Tamarix Chinensis Research Articles

Responses of soil nutrient contents and eco-stoichiometric characteristics to fiddler crab activities in coastal wetland of the yellow river delta

The four typical wetlands of Phragmites australis wetland (TPa), Tamarix chinensis wetland (Tc), Suaeda salsa wetland (Ss) and Spartina alterniflora wetland (Sa) in the Yellow River Delta were selected to clarify the spatial heterogeneity of soil nutrients and their ecological stoichiometric characteristics under fiddler crab activities. The results showed that soil particle size, soil salinity and pH in Tc, TPa and Ss were greatly changed by fiddler crab activities. The averaged contents of TOC and TN in wetlands with fiddler crab activities (FC) were higher than those in wetlands without fiddler crab activities (CK). The averaged NH4+-N contents of FC group in Tc, Ss and Sa were 93.42%, 52.14% and 20.05% higher than those of CK group (p<0.05), respectively. The averaged NO3−-N contents of Tc and Sa in FC group were 89.79% and 167.70% higher than those of CK group (p<0.01), respectively. The variation tendency of C/N and C/P in four wetland types were greatly similar with the TOC, and N/P was similar with TN. Multi-ANOVA results showed that soil carbon and nitrogen were significantly influenced by fiddler crab activities and wetland types (p<0.05). The PCA and RDA analysis results indicated that the bioturbation from fiddler crab made the influencing factors of nutrient elements diversified. The fiddler crab activities were favorable to the soil nutrients accumulation and could reduce the nitrogen limitation of coastal ecosystem. Our results should be of importance to insight the biogeochemical process of soil nutrient elements differentiation by fiddler crab activities in coastal wetlands.

Water Use Characteristics of Populus euphratica Oliv. and Tamarix chinensis Lour. at Different Growth Stages in a Desert Oasis

Understanding the water use characteristics of vegetation is crucial for guiding the rational allocation of water resources and the restoration of sustainable vegetation in natural oases in arid desert areas. To analyze the water use characteristics of Populus euphratica Oliv. and Tamarix chinensis Lour. at different stages of growth in the Daliyabuyi natural pristine oasis in northwestern China, the δ18O values of plant xylem of 15 sample trees with different sizes per species, potential water sources (i.e., river water, soil water, and groundwater), and the δ13C values of plant leaves of sample trees were measured in August 2019 and June 2020. The results show that the δ18O values of the xylem water of P. euphratica at different growth stages were similar, but water uptake proportions from deep soil water changed in P. euphratica trees at different growth stages between years with (2019) and without (2020) river water. In contrast, the main water source of young T. chinensis shrubs was deep soil water, and those of mature and overmature shrubs were deep soil water and groundwater in 2020. However, the plant leaf water use efficiency (WUE) of the P. euphratica and T. chinensis were higher without river water. Overall, the water uptake proportion from groundwater and the WUE for T. chinensis were higher than those for P. euphratica, and thus, T. chinensis was more dependent on groundwater. This means that vegetation types and growth stages are the essential factors to be considered in ecological restoration management, which can enhance the effectiveness of vegetation restoration strategies.

Effects of wetland plant biochars on heavy metal immobilization and enzyme activity in soils from the Yellow River estuary.

The purpose of this study was to assess the effects of wetland plant biochars on the enzyme activity in heavy metal contaminated soil. The biochars were produced from Phragmites australis (PB), Suaeda salsa (SB), and Tamarix chinensis (TB) under different pyrolysis temperatures and times. The detected pyrolysis products showed that the ash, pH, electrical conductivity, and carbon content of the biochars increased significantly, while the production rate of the biochars decreased with increasing pyrolysis temperature and time. The results of the adsorption experiments indicated that biochar addition could effectively reduce the concentration of Pb and/or Cd in the Pb2+/Cd2+ single or mixed solutions, but the Pb2+ and Cd2+ in the mixed solution indicated a competitive adsorption. A 30-day incubation experiment was conducted using salt marsh soil amended with different biochar application rates to investigate the short-term effects of biochar addition on Pb and Cd immobilization. The PB and SB significantly immobilized Pb within the first 15days, but Pb remobilized within the next 15-day period. In contrast, TB addition did not significantly fix Pb. Moreover, biochar addition promoted the conversion of Cd from the residue to the less immobile fractions. The addition of three types of plant biochar had no significant effect on the urease activity in wetland soil but significantly increased soil sucrase activity. PB and SB significantly promoted catalase activity, while TB significantly inhibited soil catalase activity. According to the adsorption effect, the fixation effect, and the promotion of enzyme activities, the Suaeda salsa biochars are suitable for the remediation of heavy metal pollution in wetland soils.

Analysis on ecological status and spatial-temporal variation of Tamarix chinensis forest based on spectral characteristics and remote sensing vegetation indices.

The reserve of Tamarix forest, located in Changyi, China, is the only national marine special reserve taking Tamarix as the main object of protection. Compared with conventional monitoring technology, remote sensing technology can more comprehensively reflect the ecological environment status and spatial-temporal variation of monitoring objects. Based on spectral characteristics and remote sensing vegetation indices, the ecological status and spatial-temporal variation of Tamarix chinensis forest in the reserve deserve further exploration. Therefore, spectral characteristic, typical vegetation indices, comprehensive health index, VFC, and REP were analyzed based on Sentinel-2A images. Spatial-temporal variation analysis during 2014 to 2018 was analyzed based on GF-1 images. The research result indicated that ecological quality of protection zone showed an overall growth trend with the help of artificial ecological restoration, and it is possible to continuously implement ecological recovery towards the protection zone.

“Fertile island” of Tamarix Chinensis accelerated the carbon decomposition in the coastal wetlands of the Yellow River Delta, China

Fertile island of shrub in the grass-dominated ecosystems would change the spatial distribution of soil organic carbon (SOC) and its fractions, adjusting the SOC dynamics and its response to global warming. However, the effects of fertile island on SOC decomposition and its temperature responses were still less known. An incubation experiment was conducted to investigate how the fertile island of Tamarix Chinensis affects SOC decomposition and its temperature sensitivity (Q10) in the coastal wetlands of the Yellow River Delta, China. Soil samples were collected from two areas, Tamarix Chinensis growing on bare land (SB) and the mixed-growing area of Tamarix Chinensis and herbage (SH). In each area, soil samples were collected from three sites, under the canopy of Tamarix Chinensis (CM), at the edge of the canopy (CP), and outside the canopy (OL). Results showed that the cumulative CO2 production increased from OL to CM due to the following reasons. Fertile island enriched SOC, labile fractions (i.e., O-alkyl and di- O-alkyl C), ammonium under the canopy in both sample areas and increased the relative abundance of labile SOC fractions (i.e., O-alkyl C) in SB, supplying more substrates for microbial decomposition. Subsequently, fertile island stimulated β-glucosidase and invertase activities, accelerating SOC decomposition. Moreover, fertile island decreased the Q10 value in the SB area because of the increased relative abundance of O-alkyl C. This study highlights the importance of O-alkyl C on SOC decomposition and its temperature sensitivity in the coastal wetlands of the Yellow River Delta.

Predicting plant diversity in beach wetland downstream of Xiaolangdi reservoir with UAV and satellite multispectral images

Accurate and timely acquisition of plant diversity information downstream of the reservoir is helpful to understand the impact mechanism of reservoir operation on wetland plant diversity and formulate reasonable water and sediment regulation strategies. In this study, we conducted field surveys in two communities (Phragmites australis and Tamarix chinensis) at a typical wetland in the lower reaches of Xiaolangdi Reservoir on the Yellow River, and employed UAV and Gaofen 1B multispectral images to estimate the wetland plant diversity. Results showed that most diversity indexes had a higher correlation with the mean of spectral vegetation indexes (DVI, RVI, NDVI, SAVI, and MSAVI). The diversity indexes (C_SP and C_SW) constructed by relative coverage had a better overall correlation with spectral indexes. Interestingly, opposite correlations were found between Tamarix chinensis and Phragmites australis plots. We further gave a deep insight into the interspecific associations in Phragmites australis and Tamarix chinensis plots with the variance ratio (VR) method. It was found that plant species in Tamarix chinensis plot showed positive association (VR > 1), with a VR value of 1.095. Plant species in Phragmites australis plot had a negative association (VR < 1), with a VR value of 0.983. In Phragmites australis plot, C_SP and C_SW showed a significant decreasing trend (r2 of 0.36 and 0.33 respectively, and P values less than 0.001) with the increase of Phragmites australis coverage. Moreover, the effect of spatial resolution was not significant on plant diversity estimation. Correlations between remote sensing indexes and diversity indexes were improved with the quadrat size changing from 2 m × 2 m to 4 m × 4 m. These findings demonstrate promising approaches for remote sensing of wetland plant diversity and indicate that the type of wetland plant community determines the relationship between diversity index and spectral index.

Aboveground biomass of salt-marsh vegetation in coastal wetlands: Sample expansion of in situ hyperspectral and Sentinel-2 data using a generative adversarial network

Coastal wetlands are main components of the “blue carbon” ecosystems in coastal zones. Salt-marsh biomass is especially important regarding climate-change mitigation. Generating high precision biomass maps for evaluating the ecological functions of coastal wetlands is essential; however, conducting accurate biomass inversions with limited in situ observations from coastal wetlands is challenging. We propose a generative adversarial network with a constrained factor model (GAN-CF) for expanding limited in situ salt-marsh biomass observations. We used Sentinel-2 images and a deep belief network based on the conjugate gradient method (CG-DBN) for obtaining land-cover maps and the salt-marsh distribution (species: Phragmites australis, Suaeda glauca, Spartina alterniflora, and mixed species dominated by Tamarix chinensis) in the study area. This study bridges in situ hyperspectral and Sentinel-2 multispectral data by a satellite-band equivalent conversion model. The biomass and multispectral data derived from Sentinel-2 were used as input for the proposed GAN-CF model, which produced and constrained the generated samples based on the features (i.e., spectra, vegetation index, and biomass) of the in situ observations. Aboveground biomass (AGB) maps at 10-m spatial resolution were produced by constructing multiple linear regression models (MLRMs) based on the generated samples of each salt-marsh type using Sentinel-2 images. The quantity and richness of the generated samples improved the AGB estimations in the study area. The inversion accuracy of S. alterniflora was significantly improved (RMSE = 3.71 Mg/ha); the estimated AGB was strongly related to the in situ observations (R = 0.923). The estimated AGB was validated using in situ observations. The total amount of salt-marsh AGB in the study area in 2019 was estimated at 2.36 × 105 Mg, with 7.95 Mg/ha average. The salt-marsh biomass in decreasing order was as follows: P. australis (12.7 Mg/ha) > S. alterniflora (11.5 Mg/ha) > mixed species (8.97 Mg/ha) > S. glauca (2.18 Mg/ha). The salt-marsh area in decreasing order was as follows: S. glauca (10,410 ha) > P. australis (7320 ha) > mixed species (6740 ha) > S. alterniflora (5240 ha). By a feasibility analysis we estimated the biomass based on the Sentinel-2 data covering the Yellow River delta wetland in May, July, and September 2019 and the Jiaozhou Bay wetland in September 2019 by using the generated samples. The generated samples based on the 2013–2019 in situ observations constitute a salt-marsh biomass database, which can be useful for quantifying the regional carbon storage and ecological restoration monitoring.

Tamarix chinensis (five-stamen tamarisk)

This datasheet on Tamarix chinensis covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology &amp; Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Management, Economics, Further Information.

Spatiotemporal Mapping of Salt Marshes in the Intertidal Zone of China during 1985–2019

This study mapped the areal extent, identified the species composition, and analyzed the changes of salt marshes in the intertidal zone of China during the period 1985–2019. With the aid of the cloud platform of the Google Earth Engine, we selected Landsat 5/8 and Sentinel-2 images and used the support vector machine classification method to extract salt marsh information for the years of 1985, 1990, 1995, 2000, 2005, 2010, 2015, and 2019. Seven major species of salt marshes: Phragmites australis , Suaeda spp., Spartina alterniflora , Scirpus mariqueter , Tamarix chinensis , Cyperus malaccensis , and Sesuvium portulacastrum were identified. Our results showed that salt marshes are mainly distributed in Liaoning, Shandong, Jiangsu, Shanghai, and Zhejiang, with varying patterns of shrinking, expansion, or wavering in different places. The distribution of salt marshes has declined considerably from 151,324 ha in 1985 to 115,397 ha in 2019, a drop of 23.7%. During the same period, the area of native species has dropped 95.4% from 77,741 ha to 3,563 ha for Suaeda spp. and 45.1% from 60,511 ha to 33,193 ha for P. australis ; on the contrary, the area of exotic species, S. alterniflora , has exhibited a sharp rise from just 99 ha to 67,527 ha. For the past 35 years, the driving factors causing salt marsh changes are mainly land reclamation, variations in water and sand fluxes, and interspecific competition and succession of salt marsh vegetation. These results provide fundamental reference information and could form the scientific basis for formulating policies for the conservation and utilization of salt marsh resources in China.

Above and Below-Ground Biomass and Nutrients Stoichiometry of Tamarix Chinensis Grown Under Salinity Soil in East-Central China

Above and Below-Ground Biomass and Nutrients Stoichiometry of Tamarix Chinensis Grown Under Salinity Soil in East-Central China

The flora of Erath County, Texas, U.S.A.

Knowledge of county floras in Texas is crucial for determining species composition, management, preservation, and restoration across the state. Like most Texas counties, floristic data for Erath County, Texas, is poorly known. The objectives of this investigation were to compile a flora for Erath County, determine the intro-duced, endemic, threatened, and endangered species, as well as make comparisons to the county’s original flora and that of the North Central Texas region. Field work was conducted from September 2003 to December 2009 at 35 sites in Erath County. In addition herbaria were searched to locate specimens from Erath County. A total of 870 species (888 taxa) were identified in 103 families. One hundred forty-four taxa were introduced while 744 taxa were native. Eighteen of the species are Texas endemics. There were two rare plants, Dalea reverchonii and Penstemon guadalupensis, but no threatened or endangered plants were found during the inves-tigation. Four state-listed noxious species were collected during the investigation—Arundo donax (giant reed), Convolvulus arvensis (field bindweed), Tamarix chinensis, and T. gallica (salt-cedars).

Energy Exchange and Evapotranspiration over the Ejina Oasis Riparian Forest Ecosystem with Different Land-Cover Types

Investigating the energy and water vapor exchange in oasis riparian forest ecosystems is of significant importance to improve scientific understanding of land surface processes in extreme arid regions. The Heihe Watershed Allied Telemetry Experimental Research (HiWATER) provided many observations of water vapor and heat fluxes from riparian forest ecosystem by using a network of eddy-covariance (EC) systems installed over representative surfaces in the Ejina Oasis, which is located in the downstream areas of the Heihe River Basin, northwestern China. Based on EC flux measurements and meteorological data performed at five stations and covering representative surface types of Populus euphratica tree with associated Tamarix chinensis shrub, Tamarix chinensis shrubland, cantaloupe cropland, and barren-land, this study explored the spatio-temporal patterns of heat and water vapor fluxes over the Ejina Oasis riparian forest ecosystem with five different surface types over the course of a growing season in 2014. Energy balance closure of the flux data was evaluated; footprint analysis for each EC site was also performed. Results showed that energy balance closure for the flux data was reasonably good, with average energy balance ratio (EBR) of 1.03. The seasonal variations in net radiation (Rn), latent (LE), and sensible heat flux (H) over the five contrasting surfaces were similar, and a reverse seasonal change was observed in energy partitioning into LE and H. Remarkable differences in Rn, LE, and H between the five surfaces were explored preliminarily, associated closely with the soil properties and foliage phenology. Over the growing season (May–October) in 2014, the total ET ranged 622–731 mm for mixed forest of P. euphratica trees with associated T. chinensis shrubs with average daily ET of 3.6–4.2 mm; ET from T. chinensis shrubland was about 541 mm, with average daily ET of 3.6 mm. ET for barren-land was 195 mm. The total ET in irrigated cantaloupe cropland with plastic mulch was 431 mm for its four-month growing period with a total average of 3.8 mm d−1. Determination of ET over riparian forest ecosystem helps to improve reasonable use of limited water resource in the Ejina Oasis.

Applicability of multiple remotely sensed vegetation indices for extracting key phenological metrics of Tamarix chinensis shrubs based on CO2 flux observation and Sentinel-2 data

We analyzed the relationship between gross primary productivity (GPP) and environmental factors at Sidaoqiao Superstation of the Ejina Oasis in China's Gobi Desert, by combining eddy flux and meteorological data from 2018 to 2019 and Sentinel-2 remote sensing images from 2017 to 2020. We evaluated the applicability of 12 remote sensing vegetation indices to simulate the growth of Tamarix chinensis and extract key phenological metrics. A seven-parameter double-logistic function (DL-7) + global model function (GMF) was used to fit the growth curves of GPP and vegetation indices. Three key phenological metrics, i.e., the start of the growing season (SOS), the peak of the growing season (POS), and the end of the growing season (EOS), were extracted for each year. Growing season degree days (GDD) and soil water content were the main environmental factors affecting the phenological dynamics of T. chinensis. Compared with 2018, the lower temperatures in 2019 resulted in slower accumulation rate of accumulated temperature before the SOS. T. chinensis required longer heat accumulation to enter growing season, which might cause later SOS in 2019. The hydrothermal conditions between SOS and POS were similar for 2018 and 2019. Howe-ver, the POS in 2019 was 8 days later than that in 2018, because of the late SOS in 2019. Following the POS in 2019, high GDD and low soil water content caused the T. chinensis to suffer from water stress, resulting in a shortened late growing season. The linear regression between the standardized Sentinel-2 vegetation index and the average value of GPP between 10:00 and 14:00 indicated that the enhanced vegetation index of the broadband vegetation index and the chlorophyll red edge index, inverted red edge chlorophyll index, and red-edge normalized difference vegetation index (NDVI705) of the narrowband vegetation index were highly consistent with the GPP of T. chinensis. Remote sensing extraction of SOS and POS of T. chinensis suggested that the Sentinel-2 narrowband vegetation index was more accurate than the broadband vegetation index. The modified chlorophyll absorption in reflectance index provided the most accurate extraction of SOS, while the MERIS terrestrial chlorophyll index provided the most accurate extraction of EOS. Conversely, the Sentinel-2 broadband vegetation index was the most accurate for extracting POS, especially the 2-band enhanced vegetation index and the near-infrared reflectance of vegetation. Overall, NDVI705 was the best index to estimate phenological metrics.

Identification of 16SrXXX-A Phytoplasma Associated with Salt cedar (Tamarix chinensis Lour.) witches'-broom (SCWB) in Southern Xinjiang of China.

Salt cedar is an ornamental shrub/moderate tree species native to Asia and East Europe, and grows in salt-alkali soil, desert and other dry areas, which plays an important role in wind prevention and sand fixation as well as maintaining ecological balance. Salt cedar witches'-broom (SCWB), which was extremely pernicious to Salt cedar. It was first observed and reported in Xi'an, China in 2005 (Zhao et al.2005). Witches' broom symptoms were observed on 20 out of 150 (13.3%) salt plants surveyed from the Alar region and 10 out of 86 (11.6%) plants from the Akesu region in southern of Xinjiang in May 2020. The damaged plants compared with asymptomatic plants (Fig.1A), the major symptoms included branches clustered, intersegment shorten and coarsen, giving rise to the formation of clusters (Fig.1B). Total plant DNA was extracted from phloem tissues with asymptomatic symptoms and phloem tissues with witches'-broom symptoms by a CTAB-based DNA extraction method (Green et al.1999). The 16S rRNA gene and the phytoplasma universal primers P1/P7 and rpF1/rpR1 of the rp (ribosomal protein) gene were used for Polymerase chain reaction (PCR) amplification by using the extracted plant total DNA as the template. The PCR product was used as the template and the R16F2n/R16R2 prmer was used for nested PCR amplification of the 16S rRNA gene after the amplification was completed. The results show that no product was obtained in asymptomatic plants. When DNA samples from witches'-broom symptomatic plants were used as templates, fragments with lengths 1219 bp and 1174 bp, corresponding to 16S rRNA gene and rp gene, were obtained. 16S rRNA gene was sequenced and deposited in GenBank under accession number MW447513. BLAST analysis revealed that the partial 16S rRNA sequence of the phytoplasma associated with P. aphylla witches' broom showed highest sequence identity (99.67%) to salt cedar witches' broom phytoplasma, 'Candidatus Phytoplasma tamaricis' (Accession Number: FJ432664). Phylogenetic and molecular evolutionary analyses were conducted using MEGA-X (Kumar et al., 2018). Results showed taht the SCWB and 16S rXXX group's'Candidatus Phytoplasma tamaricis', (GenBank accession: FJ432664) have the highest affinity (Fig.2A). A virtual restriction fragment length polymorphism(RFLP) was done to determinethe subgroup ( Zhao et al. 2009). The 16S rDNA sequence from the Tamarix chinensis plant showed 99.3% similarity with that of the "Candidatus Phytoplasma tamaricis" reference strain (GenBank accession: FJ432664), suggesting that the phytoplasma in this study belongs to "Candidatus Phytoplasma tamaricis"-related strain. Therefore, it can be stated that SCWB belongs to the 16S rXXX group. The partial rp sequences only shared 84.74% sequence similarity with that of 'Candidatus Phytoplasma prunorum' (MG383523) of Apple proliferation group, a known subgroup 16S rX. Blast analysis based on the partial rp sequences showed that it shares less than 90% similarity with that of any known phytoplasma (Fig 2B), we suspect that this is due to a lack of sequenced rp gene sequences for the 16S rXXX group. To our knowledge, this is the first report of Salt Cedar Witches' Broom phytoplasma in Xinjiang province, China. As a consequence, we guess the SCWB phytoplasma rp gene belongs to 16S rXXX-rp group, which is also the first report about the 16SrXXX-rp group. Because SCWB1 is the only strain in the 16S rXXX group, and it is the representative strain of the 16S rXXX-A subgroup (Zhao et al. 2009). So, the SCWB disease we found in southern Xinjiang belongs to the 16S rXXX-A subgroup.

Comparative study on windbreak effects of two different configuration shelterbelts

Pinus sylvestris, Artemisia ordosica, Tamarix chinensis Lour, Elaeagnus angustifolia and Salix matsudana Koidz were selected to design the models of forest belts. Through wind tunnel experiments, we analyzed the wind speed frequency, wind speed flow field and wind protection efficiency of two different configuration shelterbelts. The results showed the wind speed frequency of mixed shelterbelts was generally lower than that of single shelterbelts with the same configuration. The similarity of the average wind speed between No.1 A3 and No.2 C3 indicates that the windbreak effect of low-density arbor-shrub mixed shelterbelt was similar to that of high-density single shelterbelt. The average wind protection efficiency of No.1 A1 was similar to that of No.1 C2, indicating that the influence of density of pinus sylvestrison of wind protection efficiency is greater than the height of forest belt. the average wind protection efficiency of No. 2 A2 was 57.64%, which was similar to that of No. 2 B3, indicating that the height of the forest belt increased, and the influence of density on the protection effect of the forest belt decreased.Therefore, the wind protection ability of multi-species and highly hierarchical mixed forests was higher than that of single shelterbelt.

Characterization of halophyte biochar and its effects on water and salt contents in saline soil.

Biochar is a beneficial soil amendment; however, biochar-based properties are mainly determined by the feedstocks and the pyrolysis temperature. Nevertheless, considering the vast biomass of halophyte, little is known about how the halophyte-derived biochar improves saline soils. In this study, we firstly produced biochars by using three different halophytes, including Tamarix chinensis (recretohalophyte), Suaeda salsa (euhalophyte), and Phragmites australis (pseudo-halophyte) at 300, 500, and 700 °C, and compared their chemical and physical properties. We applied halophyte (Tamarix chinensis and Phragmites australis) biochars (pyrolysis at 500 °C) into 0-20 cm saline soil at 2% and 4% (w/w) rates to investigate the saline soil water, salt, and pH dynamics in a 12-month column experiment. The results showed that as the pyrolytic temperature increase, biochar yield and pore diameter decreased by 37.5-44.0% and 34.6-89.7%, respectively; in contrast, biochar pH, specific surface area, and total volume increased by 24.8-47.8%, 3-37 times and 1-9 times, respectively. The halophyte types significantly controlled biochar carbon and dissolved salt content and electrical conductivity. Halophyte biochar application can increase soil water and salt content, and application of 4% of Tamarix chinensis-derived biochar can increase more soil moisture than the soil salinity, and it can maintain soil pH at a stable level, which would be a potential way to improve saline soil properties. The results are valuable for choosing halophyte types and optimizing pyrolytic temperatures for halophyte biochar production through specific environmental usage.

The complete chloroplast genome of Tamarix ramosissima and comparative analysis of Tamaricaceae species

Tamarix ramosissima is a deciduous shrub that resides in arid and semi-arid regions. Although of ecological and medicinal values, some Tamarix species are considered invasive as they have dominated the riparian zones of dryland in some parts of the world. Here, the complete chloroplast (cp) genome of T. ramosissima was sequenced and analyzed, showing a size of 156 150 bp and a GC content of 36.5 %. The plastome displayed a typical quadripartite structure, consisting of a pair of inverted repeat (IR) regions of 26 554 bp, separated by a large single copy (LSC) region of 84 795 bp, and a small single copy (SSC) region of 18 247 bp. The cp genome encoded 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. A total of 32 repeat sequences and 64 simple sequence repeat (SSR) were identified in the plastome, and an obvious A/T bias was observed in the majority of the SSRs detected. By comparing the T. ramosissima cp genome with those of the other four Tamaricaceae species, a number of divergence hotspots were identified among these plastomes. Together with SSRs and long repeats identified, these divergence hotspots could be developed as potential molecular markers facilitating species discrimination and evolutionary studies. Using plastome sequences, we re-investigated the phylogenetic relationship among 19 species, and T. ramosissima was found to be a sister of Tamarix chinensis. Taken together, our study provides valuable genomic resources to deepen the understanding of plant photosynthetic mechanism and phylogenomics.

Pseudoroseicyclus tamaricis sp. nov., isolated from seashore sediment of a Tamarix chinensis forest and emended descriptions of the genus Pseudoroseicyclus Park et al. 2016.

An aerobic, Gram-stain-negative, bacterium, designated CLL3-39T was isolated from seashore sediment collected at a Tamarix chinensis forest in the Marine Ecology Special Reserve of Changyi, Shandong Province, PR China. Cells of strain CLL3-39T were olive-shaped and no flagellum was observed. Strain CLL3-39T grew optimally at 33 °C, pH 7.5 and salinity (sea salts) of 40 g l-1. The main fatty acids in the cell membrane of strain CLL3-39T comprised anteiso-C15 : 0 (22.3 %), iso-C15 : 0 (14.0 %), C16 : 0 (9.2 %) and summed feature 8 (contains C18 : 1 ω7c/C18 : 1 ω6c. 26. 7 %). The main polar lipids of CLL3-39T were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. The respiratory quinone was Q10. The G+C content of the genomic DNA of strain CLL3-39T was 69.6 mol%. The average nucleotide identity between CLL3-39T and Pseudoroseicyclus aestuarii DB-4T was 74.7 % and the in silico DNA-DNA hybridization value was 20.1 %. Phylogenetically, strain CLL3-39T belonged to the genus Pseudoroseicyclus, branching with only one type strain P. aestuarii DB-4T with 96.3 % 16S rRNA gene similarity, followed by Limimaricola cinnabarinus LL-001T (95.2 %). Based on its phenotypic, phylogenetic and chemotaxonomic characteristics, we propose strain CLL3-39T (=MCCC 1A14815T =KCTC 72665T) as a representative of a novel species in the genus Pseudoroseicyclus, for which the name Pseudoroseicyclus tamaricis sp. nov. is proposed.

Spatial Analysis as a Tool for Plant Population Conservation: A Case Study of Tamarix chinensis in the Yellow River Delta, China

Saltcedar (Tamarix chinensis) is undergoing population declination and fragmentation due to climate change and human disturbance. The existing restoration strategies usually focus on improving the environmental conditions based on the environment–saltcedar relationship, while they ignore the role of spatial autocorrelation resulting from biological interaction and ecological processes. This oversight limits the efficiency and sustainability of the restoration. Here, we explored the spatial pattern of the saltcedar population in the Yellow River Delta, China, and its relationship with environmental factors, incorporating spatial autocorrelation. The plant and soil parameters were extracted by an airborne LiDAR system integrated with fixed soil environment measurements. The environment–saltcedar relationship incorporating spatial autocorrelation was evaluated with different regression models. Results showed that saltcedars aggregated at small scales (2–6 m), resulting from intraspecific facilitation and wind dispersal of seeds, while intraspecific competition was responsible for the random distribution at large scales (&gt;10 m). The long-distance dispersal of seeds through water explained the significant positive spatial autocorrelation of saltcedars at distances up to 125 m. Consequently, resulting from intraspecific facilitation and seed dispersal, aggregation distribution and positive spatial autocorrelation within the saltcedar population improved the adaptability of saltcedar to environmental stress and thereby reduced the impact of environmental factors on the abundance of saltcedar.

Soil Moisture and Soluble Salt Content Dominate Changes in Foliar δ13C and δ15N of Desert Communities in the Qaidam Basin, Qinghai-Tibetan Plateau

Changing precipitation and temperature are principal drivers for nutrient cycling dynamics in drylands. Foliar isotopic carbon (C) and nitrogen (N) composition (δ13C and δ15N) are often used to describe the plant’s water use efficiency and nitrogen use strategy in plant ecology research. However, the drivers and mechanisms under differential foliar δ13C and δ15N among plant species and communities are largely unknown for arid high-elevation regions. This study collected 462 leaf samples of ten top-dominant plant species (two or three replicates per species) across 16 sites in 2005 and 2010 to measure the community-weighted means (CWMs) of foliar δ13C and δ15N, northeastern Qaidam Basin, Qinghai-Tibetan Plateau. Our results showed that the CWM of foliar δ15N was higher in 2005 than in 2010 and was lower in the warm-dry season (July and August) than the cool-wet one (June and September) in 2010. Similarly, the CWM of foliar δ13C was higher in 2005 than in 2010, but no difference between warm-dry and cool-wet seasons in 2010. C4 plants have higher δ13C and generally grow faster than C3 species under warm-wet weathers. This might be why the CWM of foliar δ13C was high, while the CWM of foliar δ15N was low in the wet sampling year (2010). The general linear mixed models revealed that soil moisture was the most critical driver for the CWM of foliar δ15N, which explained 42.1% of the variance alone. However, the total soluble salt content was the crucial factor for the CWM of foliar δ13C, being responsible for 29.7% of the variance. Growing season temperature (GST) was the second most vital factor and explained 28.0% and 21.9% of the variance in the CWMs of foliar δ15N and δ13C. Meanwhile, remarkable differences in the CWMs of foliar δ15N and δ13C were also found at the species level. Specifically, Kalidium gracile and Salsola abrotanoides have higher foliar δ15N, while Ephedra sinica and Tamarix chinensis have lower foliar δ15N than other species. The foliar δ13C of Calligonum Kozlov and H. ammodendron was the highest among the ten species. Except for the foliar δ13C of E. sinica was higher than Ceratoide latens between the two sampling years or between the cool-wet and warm-dry seasons, no significant difference in foliar δ13C was found for other species. Overall, the CWMs of foliar δ15N and δ13C dynamics were affected by soil properties, wet-dry climate change, and species identity in high-elevation deserts on the Qinghai Tibetan Plateau.