Leaf Apex Research Articles

Distribution Characteristics of Phenanthrene in Wheat, Soybean and Maize Leaves

The pollution of polycyclic aromatic hydrocarbons (PAHs) in food crops has been drawing worldwide attention due to their toxicity and carcinogenicity. However, the distribution process of PAHs in crop leaves is not clear. Here, we firstly study the distribution of phenanthrene in wheat, soybean and maize seedling leaves. High performance liquid chromatography was used to determine phenanthrene concentration in crop leaves. Over the exposure time, phenanthrene concentration in young and mature leaves of wheat and soybean increased to the maximum at 72 h, which were 8.25 and 1.47 mg kg−1, and 5.91 and 3.02 mg kg−1, respectively, and phenanthrene concentration of young leaves was higher. Inversely, phenanthrene concentration in maize mature leaves was the highest and that in the second leaves was the lowest. The distributions of phenanthrene concentration in leaf base, leaf medium and leaf apex of the three crops were as follows: it was leaf medium > leaf base > leaf apex in wheat; it was same for soybean and maize, with leaf apex > leaf medium > leaf base. Phenanthrene concentrations of leaf edge in wheat, soybean and maize were 10.55, 3.88 and 18.96 mg kg−1 at 72 h, which were higher than those of leaf middle (10.21, 3.39 and 10.47 mg kg−1), respectively. Phenanthrene concentrations of mesophylls and veins increased with time, and phenanthrene concentration of veins was higher. The observation of two-photon fluorescence microscopy showed that phenanthrene was mainly accumulated near the vascular bundles of major vein. Accordingly, distribution of phenanthrene in crop leaves depends on the type of crop, growth period, and contribution of xylem and phloem to acropetal transport. Our results are helpful not only for better understanding the distribution of PAHs in crop leaves, but also for effectively controlling the translocation of PAHs into the leaves to ensure the safety of agricultural products.

Apex structures enhance water drainage on leaves

The rapid removal of rain droplets at the leaf apex is critical for leaves to avoid damage under rainfall conditions, but the general water drainage principle remains unclear. We demonstrate that the apex structure enhances water drainage on the leaf by employing a curvature-controlled mechanism that is based on shaping a balance between reduced capillarity and enhanced gravity components. The leaf apex shape changes from round to triangle to acuminate, and the leaf surface changes from flat to bent, resulting in the increase of the water drainage rate, high-dripping frequencies, and the reduction of retention volumes. For wet tropical plants, such as Alocasia macrorrhiza, Gaussian curvature reconfiguration at the drip tip leads to the capillarity transition from resistance to actuation, further enhancing water drainage to the largest degree possible. The phenomenon is distinct from the widely researched liquid motion control mechanisms, and it offers a specific parametric approach that can be applied to achieve the desired fluidic behavior in a well-controlled way.

Disentangling Scandinavian species hidden within Meesia uliginosa Hedw. s.l. (Bryophyta, Meesiaceae)

The molecular variation (atpB–rbcL spacer, rpl16 G2 intron, trnGUCC G2 intron) among 50 Scandinavian specimens of Meesia uliginosa s.l. was analysed in the context of three other Meesia species, with Paludella squarrosa as outgroup. The molecular variation within M. uliginosa correlates with morphology, and shows that three species exist: M. uliginosa Hedw., M. minor Brid. and M. minutissima Hedenas sp. nov. Whereas M. uliginosa s.str. is widespread, in Scandinavia the other two species are restricted to the mountains. The three species differ in quantitative features, such as, plant size, leaf size, costa width, leaf apex shape, seta length and spore capsule size. Because the species overlap in several of these features, a combination of seta length and the ornamentation of the exostome outside are the safest characters for identification. Leaf apex shape, small spore capsules in M. minutissima and large spores in M. minor serve as additional identification help. Meesia minutissima is presently only known from Scandinavia. The other two species are more widespread, although further investigations are required to find out their exact distributions.

DNA barcoding and morpho-anatomical characters of two forms of <i>Convolvulus arvensis</i> L. (Convolvulaceae) grown in Asir region, Saudi Arabia

DNA barcoding and morpho-anatomical characters of two forms of Convolvulus arvensis L. growing in Asir region, Saudi Arabia were studied. We applied three molecular markers, ITS, rbcL and matK for phylogenetic reconstruction in combination with 24 morpho-anatomical characters to provide proposal for the recognition of its population under two forms. Plant samples were collected from ten various populations of C. arvensis supposed to be of two different forms, and finally these have been found to be of two new forms (small leaf) and form (large leaf) for the flora of Saudi Arabia. TWINSPAN results showed that there was negative group with twenty one objects including stem length, stem thickness, seed shapes, petiole length, leaf apex, leaf length, petal circumference, leaf width, capsule length, capsule width, stamen length, anther width, anther length, carpel length, venations type, pollen grains shape, T.S of stem, root and leaf, stigma shape and anther base surface and positive group including hairs, stomata and anther shape. Dendrogram upon morpho-anatomical characters resolved two main clusters, one cluster of form (large leaf) and the other of form (small leaf). Amplified gene region for the form (small leaf)-rbcL showed 100% identity with C. lineatus; form (small leaf)-matK and form (large leaf)-matK had 99% identity with Calystegia sepium (L.) R. Br. Form of (small leaf)–ITS had 100% identity with that of C. arvensis; form (large leaf)-rbcL had 100% identity with those of C. arvensis and C. lineatus. Form (large leaf)–ITS had 99% identity with that of C. arvensis. The results of molecular phylogenetic analyses based on certain morphological and rbcL data support two main clusters within C. arvensis which is consistent with two forms, form (small leaf) and form (large leaf).

Alternaria tenuissima Causing Leaf Necrosis on Polygonatum cyrtonema in Jinzhai, China

Polygonatum cyrtonema Hua is one of the most important traditional Chinese medicine herbs used for treating stomach weakness, palpitation, diabetes, and dry cough and is commonly planted in the mountain area of southeast and southwest China. During June of 2018 and 2019, necrotic lesions on the leaf apex and leaf margin of P. cyrtonema were observed in seven greenhouses, affecting approximately 2 ha, in Jinzhai County, Anhui Province, China. Disease incidence averaged approximately 30% among all affected greenhouses. The symptoms initially appeared on the leaf apex and leaf margin as small dark brown spots surrounded by light yellow halos. Over time, the lesions enlarged and coalesced to form large areas of necrotic lesions on leaves. To identify the pathogen, 15 symptomatic leaves were collected and surface disinfested with 2% sodium hypochlorite for 2 min followed by 70% ethanol for 30 s, rinsed in sterile water, and dried on filter paper. Plant tissues were then transferred onto potato dextrose agar (PDA) and incubated at 28°C for 3 days in the dark. Five fungal isolates were obtained from the diseased P. cyrtonema leaves by a single-spore isolation method. Colonies of the isolates had round margins and thick fluffy aerial mycelia with olive-green to brown coloration after 5 days on PDA. Conidiophores were pale brown, straight or flexuous, septate, single or in clusters. Conidia were obclavate or oval, multicellular, pale brown, and ranged from 4.91 to 15.83 × 17.29 to 47.32 μm (n = 50), with longitudinal and transverse septa varying from zero to three and from one to six, respectively. Conidia beaks were cylindrical, pale brown, and measured 2.00 to 7.46 × 2.00 to 5.28 μm. On the basis of morphological characteristics, the fungal isolates were preliminary identified as Alternaria spp. (Simmons 2007). To further identify the fungal isolates, the internal transcribed spacer (ITS) region of rDNA of each isolate was amplified and sequenced using the primers ITS4/ITS5 (Guo et al. 2012). The ITS sequence (accession no. MN249629) was 99.45% similar to the reference sequences of Alternaria alternata (KU527784) and A. tenuissima (KX664408) in GenBank, respectively. Partial regions of β-tubulin 2 (TUB2) and histone 3 (H3) genes were sequenced using primers T1/T2 (O’Donnell and Cigelnik 1997) and H3-1a/H3-1b (Glass et al. 1995), respectively. Sequences of TUB2 and H3 (MN256456 and MN256455) of the isolate were 100 and 99.80% similar to the fungus A. tenuissima (JQ811941 and MH647724), respectively. To complete Koch’s postulates, a pathogenicity test of the A. tenuissima isolates was performed on sterile leaves of P. cyrtonema. Ten milliliters of conidial suspension (5 × 10⁵ spores/ml) from each of the five isolates was sprayed on five 6-month-old plants. As a control, five plants were sprayed with sterile water. All treated plants were placed in a moist chamber at 26°C, with 90% relative humidity and an 8-h photoperiod of fluorescent light. Ten days later, 90% of the inoculated plant leaves developed brown spots and necrotic lesions similar to those observed in the field, whereas the control plants were asymptomatic. The same pathogens were again isolated from the necrotic leaves and confirmed as A. tenuissima by DNA sequencing. A. tenuissima is known to cause leaf spot and necrosis on many economically important crops, including lotus (Nelumbo nucifera) and kiwifruit (Actinidia spp.), in China (Li et al. 2019; Zhang et al. 2019). To our knowledge, this is the first report of A. tenuissima causing leaf necrosis on P. cyrtonema in Jinzhai, China.

First Report of an Alternaria alternata Isolate That Causes Leaf Spot Disease on Ilex crenata var. convexa in China

Ilex crenata var. convexa is an evergreen, obtuse-toothed, and cultivated shrub belonging to the Ilex family and is often used as a ground cover or hedge in landscape greening and as a potted plant. In three surveys conducted in 2019 in Qingdao city, Shandong Province, China, many I. crenata var. convexa plants with obvious brown spots on the leaves were seen in a large area of the city, and the incidence was about 60%. The lesions usually first emerged at the leaf apex, gradually enlarged, and finally led to withering and necrosis of the leaves. To isolate the causative pathogenic fungus of this disease, leaf tissues (5 × 5 mm) were cut from the margins of lesions, surface disinfected with 70% ethanol, placed on potato dextrose agar, and incubated at 28°C with a 12-h photoperiod for 9 days. Colonies had round margins with some grayish/blackish aerial mycelia. Based on its dark brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa (Simmons 2007; Zhang 2003), the fungus was identified as Alternaria sp. Single spores were isolated to obtain the pure culture of the fungus. Fifty spores and 50 conidiophores were measured. Conidiophores arose singly and were 22.3 to 56.5 μm long and 3.1 to 5.7 μm wide. Conidia ranged from 17.4 to 37.9 × 7.2 to 12.9 μm and had three to six transverse and zero to three longitudinal septa, with a beak ranging from 4.6 to 13.2 μm long. To further identify the fungal species, the internal transcribed spacer (ITS) region of rDNA was PCR amplified using primers ITS1/ITS4 and sequenced. A BLAST search showed 100% similarity with those of Alternaria alternata (accession no. MN044802.1) and A. tenuissima (accession no. MK967997.1). The ITS sequence of rDNA amplified by primers ITS1/ITS4 could not be used to differentiate between A. tenuissima and A. alternata (Zheng et al. 2015). Hence, the partial coding sequence of the histone 3 gene was amplified using primers H3-1a/H3-1b (Zheng et al. 2015) and sequenced. The resulting 409-bp sequence was identical to that of A. alternata histone 3 gene (accession no. MG012317.1) and was deposited in GenBank (accession no. MN161248). Therefore, the Alternaria isolate was identified as A. alternata based on its morphological characteristics as well as ITS and histone 3 gene sequences. To further verify Koch’s postulates, three healthy I. crenata plants were inoculated with an aqueous spore suspension (6 × 10³ spores/ml) by spraying the whole plants until run-off. Three other healthy I. crenata plants were sprayed with sterile water and served as controls. All plants were kept in a humid chamber at 25°C for 6 days. Starting 6 days after inoculation, symptoms identical of those observed in the field were observed on the leaves inoculated with the spores, whereas the control plants remained symptomless. Moreover, a fungus with the same colony and conidial morphology was reisolated from the diseased leaves. To our knowledge, this is the first report of an A. alternata isolate that causes leaf spot disease on I. crenata var. convexa in China. Leaf spot disease largely damages the aesthetic aspect of I. crenata plants. This report provides a foundation for further studies on A. alternata infecting I. crenata.

<p><strong><em>Festuca devesae </em></strong><strong>(Poaceae), a new species from northern Spain</strong></p>

Festuca devesae (Poaceae), a new species from the low mountains of northern Iberian Peninsula (Burgos and Álava provinces, Spain), is described. According to its morphology, it belongs to Festuca subsect. Festuca, the most diverse group within the genus. The new species differs from other known consectional taxa by having a continuous layer of abaxial subepidermal sclerenchyma in the leaf cross-sections, and by the leaf sheaths closed to the mouth. Both traits are found together only in F. segimonensis and F. hystrix, from which F. devesae clearly differs in the leaf apex shape, the size of the auricles, and the leaf anatomy in cross-section, among other traits. A detailed morphometric description, photographs, and data on leaf anatomy, phenology, ecology, and distribution are given. A comparison with morphologically similar species and an identification key are also provided.

Biocidal potential of Eugenia pyriformis essential oil in the control of Rhipicephalus (Boophilus) microplus in the free-living cycle

ABSTRACT: Brazil has one of the largest commercial cattle herds in the world, which naturally coexist with an enormous number of parasitic species. Southern cattle tick, Rhipicephalus (Boophilus) microplus, is among these species, interfering with animal productivity and causing losses to the beef and dairy cattle sector. The use of chemical acaricides in the control of this mite has resulted in the emergence of resistant populations. In this sense, alternative control measures using plants as sources of botanical acaricides have shown to be effective. Eugenia pyriformis Cambess is a Brazilian plant with antioxidant and antimicrobial activity; however, there are no reports on its acaricidal activity in the literature. The present study aimed to evaluate the acaricidal and larvicidal potential of E. pyriformis leaf essential oil (EO) on southern cattle tick at different stages of the reproductive cycle. E. pyriformis leaves were collected and dried, and had their EO extracted by hydrodistillation (3h) using a modified Clevenger apparatus. Chemical analysis was performed by gas chromatography coupled with mass spectrometry (GC/MS), and 32 compounds belonging to the sesquiterpene class were identified: hydrocarbons (17.98%) and oxygenated forms (81.96%), with spathulenol (43.65%) and caryophyllene oxide (12.17%) as the most common. The EO was evaluated by the Adult Immersion Test at the concentrations (500.00 to 3.12mg/mL) in which the following parameters were measured: mortality of females (%), hatchability of eggs (%), and product efficiency (%). Larvae were assessed by the Larval Packet Test at concentrations ranging from 25.00 to 0.00004mg/mL. Lethal concentrations (LC) required for killing 50 and 99.9% of adult females and larvae were determined using Probit analysis. LC50 and LC99.9 of EO were 0.06 and 24.60mg/mL and 1,208.80 and 2,538mg/mL for larvae and adult females, respectively. Action of the EO in the free-living cycle of R. (B.) microplus larvae was another parameter assessed. To this end, the larvae were deposited in pots containing Brachiaria decumbens and, after migration to the leaf apex, a solution containing LC99.9 (24.60mg/mL) of the EO was sprayed. After 24h, 72.25% of the larvae had died, indicating stability of the EO when subjected to uncontrolled temperature and humidity conditions. The mechanism of action through which the EO killed the larvae and adult females was investigated by the Bioautographic Method, which showed inhibition of 3.15mg/mL of the EO on the acetylcholinesterase (AChE) enzyme. The results found in the present experiment indicate that E. pyriformis essential oil is an alternative in the control of southern cattle tick in the larval (parasitic) and free-living cycle (non-parasitic) stages under field conditions.

Transcriptional foliar profile of the C3-CAM bromeliad Guzmania monostachia.

Guzmania monostachia is an epiphytic tank bromeliad that displays the inducible CAM photosynthesis under stressful conditions and had the highest stomata density in the leaf apex, while the base portion has the highest density of trichomes, which are specialized structures used to acquire water and nutrients from the tank solution. In order to correlate the genetic factors behind these morpho-physiological characteristics along the leaf blade of G. monostachia, a comparative transcriptome analysis was performed to identify the functional enriched pathways and unigenes that could play a role in the apical, middle and basal leaf portions. A total of 653 million reads were used for de novo transcriptome assembly, resulting in 48,051 annotated unigenes. Analysis of differentially expressed genes (DEGs) among distinct leaf regions revealed that 806 DEGs were upregulated in the apex compared to the middle portion, while 9685 DEGs were upregulated in the apex and 9784 DEGs were upregulated in the middle portions compared to the base. Our outcomes correlated some DEGs and identified unigenes with their physiological functions, mainly suggesting that the leaf apex was related to the regulation of stomatal movement, production of chlorophyll, cellular response to stress, and H2O2 catabolic process. In contrast, the middle portion showed DEGs associated with the transport of amino acids. Furthermore, DEGs from the leaf base were mainly correlated with responses to nutrients and nitrogen compounds, regulation of potassium ion import, response to water deprivation, and trichome branching, indicating that, at least in part, this leaf portion can replace some of the root functions of terrestrial plants. Therefore, possibly candidate unigenes and enriched pathways presented here could be prospected in future experimental work, opening new possibilities to bioengineer non-inducible CAM plants and/or improve the fertilization use efficiency by increasing leaf nutrient acquisition of crop plants.

Cyanocephalus veadeiroensis (Hyptidinae–Lamiaceae): A striking new species from the Chapada dos Veadeiros, Goiás, Brazil1

A new species, Cyanocephalus veadeiroensis, from the Chapada dos Veadeiros region, Goias state, which was first recognized on Facebook, is here described and illustrated. This new species is unique due to the combination of densely imbricate leaves obscuring the stems, the leaves longer than the internodes, the secondary veins almost parallel to the main vein, the margin entire to serrate and the leaf apex acuminate. The new species is compared with morphologically similar species such as Cyanocephalus adpressus and Cyanocephalus lanatus. We also provide comments on the distribution, ecological aspects and recognition of this taxon.

Variation studies of morphological characters of cashew trees (Anacardium occidentale) on Kogi State University Campus, Anyigba, Kogi State, Nigeria

Variability could exist in a typical cashew field for most morphological characters and such morphological characters have been used as a powerful tool in the classification of cultivars and as such morphological traits continue to be the first step in the studies of genetic relationships. In this research work using morphological traits effort was made to access the variations among sixty (60) randomly selected trees from different locations across Kogi State University campus, from Faculties of Management Sciences, Natural sciences, Social sciences, Law, Agriculture and the Botanical garden. Morphological characters from Cashew descriptors by International Board for plant Genetic Resources (IBPGR) were used to determine the variations among the trees. Results indicate variations among trees on the campus, the dominant fruit shape observed was conical-obovate, the dominant fruit colour observed was yellow with a high percentage (71.67%), the dominant nut weight was intermediate (5-6 g), the dominant shape of leaves in the sampled population is obovate with 43.33%, the dominant leaf apex shape was rounded with 41.6%. The tree habit is quite variable with upright and open habit having 50% while upright and compact habit have the least 15%. Three cashew descriptors were not observed in the trees on campus which are very low nut weight, cylindrical apple shape and pointed leaf apex shape. Variations were also observed in fruiting time, flower colours. Variation could be attributed to genetic history, though molecular studies would be needed to ascertain the genetic nature of observed variations.

Complex Horticultural Quality Traits in Broccoli Are Illuminated by Evaluation of the Immortal BolTBDH Mapping Population

Improving horticultural quality in regionally adapted broccoli (Brassica oleracea var. italica) and other B. oleracea crops is challenging due to complex genetic control of traits affecting morphology, development, and yield. Mapping horticultural quality traits to genomic loci is an essential step in these improvement efforts. Understanding the mechanisms underlying horticultural quality enables multi-trait marker-assisted selection for improved, resilient, and regionally adapted B. oleracea germplasm. The publicly-available biparental double-haploid BolTBDH mapping population (Chinese kale × broccoli; N = 175) was evaluated for 25 horticultural traits in six trait classes (architecture, biomass, phenology, leaf morphology, floral morphology, and head quality) by multiple quantitative trait loci mapping using 1,881 genotype-by-sequencing derived single nucleotide polymorphisms. The physical locations of 56 single and 41 epistatic quantitative trait locus (QTL) were identified. Four head quality QTL (OQ_C03@57.0, OQ_C04@33.3, OQ_CC08@25.5, and OQ_C09@49.7) explain a cumulative 81.9% of phenotypic variance in the broccoli heading phenotype, contain the FLOWERING LOCUS C (FLC) homologs Bo9g173400 and Bo9g173370, and exhibit epistatic effects. Three key genomic hotspots associated with pleiotropic control of the broccoli heading phenotype were identified. One phenology hotspot reduces days to flowering by 7.0 days and includes an additional FLC homolog Bo3g024250 that does not exhibit epistatic effects with the three horticultural quality hotspots. Strong candidates for other horticultural traits were identified: BoLMI1 (Bo3g002560) associated with serrated leaf margins and leaf apex shape, BoCCD4 (Bo3g158650) implicated in flower color, and BoAP2 (Bo1g004960) implicated in the hooked sepal horticultural trait. The BolTBDH population provides a framework for B. oleracea improvement by targeting key genomic loci contributing to high horticultural quality broccoli and enabling de novo mapping of currently unexplored traits.

Morphological characterization of Indian pummelo (Citrus maxima)

The present study was conducted with the aim to characterize different indigenous pummelo genotypes based on 19 quantitative and 9 qualitative traits. Leaf shape, leaf margin shape, leaf apex shape, petiole wing, petiole wing shape, fruit shape, fruit apex shape, fruit axis, fruit surface texture and pulp colour were the main qualitative characters of study. The higher coefficients of variation were determined for petiole area (36.33%), juice quantity (17.38%), leaf area (14.50%) and fruit weight (14.22%). Principal component analysis (PCA) for quantitative traits indicated that six PCA had Eigen-value greater than one. The cumulative variation explained by six components, viz. leaf length, fruit width, leaf length: width ratio, leaf area, petiole area and lamina wing ratio accounted over 86.12 % variability. However, the result of the PCA for qualitative traits showed that three parameters namely leaf shape, leaf margin shape and leaf apex shape among 10 Principal Component Axis (PCA) had Eigen-values greater than one, and accounted for over 70.23% of the total variability. Based on PCA and coefficient of variation, traits like fruit weight, seed content, juice content, leaf and petiole area, leaf length, leaf width and leaf length: width ratio had significant involvement in pummelo diversity, and can be used in differentiating accessions of citrus.

<p><strong>A new species of <em>Tashiroea</em> (Melastomataceae, Sonerileae) from Guangxi, China</strong></p>

Tashiroea dayaoshanensis (Melastomataceae, Sonerileae), a species from northeastern Guangxi, China and previously often identified as Phyllagathis nudipes or P. oligotricha in Chinese herbaria, is described as new based on morphological and molecular data. Indumentum, leaf texture and surface sculpture, capsule morphology and molecular phylogenetic data strongly support the placement of T. dayaoshanensis within the Tashiroea clade which should be accommodated in Tashiroea. Morphology as well as sequence divergence of the nrITS region indicate that T. dayaoshanensis is well differentiated from other species in the same clade, and thus should be treated as a distinct species. Tashiroea dayaoshanensis is phylogenetically closest to Bredia sessilifolia but can be easily distinguished by its petiolate leaves (vs. sessile or subsessile), and crowned ovary (vs. uncrowned). It resembles P. nudipes and P. oligotricha in habit and stamen morphology but differs from both in its leaf apex acuminate (vs. acute to obtuse), connective ventrally tuberculate (vs. not tuberculate) and ovary crown exerted from calyx tube during young fruit stage (vs. not exerted).

Gamma radiosensitivity of coffee (Coffea arabica L. var. typica)

The effects of gamma radiation on the germination, survival, and morphological damage in characteristics of the M1 generation of coffee (Coffea arabica L. var. typica) plants was evaluated using seeds collected from Santa Teresa and Chaupimayo, Peru. Under net house, the percentage of germination was 68%, 35%, 10%, and 0% for the Santa Teresa seeds and 75%, 49%, 17% and 0% for the Chaupimayo seeds with irradiation treatments of 0, 50, 100 and 150 Gy, respectively, whereas under laboratory conditions, germination levels were between 70% and 94% across all treatments. The survival rate also decreased with increasing radiation levels, with values of 45%, 32%, 28%, and 10% in the laboratory and 29%, 9%, 6%, and 0% in the net house for the Santa Teresa seeds and 58%, 45%, 38%, and 8% in the laboratory and 42%, 15%, 7%, and 0% in the net house for the Chaupimayo seeds with irradiation treatments of 0, 50, 100, and 150 Gy, respectively. Morphological changes were observed in the plants that survived irradiation at a dose of 100 Gy in terms of the leaf shape, leaf apex shape, young leaf color, plant height, stem diameter, number of leaves per plant, leaf length, leaf width, and distance from the cotyledon to the first node.

Umaltolepis and associated Pseudotorellia leaves from the Middle Jurassic of Yima in Henan Province, Central China

The seed-bearing structure Umaltolepis is considered to be produced by the same plants of Pseudotorellia leaves based on their close association in the same fossil bearing horizon and similarities in their cuticles, especially in stomatal structures. In this paper we describe new material of Umaltolepis and Pseudotorellia from the Middle Jurassic Yima Formation in Yima, Henan Province, Central China. Umaltolepis yimaensis sp. nov. is an umbrella-like, ovate to elliptical, four-lobed cupule. The cupule lobes are resinous with thick outer cuticle, and scattered, more or less longitudinally oriented stomata. Leaves of Pseudotorellia yimaensis sp. nov. are narrowly oblanceolate, with two veins entering leaf base and dichotomizing once or twice to produce 4–6 parallel veins that converge and join together near leaf apex. The leaves have fusiform resin bodies between neighboring veins, and thick cuticles with scattered, longitudinally oriented stomata on the abaxial side. The stomata of U. yimaensis and P. yimaensis are very similar, both consisting of sunken guard cells surrounding by specialized lateral subsidiary cells and unspecialized polar cells, and both have two bow-shaped cuticular ridges flanking the stomatal pit and a butter-fly like flange between guard and subsidiary cells. The co-occurrence of U. yimaensis and P. yimaensis in the Yima Formation and their similarities in cuticular structures and in the presence of resin bodies further confirm that Umaltolepis and Pseudotorellia are produced by the same group of plants. These fossils also provide new evidence for a high diversity of ginkgophyte reproductive organs in the Middle Jurassic of Central China.

Justicia longipetiolata , a new species of Acanthaceae from Yunnan, China

A new species of Justicia (Acanthaceae), J. longipetiolata, is described and illustrated from Yunnan, China. The new species belongs to Justicia sect. Harnieria, and it is similar to J. championii and J. quadrifaria, but differs by the caudate leaf apex, obviously long petiole, short calyx and the length ratio of calyx to mature capsule. It is assessed to be “Least Concern” (LC) according to IUCN Red List Category and Criteria. Morphological characters of pollen grains and seeds are also reported.

Leaf spot of Hydrangea macrophylla caused by Corynespora cassiicola in China

Hydrangea macrophylla, also known as big leaf hydrangea, is an economically valuable ornamental garden plant. From 2016 to 2018, a high incidence of leaf spot disease of hydrangea occurred in Hunan Province of China. Symptoms consisted of irregular to circular lesions, dark brown in color with gray-white centers and delimited by dark brown borders. The lesions further coalesced to form irregularly shaped necrotic areas and extended to the leaf apex resulting in leaf wilt. A fungus was consistently isolated from the symptomatic plants and identified as Corynespora cassiicola by morphological characters and phylogenetic analyses. Pathogenicity was confirmed by fulfilling Koch’s postulates. This is the first report of C. cassiicola causing leaf spot on H. macrophylla in China.

Chemotaxonomy, Morphology and Chemo Diversity of Scutellaria (Lamiaceae) Species in Zagros, Iran

This study concerns to evaluate the morphological and flavonoid variations, and chemotaxonomy among seven Scutellaria species. The limits of Scutellaria species were disturbed by different factors including hybridization and polymorphism. For this purpose, 39 Scutellaria accessions were collected from different natural habitats of Zagros region, Iran. A total of 15 quantitative and 20 qualitative morphological characters were studied. Leaf flavonoids were extracted using MeOH solution. The flavonoid classes were investigated using thin layer chromatography, column chromatography, UV-spect and LC-MS/MS (liquid chromatography mass spectrometry). To detect the taxonomic status of Scutellaria species, statistical analyses such as cluster, dissimilarity tree, and ordination methods were applied. The results of this research showed five flavonoid classes in different Scutellaria species including isoflavone, flavone, flavanone, flavonol and chalcone. Based on the cluster analysis of flavonoid and morphological data, the members of Scutellaria section Scutellaria were accurately separated from those of Scutellaria section Lupulinaria. Our study revealed a relationship between Scutellaria patonii and Scutellaria multicaulis. Moreover, the trichomes such as strigose, lanate, tomentose, pannous in leaf and stem, petiole, calyx, the form of leaf apex, and inflorescence length were found as diagnostic characters. Based on our results, the flavonoid and morphological markers display the taxonomic status of inter and intra-specific levels in Scutellaria.

Drepanolejeunea robinsonii (Lejeuneaceae: Drepanolejeuneinae), a new epiphyllous species from the Amazon forest

Drepanolejeunea robinsonii C.E.Zartman & A.M.Sierra is described and illustrated herein as a new species from the Amazon basin. The type collections are from lowland rainforest habitat in the central Amazon of Brazil. Morphological characters which distinguish the new species from the phenotypically similar Drepanolejeunea polyrhiza (Nees) Grolle & R.L.Zhu, are: 1) ovate leaf form; 2) conspicuously acute leaf apices; and 3) irregularly dentate to serrate teeth composed of 2–5 cells on leaf margins. Androecia were repeatedly observed on separate gametophytes suggesting the new taxon is dioecious, however neither gynoecia nor perianths have yet to be observed.