An Experimental Investigation of the Precipitation Utilization of Plants in Arid Regions.

What represents a water source for the ecological restoration of a plant in an arid region is still up to debate. To address this issue, we conducted an in situ experiment in the Ulan Buh Desert of China, to study desert plants absorbing atmospheric water vapor. We selected Tamarisk, a common drought-salt-tolerant species in the desert, for ecological restoration as our research subject, used a newly designed lysimeter to monitor precipitation infiltration, and a sap flow system to track reverse sap flow that occurred in the shoot, branch, and stem during the precipitation event, and observed the precipitation redistribution process of the Tamarisk plot. The results showed that Tamarisk indeed directly absorbs precipitation water: when precipitation occurs, the main stem, lateral branch, and shoot all show the signs of reversed sap flow, and the reversed sap flow accounted for 21.5% of the annual sap flow in the shoot and branch, and 13.6% in the stem. The precipitation event in the desert was dominated by light precipitation events, which accounted for 81% of the annual precipitation events. It was found that light precipitation can be directly absorbed by the Tamarisk leaves, especially during nighttime or cloudy days. Even when the precipitation is absent, it was found that desert plants can still absorb water from the unsaturated atmospheric vapor; even the absorbed atmospheric water vapor was transported from the leaves to the stem, forming a reversed sap flow, as a reversed sap flow was observed when the atmospheric relative humidity reached 75%. This study indicated that the effect of light precipitation on desert plants was significant and should not be overlooked in terms of managing the ecological and hydrological systems in arid regions.

Atmospheric Vapor Impact on Desert Vegetation and Desert Ecohydrological System.

The ability of plants to absorb unsaturated atmospheric water vapor is a controversial topic. To study how vegetation in arid areas survives under limited water resources, this study uses Tamarisk in the Ulan Buh Desert of China as an example. The in-situ observation of a newly designed Lysimeter and sap flow meter system were used to monitor the precipitation infiltration and the utilization efficiency of Tamarisk of atmospheric vapor. The results show that the annual precipitation of 84 mm in arid areas could still result in deep soil recharge (DSR) with a recharge rate of 5 mm/year. Furthermore, DSR is detectable even in the winter, and the 5-year average DSR was 5.77% of the annual precipitation. It appears that the small precipitation events are critically important for the survival of Tamarisk. When the atmospheric relative humidity reaches 70%, Tamarisk leaves can absorb the unsaturated atmospheric vapor, which accounts for 13.2% of the annual precipitation amount. To adapt to the arid environment, Tamarisk can harvest its water supply from several sources including atmospheric vapor and micro-precipitation events (whose precipitation is below the measurement limit of 0.2 mm of the precipitation gauge) and can still permit a certain amount of recharge to replenish the deep soil moisture. Such an ecohydrological dynamic is of great significance to desert vegetation.

Recent Progress on the Salt Tolerance Mechanisms and Application of Tamarisk.

Salinized soil is a major environmental stress affecting plant growth and development. Excessive salt in the soil inhibits the growth of most plants and even threatens their survival. Halophytes are plants that can grow and develop normally on saline-alkali soil due to salt tolerance mechanisms that emerged during evolution. For this reason, halophytes are used as pioneer plants for improving and utilizing saline land. Tamarisk, a family of woody halophytes, is highly salt tolerant and has high economic value. Understanding the mechanisms of salt tolerance in tamarisk and identifying the key genes involved are important for improving saline land and increasing the salt tolerance of crops. Here, we review recent advances in our understanding of the salt tolerance mechanisms of tamarisk and the economic and medicinal value of this halophyte.

Phytochemical and toxicological evaluation of Tamarix stricta Boiss.

The genus Tamarix includes several plant species well-known for their medicinal properties since ancient times. Tamarix stricta Boiss is a plant native to Iran which has not been previously investigated regarding its phytochemical and biological properties. This study assessed phytochemical and toxicological aspects of T. stricta. The plant was collected from Kerman province of Iran and after authentication by botanist, it was extracted with 70% ethanol. Total phenolic compounds, total flavonoids, and antioxidant properties were measured using spectrophometric methods. Quercetin content of the extract was measured after complete acid hydrolysis with high-performance liquid chromatography. The phytochemical profile of the extract was provided using liquid chromatography-mass spectrometry method. Acute toxicity study with a single intragastric dose of 5000 mg/kg of the extract and sub-chronic toxicity using 50, 100, and 250 mg/kg of the extract was assessed in Wistar rats. Phytochemical analysis showed that polyphenols constitute the major components of the extract. Also, the extract contained 1.552 ± 0.35 mg/g of quercetin. Biochemical, hematological, and histological evaluations showed no sign of toxicity in animals. Our experiment showed that T. stricta is a rich source of polyphenols and can be a safe medicinal plant. Further pharmacological evaluations are recommended to assess the therapeutic properties of this plant.

Water Deficit Transcriptomic Responses Differ in the Invasive Tamarix chinensis and T. ramosissima Established in the Southern and Northern United States.

Tamarix spp. (saltcedar) were introduced from Asia to the southern United States as windbreak and ornamental plants and have spread into natural areas. This study determined differential gene expression responses to water deficit (WD) in seedlings of T. chinensis and T. ramosissima from established invasive stands in New Mexico and Montana, respectively. A reference de novo transcriptome was developed using RNA sequences from WD and well-watered samples. Blast2GO analysis of the resulting 271,872 transcripts yielded 89,389 homologs. The reference Tamarix (Tamaricaceae, Carophyllales order) transcriptome showed homology with 14,247 predicted genes of the Beta vulgaris subsp. vulgaris (Amaranthaceae, Carophyllales order) genome assembly. T. ramosissima took longer to show water stress symptoms than T. chinensis. There were 2068 and 669 differentially expressed genes (DEG) in T. chinensis and T. ramosissima, respectively; 332 were DEG in common between the two species. Network analysis showed large biological process networks of similar gene content for each of the species under water deficit. Two distinct molecular function gene ontology networks (binding and transcription factor-related) encompassing multiple up-regulated transcription factors (MYB, NAC, and WRKY) and a cellular components network containing many down-regulated photosynthesis-related genes were identified in T. chinensis, in contrast to one small molecular function network in T. ramosissima.

The genus Tamarix: Traditional uses, phytochemistry, and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Tamarix L., with the common name of tamarisk, consists of more than 60 species of halophyte plants which are used for medicinal purposes such as infections, wounds, and liver and spleen disorders by local people mostly in Asian and African countries. AIM OF THE REVIEW: In spite of the potential health benefits of Tamarix spp., the plant is not yet well-known in modern medicine; thus, the aim of the present review is to provide a critical appraisal of the current state of the art regarding the ethnomedicinal uses, phytochemistry, and pharmacological properties of Tamarix spp. MATERIALS AND METHODS: Electronic databases (Medline, Cochrane library, Science Direct, and Scopus) were searched with the words "Tamarix" and "Tamarisk" to collect all available data regarding different Tamarix species from the inception until May 2019. RESULTS: Tamarix spp. is traditionally used for gastrointestinal disorders, wounds, diabetes, and dental problems. Phenolic acids, flavonoids, and tannins constitute the main phytochemicals of these plants. Preclinical pharmacological evaluations have demonstrated several biological activities for Tamarix spp. including antidiabetic, hepatoprotective, wound healing, and anti-inflammatory; however, no clinical evidence have yet been provided to support the health benefits of these plants. CONCLUSIONS: Tamarix spp. are plants rich in polyphenolic compounds with valuable medicinal properties; though, there are several methodological problems such as lack of a mechanistic approach and taxonomic ambiguities in the current available data. High-quality preclinical studies, as well as well-designed clinical trials are necessary to confirm the safety and efficacy of these plants in humans.

Vegetation response to invasive Tamarix control in southwestern U.S. rivers: a collaborative study including 416 sites.

Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced the abundance of Tamarix less than active removal by mechanically using hand and chain-saws (2), heavy machinery (3) or burning (4). Tamarix abundance also decreased with lower temperatures, higher precipitation, and follow-up treatments for Tamarix resprouting. Native cover generally increased over time in active Tamarix removal sites, however, the increases observed were small and was not consistently increased by active revegetation. Overall, native cover was correlated to permanent stream flow, lower grazing pressure, lower soil salinity and temperatures, and higher precipitation. Species diversity also increased where Tamarix was removed. However, Tamarix treatments, especially those generating the highest disturbance (burning and heavy machinery), also often promoted secondary invasions of exotic forbs. The abundance of hydrophytic species was much lower in treated than in reference sites, suggesting that management of southwestern U.S. rivers has focused too much on weed control, overlooking restoration of fluvial processes that provide habitat for hydrophytic and floodplain vegetation. These results can help inform future management of Tamarix-infested rivers to restore hydrogeomorphic processes, increase native biodiversity and reduce abundance of noxious species.

The complete mitochondrial genome of the Tamarisk gerbil, Meriones tamariscinus (Rodentia: Muridae).

The complete mitochondrial genome of the Tamarisk jird, Meriones tamariscinus, was sequenced. The 16,389bp genome contains 37 genes, typical for rodent mitogenomes, including 22 tRNA genes, 2 rRNA genes, and 13 protein-coding genes. The total GC content of the mitochondrial genome is 36.8%, with a base composition of 34.0% A, 24.5% C, 12.3% G, and 29.2% T. The phylogenetic analysis showed that M. tamariscinus was classified in the genus Meriones, Muridae.

Efficacy and environmental fate of imazapyr from directed helicopter applications targeting Tamarix species infestations in Colorado.

BACKGROUND: Aerial imazapyr applications are the most common and cost-effective method for controlling invasive tamarisk, but few studies have investigated whether or how infestation and site characteristics influence control and non-target impacts. This study used vertical stands with filter papers, plus soil and tree canopy sampling, to investigate how tamarisk canopies affected retention of applied imazapyr, soil herbicide residues and tree mortality. RESULTS: Tamarisk canopies captured 71% of aerially applied imazapyr, resulting in significantly lower soil residues beneath the tree canopy. Although initial imazapyr soil residue levels outside the tree canopy were 4 times greater than those inside, soil degradation occurred 2.4 times faster outside the tamarisk canopy and resulted in lower herbicide residues. Tamarisk mortality within 3 years was 70%, but variability in control appeared to be affected by non-linear stand boundaries and tall site obstructions. These same factors also increased variability in the actual quantity of herbicide applied, exacerbating collateral impacts on desirable understory species. CONCLUSION: While aerial imazapyr applications are highly effective in controlling tamarisk, our study provides evidence for the importance of evaluating overall site suitability for this management strategy so the probability of unintended ecological effects can be minimized.

Metabolite profiling of polyphenols in the Tunisian plant Tamarix aphylla (L.) Karst.

In this study, a detailed investigation on the composition of polyphenols of Tamarix aphylla (L.) Karst., consisting of phenolic acids and flavonoids, was carried out. In order to optimize the yield of secondary metabolites, three extraction techniques were compared, including dynamic maceration, ultrasound-assisted extraction and Soxhlet extraction. The latter technique provided the best results in terms of both recovery and selectivity, using ethyl acetate as extraction solvent for 2h. The analysis of T. aphylla polyphenols was performed by means of HPLC-UV/DAD, HPLC-ESI-MS and MS(2), using an ion trap mass analyzer. Phenolic acids and flavonoids were separated on an Ascentis C18 column (250mm×4.6mm I.D., 5µm), with a mobile phase composed of 0.1M formic acid in water and acetonitrile, under gradient elution. The proposed method was fully validated in agreement with ICH guidelines and then applied to the analysis of T. aphylla leaves and stems. A total of 14 phenolic compounds were characterized for the first time in this plant extracts by using UV, MS and MS(2) data. The amount of total phenolics was found to be 993.1±22.5µg/g in the leaves and 113.1±25.8µg/g in the stems, respectively. The most abundant constituents found in the leaves include ellagic acid (211.4±10.8µg/g), quercetin (125.7±4.7µg/g) and gallic acid (120.6±1.2µg/g), whereas those in the stems were ellagic acid (44.4±3.9µg/g), gallic acid (24.3±3.3µg/g) and kaempferol (16.3±1.6µg/g). The developed method can be considered a useful tool for the metabolite profiling of T. aphylla, which represents a potential source of bioactive compounds to be used in phytotherapy.

Artificial neural network and particle swarm optimization for removal of methyl orange by gold nanoparticles loaded on activated carbon and Tamarisk.

The influence of variables, namely initial dye concentration, adsorbent dosage (g), stirrer speed (rpm) and contact time (min) on the removal of methyl orange (MO) by gold nanoparticles loaded on activated carbon (Au-NP-AC) and Tamarisk were investigated using multiple linear regression (MLR) and artificial neural network (ANN) and the variables were optimized by partial swarm optimization (PSO). Comparison of the results achieved using proposed models, showed the ANN model was better than the MLR model for prediction of methyl orange removal using Au-NP-AC and Tamarisk. Using the optimal ANN model the coefficient of determination (R2) for the test data set were 0.958 and 0.989; mean squared error (MSE) values were 0.00082 and 0.0006 for Au-NP-AC and Tamarisk adsorbent, respectively. In this study a novel and green approach were reported for the synthesis of gold nanoparticle and activated carbon by Tamarisk. This material was characterized using different techniques such as SEM, TEM, XRD and BET. The usability of Au-NP-AC and activated carbon (AC) Tamarisk for the methyl orange from aqueous solutions was investigated. The effect of variables such as pH, initial dye concentration, adsorbent dosage (g) and contact time (min) on methyl orange removal were studied. Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show the suitability and applicability of the Langmuir model. Kinetic models such as pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models indicate that the second-order equation and intraparticle diffusion models control the kinetic of the adsorption process. The small amount of proposed Au-NP-AC and activated carbon (0.015 g and 0.75 g) is applicable for successful removal of methyl orange (>98%) in short time (20 min for Au-NP-AC and 45 min for Tamarisk-AC) with high adsorption capacity 161 mg g(-1) for Au-NP-AC and 3.84 mg g(-1) for Tamarisk-AC.