Lower Leaf Surface Research Articles

First report of leaf spot caused by Paramyrothecium roridum on Coffea arabica in Hawai'i, USA.

During the 2022-2023 season, the harvested coffee crop in Hawai'i (Coffea arabica) was valued at $57.1 million (USDA NASS 2023). In September 2022, coffee leaf samples with foliar leaf spots affecting the Kona Typica variety were collected from Hōnaunau, Hawai'i, incidence <10%. The symptoms were circular, necrotic leaf spots with yellow margins, which merged, resulting in complete leaf blade coverage and subsequent leaf drop. Sporodochia were present on the abaxial leaf surface. Symptomatic leaf tissue was disinfected in 10% bleach solution for 60 seconds and chlorotic leaf tissue from the spot margins were excised and placed onto water agar and potato dextrose agar (PDA; Difco, USA). After a 7-day incubation period, pure cultures with white aerial mycelium having sporodochia arranged in concentric rings with olivaceous to black conidial masses were isolated. The conidia were aseptate, hyaline, smooth, cylindrical with rounded ends, measuring 5.1 to 6.8 μm long and 1.7 to 2.3 μm wide (n=50). Based on symptomology and cultural/morphological characteristics (Huaman-Pilco et al. 2023; Lombard et al. 2016; Pelayo-Sanchez et al. 2017), the isolates were initially identified as Paramyrothecium roridum (Tode) L. Lombard & Crous, comb. nov. (syn. Myrothecium roridum Tode). Fungal identification of isolate P22-81-2 was further confirmed using BLAST analysis of bulk sequenced PCR products of the ribosomal DNA internal transcribed spacer (ITS) region (White et al. 1990), β-tubulin (βtub), RNA polymerase II (RPB2), and calmodulin genes (Lombard et al., 2016; Huaman-Pilco et al., 2023). The gene sequences (GenBank accession nos. PP211198, PQ192517-19) were >98.4% identical to the P. roridum type specimen (CBS 357.89). A multilocus maximum likelihood phylogenetic analysis incorporating sequence data from previous relevant studies (Lombard et al., 2016; Pinruan et al. 2022) confirmed species identification. To prove pathogenicity, four, 26-month-old Kona Typica variety seedlings were foliar inoculated with a 1 X 106 conidia/ml suspension using a perfume atomizer. An additional four plants were inoculated in a similar manner with sterile water which served as controls. All plants were sprayed to drip on both the upper and lower leaf surfaces and incubated in a clear plastic bag to keep the humidity levels between 90 to 100% for 48 hours at 24°C. After 48 hours, the plants were removed from the bags, placed on a greenhouse bench, and observed weekly for symptom development. Within seven days light brown sunken spots had developed on all inoculated plants. The spots continued to enlarge having a dark distinct margin, light tan center, chlorotic halo, and formed concentric rings, which were identical to the original diseased samples. Leaf spots were not present on any of the control plants. The test was conducted twice. A fungus was consistently reisolated from the leaf spot margins of inoculated plants and morphologically (PDA) and molecularly (ITS, βtub, RPB2, calmodulin) identified as P. roridum, thus fulfilling Koch's Postulates. To the best of our knowledge, this is the first report of P. roridum causing leafspots on C. arabica plants in Hawai'i. This pathogen has been reported on coffee in other parts of the world including Colombia, Costa Rica, Guatemala, Puerto Rico, and Mexico (USDA Fungus-Host Database). Under the right conditions, P. roridum has the potential to cause leafspots and defoliation resulting in economic losses for coffee growers in Hawai'i.

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 thaliana, 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 addressed the role of leaf number in determination of stomatal density and stomatal ratio, and studied adaxial and abaxial stomatal patterns in mutants deficient in known abaxial stomatal development regulators. We found that stomatal density in some genetic backgrounds varies between different fully expanded leaves and 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.

Pharmacognostic Evaluation and Antioxidant Activities of Tetracera indica (Christm. and Panz.) Merr

The community uses Tetracera indica (Christm. and Panz.) Merr extensively as a traditional medicine. This plant was the main source of raw materials for herbal medicinal products, so identification was needed to ensure its authenticity through pharmacognosy evaluation. The present study evaluated macros- and microscopic characteristics, performed phytochemical analysis, and performed total phenolic (TPC) and flavonoid content (TFC) analysis. The organoleptic and macroscopic studies were carried out through sensory organs. The microscopic characteristics of leaf powder and twigs identification using chloral hydrate and distilled water. Numerous chemical reagents, TLC methods and LC-MS/MS analysis were employed in the phytochemical study. Research employed DPPH and FRAP tests to assess the antioxidant activity. Furthermore, quercetin was used as a marker of antioxidant activity. The morphological marker of the leaf T. indica showed the surface of the leaves is rough bristles, shape elliptic-oblong, margin serratus and phyllotaxy alternate. The stem is lignosus, and the rough stem surface is slightly peeling. The lower leaf surface had paracytic stomata and uniseriate trichomes with tapering ends. Raphide crystals and cork cells were detected in the powder analysis of the twigs. The ethyl acetate extract's twig had the highest TPC and TFC values. Ethyl acetate extract from Tetracera indica twigs has potent antioxidant activity with IC50 = 99.84±0.011 µg/ml (DPPH) and 4296.67±0.024 mol/g (FRAP). The study showed that Tetracera indica contains possible active components that could be developed as novel antioxidants. The result of this study might provide early verification and identification to obtain quality medicinal raw materials.

New masquerade observations of Turkish leaf beetles (Coleoptera: Chrysomelidae)

Thirty-five observations of 25 leaf beetle species and their feeding damage are reported. The beetles belong to 13 genera. Obvious masquerade is found in 29 observations. Nine beetle species in our sample are light in color, but two, being generally light colored, have a wide dark stripe along the elytral suture, so that on the photos (and presumably to visual predators in the field) they appear dark. Feeding damage that these two are surrounded with is also dark. In six observations light colored beetles were making light colored damage. In five examples dark colored beetles were observed among both light and dark colored damage. In remaining observations dark colored beetles were making dark colored damage. Masquerade in Cassidinae and larvae of Alticini and Galerucini is reported here for the first time. In addition, observation of flea beetle interacting with ants on leaf surface and use of feeding holes to move from the upper to the lower leaf surface are reported.

First Report of Powdery Mildew on Viburnum chinshanense Caused by Erysiphe pseudoviburni in China.

Viburnum chinshanense, a deciduous shrub in the family Caprifoliaceae, is a dominant tree distributed mainly in the North-Central and South-Central regions of China (Zhu et al. 2023). Because of its lush white flowers and vibrant red fruits, V. chinshanense is used widely as ornamental tree in China. In May 2022, severe powdery mildew symptoms were observed on V. chinshanense on the Huaxi Campus of Guizhou Normal University, Guiyang, China. The incidence was approximately 75% among 80 V. chinshanense plants observed. White mycelia were present on both adaxial and abaxial leaf sides, but not on fruits, petioles, or stems. Infected leaves showed slight chlorosis and twisting. The mycelia were amphigenous, forming small-to-large patches, often sparse on the upper leaf surface, but mostly confluent on the lower leaf surface. Hyphae were hyaline, 4-7 μm wide. Hyphal appressoria were lobed to multilobed, in opposite pairs or solitary. Conidiophores were erect, straight, or somewhat flexuous, 60-130 µm long (n = 30). Foot cells were subcylindrical to slightly curved-sinuous at the base, 20-40 × 6-10 µm (n = 30) in size, followed by 1-3 shorter cells. Conidia formed singly, occasionally two to three in a chain. Conidia were ellipsoid to ovoid, cylindrical, and 24-40 × 16-20 µm (n = 50). No fibrosin bodies were observed on the conidia. Chasmothecia were subglobose, 56-115 µm in diameter. The appendages were 35-70 µm long. Based on these morphological characteristics, the powdery mildew fungus was identified as Erysiphe pseudoviburni (Bradshaw et al. 2020). To confirm the identification, the ribosomal DNA internal transcribed spacer (ITS) and the ribosomal large subunit (LSU) region were amplified and sequenced using the ITS1/ITS4 primer pair (White et al. 1990) and the NL1/NL4 primer pair (Ziemiecki et al. 1990), respectively. The obtained 643-bp ITS sequence (GenBank accession no. ON729292) had 99.84% identity with E. pseudoviburni strains KUS-F27310 (MN431595) and MUMH0001 (LC009904). The obtained 593-bp LSU sequence (ON729293) had 99.83% identity with E. pseudoviburni (LC009904 and MN431595). Based on the phylogenetic analysis of the combined ITS and LSU dataset (Bradshaw et al. 2020), the isolate (GZVD-1) was grouped in a clade with the E. pseudoviburni strains KUS-F27319, KUS-F27310, and MUMH0001. To fulfill Koch's postulates, leaves of three healthy potted V. chinshanense plants were inoculated by gently pressing with diseased leaves. Non-contact plants were used as controls. All plants were incubated in a greenhouse at 25 ± 2°C, 80% relative humidity. Similar powdery mildew symptoms were observed on the inoculated plants 12 days after inoculation, whereas the control plants remained symptomless. The reisolated fungus from the inoculated plants was morphologically identical to that on originally diseased plants. ITS and LSU sequences of the reisolated fungus showed 100% identity with ON729292 and ON729293, respectively. E. pseudoviburni has previously been reported to infect some Viburnum species, including V. sieboldii in Japan (Takamatsu et al. 2015) and V. odoratissimum in South Korea (Bradshaw et al. 2020). To the best of our knowledge, this is the first report of powdery mildew caused by E. pseudoviburni on V. chinshanense in China. This work expands the known host range of E. pseudoviburni in the Viburnum genus.

Leaf Architecture and Genome Size Variation of Durio zibethinus L. from Jelebu, Negeri Sembilan, Malaysia.

Durio zibethinus L. is known as the "king of fruit" in Malaysia. Meanwhile, Jelebu, Negeri Sembilan has always become the top choice district to visit for durian lover for its Durian Kampung Jelebu, which possessed good quality on par with top D. zibethinus clones such as D197 Musang King and D24. However, there is still lacking in taxonomic data of D. zibethinus especially from Jelebu. This study aimed to analyse the leaf architecture and genome size variations of selected D. zibethinus accessions from Jelebu. Five D. zibethinus accessions from Jelebu were examined. Thirty-seven parameters of gross leaf morphological characteristics and leaf venation pattern were observed and recorded for identification and classification of D. zibethinus accessions from Jelebu. Seven parameters have been recorded which are petiole length, petiole features, leaf size, leaf shape, leaf base shape, lower leaf surface colour and areolation could be used in differentiating between accessions. Results of this study showed the intraspecific variations existed among D. zibethinus accessions from Jelebu with a genome size varying between 1.7433 pg and 1.800 pg. In conclusion, data on leaf architecture and genome size variations from D. zibethinus accessions are beneficial for early plant identification and classification.

Amphistomy increases leaf photosynthesis more in coastal than montane plants of Hawaiian 'ilima (Sida fallax).

The adaptive significance of amphistomy (stomata on both upper and lower leaf surfaces) is unresolved. A widespread association between amphistomy and open, sunny habitats suggests the adaptive benefit of amphistomy may be greatest in these contexts, but this hypothesis has not been tested experimentally. Understanding amphistomy informs its potential as a target for crop improvement and paleoenvironment reconstruction. We developed a method to quantify "amphistomy advantage" ( ) as the log-ratio of photosynthesis in an amphistomatous leaf to that of the same leaf but with gas exchange blocked through the upper surface (pseudohypostomy). Humidity modulated stomatal conductance and thus enabled comparing photosynthesis at the same total stomatal conductance. We estimated and leaf traits in six coastal (open, sunny) and six montane (closed, shaded) populations of the indigenous Hawaiian species 'ilima (Sida fallax). Coastal 'ilima leaves benefit 4.04 times more from amphistomy than montane leaves. Evidence was equivocal with respect to two hypotheses: (1) that coastal leaves benefit more because they are thicker and have lower CO2 conductance through the internal airspace and (2) that they benefit more because they have similar conductance on each surface, as opposed to most conductance being through the lower surface. This is the first direct experimental evidence that amphistomy increases photosynthesis, consistent with the hypothesis that parallel pathways through upper and lower mesophyll increase CO2 supply to chloroplasts. The prevalence of amphistomatous leaves in open, sunny habitats can partially be explained by the increased benefit of amphistomy in "sun" leaves, but the mechanistic basis remains uncertain.

Susceptibility of centipede tongavine (Epipremnum pinnatum) commercially grown in nurseries in Florida to aroid leaf rust (Pseudocerradoa paullula).

Epipremnum pinnatum (L.) Engl., (Araceae, Monocots) known as dragon-tail plant or centipede tongavine, is the most cultivated aroid species worldwide (Boyce 2004). In 2022, symptomatic dragon-tail plants, collected from plant nurseries in south Florida (e-Xtra Fig.1). Symptoms included round leaf spots often with a yellow halo and erupting pustules mainly distributed in the underside of the leaves. Visits to the nurseries revealed a 60% incidence of approximability 50 mature plants, with some leaves showing up to 30% of tissue damage. The putative pathogen was identified morphologically as Pseudocerradoa paullula (Syd. & P. Syd.) M. Ebinghaus & Dianese (Pucciniaceae, Basidiomycota) (Ebinghaus et al. 2022), characterized by the production of pseudosuprastomatal uredinia with globose to subglobose urediniospores, light-brown, echinulate (1 µm height), 24-31 µm diam with thick walls, 1.5-2.5 µm in height (n=30). Identical morphological features reported by Urbina et al. (2023) (e-Xtra Fig. 1). PCR amplification followed by Sanger sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal RNA genes (Aime 2006) together with LSU internal species specific primer (Urbina et al. 2023) were used to confirm the identification of the pathogen (GenBank ON887194-ON887196). MegaBlast (Chen et al. 2015) searches resulted in a >99% sequence similarity to a P. paullula specimen collected in Florida (2019-101665, GenBank ON887197). Host identification was made by using the Ribulose-1,5-bisphosphate carboxylase-oxygenase (rbcL. GenBank ON887186, ON887187) and Maturase K (matK) loci (GenBank ON887190, ON887191) (Fazekas et al. 2012). Both barcodes resulted in >99.13% sequence similarity to voucher J.R. Abbott 24912 FLAS (GenBank GU135198 and GU135036, respectively). Symptomatic dried specimens were deposited in the Plant Industry Herbarium (PIHG 16229 - 16232). Koch's postulates were fulfilled using urediniospores collected from an infected E. pinnatum sample that was kept in darkness at 4°C for seven days until inoculation. Eight potted dragon-tail plants were inoculated by hand rubbing urediniospores against upper and lower leaf surfaces and three plants were used as controls. All plants were misted with sterile water and covered with plastic bags (23 °C, >90% RH, 12/12 h daylight). Bags were removed 48 h after inoculation, plants were set in a climate-controlled greenhouse (~30 °C, ~65% RH, 12/12 h light cycle) and monitored daily for symptoms. Chlorotic spots appeared after 10 days, and pustules after 25 days while the non-inoculated controls remained symptomless. Aroid leaf rust is known to infect several aroid species, including dragon-tail (Shaw 1995), which some varieties capable to outdoors in USDA 9a hardiness zones (Wunderlin et al. 2023), but the rust fungus has not been observed on any species of Epipremnum in the landscape yet, suggesting that its susceptibility could be driven by plant growth conditions that favor pathogen infection (e.g., excess of humidity and nutrients, dense planting, overhead irrigation, etc.). Here we encourage dragon-tail plant growers to be aware of its susceptibility to P. paullula and to stay vigilant of the culture conditions to avoid plants from getting infected with this airborne pathogen.

Anatomical Identification of Leaf Stomatal Cell Types in The Family Euphorbiacea

Stomata, which are specialized cells on the surface of leaves, undergo modification to form structures containing two guard cells. These cells play a crucial role in facilitating the exchange of water vapor and gases between the plant's internal environment and the surrounding atmosphere. Typically located on plant parts exposed to air, such as leaves, stems, and rhizomes, stomata distribution varies among different species. While some plants exhibit stomata on both upper and lower leaf surfaces, others, like water lilies, exclusively feature stomata on the upper side.The objective of the current investigation was to analyze the stomatal anatomy of various plant species within the Euphorbiaceae family. Employing a qualitative descriptive approach, the study aimed to characterize and interpret the stomatal types present on the leaves of Euphorbiaceae plants in the Langsa City region. The findings revealed the presence of five Euphorbiaceae species in Langsa City, including Euphorbia mili (jade fern), Jatropha curcas (Jatropha curcas), Codiaeum variegatum 'Norma' (norma puring), Codiaeum variegatum Bi (jet puring), and Codiaeum finger (finger puring), all of which exhibited parasitic stomatal types.

Impact of Environmental Pollution by Spent Oil Levels on Leaf Anatomy of Eruca Sativa

Pollution is the quantitative change that occurs to one or more of the elements of the environment that would harm the life of the living organism and weaken the ability of the environment to continue its production. The current research was carried out to study the impact of spent engine oil pollution on some anatomical leaf characters of Eruca Sativa. The pots of sandy soils were contaminated by adding spent engine oil levels of 0.0, 2.5, 5.0, 15.0 and 30.0 ml.3kg-1. From the results, it is noted that a convergence and a slight decrease in the thickness of the cuticle layer of the upper and lower surface of the leaf at the levels of added oil 1.5 and 2.5 ml.kg -1. It was observed, that there was a relative decrease in the thickness of the upper and lower epidermal cells layer at the low levels of addition, with the increase in the decrease in thickness with the increase in the levels of spent oil. And it was found that a clear increase in the thickness of the palisade layer with the increase in the levels of spent oil addition compared to the thickness of the layer in the leaves of plants grown in soil with an addition level of 0 ml.kg-1. It is clear that the dimensions of the stomata for the upper and lower leaf surface of the plant leaf increased and took a behavior that corresponded to the increase in the levels of spent engine oil.

Study of some Physiological and Molecular Indicators of Bread Wheat Treated with Colchicine

During the winter agricultural season of 2022-2023, a field experiment was carried out in the Al-Basatin Al-Sharqiya, located 4 km away from the center of Al-Muthanna governorate. The objective of this study was to investigate various anatomical and genetic parameters of wheat varieties under the influence of the mutagenic alkaloid colchicine at concentrations of 0, 250, 500, and 750 mg L-1. The study employed a split plot design with three replications. The main plots consisted of different concentrations of the colchicine compound, while the secondary plots comprised four varieties (Ibaa99, Mawadah, Bohuth 22, Babel). The statistical analysis yielded significant variations in the anatomical and molecular traits among the cultivars. Notably, the cultivar Mawada demonstrated superior performance in terms of stoma density on the upper leaf surface, with an average of 118.15 stomata mm-2. Conversely, the Babel variety exhibited the highest average stoma density of 113.70 stomata mm-2 on the lower leaf surface. Regarding Bohuth 22, it demonstrated notable proficiency in terms of stoma length, exhibiting an average measurement of 3.82 μm for both the upper and lower leaf surfaces. Additionally, it displayed the highest average stoma width for the lower surface, measuring at 2.66 μm. The highest mean stomatal density for both the upper and lower leaf surfaces (114.1, 104.44 stomata mm-2) was observed at a colchicine concentration of 750 mg L-1. Regarding the intersection of the treatments, it was observed that treatment C1V3 exhibited superior performance in terms of the dimensions of the stoma, specifically the length and width on the lower surface of the leaf. The average difference between the measurements was found to be 4.40-2.96 μm, consecutively. The C2V2 treatment demonstrated superior performance in relation to the stomatal density observed on the upper surface of the leaf, exhibiting an average of 132.6 stomata mm-2. The treatment labelled as C2V4 exhibited the highest average stomata density (131.85 stomata mm-2) on the lower surface of the leaf. The molecular analysis conducted using RAPD-PCR technology revealed that the primer OPA 9 exhibited a total of 37 bands. Among these bands, 6 were found to be unique, while the remaining 31 bands displayed divergence. The OPA12 primer exhibits a minimum total of 29 bands, consisting of 24 distinct bands and 5 unique bands. Notably, all primers demonstrate a 100% occurrence of differentiated bands.

Five New Species of Aniba (Lauraceae) from Colombia, Ecuador, and Peru

Five new species of Aniba Aubl. (Lauraceae) with clustered or verticillate leaves are described and illustrated. Aniba brochidodroma van der Werff from Peru stands out by its short petioles and soft whitish hairs on the lower leaf surface. Aniba glabra van der Werff from Colombia is distinguished by its glabrous flowers and inflorescences. Aniba palaciosii van der Werff from Ecuador can be recognized by the indument of the outer surface of the tepals, with the outer three tepals finely appressed pubescent and the inner three tepals glabrous. Aniba tomentella van der Werff from Peru differs from its congeners in its flower shape; its flowers are wider than long and the tepals are incurved leaving only a small apical pore. Finally, A. verticillata van der Werff from Ecuador differs from morphologically similar species by its subcoriaceous leaves with prominently raised secondary veins and its montane habitat.

Combined nighttime ultraviolet B irradiation and phytoseiid mite application provide optimal control of the spider mite Tetranychus urticae on greenhouse strawberry plants.

Tetranychus urticae is a hard-to-control pest of greenhouse strawberry production. Nighttime ultraviolet B (UV-B) radiation using light reflection sheets (LRS) has been applied as a physical method to control T. urticae through direct ovicidal effects (the UV method). However, because strawberry leaves grow more densely, UV-B radiation fails to reach the lower leaf surfaces inhabited by spider mites; therefore, a complementary method is required. We propose the supplemental application of phytoseiid mites in greenhouse strawberry production. We evaluated the control effects of UV-B irradiation, phytoseiid mite application and their combined use. The effects of UV-B irradiation on the degree of overlap relative to the independent distributions (ω) between predators and prey were also analyzed. The UV method alone maintained low T. urticae density levels from November to February; however, mite populations increased from March onward. Phytoseiid mite application in January and February without UV-B irradiation resulted in a temporary increase in spider mites in March and/or April. By contrast, combined application of the UV method and phytoseiid mites had a greater control effect during the strawberry growing season. The ω values were higher for the UV method compared with no UV-B irradiation, suggesting that UV-B irradiation increased phytoseiid mite foraging rates. The release of phytoseiid mites compensated for the shortcomings of the UV method, and UV-B irradiation promoted predation by phytoseiid mites by increasing the behavioral numerical response. Consequently, combined application of UV-B irradiation and phytoseiid mites is optimal for T. urticae control in greenhouse strawberry production. © 2023 Society of Chemical Industry.

Size distribution and elemental composition of airborne particulate matter on four plant species in vertical greenery systems

Vertical greenery systems (VGSs) have been proven to greatly improve the urban thermal environment. However, their effect on the retention of airborne particulate matter (PM) in the road environment remains unclear. This study aimed to assess the quantity of size-segregated PMs on both the upper (adaxial) and lower (abaxial) leaf surfaces, the mass of size-segregated PMs on the leaf surface and within the leaf wax, as well as the elemental composition of PMs retained in leaf stomata of four plant species in VGSs in Guangzhou. The findings revealed that VGSs exhibited greater retention of fine (<2.5 μm) PMs when compared to coarse (2.5–10 μm) and large (>10 μm) PMs. Among the four species studied, Tradescantia spathacea exhibited the highest PM retention in VGSs. The number density of accumulated PMs on the upper and lower leaf surfaces of the four plant species of VGSs at three heights varied significantly with species, heights, and their interaction (P < 0.05). The greatest stomatal block rate by PM occurred at a height of 0.6 m, the range was 91.1%–98.0%. The composition of PMs retained by the leaves primarily consisted of common element of C, O, Ca, K, Mg, and Si, which likely originated from natural sources. Heavy metals (HMs) such as Cr and Cd may have originated from brakes, while Zn and Cu might be attributed to tire wear and exhaust emissions. Therefore, VGSs effectively retained a substantial quantity of airborne PM and contributed to the mitigation of urban air pollution issues.

Two New Species of Persea (Lauraceae) from Ecuador

Two new species of Persea Mill. (Lauraceae) are described from Ecuador. Persea basiobtusa Rohwer is a typical member of subgenus Eriodaphne Nees sect. Eriodaphne (Nees) Meisn., but stands out by its small flowers and obtuse to truncate leaf bases. Persea dryadum Rohwer belongs to subgenus Eriodaphne sect. Hexanthera (Mez) L. E. Kopp and is distinct by its lanate lower leaf surface.

COMPARATIVE LEAF ANATOMY OF SOME ASYNEUMA GRISEB. &amp; SCHENK TAXA

Objective: The Asyneuma Griseb. &amp;amp; Schenk is represented by 34 accepted species worldwide and its native range covers a wide area from East Central Europe to Japan and Northern Indo-china. The plants of Asyneuma are characterized by herbaceous, simple or branched inflorescences, purple, violet or blue corolla and capsule fruits. Studies show that the Campanulaceae family contains bioactive compounds phenylethanoid (phenylproponoid), alkaloids, cyanogenetic heteroside, flavonoid, triterpene, anthocyanin, phenolic acid, essential oil, coumarin and polysaccharide. In addition, it is known that plants in the family have antioxidant, wound healing, anti-inflammatory, analgesic, antiobesity, expectorant antihepatotoxic, antitumoral, antiatherosclerotic, neuroprotective, antidepressant, tonic and α-glucosidase inhibitory activities. In this study, the anatomical structures of Asyneuma limonifolium subsp. limonifolium, A. limonifolium subsp. pestalozzae (Boiss.) Damboldt, A. linifolium subsp. linifolium and A. linifolium subsp. nallihanicum Kit Tan &amp;amp; Yıldız leaves were examined. Material and Method: Asyneuma limonifolium subsp. limonifolium, A. limonifolium subsp. pestalozzae (Boiss.) Damboldt, A. linifolium subsp. nallihanicum Kit Tan &amp;amp; Yıldız were collected from Ankara. A. linifolium subsp. linifolium was collected from Antalya. Plant parts preserved in alcohol (70%). Microscopic sections were taken using a razor blade. Tissues were stained with Sartur's reagent and examined with a light microscope. Microphotographs were taken with a camera attached to a light microscope. Result and Discussion: The results showed that, the anatomical structures of the basal and cauline leaves of Asyneuma limonifolium subsp. limonifolium and A. limonifolium subsp. pestalozzae were similar. The leaves are bifacial and the palisade parenchyma 1-2 rows. In addition, the unicellular, non-glandular hairs and anomocytic stomata were observed on both epidermal surfaces. Besides, the leaf of A. linifolium subsp. linifolium is monofacial while that of A. linifolium subsp. nallihanicum is bifacial. Also, unicellular hairs were present on epidermal layer of A. linifolium subsp. linifolium while A. linifolium subsp. nallihanicum were not. The anomocytic stomata were determined on the upper and lower leaf surfaces of both subspecies.

A Research on the Anatomical and Ecological Characteristic of Onosma mollis DC. (Boraginaceae)

In this study, endemic Onosma mollis DC. it is aimed to examine the anatomical and ecological features of (Boraginaceae) plant in detail and to be compared with the other studies. According to the cross-sections, the root is secondary. Primary pith rays that 2-3 layered are observed. Epidermis is single-layered in stem transverse section. Eglandular hairs in the epidermis are simple, with one and two cells. Glandular hairs are capitate, digitate and with two cells. Just under the epidermis, 2-3 rows of collenchyma cells are formed. Both the upper and the lower surface of leaf is covered with numerous eglandular hairs. Eglandular hairs are 2-3 branched. Glandular hairs are of capitate, digitate and peltate type. The habitat of the O. mollis plant is mountain slopes, meadows, and prairies. The soil in which the species grows is clay and loamy. It is also classified as slightly alkaline, salty, calcareous, low phosphorus and high in potassium. According to its organic matter content, it is in the group of good humus soils.

Three new species of eriophyoid mites (Acari: Eriophyoidea) from South China

ABSTRACT Three new species of eriophyoid mites from South China are described and illustrated: Dichopelmus homalii sp. nov. and Agenuseta tianliaomus sp. nov. from Homalium cochinchinense (Lour.) Druce (Salicaceae). Levonga melicopeae sp. nov. from Melicope pteleifolia (Champ. ex Benth.) T. G. Hartley (Rutaceae). All of them are vagrants on lower leaf surface and cause no apparent symptom to their host plants.

Leaf side determines the relative importance of dispersal versus host filtering in the phyllosphere microbiome.

Leaves harbor distinct microbial communities that can have an important impact on plant health and microbial ecosystems worldwide. Nevertheless, the ecological processes that shape the composition of leaf microbial communities remain unclear, with previous studies reporting contradictory results regarding the importance of bacterial dispersal versus host selection. This discrepancy could be driven in part because leaf microbiome studies typically consider the upper and lower leaf surfaces as a single entity despite these habitats possessing considerable anatomical differences. We characterized the composition of bacterial phyllosphere communities from the upper and lower leaf surfaces across 24 plant species. Leaf surface pH and stomatal density were found to shape phyllosphere community composition, and the underside of leaves had lower richness and higher abundances of core community members than upper leaf surfaces. We found fewer endemic bacteria on the upper leaf surfaces, suggesting that dispersal is more important in shaping these communities, with host selection being a more important force in microbiome assembly on lower leaf surfaces. Our study illustrates how changing the scale in which we observe microbial communities can impact our ability to resolve and predict microbial community assembly patterns on leaf surfaces. IMPORTANCE Leaves can harbor hundreds of different bacterial species that form unique communities for every plant species. Bacterial communities on leaves are really important because they can, for example, protect their host against plant diseases. Usually, bacteria from the whole leaf are considered when trying to understand these communities; however, this study shows that the upper and lower sides of a leaf have a very different impact on how these communities are shaped. It seems that the bacteria on the lower leaf side are more closely associated with the plant host, and communities on the upper leaf side are more impacted by immigrating bacteria. This can be really important when we want to treat, for example, crops in the field with beneficial bacteria or when trying to understand host-microbe interactions on the leaves.

Roles of lower-side leaf trichomes in diffusion resistance and gas-exchange characteristics across environmental gradients in Metrosideros polymorpha.

Leaf trichomes on the lower leaf surface are common in many plant species, especially those grown under dry and/or low-temperature conditions; however, their adaptive significance remains unclear. Lower-side leaf trichomes can directly decrease gas fluxes through increased gas-diffusion resistance but can indirectly increase gas fluxes through increased leaf temperature owing to increased heat-diffusion resistance. We examined whether the combined direct and indirect effects of trichome resistance increase photosynthetic rates and water-use efficiency (WUE) using Metrosideros polymorpha Gaud., which varies widely in the masses of lower-side non-glandular leaf trichomes across various environments on the Hawaiian Islands. We employed both field surveys, including ecophysiological measurements at five elevation sites, and simulation analyses to predict the gas-exchange rates of leaves with various trichome-layer thicknesses across a wide range of environmental conditions. Field surveys showed that the trichome-layer thickness was the largest at the coldest and driest site and the thinnest at the wettest site. Field surveys, experimental manipulations and simulation analyses demonstrated that leaf trichomes significantly increased leaf temperature owing to the increased heat resistance. Simulation analyses showed that the effect of leaf trichomes on heat resistance was much larger than that on gas-flux resistance. Leaf trichomes can increase daily photosynthesis only in cold dry areas by increasing the leaf temperature. However, the increased leaf temperature with leaf trichomes resulted in a consistent decrease in the daily WUE at all elevation sites. The magnitudes of trichome effects on gas-exchange rates were associated with the temperature difference across the elevational gradient, the strong light intensity in Hawaii, the leaf-size variation and the conservative stomatal behavior of M. polymorpha as well as the trichome-layer thickness. In summary, the lower-side leaf trichomes in M. polymorpha can be beneficial for carbon assimilation in low-temperature environments but not for water conservation in most environments in terms of diffusion resistance.