Major Plant Species Research Articles

Projecting the impact of climate change on honey bee plant habitat distribution in Northern Ethiopia

Climate change significantly affects the diversity, growth, and survival of indigenous plant species thereby influencing the nutrition, health and productivity of honey bees (Apis mellifera). Hypoestes forskaolii (Vahl) is one of the major honey bee plant species in Ethiopia’s Tigray region. It is rich in pollen and nectar that typically provides white honey, which fetches a premium price in both local and inter-national markets. Despite its socio-economic and apicultural significance, the distribution of H. forskaolii has been declining, raising concerns regarding its conservation efforts. However, there is limited knowledge on how environmental and climatic factors affect its current distribution and response to future climate change. The study investigates the current and projected (the 2030s, 2050s, 2070s, and 2090s) habitat distributions of H. forskaolii under three future climate change scenarios (ssp126, ssp245, and ssp585) using the Maximum Entropy Model (MaxEnt). The results show that land use (50.1%), agro-ecology (28%), precipitation during the Driest Quarter (11.2%) and soil texture (6.1%) predominantly influence the distribution of H. forskaolii, collectively explaining 95.4% of the model's predictive power. Habitats rich in evergreen trees and mosaic herbaceous with good vegetation cover are identified as the most suitable for H. forskaolii. The spatial distribution of H. forskaolii is concentrated in the highlands and mid-highlands of the eastern and southern parts of Tigray, characterized by a colder temperature. Across the three climate change scenarios, the size of suitable habitat for H. forskaolii is projected to decrease over the four time periods studied. Predictions under the ssp585 scenario reveal alarming results, indicating a substantial decrease in the suitable habitat for H. forskaolii from 4.26% in the 2030s to 19.09% in the 2090s. Therefore, given the challenges posed by climate change, research efforts should focus on identifying and evaluating new technologies that can help the H. forskaolii species in adapting and mitigating the effects of climate change.

Major Dominant Invasive Alien Plant Species, Land Uses Types and Their Management Practice in Dedessa, Bedelle and Chora Districts, Buno Bedelle Zone, Southwest Ethiopia

Major Dominant Invasive Alien Plant Species, Land Uses Types and Their Management Practice in Dedessa, Bedelle and Chora Districts, Buno Bedelle Zone, Southwest Ethiopia

ASSESSMENT OF ANGIOSPERMIC FLORA AT RAJSHAHI METROPOLITAN AREA OF BANGLADESH

Objectives: The study aimed to document the angiospermic flora at Rajshahi metropolitan area of Bangladesh. The study also examined the species diversity in the study area. Methods: The research work is based on fresh materials collected during 33 field visits at Rajshahi metropolitan area of Bangladesh was carried out from February 2016 to March 2017 to cover the seasonal variations. Plant parts with either flower or fruits collected using traditional herbarium techniques to make voucher specimens for documentation. Results: The results show that a total of 494 species belonging to 455 genera and 106 families were recorded. Of these, Magnoliopsida (Dicotyledones) is represented by 413 species under 390 genera and 84 families while Liliopsida (Monocotyledones) is represented by 81 species under 65 genera and 22 families. For each species scientific name, local name, family name, habit, relative occurrence, and flowering time were recorded. The present study will help in identifying the major angiospermic plant species for further investigation. Conclusion: The present research focused on the angiospermic flora growing throughout the Rajshahi metropolitan area of Bangladesh. A total of 494 angiospermic plant species were recorded.

Precipitation and local adaptation drive spatiotemporal variations of aboveground biomass and species richness in Tibetan alpine grasslands.

The Tibetan Plateau contains the highest and largest alpine pasture in the world, which is adapted to the cold and arid climate. It is challenging to understand how the vast alpine grasslands respond to climate change. We aim to test the hypothesis that there is local adaptation in elevational populations of major plant species in Tibetan alpine grasslands, and that the spatiotemporal variations of aboveground biomass (AGB) and species richness (S) can be mainly explained by climate change only when the effect of local adaptation is removed. A 7-year reciprocal transplant experiment was conducted among the distribution center (4950m), upper (5200m) and lower (4650m) limits of alpine Kobresia meadow in central Tibetan Plateau. We observed interannual variations in S and AGB of 5 functional groups and 4 major species, and meteorological factors in each of the three elevations during 2012-2018. Relationships between interannual changes of AGB and climatic factors varied greatly with elevational populations within a species. Elevation of population origin generally had a greater or an equal contribution to interannual variation in AGB of the 4 major species, compared to temperature and precipitation effects. While the effect of local adaptation was removed by calculating differences in AGB and S between elevations of migration and origin, relative changes in AGB and S were mainly explained by precipitation change rather than by temperature change. Our data support the hypothesis, and further provide evidence that the monsoon-adapted alpine grasslands are more sensitive to precipitation change than to warming.

Magnetically Treated Water in Phaseolus vulgaris L.: An Alternative to Develop Organic Farming in Cuba

Phaseolus vulgaris L. (common bean) significantly contributes to the human diet due to its protein, vitamin and mineral contents, making it one of the major edible plant species worldwide. Currently, the genetic resources conserved in germplasm banks in Cuba have experienced a loss of viability, which makes their propagation difficult. Magnetically treated water has been used to improve the response of seeds and plants of different species. However, there is little experimental evidence on the cultivation of the common bean irrigated with magnetically treated water or its positive effects on seed germination recovery and its effects on physiological, anatomical and morphological characteristics. This study aims to evaluate the growth and development of common bean with magnetically treated water as an alternative to rejuvenate the seeds for organic agriculture. A two-group experimental design was used: a group of plants irrigated with water without a magnetic field and a group of plants irrigated with water treated with a magnetic field at induction in the range of 100 to 150 mT. There was an increase of 25% in the percentage of germination; the stomatal anatomical structures behaved normally; and the stem length, vigor index, leaf area and seed weight increased by 35, 100, 109 and 16%, respectively. The concentrations of chlorophyll a, chlorophyll b pigments and carbohydrates in the plants grown with magnetically treated water were also stimulated in relation to control plants with increments of 13, 21 and 26%, respectively. The technology employed in this study did not have negative effects on the plant nor did it affect the presence of structures or the net content of the assessed compounds. Its use in the cultivation of Phaseolus vulgaris L. might represent a viable alternative for the improvement of the plant in organic farming production.

Unleashing the power within short-read RNA-seq for plant research: Beyond differential expression analysis and toward regulomics.

RNA-seq has become a state-of-the-art technique for transcriptomic studies. Advances in both RNA-seq techniques and the corresponding analysis tools and pipelines have unprecedently shaped our understanding in almost every aspects of plant sciences. Notably, the integration of huge amount of RNA-seq with other omic data sets in the model plants and major crop species have facilitated plant regulomics, while the RNA-seq analysis has still been primarily used for differential expression analysis in many less-studied plant species. To unleash the analytical power of RNA-seq in plant species, especially less-studied species and biomass crops, we summarize recent achievements of RNA-seq analysis in the major plant species and representative tools in the four types of application: (1) transcriptome assembly, (2) construction of expression atlas, (3) network analysis, and (4) structural alteration. We emphasize the importance of expression atlas, coexpression networks and predictions of gene regulatory relationships in moving plant transcriptomes toward regulomics, an omic view of genome-wide transcription regulation. We highlight what can be achieved in plant research with RNA-seq by introducing a list of representative RNA-seq analysis tools and resources that are developed for certain minor species or suitable for the analysis without species limitation. In summary, we provide an updated digest on RNA-seq tools, resources and the diverse applications for plant research, and our perspective on the power and challenges of short-read RNA-seq analysis from a regulomic point view. A full utilization of these fruitful RNA-seq resources will promote plant omic research to a higher level, especially in those less studied species.

Invasive Alien Plant Species for Use in Paper and Packaging Materials

Invasive plant species can impede the establishment and growth of native plants and affect several ecosystem properties. These properties include soil cover, nutrient cycling, fire regimes, and hydrology. Controlling invasive plants is therefore a necessary, but usually expensive, step in restoring an ecosystem. The sustainability of materials with an emphasis on the use of local resources plays an important role in the circular economy. The use of alternative fibers from invasive plants promotes local production in smaller paper mills that offer the protection of local species and the reduction of waste and invasive plants. A synthesis of the literature is needed to understand the various impacts of invasive plants and their practical control in the context of papermaking applications and to identify associated knowledge gaps. To improve our understanding of the practical application of invasive species in the paper industry, we reviewed the existing literature on invasive plant species in the area of fiber production, printability, coating solution production, dyes, and extracts, and collected information on the major invasive plant species in Europe and the methods used for various applications.

Impact of buried debris from agricultural biodegradable plastic mulches on two horticultural crop plants: Tomato and lettuce

Biodegradable mulches (BDM) are increasingly valued and used for substituting non-biodegradable plastic mulches polluting agricultural soils. They are tilled into soil, where they fragment and release compounds throughout their biodegradation. The consequences of BDM use on the plant-soil environment have been partially studied with pristine and with artificially-weathered BDM fragments. However, to guarantee safety use of BDM, studies on the BDM debris effects are required. For this, to determine potential effects of the field-weathering BDM on plants, a mesocosm experiment was performed by sowing seeds from two major plant species commonly cultivated with BDM, tomato (Lycopersicon esculentum) and lettuce (Lactuca sativa), in plant pots containing pristine and field-weathered pieces from seven different BDM formulations, one paper mulch, a polyethylene (PE) mulch, and no-mulch control pots.Germination of both plant species was unaffected by any of the mulch treatments; however, PHB (polyhydroxybutyrate)-based BDM fragments severely inhibited tomato and lettuce plant growth, 90 and 95 %, respectively. Moreover, all pristine and field-weathered BDM significantly delayed lettuce plant development. Tomato plant growth progressed better, but growth retardation was also evidenced with most field-weathered BDM treatments. Overall, field-weathered fragments caused stronger effects on plants than the pristine unused ones. No effects were found for PE mulch, either pristine or field-weathered. The obtained results highlight that BDM debris may alter plant development depending on their nature and on their weathering, rather than on their physical presence, and evidence the need to conduct further experiments on the impact of field-weathered BDM on the plant-soil environment.

Characteristics and factors driving the variations in bark thickness of major woody plants in China

Bark is an important protective tissue and vegetative organ of woody plants. Variations in bark thickness have a direct effect on plant growth and development, forest community structure, and terrestrial ecosystem function. However, the characteristics of these variations in tree bark thickness (BT) and adaptation to environmental factors remain unclear. In this study, we established comprehensive BT traits and environmental factor dataset for 75 major woody plant species in China and analyzed the spatial pattern and factors driving BT traits in the major woody plants of China. As results, the BT of major woody plants in China varied significantly with spatial location (latitude and longitude) (P < 0.001). A significant difference was observed in the relative age bark thickness among different plant types (gymnosperms and angiosperms) and life forms (evergreen and deciduous) (P < 0.001). Significant differences in relative bark thickness (RBT) were detected among the different bark phenotypes (smooth and rough) (P < 0.05). However, no significant difference in the relative bark volume was observed among the three groups (plant types, life forms, or bark phenotypes). All BT traits had particular phylogenetic signals. The Mantel test results showed that all BT traits except RBT were correlated with the environmental factors (Mantel’s P < 0.05). The redundancy analysis revealed that the spatial variation in BT traits was significantly affected by the annual mean temperature, the mean diurnal range, and altitude (P < 0.05). The results of variance decomposition showed that the BT traits were affected by spatial factors (20 %), climatic factors (8 %), and their interaction (8 %), while the effects of soil factors could be ignored. Our results demonstrate that the biotic factors affecting the BT of woody plants in China were the different plant types, life forms, and bark phenotypes, while the abiotic factors were the spatial and climatic factors and their combined effects.

Modelling the distribution of Oxytenanthera abyssinica (A. Richard) under changing climate: implications for future dryland ecosystem restoration

Bamboo is the world's most widely exploited plant resource, with significant socio-economic and cultural values. In most parts of Africa, the population is in jeopardy due to the high pressure from human and natural forces. Of these, Oxytenanthera abyssinica (A. Richard) is among the threatened bamboo species. Furthermore, the effect of climate change on the distribution of bamboo has not yet been adequately studied. Therefore, this study aims to model and map the current and future distribution of O. abyssinica in Africa under four representative concentration pathways (RCPs), such as RCP2.6, RCP4.5, RCP6, and RCP8.5. The future projections were done for the years 2050 and 2070 using SDM ensemble approaches. To model the current and future distribution of O. abyssinica in Africa, 737 presence data were collected from various sources. For this study, a total of eight (8) temperature and precipitation-related variables were used as inputs to the Species Distribution Model (SDM). Finally, the model performance was assessed based on the area under the curve (AUC) and true skills statistics (TSS) measures of statistics. Our results showed an upsurge in the distribution of O. abyssinica across the study area for the low and moderate suitability classes for the climatic conditions considered in this study. However, a steady shrinkage in the habitat was found for the higher suitability classes. The model indicated climatic-related factors such as precipitation during the cold and warm quarters (57.8%), followed by mean temperature during the coldest quarter, isothermality (41.9%) and topographic factors such as elevation and slope (31.6%) were identified as the main limiting factors for the growth of O. abyssinica. Precipitation and temperature during the dry period, on the other hand, had the least impact on the growth of O. abyssinica. Except for RCP2.6, the majority of south-western African countries and the Sahel region remain the most climatically stable ecosystems for O. abyssinica growth under the three climatic scenarios RCP45, RCP6 and RCP8.5. Our results revealed a steady increase in the future suitable habitat for O. abyssinica all over the continent under the considered climatic scenarios. Therefore, to support the future restoration of dryland ecosystems, countries should scheme a restoration policy that allows the sustainable utilization of O. abyssinica tree species. The future policy direction for biodiversity conservation and management should encourage the use of O. abyssinica as a major plant species for improving the livelihoods of people living in dryland areas.

Chilling Accumulation Is Not an Effective Predictor of Vegetation Green‐Up Date in Inner Mongolian Grasslands

AbstractChilling accumulation (CA) might be reduced under a warming climate, which raises a critical question: is vegetation green‐up date (VGD) altered by varing CA? If the answer is yes, existing thermal‐time models should be modified to include a chilling component. By collating observations from eight long‐term (1982–2019) field experiments across Inner Mongolia, we quantitatively assessed the responses of VGD of 27 grass species to CA in this region. The results indicated that effect of CA on VGD is in general negligible for most grass species. As excepted, rather than CA, VGD was predominantly determined by other climatic attributes such as heat requirement (HR) and precipitation. These results demonstrate the robustness of existing thermal‐time models without a chilling component to predict variations in VGD of major plant species in Inner Mongolian temperate grasslands.

Identification, characterization and expression analysis of lineage-specific genes within mangrove species Aegiceras corniculatum.

Lineage-specific genes (LSGs) are the genes that have no recognizable homology to any sequences in other species, which are important drivers for the generation of new functions, phenotypic changes, and facilitating species adaptation to environment. Aegiceras corniculatum is one of major mangrove plant species adapted to waterlogging and saline conditions, and the exploration of aegiceras-specific genes (ASGs) is important to reveal its adaptation to the harsh environment. Here, we performed a systematic analysis on ASGs, focusing on their sequence characterization, origination and expression patterns. Our results reveal that there are 4823 ASGs in the genome, approximately 11.84% of all protein-coding genes. High proportion (45.78%) of ASGs originate from gene duplication, and the time of gene duplication of ASGs is consistent with the timing of two genome-wide replication (WGD) events that occurred in A. corniculatum, and also coincides with a short period of global warming during the Paleocene-Eocene Maximum (PETM, 55.5million years ago). Gene structure analysis showed that ASGs have shorter protein lengths, fewer exons, and higher isoelectric point. Expression patterns analysis showed that ASGs had low levels of expression and more tissue-specific expression. Weighted gene co-expression network analysis (WGCNA) revealed that 86 ASGs co-expressed gene modules were primarily involved in pathways related to adversity stress, including plant hormone signal transduction, phenylpropanoid biosynthesis, photosynthesis, peroxisome and pentose phosphate pathway. This study provides a comprehensive analysis of the characteristics and potential functions of ASGs and identifies key candidate genes, which will contribute to the subsequent further investigation of the adaptation of A. corniculatum to intertidal coastal wetland habitats.

Carbon Stock of Different Parts of Major Plant Species of Three Ecological Zones of Bangladesh Sundarbans

The biomass and carbon sequestration by different parts namely leaf, stem and roots of major dominant plant species of different quadrats established in three ecological zones of Bangladesh Sundarban Mangrove Forests (SMF) were determined. A visit was done during 28 March to 1 April 2016 covering the oligohaline, mesohaline and polyhaline zones of SMF. Plant parts (stem, branch and leaf) of major plant species were collected from 16 quadrats of different locations. The major plant species were selected on the basis of abundance (number). Aboveground biomass (AGB) was estimated as the product of tree volume and wood density. Below ground biomass (BGB) were estimated from the 20% of above ground stem biomass. Carbon stock and CO2 sequestration were estimated from the dry weight of AGB and BGB. A total of 20 species in 16 different quadrats in three ecological zones and overall SMF was recorded. Among 20 species 10 dominant tree species were considered on the basis of abundance (number) for the estimation of AGB, BGB and CO2 sequestration. Species wise mean AGB (ton/ha) of 10 dominant mangrove trees are in order Heritiera fomes (186.423) &gt; Excoecaria agallocha (28.752) &gt; Avicennia officinalis (24.082) &gt; Ceriops decandra (5.021) &gt; Cynometra ramiflora (1.403) &gt; Tamarix dioica (0.592) &gt; Xylocarpus moluccensis (0.500) &gt; Bruguiera gymnorrhiza (0.307) &gt; Aegiceras corniculata (0.241) &gt; Aglaia cuculata (0.038).Species wise mean BGB (ton/ha) of 10 dominant mangrove trees are in order H. fomes (34.99) &gt; E. agallocha (4.94) &gt; A. officinalis (4.79) &gt; C. decandra (0.704) &gt; X. moluccensis (0.47) &gt; C. ramiflora (0.15) &gt; B. gymnorrhiza (0.018) &gt; A. corniculata (0.015) &gt; T. dioica (0.008) &gt;A. cuculata (0.004). The total CO2 sequestered (above ground and below ground) in overall SMF (considered land area 4143 km2) was 192.869 megaton.&#x0D; Bangladesh J. Bot. 50(2): 373-385, 2021 (June)

Effects of allelopathy and availability of nutrients and water resources on the survival and growth of plant species in a natural Dacrydium forest

A comprehensive understanding of mechanisms of allelopathy and resource availability is critical for protecting rare and endangered species, biodiversity, and ecosystems. We treated 20 major plant species with three concentrations of an aqueous extract of Dacrydium pierrei Hickel litter and different irrigation and nutrients to compare the relative importance of allelopathy and resource availability on roots, stem growth, and seed germination, using bioassays. The results showed that the height, ground diameter, and aboveground biomass of individuals increased more quickly in the early stage, and the rate of increase tended to slow down in the later stages. The allelopathy was species specific (inhibitory, neutral, or promotive), and the survival rate and growth rate of saplings changed significantly along a resource treatment gradient (P &lt; 0.05), indicating that the native species diversity was reduced by lower or higher resource availability in natural forests. The effect of allelopathy on trees was relatively weak during the treatments, and that of resource availability was relatively strong. Resource availability is relatively more important than allelopathy in mediating the reduction in plant biodiversity. Therefore, water and nutrient availability and the species and number of allelochemicals released by plants have substantial influences on the survival and growth of plant species in a natural Dacrydium forest.

Feeding ecology of Walia Ibex Capra walie (Mammalia: Artiodactyla: Bovidae) in Simien Mountains National Park, Ethiopia

Walia Ibex Capra walie is an endemic and endangered species residing in Simien Mountains National Park, Ethiopia. It has shifted its range within the Park in the last decade, and in this study our main objective was to provide information on their feeding ecology to inform recovery goals. We used a scan sampling method to collect foraging information during October 2009 to November 2011. Our observations suggest a diverse diet of more than 28 species of grasses, forbs, and shrubs. The most commonly used plants were Festuca sp., Lobelia rhynchopetalum, Helichrysum citrispinum, and Helichrysum horridum. Walia Ibex were active in feeding before and after mid-day, and time spent feeding was the highest compared with other diurnal activities. The percentage of time spent feeding on major plant species did not differ between wet and dry seasons (p&gt; 0.05). Walia Ibex, however, tended to spend more time browsing than grazing. The generalist nature of foraging behaviour in Walia Ibex most likely contributes to complaints from the local people who witness Walia Ibex raiding crops cultivated in and around the Park. Thus, the contribution of crop raiding to the shifts in the species’ range towards higher altitudes at Sebatminch within Simien Mountains National Park emphasizes the need to consider foraging ecology as community-based conservation efforts are developed to support Walia Ibex in the Park.

AlnC: An extensive database of long non-coding RNAs in angiosperms.

Long non-coding RNAs (lncRNAs) are defined as transcripts of greater than 200 nucleotides that play a crucial role in various cellular processes such as the development, differentiation and gene regulation across all eukaryotes, including plant cells. Since the last decade, there has been a significant rise in our understanding of lncRNA molecular functions in plants, resulting in an exponential increase in lncRNA transcripts, while these went unannounced from the major Angiosperm plant species despite the availability of large-scale high throughput sequencing data in public repositories. We, therefore, developed a user-friendly, open-access web interface, AlnC (Angiosperm lncRNA Catalogue) for the exploration of lncRNAs in diverse Angiosperm plant species using recent 1000 plant (1KP) trancriptomes data. The current version of AlnC offers 10,855,598 annotated lncRNA transcripts across 682 Angiosperm plant species encompassing 809 tissues. To improve the user interface, we added features for browsing, searching, and downloading lncRNA data, interactive graphs, and an online BLAST service. Additionally, each lncRNA record is annotated with possible small open reading frames (sORFs) to facilitate the study of peptides encoded within lncRNAs. With this user-friendly interface, we anticipate that AlnC will provide a rich source of lncRNAs for small-and large-scale studies in a variety of flowering plants, as well as aid in the improvement of key characteristics in relevance to their economic importance. Database URL: http://www.nipgr.ac.in/AlnC

Chromosome-level assembly of the mangrove plant Aegiceras corniculatum genome generated through Illumina, PacBio and Hi-C sequencing technologies.

Aegiceras corniculatum is a major mangrove plant species adapted to waterlogging and saline conditions, grows in the coastal intertidal zone of tropical and subtropical regions. Here, we present a chromosome-level genome assembly of A. corniculatum by incorporating PacBio long-read sequencing and Hi-C technology. The results showed that the PacBio draft genome size is 906.63Mb. Hi-C scaffolding anchored 885.06Mb contigs (97.62% of draft assembly) onto 24 pseudochromosomes. The contig N50 and scaffold N50 were 7.1Mb and 37.74Mb, respectively. Out of 40,727 protein-coding genes predicted in the study, 89% have functional annotations in public databases. We also showed that of the 603.93Mb repetitive sequences predicted in the assembled genome, long terminal repeat retrotransposons constitute 41.52%. The genome evolution analysis showed that the A. corniculatum genome experienced two whole-genome duplication events and shared the ancient γ whole-genome triplication event. A comparative genomic analysis revealed an incidence of expansion in 1,488 gene families associated with essential metabolism and biosynthetic pathways, including photosynthesis, oxidative phosphorylation, phenylalanine, glyoxylate, dicarboxylate metabolism, and DNA replication, which probably constitute adaptation traits that allow the A. corniculatum to survive in the intertidal zone. Also, the systematic characterization of genes associated with flavonoid biosynthesis pathway and the AcNHX gene family conducted in this study will provide insight into the adaptation mechanism of A. corniculatum to intertidal environments. The high-quality genome reported here can provide historical insights into genomic transformations that support the survival of A. corniculatum under harsh intertidal habitats.

Phylogenetic and Haplotype Network Analyses of Diaporthe eres Species in China Based on Sequences of Multiple Loci.

Diaporthe eres is considered one of the most important causal agents of many plant diseases, with a broad host range worldwide. In this study, multiple sequences of ribosomal internal transcribed spacer region (ITS), translation elongation factor 1-α gene (EF1-α), beta-tubulin gene (TUB2), calmodulin gene (CAL), and histone-3 gene (HIS) were used for multi-locus phylogenetic analysis. For phylogenetic analysis, maximum likelihood (ML), maximum parsimony (MP), and Bayesian inferred (BI) approaches were performed to investigate relationships of D. eres with closely related species. The results strongly support that the D. eres species falls into a monophyletic lineage, with the characteristics of a species complex. Phylogenetic informativeness (PI) analysis showed that clear boundaries could be proposed by using EF1-α, whereas ITS showed an ineffective reconstruction and, thus, was unsuitable for speciating boundaries for Diaporthe species. A combined dataset of EF1-α, CAL, TUB2, and HIS showed strong resolution for Diaporthe species, providing insights for the D. eres complex. Accordingly, besides D. biguttusis, D. camptothecicola, D. castaneae-mollissimae, D. cotoneastri, D. ellipicola, D. longicicola, D. mahothocarpus, D. momicola, D. nobilis, and Phomopsis fukushii, which have already been previously considered the synonymous species of D. eres, another three species, D. henanensis, D. lonicerae and D. rosicola, were further revealed to be synonyms of D. eres in this study. In order to demonstrate the genetic diversity of D. eres species in China, 138 D. eres isolates were randomly selected from previous studies in 16 provinces. These isolates were obtained from different major plant species from 2006 to 2020. The genetic distance was estimated with phylogenetic analysis and haplotype networks, and it was revealed that two major haplotypes existed in the Chinese populations of D. eres. The haplotype networks were widely dispersed and not uniquely correlated to specific populations. Overall, our analyses evaluated the phylogenetic identification for D. eres species and demonstrated the population diversity of D. eres in China.

城市花粉致敏植物种类构成、分布与潜在危害评估——以深圳市为例

气传致敏花粉会引发过敏症，且可通过每年在花粉季的反复接触逐渐加重，危害人体健康，严重时甚至危害生命。花粉致敏植物在城市中被广泛引种栽培，导致城市花粉症患者数量激增。以深圳市为案例，基于建成区600个样地的实地调查数据，分析花粉致敏植物的种类构成与时空分布，通过构建花粉浓度及花粉致敏危害潜力计算公式，评估花粉致敏危害潜力及其分布特点。结果显示：①调查记录到深圳市建成区花粉致敏植物46科92属186种，其中外来种占43.37%，其中美洲、亚洲和大洋洲来源占国外外来种的81.00%。花粉致敏植物种数以公园绿地最多，达126种。植物花粉致敏等级以Ⅰ级为主，达154种。②花粉致敏植物的盛花期为春夏季，占全年累计开花种数的65.02%。最高峰出现在8月，开花种数达92种。 ③花粉浓度潜力最高值也出现在8月，占全年总值的12.13%。豆科和禾本科植物贡献比例较大，分别占乔木和草本总值的40.86%和64.13%。龙岗区花粉浓度潜力占比较高，占各季花粉量的26.06%-29.42%。④冬春两季各样地花粉致敏危害等级均不高，但夏秋季有些样地达到二级重度危害。罗湖区调查样地全年花粉致敏危害等级均较低，光明区在春夏秋季致敏危害等级皆较高。高危害等级样地主要出现在附属绿地及公园绿地。⑤花粉致敏植物防控措施情景模拟结果，去除主要花粉致敏植物种类比降低所有花粉致敏植物的花粉浓度潜力更有效。本研究为城市花粉致敏植物的管理、规划、养护和研究提供参考。;Airborne allergenic pollen can cause pollinosis and aggravate every year through repeated exposure in the pollen seasons, endangering human health and even life in severe cases. Allergenic pollen plants have been widely introduced and cultivated in cities, leading to a sharp increase in the number of urban pollinosis patients. In this study, based on the investigation data of 600 plots in the built-up area of Shenzhen as a case study, the species composition and the spatiotemporal distribution of allergenic pollen plants were analyzed, and the potential allergenic hazard with its distribution characteristics was evaluated by constructing calculation formulas of pollen concentration and pollen allergenic potential. The results showed that: ① In the built-up area of Shenzhen, a total of 186 species of allergenic pollen plants from 46 families and 92 genera were recorded. Among the allergenic pollen plant species, 43.37% were alien species, with 81.00% of them originated from America, Asia, and Oceania. The number of allergenic pollen plant species was highest in park green space, up to 126. Allergenic levels were mainly graded Ⅰ, covering 154 species. ② The peak bloom stages of allergenic pollen plants were spring and summer, with flowering species accounted for 65.02% of the annual total. The peak month appeared in August, concerning 92 flowering species. ③ August had the highest potential value of pollen concentrations, accounting for 12.13% of the annual year total. The contribution of Leguminosae and Poaceae were relatively high, respectively, accounting for 40.86% and 64.13% of the arbors and the herbs totals. The values in the Longgang District were relatively high in all seasons, reaching 26.06%-29.42% of respectively seasonal total. ④ The allergenic hazard levels in all plots were not high in winter and spring, but some plots reached second-level severe in summer and autumn. The hazard levels of investigated plots in the Luohu District were relatively low throughout the year. In contrast, those of investigated plots in the Guangming District were relatively high in spring, summer, and autumn. The high-hazard-level plots mainly appeared in the subsidiary green space and park green space. ⑤ Results of scenario-simulation for allergenic pollen plants prevention and control measures showed that the effect of removing major allergenic pollen plant species might be better than that of reducing the pollen concentrations of all allergenic pollen plant species. This study provides a reference for the management, planning, and maintenance of urban allergenic pollen plants, and the research and solution of urban pollen allergenic problems.

Water sources of major plant species along a strong climatic gradient in the inland Heihe River Basin

Knowledge on vegetation water sources is crucial to understand the ecohydrological processes and ecological management of arid and semi-arid ecosystems. The identification and quantification of plant water uptake from precipitation, soil and groundwater remain challenging along large climatic gradient. Stable oxygen isotope compositions of xylem water, soil water and groundwater were analyzed to assess seasonal and spatial patterns of water uptake of 11 major plant species along the Heihe River Basin. In the upper reaches, soil water recharged by precipitation was the main plant water source, and plants extracted water from the shallow soil water in wet season while used more deep soil water in dry season. In the middle reaches of desert-oasis ecotone, the water sources of shrubs shifted between soil moisture and groundwater depending on variations of precipitation and groundwater level, while shrubs at Gobi relied on deep soil water and shallow soil water after rainfall. In the lower reaches, the driest part of the region, groundwater and deep soil water were main water sources for the riparian plants. Groundwater was stable water source for shrubs growing on the planted shrubland, and soil water was stable water sources for shrubs growing at Gobi. Our results also revealed that water use strategies of the same species were plastic under different groundwater level and precipitation. This study identified water use patterns of different plant species along a climatic gradient and provided scientific implication for water management of different ecosystems of the arid and semi-arid ecosystems.