The PtobZIP55-PtoMYB170 module regulates the wood anatomical and chemical properties of Populus tomentosa in acclimation to low nitrogen availability.

Poplar plantations are often established on nitrogen-poor land, and poplar growth and wood formation are constrained by low nitrogen (LN) availability. However, the molecular mechanisms by which specific genes regulate wood formation in acclimation to LN availability remain unclear. Here, we report a previously unrecognized module, basic region/leucine zipper 55 (PtobZIP55)-PtoMYB170, which regulates the wood formation of Populus tomentosa in acclimation to LN availability.

PcWRKY1 Represses Transcription of Yellow Stripe-Like 3 (PcYSL3) to Negatively Regulate Radial Cadmium Transport in Poplar Stems.

A considerable amount of cadmium (Cd) can accumulate in the bark of poplar stems, but the Cd transport pathway and its underlying molecular mechanisms remain unknown. Here, a Cd radial transport pathway in poplar stems and a previously unrecognized PcWRKY1-Yellow Stripe-Like 3 (PcYSL3) module that regulates Cd transport are identified in Populus × canescens (Aiton) Sm. Cadmiun-nicotianamine (Cd-NA) in xylem vessels in poplar stem-wood is unloaded to adjacent ray parenchyma cells and further radially transported to bark-phloem.

Vascular anomalies of the limb and trunk in children: a retrospective comparative study of endoscopic surgery and open surgery.

Background: Endoscopic resection has been reported for vascular anomalies (VA) previously. However, there is no study comparing endoscopic resection surgery (ERS) with open resection surgery (ORS) in children. We aimed to compare clinical and cosmetic outcomes between two approaches in pediatric VA.

Homolog of Human placenta-specific gene 8, PcPLAC8-10, enhances cadmium uptake by Populus roots.

Cadmium (Cd) pollution of soil occurs worldwide. Phytoremediation is an effective approach for cleaning up Cd polluted soil. Fast growing Populus species with high Cd uptake capacities are desirable for phytoremediation.

Identification and Functional Prediction of Poplar Root circRNAs Involved in Treatment With Different Forms of Nitrogen.

Circular RNAs (circRNAs) are a class of noncoding RNA molecules with ring structures formed by covalent bonds and are commonly present in organisms, playing an important regulatory role in plant growth and development. However, the mechanism of circRNAs in poplar root responses to different forms of nitrogen (N) is still unclear. In this study, high-throughput sequencing was used to identify and predict the function of circRNAs in the roots of poplar exposed to three N forms [1 mM NO (T1), 0.

Sulfur metabolism, organic acid accumulation and phytohormone regulation are crucial physiological processes modulating the different tolerance to Pb stress of two contrasting poplars.

To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of poplars, the saplings of two contrasting poplar species, Populus × canescens with high Pb sensitivity and Populus nigra with relatively low Pb sensitivity, were treated with either 0 or 8 mM Pb for 6 weeks. Lead was absorbed by the roots and accumulated massively in the roots and leaves, leading to overproduction of reactive oxygen species, reduced photosynthesis and biomass in both poplar species. Particularly, the tolerance index of P.

Physiological Characteristics and Transcriptomic Dissection in Two Root Segments with Contrasting Net Fluxes of Ammonium and Nitrate of Poplar Under Low Nitrogen Availability.

To investigate physiological and transcriptomic regulation mechanisms underlying the distinct net fluxes of NH4+ and NO3- in different root segments of Populus species under low nitrogen (N) conditions, we used saplings of Populus × canescens supplied with either 500 (normal N) or 50 (low N) μM NH4NO3. The net fluxes of NH4+ and NO3-, the concentrations of NH4+, amino acids and organic acids and the enzymatic activities of nitrite reductase (NiR) and glutamine synthetase (GS) in root segment II (SII, 35-70 mm to the apex) were lower than those in root segment I (SI, 0-35 mm to the apex). The net NH4+ influxes and the concentrations of organic acids were elevated, whereas the concentrations of NH4+ and NO3- and the activities of NiR and GS were reduced in SI and SII in response to low N.

Lead exposure-induced defense responses result in low lead translocation from the roots to aerial tissues of two contrasting poplar species.

To explore whether lead (Pb)-induced defense responses are responsible for the low root-to-shoot Pb translocation, we exposed saplings of the two contrasting poplar species, Populus × canescens with relatively high root-to-shoot Pb translocation and P. nigra with low Pb translocation, to 0 or 8 mM PbCl. Pb translocation from the roots to aboveground tissues was lower by 57% in P.

Dissecting MicroRNA-mRNA Regulatory Networks Underlying Sulfur Assimilation and Cadmium Accumulation in Poplar Leaves.

The process of cadmium (Cd) accumulation and detoxification under different sulfur levels remains largely unknown in woody plants. To investigate the physiological and transcriptomic regulation mechanisms of poplars in response to different sulfate (S) supply levels and Cd exposure, we exposed Populus deltoides saplings to one of the low, moderate and high S levels together with either 0 or 50 µM Cd. Cd accumulation was decreased in low S-treated poplar leaves, and it tended to be increased in high S-supplied leaves under the Cd exposure condition.

Physiological characteristics and RNA sequencing in two root zones with contrasting nitrate assimilation of Populus × canescens.

Different root zones have distinct capacities for nitrate (NO3-) uptake in Populus species, but the underlying physiological and microRNA (miRNA) regulatory mechanisms remain largely unknown. To address this question, two root zones of Populus × canescens (Ait.) Smith.

Competing Endogenous RNA Networks Underlying Anatomical and Physiological Characteristics of Poplar Wood in Acclimation to Low Nitrogen Availability.

Although poplar plantations are often established on nitrogen (N)-poor soil, the physiological and molecular mechanisms underlying wood properties of poplars in acclimation to low N availability remain largely unknown. To investigate wood properties of poplars in acclimation to low N, Populus � canescens saplings were exposed to either 50 (low N) or 500 (normal N) �M NH4NO3 for 2 months. Low N resulted in decreased xylem width and cell layers of the xylem (the number of cells counted along the ray parenchyma on the stem cross section), narrower lumina of vessels and fibers, greater thickness of double fiber walls (the walls between two adjacent fiber cells), more hemicellulose and lignin deposition, and reduced cellulose accumulation in poplar wood.

Physiological and molecular mechanisms of heavy metal accumulation in nonmycorrhizal versus mycorrhizal plants.

Uptake, translocation, detoxification, and sequestration of heavy metals (HMs) are key processes in plants to deal with excess amounts of HM. Under natural conditions, plant roots often establish ecto- and/or arbuscular-mycorrhizae with their fungal partners, thereby altering HM accumulation in host plants. This review considers the progress in understanding the physiological and molecular mechanisms involved in HM accumulation in nonmycorrhizal versus mycorrhizal plants.

Abscisic acid enhances lead translocation from the roots to the leaves and alleviates its toxicity in Populus × canescens.

To shed light on physiological mechanisms underlying abscisic-acid (ABA)-mediated lead (Pb) uptake, translocation and detoxification, we exposed Populus × canescens saplings to either 0 or 3 mM Pb in combination with either 0 or 10 μM exogenous ABA. Pb was taken up by the roots and accumulated mainly in the cortex. A fraction of the Pb in the roots was translocated to the leaves, thereby resulting in decreased photosynthesis and biomass.

Sulfur nutrition stimulates lead accumulation and alleviates its toxicity in Populus deltoides.

Sulfur (S) can modulate plant responses to toxic heavy metals, but the underlying physiological and transcriptional regulation mechanisms remain largely unknown. To investigate the effects of S supply on lead (Pb)-induced toxicity in poplars, Populus deltoides monilifera (Aiton) Eckenw. saplings were exposed to 0 or 50 μM Pb together with one of the three S concentrations (0 (low S), 100 (moderate S) or 1500 (high S) μM Na2SO4).

Exogenous glutathione enhances cadmium accumulation and alleviates its toxicity in Populus × canescens.

Glutathione (GSH) plays an important role in cadmium (Cd) tolerance in woody plants, but the underlying mechanisms remain largely unknown. To elucidate the physiological and transcriptional regulation mechanisms of GSH-mediated Cd tolerance in woody plants, we exposed Populus × canescens (Ait.) Smith saplings to either 0 or 75 μM Cd together with one of three external GSH levels.

Phenylalanine as a nitrogen source induces root growth and nitrogen-use efficiency in Populus × canescens.

To investigate the physiological responses of poplars to amino acids as sole nitrogen (N) sources, Populus × canescens (Ait.) Smith plants were supplied with one of three nitrogen fertilizers (NH4NO3, phenylalanine (Phe) or the mixture of NH4NO3 and Phe) in sand culture. A larger root system, and decreased leaf size and CO2 assimilation rate was observed in Phe- versus NH4NO3-treated poplars.

Comparative transcriptomic analysis reveals the roles of overlapping heat-/drought-responsive genes in poplars exposed to high temperature and drought.

High temperature (HT) and drought are both critical factors that constrain tree growth and survival under global climate change, but it is surprising that the transcriptomic reprogramming and physiological relays involved in the response to HT and/or drought remain unknown in woody plants. Thus, Populus simonii saplings were exposed to either ambient temperature or HT combined with sufficient watering or drought. RNA-sequencing analysis showed that a large number of genes were differentially expressed in poplar roots and leaves in response to HT and/or desiccation, but only a small number of these genes were identified as overlapping heat-/drought-responsive genes that are mainly involved in RNA regulation, transport, hormone metabolism, and stress.

Heavy metal accumulation and signal transduction in herbaceous and woody plants: Paving the way for enhancing phytoremediation efficiency.

Heavy metal (HM)-accumulating herbaceous and woody plants are employed for phytoremediation. To develop improved strategies for enhancing phytoremediation efficiency, knowledge of the microstructural, physiological and molecular responses underlying HM-accumulation is required. Here we review the progress in understanding the structural, physiological and molecular mechanisms underlying HM uptake, transport, sequestration and detoxification, as well as the regulation of these processes by signal transduction in response to HM exposure.

Physiological and transcriptional regulation in poplar roots and leaves during acclimation to high temperature and drought.

To elucidate the physiological and transcriptional regulatory mechanisms that underlie the responses of poplars to high temperature (HT) and/or drought in woody plants, we exposed Populus alba × Populus tremula var. glandulosa saplings to ambient temperature (AT) or HT under 80 or 40% field capacities (FC), or no watering. HT increased the foliar total carbon (C) concentrations, and foliar δ(13) C and δ(18) O.

Phosphorus and nitrogen physiology of two contrasting poplar genotypes when exposed to phosphorus and/or nitrogen starvation.

Phosphorus (P) and nitrogen (N) are the two essential macronutrients for tree growth and development. To elucidate the P and N physiology of woody plants during acclimation to P and/or N starvation, we exposed saplings of the slow-growing Populus simonii Carr (Ps) and the fast-growing Populus × euramericana Dode (Pe) to complete nutrients or starvation of P, N or both elements (NP). P.

Global poplar root and leaf transcriptomes reveal links between growth and stress responses under nitrogen starvation and excess.

Nitrogen (N) starvation and excess have distinct effects on N uptake and metabolism in poplars, but the global transcriptomic changes underlying morphological and physiological acclimation to altered N availability are unknown. We found that N starvation stimulated the fine root length and surface area by 54 and 49%, respectively, decreased the net photosynthetic rate by 15% and reduced the concentrations of NH4+, NO3(-) and total free amino acids in the roots and leaves of Populus simonii Carr. in comparison with normal N supply, whereas N excess had the opposite effect in most cases.

[Prognostic significance of morbidly hematopoietic characteristics in 69 patients with myelodysplastic syndrome].

Objective: This study was to investigate the influence of morbidly hematopoietic characteristics on the prognosis of patients with myelodysplastic syndrome (MDS).

Methods: A total of 69 cases of MDS were analyzed retrospectively on ralatienship between sex, age, MDS types, WBC count, hemoglobin (Hb) level, platelet (Plt) count at diagnosis, morbidly cytologic features of bone marrow and survival time of MDS patients.

Results: The median survival time of 69 cases of MDS was 29.

Overexpression of bacterial γ-glutamylcysteine synthetase mediates changes in cadmium influx, allocation and detoxification in poplar.

Overexpression of bacterial γ-glutamylcysteine synthetase in the cytosol of Populus tremula × P. alba produces higher glutathione (GSH) concentrations in leaves, thereby indicating the potential for cadmium (Cd) phytoremediation. However, the net Cd(2+) influx in association with H(+) /Ca(2+) , Cd tolerance, and the underlying molecular and physiological mechanisms are uncharacterized in these poplars.