Distribution pattern of arthropods on the leaf surfaces of Acacia auriculiformis saplings

Acacia auriculiformis A. Cunn. Ex Benth. (Fabaceae), a non-native pioneer species in Brazil with fast growth and rusticity, is used in restoration programs. Our goal was to assess during a 24-month survey the pattern of arthropods (phytophagous insects, bees, spiders, and predator insects) on the leaf surfaces of A. auriculiformis saplings. Fourteen species of phytophagous, two of bees and eleven of predators were most abundant on the adaxial surface. The values of the ecological indexes (abundance, diversity, and species richness) and the rarefaction, and k-dominance curves of phytophagous, bees and arthropod predators were highest on the adaxial leaf surface of A. auriculiformis. The k-dominance and abundance of Aleyrodidae (Hemiptera) (both leaf surfaces), the native stingless bee Tetragonisca angustula Latreille (Hymenoptera: Apidae) (both leaf surfaces) and the ant Brachymyrmex sp. (adaxial surface) and Pheidole sp. (Hymenoptera: Formicidae) (abaxial surface) were the highest between the taxonomic groups of phytophagous, bees, and predators, respectively on A. auriculiformis saplings. The ecological indexes and rarefaction, abundance, and k-dominance curves of phytophagous insects, bees, and predators were highest on the adaxial leaf surface. The preference of phytophagous insects for the adaxial leaf surface is probably due to the lower effort required to move on this surface. Understanding the arthropod preferences between leaf surfaces may help to develop sampling and pest management plans for the most abundant phytophagous insects on A. auriculiformis saplings. Also, knowledge on the preference pattern of bees and predators may be used to favour their conservation.

First Report of Coleosporium helianthi infecting Helianthus verticillatus (Whorled Sunflower)in the United States

Helianthus verticillatus, the whorled sunflower, is an endangered species found only in the southern United States (Trigiano et al. 2021) that is being developed for ornamental uses. This sunflower species requires little to no maintenance, produces spectacular floral displays from September into October, and attracts numerous potential pollinators including many native bees (Strange et al. 2020). In June and July of 2021, chlorotic, irregularly shaped spots were observed on the adaxial surface of mature leaves of two vegetatively produced clones of H. verticillatus (Trigiano et al., 2021) at three locations in Knoxville, TN. In September, yellow (4A, Royal Horticultural Society Color Chart) sori were abundant on abaxial surfaces and more rarely on the adaxial leaf surfaces of both clones at all locations. Globose-to-cylindrical, yellow urediniospores were 23.7µm (20-32) x 18.9 (16-22) µm (n = 30) with irregular, verrucose ornamentation. The morphology and dimensions of the urediniospores were similar to other Coleosporium species (e.g., C. asterum, Back et al., 2014). Telia were waxy, red-brown (167A; B) and developed in October with colder temperatures. Cylindrical teliospores were sessile, 1-celled, thin-walled with basidia ca. 93 µm (70-117) x 25 µm (19-29), consistent with spores of C. helianthi (Cummins, 1978). DNA was obtained from urediniospores using a Phire kit (ThermoFisher Scientific, Waltham, MA) and the 28S rDNA region was amplified using the NL1 and NL4 primers (Back et al. 2014) (Genbank accession # OL364847) as well as ITS 1-4 primers (White et al. 1990) (GenBank accession OL364848). For comparison, DNA sequences were also obtained from authentic C. helianthi on H. divaricatus in the Arthur Fungarium at Purdue University (#PURN11678; GenBank accession OL364846) using the protocols of Aime et al. (2018). 28S sequences shared 99.65% (568/570 bp) identity. To test Koch’s postulates, seven healthy detached leaves were lightly brushed on both leaf surfaces with leaves with uredia producing urediniospores. The leaves were incubated adaxial side up in 9-cm-diameter Petri dishes on moistened filter paper at ambient laboratory conditions. A similar number of healthy leaves were brushed with healthy leaves, incubated in the laboratory and served as the control treatment. After 7-10 days, uredia with urediniospores formed primarily on the abaxial leaf surface, but a few were present on the adaxial surface of leaves treated with urediniospores, whereas the leaves in the control remained healthy. Molecular, morphological and infectivity studies identified C. helianthi as the pathogen. Coleosporium helianthi occurs on the commercial sunflower, H. annuus, and several wild sunflower species, including H. tuberosum (Jerusalem artichoke) and H. microcephalus (small-headed sunflower), among others in the southern U.S. (Farr and Rossman 2021). Coleosporium species are heteroecious and mostly macrocyclic rusts (McTaggart and Aime, 2018) with aecia and aeciospores typically found on pines (Pinus spp.). Although H. verticillatus is very susceptible to rust infection and it probably reduces photosynthetic capability, it does not appear to adversely affect flowering in the fall. The disease primarily degrades the aesthetic appeal of the plant but does not require control measures. To our knowledge, this is the first report of C. helianthi infecting H. verticillatus. Voucher material is deposited in the Arthur Herbarium (#PURN23470).

Comparative leaf morphology and anatomy on ten taxa of Calycanthaceae Lindl. (Laurales)

The comparative leaf morphology and anatomy of ten species of family Calycanthaceae have been studied. Leaf anatomy is very comparable to each other in cell shape and their arrangement. Collected leaves were preserved in FAA and alcohol series were applied for LM and SEM. The layer of epidermis is two in Idiospermum and one in rest of other genera. The structure of vascular bundle is V-shape in Sinocalycanthus and Calycanthus whereas U-shape in Idiospermum and Chimonanthus. The density of trichome is higher in Calycanthus than other genera. The presence of trichome, stomata, epidermal layer, density of trichome and stomata, and leaf surface are represented the distinction among the genera. The adaxial surface of Idiospermum and Sinocalycanthus are smooth whereas of Calycanthus and Chimonanthus are rough. The crystals are present in Calycanthus, Sinocalycanthus and Chimonanthus whereas absent in Idiospermum. The shape of the vascular bundle, density of trichome, epidermal layer, and crystals play important role in the phylogenetic relationship of Calycanthaceae.

Differential Survivability of Two Genetically Similar Salmonella Thompson Strains on Pre-harvest Sweet Basil (Ocimum basilicum) Leaves

Although conventionally considered an animal pathogen, recent evidence increasingly suggests that fresh produce may act as significant transmission vehicles and alternative hosts to Salmonella. This study reports the differential survivability of two genetically similar Salmonella Thompson strains (ST 889B and ST 688C) on the adaxial surface of pre-harvest basil (Ocimum basilicum) leaves. Upon inoculation, two distinct phenomena, a dried water-print or a macroscopic lesion, were observed within 24 h. ST 889B survived better than ST 688C on healthy-looking leaves without lesions, possibly due to its higher biofilm-forming ability. Both strains survived better on the leaves with lesions than on the healthy-looking leaves (ST 688C: 4.39 ± 0.68 vs. 2.18 ± 0.29; ST 889B: 4.78 ± 0.12 vs. 2.83 ± 0.18 log CFU per sample at 6 days post-inoculation). ST 889B caused the formation of lesions at a higher frequency [70/117 leaves (59.8%)] than ST 688C [35/96 leaves (36.5%)]. Thus, we highlighted two distinct Salmonella survival strategies in the basil pathosystem and demonstrated gene expression polymorphism (variations in the expression of the same set of genes) as an indispensable strategy in the colonization of plants as hosts by the human pathogens.

First Report of Powdery Mildew Caused by Blumeria graminis on Poa pratensis var. anceps Gaud cv. Qinghai in China

Poa pratensis, an important cool-season perennial grass, is widely cultivated for construction of grasslands and ecological management of Qinghai-Tibet Plateau (Dong et al. 2020). Poa pratensis var. anceps Gaud cv. Qinghai (PPAQ) is a variant of P. pratensis (Liu et al. 2009). In June 2016, powdery mildew was observed on PPAQ in an artificial field of PPAQ in Haiyan county of Haibei Tibetan Autonomous Prefecture, Qinghai province, China (36°59′17.76″N, 100°52′54.01″E). Approximately 30 to 50% of leaves (approximate 10 ha) were affected. Initially, irregular white mycelial colonies were observed on the adaxial surface of affected leaves. The colonies increased in number and size, and later covered a large area of leaves and stems. In advanced stages of disease, the colonies covered the whole adaxial surface and white patches appeared on the abaxial surface of affected leaves, and eventually caused leaf death. Conidiophores were unbranched, measuring 160 to 235 × 4 to 13 μm, and borne vertically on hyphae. Each conidiophore produced 4 to 11 conidia in a chain. The conidia were oval, one-celled, and hyaline, measuring 22 to 40 ×10 to 21 μm (n = 50). Chasmothecia were yellow, spherical, and 172 to 240 μm in diameter (n = 20), each of which contained 8 to 17 asci. The appendages were few, and hyphoid. Asci were oblong or ovate, measuring 79 to 115 × 31 to 45 μm (n = 20). Asci were petiolate, containing eight ascospores. Ascospores were round to oval, colorless, one-celled, measuring 17 to 33 × 8 to 14 μm (n = 50). Based on morphological characteristics, the fungal organism was identified as Blumeria graminis (DC.) Speer. To confirm the identification, the internal transcribed spacer (ITS) of 612 bp was amplified from DNA of conidia using ITS5 and P3 primers (Takamatsu et al. 2009). The ITS sequence was deposited in GenBank database (Accession No. MF429949). The ITS showed 95% sequence similarity with those of B. graminis on Poa nemoralis in USA (Accession No. AB273560) and on P. bullbosa in Iran (Accession No. AB273551) (Inuma et al. 2007). Five two-month-old healthy plants were inoculated by spraying a spore suspension (1× 105 conidia ml-1) prepared from conidia brushed from infected plants; five plants sprayed with sterile distilled water served as controls. All the plants were maintained in a growth chamber with a constant temperature of 20°C, a 12 h/12 h light/dark diurnal cycle, and 70% humidity. Two weeks after inoculation, symptoms of powdery mildew were observed on all inoculated plants, whereas the control plants remained symptomless. The same fungus was confirmed by morphological characterization and molecular assays as described above. B. graminis has been reported on P. pratensis in USA (Dugan and Newcombe 2007), Israel (Voytyuk et al. 2009), and China (Zhang et al. 2014), but has not previously been reported on PPAQ. As far as we know, this is the first report of powdery mildew caused by B. graminis on PPAQ in China. These findings indicated that the health of PPAQ was substantially threaten when infected by powdery mildew, therefore, our results also contributed some valuable information how to diagnose this disease on PPAQ in China.

Coupling Relationship of Leaf Economic and Hydraulic Traits of Alhagisparsifolia Shap. in a Hyper-Arid Desert Ecosystem

In this study, Alhagisparsifolia Shap. was used to test the hypothesis that leaf economic and hydraulic traits are coupled in plants in a hyper-arid region. Five economic traits and six hydraulic traits were examined to explore the relationship. Results showed that the stomatal density (SD) on both surfaces was coupled with maximum stomatal conductance to water vapor (gwmax) and leaf tissue density (TD). SD on adaxial surface (SDaba) was significantly positively related to vein density (VD) but negatively related to leaf thickness (LT) and stomatal length on adaxial surface (SLada). Nitrogen concentration based on mass (Nmass) was significantly negatively correlated with leaf mass per area (LMA), LT, and VD, whereas nitrogen concentration based on area (Narea) was significantly positively related to LMA and TD. Mean annual precipitation (MAP) contributed the most to the changes in LT and stomatal length (SL). Soil salt contributed the most to TD, SD, and gwmax. Soli nutrients influenced the most of LMA and VD. Mean annual temperature contributed the most to Nmass and Narea. In conclusion, the economics of leaves coupled with their hydraulic traits provides an economical and efficient strategy to adapt to the harsh environment in hyper-arid regions.

Tropidogyne euthystyla sp. nov., a new small-flowered addition to the genus from mid-Cretaceous Myanmar amber

Tropidogyne euthystyla, described here, is the fourth species of this fossil genus to have been reported from amber deposits in northern Myanmar. The species are alike in features of the calyx, the shape and venation of the inferior ovary, and the absence of petals. They differ in the number and form of the styles, the lobing of the epigynous disc, and whether the flowers are apparently bisexual or unisexual. In the one species for which several flowers are available for study, T. pentaptera, floral diameters vary from 3.5 to 5.0 mm. The present species, known only from a single flower, is the smallest in the genus, with a floral diameter of only 2 mm. It differs from the 3 previously described species in having 2 stout, erect styles bearing a terminal stigma, whereas the other species have 2 or 3 short or long, arching styles that are decurrently stigmatic along the adaxial surface.

Taxonomic studies of two trifoliate legumes of high economic importance in Ebonyi State, South-eastern Nigeria

Taxonomic studies of Sphenostylis stenocarpa and Centrosema pubescens based macro-morphology and foliar epidermises were carried out to determine their similarities and differences. The taxa are of high economic values as they are used as food and medicine in Nigeria. Standard methods were used to carry out the studies as qualitative and quantitative macromorphological characters of the taxa were obtained by visual observation and measuring with metre rule while foliar epidermal study followed standard methods previously used by other researchers. The taxa studied have trifoliate leaf type with leaf and leaflet arrangement alternate and opposite respectively. From the foliar epidermises, Sphenostylis stenocarpa possesses paracytic stomata on the abaxial surface and anisocytic stomata on the adaxial. The abaxial surface of Centrosema pubescens possesses anomocytic and paracytic stomata and anomocytic stomata on the adaxial surface. Cell shapes of the foliar epidermal surfaces are irregular with undulate anticlinal wall patterns except on the adaxial surface of Sphenostylis stenocarpa with pentagonal cell shape and straight anticlinal wall. The two taxa are similar in their leaf type and arrangement but differ greatly in their stomatal types.

Morphological features of the leaves in clematises as a reflection of their ecological peculiarities

Quantitative morpho-anatomical features of leaves of nine Clematis taxa (C. alpina ‘Pamela Jackman’, C. macropetala ‘Maidwell Hall’, C. integrifolia ‘Aljonushka’, C. ispahanica ‘Zvezdograd’, C. fargesii ‘Paul Farges’, C. texensis ‘Princess Diana’, C. tibetana, C. viticella, and C. heracleifolia) were determined with the aim to analyze their adaptation to the environmental conditions.Among investigated clematises, there were plants with hypostomatic (C. viticella, C. fargesii ‘Paul Farges’, C. heracleifolia, C. texensis ‘Princess Diana’, C. macropetala ‘Maidwell Hall’, and C. alpina ‘Pamela Jackman’), and amphistomatic leaves (C. ispahanica ‘Zvezdograd’ and C. tibetana). In C. integrifolia ‘Aljonushka’ leaves were hypostomatic, but few solitary stomata were also present on the adaxial surface. In the leaves of investigated taxa, the palisade coefficient ranged from 27.3% (C. alpina ‘Pamela Jackman’) to 49.9% (C. tibetana). The leaves also differed significantly in size. In particular, leaves of C. integrifolia ‘Aljonushka’ were almost ten times smaller than such of C. heracleifolia.As a result of UPGMA clustering, the plants that can survive in severe windy weather in open rocky areas, Clematis tibetana and C. ispahanica ‘Zvezdograd’, were joined in a separate cluster. The second cluster combined C. alpina ‘Pamela Jackman’ and C. macropetala ‘Maidwell Hall’ – cultivars blooming in the spring, during a period of significant difference in daily temperatures. A relatively small leaf area in plants from these two clusters may indicate an adaptation by reducing the transpiration area and general windage. The third cluster united the rest of investigated taxa, mostly – the mesophytic plants with a relatively large leaf area. However, due to similar morpho-anatomical structure of the leaf, the third cluster also comprised C. integrifolia ‘Aljonushka’ with the smallest leaves.

KARYOMORPHOLOGICAL AND STOMATAL STUDIES OFALLIUM HOOKERITHWAITES

AlliumhookeriThwaites belongs toAmaryllidaceae family is one of the most important medicinal plants, enormously used in cancer or inflammation because it contains large amounts of sulfonylmethane.It is also used to treat coughs, colds, fatigue and to recover immunity. Karyotypic study showed that somatic chromosome number is 2n = 22. Only nearly sub median and nearly median chromosomes are found in the complement. Karyotype formula = 1 nsm(-)+ 10 nm=2n=22. The total length of long arms is 60.36 µm, ranging from 3.16µm to 8.23µm. Total length of short arms is 31.57µm, ranging from 1.75µm to 4.11µm. The total length of the chromosome is 92.17µm, ranging from 4.78µm to 12.35µm. Relative chromosome length ranges from38.70µm to 100 µm. Arm ratio ranges from1.70 to2.38.Tf %= 41.63.Centromeric index ranges from 0.40 to 0.28 and The total chromatin index is 100, ranging from 5.18 to 13.40. Anomocytic type of stomata is observedStomatal index and stomatal size were calculated. The maximum length (53.6±2.06µm) was observed in basal portion of the adaxial surface and the minimum length (45.2 ± 1.40µm) was observed in the middle portion of abaxial surface. The maximum width size (24.8±1.11µm) was observed in the basal portion of the adaxial surface and the minimum width was (18.8 ± 1.14µm) at the middle portion of the abaxial surface. Stomatal index 12.63±0.5) maximum and minimum (6.13±0.40) was observed.