Microsatellite loci and peroxidase alleles correlation in somaclonal variation of Eucalyptus microtheca F. Muell

The aim of this study was to investigate the correlation between biochemical and molecular markers in Eucalyptus microtheca F. Muell. under in vitro culture. For this mean, twig-derived explants obtainedfrom Eucalyptus microtheca 1-year-old seedling were cultured on modified MS medium, supplemented with different concentrations of NAA, Kin and TDZ. POD (peroxidase) alleles patterns were studied among regenerated plantlets to investigate the effect of TDZ concentration on POD activity. A dimer locus, a tetramer locus and two epigenetic bands were observed. Genome variation among somaclonal plantlets were investigated using microsatellite markers. SSR (Simple Sequence Repeat) markers revealed polymorphism among the studied population. Nonparametric statistical analysis showed significant effect of simple sequence repeats loci on peroxidase alleles. Correlation of two similarity matrix POD and SSRs loci was 0.18 using Mental test. Results showed less stability of dimer locus indifferent concentrations of TDZ compared to tetramer locus. Tetramer alleles showed more correlation to SSRs than that of dimmer ones

Lead and Cadmium Concentrations in Throughfall of Pinus eldarica and Cupressus arizonica Plantations in a Semi-Arid Polluted Area

This research was carried out in order to quantify throughfall (TF) and interception loss (I) and to compare the chemical composition of TF, i.e. lead (Pb) and cadmium (Cd) as well as electrical conductivity (EC) and pH beneath Pinus eldarica and Cupressus arizonica plantations and the open field rainfall. The research was accomplished in the Chitgar Forest Park, a semi-arid polluted urban area, around Tehran, Iran. Gross rainfall (GR) was measured using ten collectors located in an open field. TF was quantified by randomly manual TF collectors placed beneath each plantation. Measurements were recorded on an event basis from 15 April 2010 to 15 February 2011. During the measurement, eighteen rainfall events with cumulative GR value of 114.8 mm were recorded. Interception loss was 35.3 mm by P. eldarica plantation and 30.4 mm by C. arizonica. There were strong correlations between I:GR and GR ((r2 Pinus = 0.686, r2 Cupressus = 0.766, p value ≤ 0.01). Pb and Cd concentrations as well as EC of TF were significantly different among P. eldarica and C. arizonica and the open field. The results demonstrated that interception represents a considerable portion of GR in P.eldarica and C. arizonica plantations and, therefore, it should be considered while choosing trees for plantations in semiarid climate zones of Iran. Our results showed that P.eldarica and C. arizonica plantations have good potentials for filtering the polluted air with Pb and Cd

Physiological responses of Celtis caucasica L. and Robinia pseudoacacia L. to the cadmium and lead stresses

Afforestation of contaminated areas is considered as a possible strategy for reduction of contaminations. In the present study, the effects of lead (Pb) and cadmium (Cd) were investigated on chlorophyll fluorescence parameters (Fv/Fm, Fo, and Fm), photosynthetic pigments (chlorophyll a, b, and total chlorophyll), and proline in one-year-old seedlings of Celtis caucasica and Robinia pseudoacacia. The seedlings were treated 2 times during 10 days, with different concentrations of Pb and Cd (0, 250, 500, 1000 and 2000 mg L-1). Saline solutions containing Pb and Cd were sprayed on the leaves. Chlorophyll fluorescence was measured every other day. Chlorophyll and proline were also measured at the end of experiment period. The results indicated that chlorophyll fluorescence of C. caucasica and R. pseaudoacacia was affected by Pb on the last days and by Cd on the first days. The chlorophyll a content of C. caucasica at 250 mg L-1 of Pb and the chlorophyll a of R. pseudoacacia at 1000 and 2000 mg L-1 of Cd increased. With increasing Cd and Pb concentrations, proline of C. caucasica increased significantly while proline of R. pseudoacacia was not affected by Cd and Pb. Our results suggested fairly similar photosynthetic responses of C. caucasica and R. pseudoacacia to Cd and Pb concentrations. We concluded that physiological sensitivity of the both species to Pb and Cd were weak and can be used for afforestation in semi-arid areas contaminated by Pb and Cd

Diversity of arbuscular mycorrhizal fungal spores associated with Sorbus torminalis (L.) Crantz

This study aimed to investigate the diversity and types of arbuscular mycorrhizal fungi (AMF) associated with the wild service tree, Sorbus torminalis (L.) Crantz in spring and autumn followed by identifying similarities among the different study sites. Three different sites were selected including Kheiroud, Lalis, and Tarkin, in the Hyrcanian forests, north of Iran. Five rhizosphere soil samples were collected from each site, and the spores were extracted. Based on their morphological features, five species of AMF belonging to two families, i.e., Claroideoglomeraceae (two species) and Glomeraceae (three species) were identified. The species richness of the studied sites was identical with only the Kheiroud site presenting an additional species. Glomus badium was the most common AMF species in Kheiroud and Lalis in spring and autumn. However, the most common species in Tarkin was Septoglomus constrictum. The Shannon–Wiener indices of diversity and evenness and Simpson’s index of dominance (Ds) showed no significant differences among the studied sites in the two seasons. In sum, it is recommended that the colonized wild service tree seedlings be produced with the more relevant species identified in this study than with commercial sources

A Fully-Configurable Open-Source Software-Defined Digital Quantized Spiking Neural Core Architecture

We introduce QUANTISENC, a fully configurable open-source software-defined digital quantized spiking neural core architecture to advance research in neuromorphic computing. QUANTISENC is designed hierarchically using a bottom-up methodology with multiple neurons in each layer and multiple layers in each core. The number of layers and neurons per layer can be configured via software in a top-down methodology to generate the hardware for a target spiking neural network (SNN) model. QUANTISENC uses leaky integrate and fire neurons (LIF) and current-based excitatory and inhibitory synapses (CUBA). The nonlinear dynamics of a neuron can be configured at run-time via programming its internal control registers. Each neuron performs signed fixed-point arithmetic with user-defined quantization and decimal precision. QUANTISENC supports all-to-all, one-to-one, and Gaussian connections between layers. Its hardware-software interface is integrated with a PyTorch-based SNN simulator. This integration allows to define and train an SNN model in PyTorch and evaluate the hardware performance (e.g., area, power, latency, and throughput) through FPGA prototyping and ASIC design. The hardware-software interface also takes advantage of the layer-based architecture and distributed memory organization of QUANTISENC to enable pipelining by overlapping computations on streaming data. Overall, the proposed software-defined hardware design methodology offers flexibility similar to that of high-level synthesis (HLS), but provides better hardware performance with zero hardware development effort. We evaluate QUANTISENC using three spiking datasets and show its superior performance against state-of the-art designs

Soil Carbon Storage Trend in Various Types of Tree Stands in Shafarood Forests, Guilan Province

The current research aimed to assess the fluctuations of Soil Organic Carbon (SOC) variations in different types of forest stands along the gradient of altitude, and identify the influential factors for the its variations. Based on the random design, four plots with the surface area of 400 m2 in different stand types were established. Soil sampling up to 15cm depth in center and the corners of the each plots were taken. The biophysical attributes of trees as well as physiographical units were measured and recorded within each plot. The results of one-way ANOSIM analysis indicated the lack of similarity of SOC between pure and mixed beech stands (R≅ 0.5) and no significant difference between other stands. The results of the two-way PERMANOVA test also showed that the amount of SOC is independent of the effects of slope and the elevation gradient. The SIMPER test illustrated that the trends of soil organic carbon and soil bulk density were inverse among the stands and the gradient of altitude. However, their trends were not symmetric based on the pairwise comparisons. As a general conclusion, the fluctuations of soil organic carbon in the different types of forest stands are independent of the altitude gradient, stand type and biophysical factors, and the relative abundance of various tree species did not have a significant contribution to the variability of the soil carbon storage of the studied stands