First record of dill powdery mildew caused by Erysiphe heraclei DC in Egypt

In Egypt, powdery mildew was observed for the first time on dill plants, during annual disease surveys of March–May 2003 and 2005. Typical symptoms of powdery mildew of dill plant (Anethum graveolens L.) were observed in Gharbeia Governorate. Symptoms of powdery mildew became common on leaves, stems inflorescences and fruits as white irregular areas. These symptoms appeared at vegetative and early flowering stages then gradually increased through fruiting and pre-maturity stages. Samples of infected leaflets, stem, inflorescences and fruits were collected for examination by light and scanning electron microscope (SEM). Microscopic examination revealed that conidiophores were short, erect–69 × 6–10 μm in dimension, conidia were observed without conspicuous fibrosin bodies singly, elliposid to ovoid 25–33 × 10–16 μm in dimension, and the length to width ratio of conidia ranged from 1.7 to 2.0 and were produced singly. Cylindrical foot cells (22.0 × 8.0 μm) were followed by one or two shorter cells (12.5 × 7.5 μm). In spring, the sexual stage (cleistothecia) appeared on infected leaves and stems in spherical, gregarious measures 105–117 (111) × 100– 87.5 μm in diameter. Each cleistothecium contained (2–4) round to ovoid asci, 45–55 (50) × 45–25 (35) μm in dimension. The ascus contained (3–4) ellipsoid to ovoid ascospores, 20–17.5 × 15–10 (13.2) μm. Cleistothecia appendages are simple myceloid branched tips measuring 80–200 (140) μm in length and 3–5 (4) μm in diameter. Based on the observations of the morphology of its anamorph and teleomorph stages, the causal agent of dill powdery mildew was identified as Erysiphe heraclei which is reported for the first time in Egypt.     

Phytoremediation of lead (Pb) and Arsenic (As) by Melastoma malabathricum L. from Contaminated Soil in Separate Exposure

This study was conducted to investigate the uptake of lead (Pb) and arsenic (As) from contaminated soil using Melastoma malabathricum L. species. The cultivated plants were exposed to As and Pb in separate soils for an observation period of 70 days. From the results of the analysis, M. malabathricum accumulated relatively high range of As concentration in its roots, up to a maximum of 2800 mg/kg. The highest accumulation of As in stems and leaves was 570 mg/kg of plant. For Pb treatment, the highest concentration (13,800 mg/kg) was accumulated in the roots of plants. The maximum accumulation in stems was 880 mg/kg while maximum accumulation in leaves was 2,200 mg/kg. Only small amounts of Pb were translocated from roots to above ground plant parts (TF < 1). However, a wider range of TF values (0.01–23) for As treated plants proved that the translocation of As from root to above ground parts was greater. However, the high capacity of roots to take up Pb and As (BF > 1) is indicative this plants is a good bioaccumulator for these metals. Therefore, phytostabilisation is the mechanism at work in M. malabathricum's uptake of Pb, while phytoextraction is the dominant mechanism with As.     

Cs phytoremediation by Sorghum bicolor cultivated in soil and in hydroponic system

Cs accumulation characteristics by Sorghum bicolor were investigated in hydroponic system (Cs level at 50–1000 μmol/L) and in soil (Cs-spiked concentration was 100 and 400 mg/kg soil). Two varieties of S. bicolor Cowly and Nengsi 2# grown on pot soil during the entire growth period (100 days) did not show significant differences on the height, dry weight (DW), and Cs accumulation. S. bicolor showed the potential phytoextraction ability for Cs-contaminated soil with the bioaccumulation factor (BCF) and the translocation factor (TF) values usually higher than 1 in soil system and in hydroponic system. The aerial parts of S. bicolor contributed to 86–92% of the total removed amounts of Cs from soil. Cs level in solution at 100 μmol/L gave the highest BCF and TF values of S. bicolor. Cs at low level tended to transfer to the aerial parts, whereas Cs at high level decreased the transfer ratio from root to shoot. In soil, the plant grew well when Cs spiked level was 100 mg/kg soil, but was inhibited by Cs at 400 mg/kg soil with Cs content in sorghum reaching 1147 mg/kg (roots), 2473 mg/kg (stems), and 2939 mg/kg (leaves). In hydroponic system, average Cs level in sorghum reached 5270 mg/kg (roots) and 4513 mg/kg (aerial parts), without significant damages to its biomass at 30 days after starting Cs treatment. Cs accumulation in sorghum tissues was positively correlated with the metal concentration in medium.     

Soil salinity is correlated with a decline in 13C discrimination in leaves of Atriplex species

Abstract A dune-swale-dune transect in north-eastern South Australia with a regular covering of saltbush (Atriplex vesicaria and Atriplex stipitata) was studied. The transect topography was surveyed, as were the Δ (discrimination against ¹³C in CO₂) of the saltbush plants, and the electrical conductivity and chloride profiles of the soil. Increasing soil salinity, surveyed as electromagnetic (EM) soil conductivity, correlated with a decrease in A composition in the leaves of the C4 Atriplex species. No such correlation occurred with the whole plant. Further, the Δ of foliage was more variable than the Δ of whole plants. The Δ of foliage was higher than that of corresponding stems. We suggest that soil conductivity measured in this way is a meaningful assessment of plant growth conditions, and that further study will demonstrate its scope for incorporation into field studies of native plants at a quantitative level.     

Simultaneous RP-HPLC-PDA-RI separation and quantification of pinitol content in Sesbania bispinosa vis-à-vis harvesting age

Sesbania bispinosa belongs to the family Fabaceae contains appreciable percentage of antidiabetic cyclitol known as (+)-pinitol. A rapid high-performance liquid chromatography method has been developed for estimating the pinitol content in methanol extracts of S. bispinosa (roots, stems, leaves, flowers and pods) with respect to its harvesting age. Chromatographic separation was carried out on XBridge Amide column (250 mm x 4.6 mm, 3.5 μm coating) using isocratic elution of solvent system comprising water: acetonitrile (80:20) and water: acetonitrile (30:70) with 0.2% triethylamine at 30^°C. The RP-HPLC-PDA-RI and LC-MS/MS analyses have shown significant variations of pinitol content in roots, stems, leaves, flowers, and pods extracts of S. bispinosa with respect to a particular harvesting age. At pre-fruiting stage, the highest percentage of pinitol was detected in all the parts of the plant extracts (roots: 2.72%, stems: 2.81%, leaves: 2.32% and pods: 3.92%). Therefore, it is recommended to harvest the plant at pre-fruiting stage for getting highest amounts (0.16%) of total pinitol. As a result, the pinitol content might be employed as a reference marker to decide the harvesting age of S. bispinosa.     

Cadmium phytoextraction from loam soil in tropical southern China by Sorghum bicolor

The cadmium (Cd) uptake characteristics by Sorghum bicolor cv. Nengsi 2# and Cowley from the acidic sandy loam soil (pH = 6.1) during the entire growth period (100 days) were investigated in pot outdoors in a tropical district of southern China, Hainan Island. The Cd-spiked levels in soil were set as 3 and 15 mg/kg. Correspondingly, the available Cd levels in soil extracted by Mehlich III solution were 2.71 and 9.41 mg/kg, respectively. Basically, two varieties in a full growth period (100 days) did not show a significant difference in their growth and Cd uptake. Under high Cd stress, the plant growth was inhibited and its biomass weight and height decreased by 38.7–51.5% and 27.6–28.5%, respectively. However, S. bicolor showed higher bioaccumulation capability of Cd from soil to plant [bioconcentration factor (BCF)>4], and higher transfer capability of Cd from roots to shoots [translocation factor (TF)>1] under high Cd stress; Cd contents in the roots, stems, and leaves of S. bicolor reached 43.79–46.07, 63.28–70.60, and 63.10–66.06 mg/kg, respectively. S. bicolor exhibited the potential phytoextraction capability for low or moderate Cd-contamination in acidic sandy loam soil.     

Root distribution of poplar at varying densities on pastoral hill country

Spaced poplar (Populus spp.) trees are used widely in New Zealand for soil conservation on erodible pastoral hill country. Their root distribution in this environment, and factors that affect it, are poorly understood. Robust recommendations on effective tree spacing depend on knowledge of root systems. This study determined the effect of tree density, position between trees, and soil depth (0–90 cm) on root number, root diameter distribution, root area ratio (RAR), and cross sectional area per root for young trees on slopes. Data were collected for lateral roots using trenches. Greater than 80% of roots were < 5 mm diameter and root attributes were highest in shallow soil. Trees at 770 stems per hectare (sph) had 3–12 times more roots and 3–9 times greater RAR than those at densities of ≤ 237 sph, representative of most tree-pasture systems. Mean cross sectional area per root was similar across densities. Positions close to trees had twice as many roots (46 vs. 23/m²) and RAR (109 vs. 52 mm²/m²) as positions midway between trees. The study provided quantitative understanding of variation in root distribution with tree density and information useful for supporting and strengthening recommendations on densities for effective erosion control.     

Linking above- and belowground phenology of hybrid walnut growing along a climatic gradient in temperate agroforestry systems

Background and aims

Plant phenology is a sensitive indicator of plant response to climate change. Observations of phenological events belowground for most ecosystems are difficult to obtain and very little is known about the relationship between tree shoot and root phenology. We examined the influence of environmental factors on fine root production and mortality in relation with shoot phenology in hybrid walnut trees (Juglans sp.) growing in three different climates (oceanic, continental and Mediterranean) along a latitudinal gradient in France.

Methods

Eight rhizotrons were installed at each site for 21 months to monitor tree root dynamics. Root elongation rate (RER), root initiation quantity (RIQ) and root mortality quantity (RMQ) were recorded frequently using a scanner and time-lapse camera. Leaf phenology and stem radial growth were also measured. Fine roots were classified by topological order and 0–1 mm, 1–2 mm and 2–5 mm diameter classes and fine root longevity and risk of mortality were calculated during different periods over the year.

Results

Root growth was not synchronous with leaf phenology in any climate or either year, but was synchronous with stem growth during the late growing season. A distinct bimodal pattern of root growth was observed during the aerial growing season. Mean RER was driven by soil temperature measured in the month preceding root growth in the oceanic climate site only. However, mean RER was significantly correlated with mean soil water potential measured in the month preceding root growth at both Mediterranean (positive relationship) and oceanic (negative relationship) sites. Mean RIQ was significantly higher at both continental and Mediterranean sites compared to the oceanic site. Soil temperature was a driver of mean RIQ during the late growing season at continental and Mediterranean sites only. Mean RMQ increased significantly with decreasing soil water potential during the late aerial growing season at the continental site only. Mean root longevity at the continental site was significantly greater than for roots at the oceanic and Mediterranean sites. Roots in the 0–1 mm and 1–2 mm diameter classes lived for significantly shorter periods compared to those in the 2–5 mm diameter class. First order roots (i.e. the primary or parents roots) lived longer than lateral branch roots at the Mediterranean site only and first order roots in the 0–1 mm diameter class had 44.5% less risk of mortality than that of lateral roots for the same class of diameter.

Conclusions

We conclude that factors driving root RER were not the same between climates. Soil temperature was the best predictor of root initiation at continental and Mediterranean sites only, but drivers of root mortality remained largely undetermined.

     

Phytostabilization potential of ornamental plants grown in soil contaminated with cadmium

In a greenhouse experiment, five ornamental plants, Osmanthus fragrans (OF), Ligustrum vicaryi L. (LV), Cinnamomum camphora (CC), Loropetalum chinense var. rubrum (LC), and Euonymus japonicas cv. Aureo-mar (EJ), were studied for the ability to phytostabilization for Cd-contaminated soil. The results showed that these five ornamental plants can grow normally when the soil Cd content is less than 24.6 mg·kg^?1. Cd was mainly deposited in the roots of OF, LV, LC and EJ which have grown in Cd-contaminated soils, and the maximum Cd contents reached 15.76, 19.09, 20.59 and 32.91 mg·kg^?1, respectively. For CC, Cd was mainly distributed in the shoots and the maximum Cd content in stems and leaves were 12.5 and 10.71 mg·kg^?1, however, the total amount of Cd in stems and leaves was similar with the other ornamental plants. The enzymatic activities in Cd-contaminated soil were benefited from the five tested ornamental plants remediation. Soil urease and sucrase activities were improved, while dehydrogenase activity was depressed. Meanwhile, the soil microbial community was slightly influenced when soil Cd content is less than 24.6 mg·kg^?1 under five ornamental plants remediation. The results further suggested that ornamental plants could be promising candidates for phytostabilization of Cd-contaminated soil.     

Efficiency of Rumex dentatus L. Leaves Extract for Enhancing Phytoremediation of Plantago major L. in Soil Contaminated by Carbosulfan

Carbosulfan and carbofuran induce water pollution and health issues. Such issues may be solved by phytoremediation. Here we tested the potential of adding Rumex dentatus L. leaves extract to Plantago major L. for enhancing phytoremediation of carbosulfan-contaminated soil. The phytoremediation efficiency of P. major L. amended with R. dentatus L. leaves extract was significantly greater than that of P. major only and R. dentatus with respect to the removal of carbosulfan from contaminated soil. The contribution of R. dentatus leaves extract to the degradation of carbosulfan in the soil were 20.95%, 18.85%, 5.2% and 1.85% after 2, 4, 8 and 16 days of treatments, respectively. The presence of P. major amended with R. dentatus leaves extract showed significant effect on uptake of carbosulfan into roots at 2 and 4 days, the uptake ratio was about 2.39 and 1.31 times higher compared to P. major alone, respectively. Carbofuran appeared in the P. major roots amended with R. dentatus leaves extract within 2 days of treatment (5.49 mg/kg) and reached the maximum over 8 days (10.19 mg/kg), while carbofuran appeared in the P. major over 4 days of treatment (4.09 mg/kg) and reached the maximum (6.92 mg/kg) over 8 days of exposure. Carbosulfan taken up into P. major leaves reached 4.36 mg/kg over 4 days, while it reached 2.75 mg/kg in P. major leaves amended with R. dentatus leaves extract over the same time. Carbofuran translocated into the P. major leaves amended with R. dentatus leaves extract and reached the maximum over 16 days of exposure (10.43 mg/kg), followed by P. major (9.47 mg/kg) and R. dentatus leaves (9.5 mg/kg), respectively. This study indicates that R. dentatus leaves extract can improve the efficiency of phytoremediation of carbosulfan.     

Il problema della Eredità considerato dal punto di vista chimico-fisico

Abstract

A study on the type and distribution of trichomes, morphological traits of the calyx and content of antioxidant compounds was conducted on Teucrium arduini L. populations in Croatia and in Bosnia and Herzegovina. Non-glandular trichomes, peltate trichomes and small capitate trichomes with four secretory head cells were observed on leaves, stems and calyx, whereas long capitate trichomes with a unicellular head cell were observed exclusively on the calyx. Average calyx length was 5.23–6.51 mm, calyx tube length 2.92–3.68 mm, lower lip length 1.25–2.42 mm and upper lip length 1.89–2.99 mm. The concentration of antioxidant compounds in all populations was the highest in leaves: total polyphenols (TP): 8.43–13.55%; tannins (T): 1.79–7.33%; flavonoids (TF): 0.28–0.40%; phenolic acids (TPA): 2.90–5.07%. Inflorescences generally contained the smallest amount of TP (5.89–11.42%), T (0.87–6.50%) and TPA (1.66–2.27%), while the smallest content of TF was obtained for the majority of stem samples (0.06–0.12%). The researched populations did not differ with regard to the type and overall distribution of the trichomes, though the Bosnian populations have a shorter calyx tube and longer upper lip. Some variability was observed in the TP and T content between sampling sites, while quite high variability was noted in the TF and TPA content.     

Trace element transfer from two contaminated soil series to Medicago sativa and one of its herbivores,Spodoptera exigua

Alfalfa was cultivated in two potted soil series obtained from two sandy soils contaminated by Cu (SM) and metal(loids)/PAH (CD). Shoot production was monitored for 8 weeks. Then, larvae of Spodoptera exigua were reared on alfalfa of both soil series for eight days. A biotest (using Phaseolus vulgaris) was used to assess the soil phytotoxicity. Increasing soil contamination reduced P. vulgaris growth, but alfalfa growth was only reduced on the SM soil series. Exposure to the SM soil was mirrored by shoot Cu and Cr concentrations of alfalfa (respectively, in mg kg ^?1 DW, Cu and Cr ranged from 11.9 and 0.4 in the CTRL soil to 98.5 and 1.2 in the SM one). Exposure to the CD soil series was mirrored by shoot Zn concentrations (i.e., 48–91.6 mg kg^?1 DW). Internal metal(loid) concentrations of S. exigua remained generally steady across both soil series (respectively Cd 0.05–0.16, Cr 0.5–3.3, Cu 5.8–98.5, Ni 0.6–1.6, Pb 0.4–1.3, and Zn 57–337 mg kg^?1 DW), and most of the associated transfer factors were lower than 1. Here, due to the excluder phenotype of alfalfa across our TE contamination gradients, S. exigua could cope with high total metal(loid) concentration in both contaminated soils.     

古尔班通古特沙漠白梭梭枝干光合及其影响因素

植物枝干光合（P_g）固定其自身呼吸所释放的CO₂,有效减少植物向大气的CO₂排放量。以古尔班通古特沙漠优势木本植物白梭梭（Haloxylon persicum）为研究对象,利用LI-COR 6400便携式光合仪与特制光合叶室（P-Chamber）相结合,观测白梭梭叶片、不同径级枝干的光响应及光合日变化特征;同时监测环境因子（大气温湿度、光合有效辐射、土壤温度及含水量等）与叶片/枝干性状指标（叶绿素含量、含水量、干物质含量、碳/氮含量等）,揭示叶片/枝干光合的主要影响因子;采用破坏性取样,量化个体水平上叶片与枝干的总表面积,阐明枝干光合对植株个体碳平衡的贡献。研究结果显示：（1）白梭梭叶片叶绿素含量是枝干叶绿素含量的12-16倍,各径级枝干叶绿素含量差异不显著;（2）枝干光饱和点低于叶片,枝干不同径级（由粗至细）,暗呼吸速率和枝干光合逐渐减小;（3）光合有效辐射、土壤含水量和空气温湿度是影响叶片光合的主要因子,对枝干光合无显著影响;（4）枝干光合可以固定其自身呼吸产生CO₂的73%,最高可达90%,枝干光合固定CO₂约占个体水平固碳量的15.4%。研究结果表明,忽视枝干光合的贡献来预测未来气候变化背景下荒漠生态系统碳过程,可能存在根本性缺陷,并且在估算枝干呼吸时,需要考虑枝干是否存在光合作用,以提高枝干呼吸的准确性。     

Phytoextraction Potential of Poplar (Populus alba L. var. pyramidalis Bunge) from Calcareous Agricultural Soils Contaminated by Cadmium

To investigate the phytoextraction potential of Populus alba L. var. pyramidalis Bunge for cadmium (Cd) contaminated calcareous soils, a concentration gradient experiment and a field sampling experiment (involving poplars of different ages) were conducted. The translocation factors for all experiments and treatments were greater than 1. The bioconcentration factor decreased from 2.37 to 0.25 with increasing soil Cd concentration in the concentration gradient experiment and generally decreased with stand age under field conditions. The Cd concentrations in P. pyramidalis organs decreased in the order of leaves > stems > roots. The shoot biomass production in the concentration gradient experiment was not significantly reduced with soil Cd concentrations up to or slightly over 50 mg kg^–1. The results show that the phytoextraction efficiency of P. pyramidalis depends on both the soil Cd concentration and the tree age. Populus pyramidalis is most suitable for remediation of slightly Cd contaminated calcareous soils through the combined harvest of stems and leaves under actual field conditions.     

胡杨茎叶化学计量和异速生长关系特征随发育阶段变化的性别差异

胡杨(Populus euphratica Oliv.)是荒漠河岸林防风固沙和水土保持的雌雄异株树种。该研究以不同径阶(8、12、16、20 cm)的胡杨雌雄株为研究对象,通过当年生茎、叶化学计量元素(C、N、P、K)含量及生长关系分析,探讨不同器官化学计量随发育阶段的变化及异速生长关系的性别差异。结果表明：(1)胡杨雌雄株叶片C含量表现为大径阶(20 cm)显著高于小径阶(8 cm),而其叶片N含量随着径阶的增加显著增加;雌雄株茎、叶化学计量随着径阶的增加总体上呈增加趋势,且C、N含量均与径阶呈显著正相关关系;随着径阶的增加,雌株叶片P含量呈下降趋势,与径阶呈显著负相关关系,而雌雄株茎的P、K含量呈上升趋势,且与径阶呈显著正相关关系。(2)雌株各径阶叶片的N含量及8、12、20 cm径阶的叶片P含量均显著大于相应雄株,8、16、20 cm径阶当年生茎C含量以及20 cm径阶茎N、P含量均显著高于相应雄株。(3)雌株叶片C与N在20 cm径阶的斜率指数最大,而雄株在12 cm径阶斜率指数最大,雌雄株在各发育阶段N与P的变化较稳定;在相同C含量时,雄株茎能获得更多的N含量,雌株茎在相同N的情况下能获得更多P元素。研究发现,胡杨雌雄株间茎、叶化学计量元素含量和异速生长关系特征在不同发育阶段存在着明显性别差异,成熟雌株叶片需要更多的化学计量特征含量来满足生殖需求,总体反映了自身生长及环境适应的养分分配策略。     

Risk of Soil Recontamination Due to Using Eleusine coracana and Panicum maximum Straw After Phytoremediation of Picloram

This study aimed to evaluate the herbicidal activity of picloram on the biomass of the remediation plants Eleusine coracana and Panicum maximum after cultivation in a soil contaminated with this herbicide. These species were grown in three soils, differentiated based on texture (clayish, middle, and sandy, with 460, 250, and 40 g kg^–1 of the clay, respectively), previously contaminated with picloram (0, 80, and 160 g ha^–1). After 90 days, the plants were harvested and an extract was produced by maceration of leaves and stems of these plants. It was applied to pots containing washed sand, comprising a bioassay in a growth chamber using soybean as a bioindicator for picloram. Soil and plant samples were analyzed by HPLC. The results showed the presence of picloram or metabolites with herbicidal activity in the shoots of E. coracana and P. maximum at phytotoxic levels with regard to soybean plants, indicating that they work only as phytoextractors and that the presence of straw on the soil surface can promote recontamination within the area. It is not recommended to cultivate species susceptible to picloram in areas where it was reported remediation by E. indica and P. maximum and still present residues of these species.     

Evaluation of Copper Bioaccumulation and Translocation in Jatropha curcas Grown in a Contaminated Soil

Contamination of soils with copper (Cu) has become a serious problem in the environment. Phytoremediation is an emerging green technology that uses green plants to remediate heavy metal contaminated areas. This study was conducted to evaluate the potential of Jatropha curcas for remediation of soils contaminated with Cu. Seedlings were planted in soils spiked with Cu in amount of 0, 50, 100, 200, 300, and 400 mg kg^–1 (Cu_0, Cu₅₀,Cu₁₀₀,Cu₂₀₀,Cu_300, and Cu₄₀₀) for a period of five months. The maximum height and number of leaves were recorded in control (Cu₀) whereas the highest basal stem diameter was found in seedlings exposed to Cu₅₀. Copper concentrations among plant parts were in the following trend: roots > stems > leaves. The highest total Cu concentration (665 ± 1 mg kg^?1) and total Cu removal (1.2 ± 0.2%) based on total plant dry biomass were found in Cu₄₀₀ and Cu₅₀ treatments, respectively. J. curcas exhibited high root concentration factor (RCF > 1) and low translocation factor (TF < 1). Although Cu accumulation by the plant didn't reach the criteria of Cu hyperaccumulators, this species showed a potential to be used in phytostabilization of mildly Cu contaminated areas. However, the plant cannot be used for phytoextraction of Cu-contaminated soils.     

Performance of rose scented geranium (Pelargonium graveolens) in heavy metal polluted soil vis-à-vis phytoaccumulation of metals

An investigation was carried out to evaluate the effect of heavy metal toxicity on growth, herb, oil yield and quality and metal accumulation in rose scented geranium (Pelargonium graveolens) grown in heavy metal enriched soils. Four heavy metals (Cd, Ni, Cr, and Pb) each at two levels (10 and 20 mg kg–1 soil) were tested on geranium. Results indicated that Cr concentration in soil at 20 mg kg–1 reduced leaves, stem and root yield by 70, 83, and 45%, respectively, over control. Root growth was significantly affected in Cr stressed soil. Nickel, Cr, and Cd concentration and accumulation in plant increased with higher application of these metals. Chromium, nickel and cadmium uptake was observed to be higher in leaves than in stem and roots. Essential oil constituents were generally not significantly affected by heavy metals except Pb at 10 and 20 ppm, which significantly increased the content of citronellol and Ni at 20 ppm increased the content of geraniol. Looking in to the higher accumulation of toxic metals by geranium and the minimal impact of heavy metals on quality of essential oil, geranium can be commercially cultivated in heavy metal polluted soil for production of high value essential oil.     

Shifts in diversity and community structure of endophytic bacteria and archaea across root, stem and leaf tissues in the common reed, Phragmites australis, along a salinity gradient in a marine tidal wetland of northern China

The effects of salt stress on endophytic prokaryotic communities in plants are largely unknown, and the distribution patterns of bacterial and archaeal endophytes in different tissues of a plant species are rarely compared. We investigated the endophytic bacterial and archaeal communities in roots, stems and leaves of the common reed, Phragmites australis, collected from three tidal zones along a salinity gradient, using terminal restriction fragment (T-RF) length polymorphism analysis of the 16S rRNA genes. The results showed that the bacterial diversity in the roots was significantly higher than that in the leaves, whereas similar archaeal diversity was revealed for either plant tissues or tidal zones. Network analysis revealed that T-RFs were grouped largely by tissue, and the major groups were generally linked by a few common T-RFs. Unique T-RFs in roots were mainly present in plants growing in the supratidal zone, but unique T-RFs in stems and leaves were mainly present in those from the middle and high tidal zones. Non-metric multidimensional scaling ordination and analysis of similarity revealed that bacterial communities were significantly different among tissues (P < 0.05), but similar among tidal zones (P = 0.49). However, the archaeal communities differed among tidal zones (P < 0.05), but were similar among tissues (P = 0.89). This study indicates that: (1) the endophytic archaeal communities are influenced more significantly than the endophytic bacterial communities by soil salinity, and (2) the differential distribution patterns of bacterial and archaeal endophytes in plant tissues along a salinity gradient imply that these two groups play different roles in coastal hydrophytes.     

Pterygiella trichosepala (Orobanchaceae), sp. nov. from Yunnan,southwest China

Pterygiella trichosepala (Orobanchaceae) is described and illustrated as a new species endemic to Yunnan, southwest China. It grows in calcareous grasslands or scrubs at elevations of 2000–2600 m a.s.l. This new species is closely related to P. nigrescens Oliv., but clearly differs from the latter by being pilose–hirsute throughout, with stems simple or rarely branched, 10–30 cm tall, and leaves 10–20 mm long and 3–6 mm wide (with L/W ratio 3.5–5.0), racemose inflorescences, and calyx 13–20 mm long and 8–13 mm in diameter; moreover its seed micromorphological features are significantly different from those of P. nigrescens.