rounded chloranthoid teeth, each bearing a papilla. Venation is semicraspedodromous to festooned-semicraspedodromous with reticulate tertiary venation. Its micromorphology is distinctive in having the entire abaxial cuticle covered by papillae. Papillae of the subsidiary cells often form as visible wreaths around the stomata. Stomata are latero-cyclocytic and stephanocytic-bicyclic.Well-pronounced and numerous papillae of the external epidermal surface are an indicator of possible fresh-water stress, identifying the taxon as possibly meso- to xerophytic. Based on macro- and micromorphological comparison with fossil and recent material, affinity of Papillaephyllum labutae with the family Chloranthaceae is highly probable.