Decay and termite resistance of medium density fiberboard (MDF) made from different wood species

Medium density fiberboard (MDF) production worldwide is increasing due to the development of new manufacturing technologies. As a result, MDF products are increasingly utilized in traditional wood applications that require fungal and insect resistance. This study evaluated the ability of white and brown rot fungi and termites to decompose MDF consisting of different wood species by measuring weight loss. Furnish in the boards was prepared from heart and sapwood portions of pine (Pinus nigra Arnold var. pallasiana), beech (Fagus orientalis Lipsky), and European oak (Quercus robur L.) species. Fungal decay resistance tests were performed according to ASTM D 2017-81 standard method using two brown-rot fungi, Gloeophyllum trabeum (Pers. ex Fr.) Murr. (Mad 617), Postia placenta (Fries) M. Larsen et Lombard (Mad 698), and one white-rot fungus, Trametes versicolor (L. ex Ft.) Pilat (Mad 697). MDF and wood specimens were also bioassayed against the eastern subterranean termite, Reticulitermes flavipes (Kollar) in order to determine termite resistance of the specimens. MDF specimens containing oak and mixed furnish demonstrated increased durability against decay fungi. Only pine, oak, and mixed MDF specimens met the 25% or less weight loss limit to be classified resistant according to ASTM D 2017-81 standard method. Overall, MDF specimens made from oak showed better performance than oak solid wood specimens. Accelerated aging according to ASTM D 1037-96a standard method before fungal bioassay decreased fungal resistance of the specimens. In contrast to the fungal bioassay, MDF specimens made from beech and mixed furnish showed decreased weight losses from termite attack after 4 weeks. However, none of the MDF specimens were resistant to termite attack. In severe conditions, the MDFs may require the incorporation of chemical biocides prior to board production for increasing the resistance of MDF to termite attack.     

Calibration,verification and stepwise analysis for numerical phenetics: Olinia (Oliniaceae) as an example

Calibration and verification techniques are discussed in the context of numerical phenetic analysis. Calibration is introduced to evaluate the character set, decide on the type of phenetic algorithm to be used, and determine the level at which to recognize taxonomic entities. Clusters are verified by analyzing sub-samples of specimens. This determines whether the groups obtained are dependent on the variation represented by particular specimens or on variation between taxa to which the specimens belong. A stepwise procedure was used to improve resolution on the ordination axes and thus to visualize differences between phenetically similar taxa. The application of these techniques in Olinia Thunb. supports the recognition of six clearly defined clusters which correspond to O. emarginata Burtt Davy, O. micrantha Decne, O. ventosa (L.) Cufod., O. capensis (Jacq.) Klotzsch, O. radiata Hofmeyr & Phill. and O. vanguerioides Bak. The analyses further revealed one highly variable group, referred to as the O. rochetiana complex, which includes O. aequipetala (Del.) Cufod, O. usambarensis Gilg, O. volkensii Engl., O. macrophylla Gilg, O. ruandensis Gilg, O. discolor Mildbraed and O. huillensis Welw. ex A.R. Fernandes.     

Isoflavonoids from Myroxylon peruiferum

Considerable differences in flavonoid composition of the trunkwood characterize different specimens of Myroxylon balsamum (L.) Harms. Only calycosin among the 11 flavonoids found in M. peruiferum L.f., presently considered synonymous with M. balsamum, had previously been located in the latter species. Two of these flavonoids, 2′-hydroxy-7,3′,4′-trimethoxyisoflavanone and 2′-hydroxy-7,3′,4′-trimethoxyisoflavone are new natural products.     

Conocephalum salebrosum (Marchantiopsida, Conocephalaceae) – a new Holarctic liverwort species

Detailed analysis of 270 specimens of Conocephalum conicum (L.) Dumort., mainly from the POZW Herbarium revealed some diagnostic differences between two cryptic species originally detected on the basis of isozyme studies. Several diagnostic characters were found in the structure of the archegoniophore, sporophyte and sterile thallus. The most reliable diagnostic features are size and structure of stomatal apparatus of the archegoniophore ‘heads’, type of junction of the air chamber walls with epidermal cells, and the thallus surface details. On the basis of morphological and anatomical diagnostic characters, two formerly cryptic species are recognized following the rules of formal taxonomy. The lectotype of C. conicum preserved in FI was found to possess characteristics of cryptic species C. conicum- species L. Accordingly, the species previously named as C. conicum–species L must bear the name Conocephalum conicum (L.) Dumort. No published name was related to C. conicum – species S, which is therefore described as a new species: Conocephalum salebrosum Szweykowski, Buczkowska &; Odrzykoski. Both species are fully described and their diagnostic characters are illustrated. Distribution maps for both species are given.     

Red algae found on European salt-marshes. II. Catenella caespitosa (Rhabdoniaceae)

A survey is given of the taxonomy, life history and geography of Catenella caespitosa (With.) L. Irv. basedon study of living specimens, culture experiments, study of herbarium material and literature. This species is conspecific with Catenella repens (Lightf.) Batt. and Catenella opuntia (Good. & Woodw.) Grev. and several other taxa. Fragmentation is the most common mode of propagation of C. caespitosa. However, reproduction by tetraspores and by carpospores is also observed. The species is found in the tropics as well a in temperate climates.     

Population Structure and Evidence for Both Clonality and Recombination among Brazilian Strains of the Subgenus Leishmania (Viannia)

Background/Objectives: Parasites of the subgenus Leishmania (Viannia) cause varying clinical symptoms ranging from cutaneous leishmaniases (CL) with single or few lesions, disseminated CL (DL) with multiple lesions to disfiguring forms of mucocutaneous leishmaniasis (MCL). In this population genetics study, 37 strains of L. (V.) guyanensis, 63 of L. (V.) braziliensis, four of L. (V.) shawi, six of L. (V.) lainsoni, seven of L. (V.) naiffi, one each of L. (V.) utingensis and L. (V.) lindenbergi, and one L. (V.) lainsoni/L. naiffi hybrid from different endemic foci in Brazil were examined for variation at 15 hyper-variable microsatellite markers. Methodology/Principal findings: The multilocus microsatellite profiles obtained for the 120 strains were analysed using both model- and distance-based methods. Significant genetic diversity was observed for all L. (Viannia) strains studied. The two cluster analysis approaches identified two principal genetic groups or populations, one consisting of strains of L. (V.) guyanensis from the Amazon region and the other of strains of L. (V.) braziliensis isolated along the Atlantic coast of Brazil. A third group comprised a heterogeneous assembly of species, including other strains of L. braziliensis isolated from the north of Brazil, which were extremely polymorphic. The latter strains seemed to be more closely related to those of L. (V.) shawi, L. (V.) naiffi, and L. (V.) lainsoni, also isolated in northern Brazilian foci. The MLMT approach identified an epidemic clone consisting of 13 strains of L. braziliensis from Minas Gerais, but evidence for recombination was obtained for the populations of L. (V.) braziliensis from the Atlantic coast and for L. (V.) guyanensis. Conclusions/Significance: Different levels of recombination versus clonality seem to occur within the subgenus L. (Viannia). Though clearly departing from panmixia, sporadic, but long-term sustained recombination might explain the tremendous genetic diversity and limited population structure found for such L. (Viannia) strains.     

Blockboard with boron-treated veneers: laboratory decay and termite resistance tests

This study is evaluated by measuring the weight loss, and the ability of white- and brown-rot fungi and termites to attack untreated and boron-treated blockboard manufactured using untreated fir (Abies bornmulleriana M.) strips sandwiched between Ekaba (Tetraberlinia bifoliolata Harms.) veneers at final assembly. The veneers were treated with either boric acid or disodium octoborate tetrahydrate, or mixtures of these chemicals, and blockboard specimens were subjected to fungal decay resistance tests performed according to the Japanese Industrial Standard (JIS) A-9201 method using the brown-rot fungus Fomitopsis palustris (Berkeley et Curtis) Murrill and the white-rot fungus, Trametes versicolor (L. ex Fr.) Quel. Blockboard specimens were also tested against the subterranean termite Coptotermes formosanus Shiraki to determine termite resistance. Blockboard specimens with boron-treated veneers demonstrated increased durability against decay fungi and termite attack. However, sealing of untreated fir strips before decay resistance tests helped reduce significantly the weight losses in blockboard with either untreated or boron-treated veneers. Although blockboard is usually used in indoor applications, incorporation of boron-based biocides may be required for increasing resistance to fungal decay and termite attack and giving fire retardancy.     

Comparative genomic analysis of Leishmania (Viannia) peruviana and Leishmania (Viannia) braziliensis

Background

The Leishmania (Viannia) braziliensis complex is responsible for most cases of New World tegumentary leishmaniasis. This complex includes two closely related species but with different geographic distribution and disease phenotypes, L. (V.) peruviana and L. (V.) braziliensis. However, the genetic basis of these differences is not well understood and the status of L. (V.) peruviana as distinct species has been questioned by some.Here we sequenced the genomes of two L. (V.) peruviana isolates (LEM1537 and PAB-4377) using Illumina high throughput sequencing and performed comparative analyses against the L. (V.) braziliensis M2904 reference genome. Comparisons were focused on the detection of Single Nucleotide Polymorphisms (SNPs), insertions and deletions (INDELs), aneuploidy and gene copy number variations.

Results

We found 94,070 variants shared by both L. (V.) peruviana isolates (144,079 in PAB-4377 and 136,946 in LEM1537) against the L. (V.) braziliensis M2904 reference genome while only 26,853 variants separated both L. (V.) peruviana genomes.Analysis in coding sequences detected 26,750 SNPs and 1,513 indels shared by both L. (V.) peruviana isolates against L. (V.) braziliensis M2904 and revealed two L. (V.) braziliensis pseudogenes that are likely to have coding potential in L. (V.) peruviana. Chromosomal read density and allele frequency profiling showed a heterogeneous pattern of aneuploidy with an overall disomic tendency in both L. (V.) peruviana isolates, in contrast with a trisomic pattern in the L. (V.) braziliensis M2904 reference.Read depth analysis allowed us to detect more than 368 gene expansions and 14 expanded gene arrays in L. (V.) peruviana, and the likely absence of expanded amastin gene arrays.

Conclusions

The greater numbers of interspecific SNP/indel differences between L. (V.) peruviana and L. (V.) braziliensis and the presence of different gene and chromosome copy number variations support the classification of both organisms as closely related but distinct species.The extensive nucleotide polymorphisms and differences in gene and chromosome copy numbers in L. (V.) peruviana suggests the possibility that these may contribute to some of the unique features of its biology, including a lower pathology and lack of mucosal development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1928-z) contains supplementary material, which is available to authorized users.     

A review of sciarids of the genus <Emphasis Type="Italic">Leptosciarella</Emphasis> Tuomikoski 1960 (Diptera,Sciaridae) in the Altai fauna,with description of three new species

The taxonomy of the genus Leptosciarella Tuomikoski, 1960 in the Altai Area within Altai Territory and the Altai Republic was studied. Eleven species were recognized, including three new species which are described and illustrated here: Leptosciarella (L.) ulagana Komarova sp. n., L. (L.) angustistylus Komarova sp. n., L. (L.) senex Komarova sp. n. Additionally, L. (L.) fuscipalpa (Mohrig et Mamaev 1979) and L. (L.) truncata (Tuomikoski 1960) are recorded from Altai for the first time. A key to the Altai species is provided.     

Pollen morphology of Lathyrus (Fabaceae) taxa in the Platystylis section from Turkey

In this study, the pollen morphology of 18 wild taxa of Lathyrus L. grown in Turkey: L. pallescens (Bieb.) Koch, L. brachypterus Cel., L. haussknechtii Sirj., L. karsianus P. H. Davis, L. satdaghensis P. H. Davis, L. nivalis Hand.-Mazz, L. atropatanus (Grossh.) Sir., L. armenus (Boiss. and Huet) Sirj., L. cyaneus (Stev.) Koch var. cyaneus, L. cyaneus var. pinnatus?Davis, L. digitatus (Bieb.) Fiori, L. tukhtensis Czecz., L. variabilis (Boiss. and Ky.) Maly, L. spathulatus Cel. L. elongatus (Bornm.) Sirj., L. cilicicus Hayek and Siehe, L. boissieri Sirj., and L. bitlisicus Pe?men was examined by light microscopy and scanning electron microscopy. The pollen grains were 3-zonocolporate, of spheroidal-subprolate-prolate (P/E?=?0.957?C1.252) types, and medium in size. Equatorial view: rectangular or elliptical-obtuse-convex, polar view: circular, triangular or quinquangular-obtuse-convex. The smallest pollen grains belonged to L. elongatus (P?=?36.972/E?=?38.636) and the largest to L. cyaneus var. cyaneus (P?=?46.332/E?=?32.864). The ornamentation was perforate-foveolate or slightly reticulate. Some photographs included in this work were taken using both light microscopy and scanning electron microscopy.     

Nectar and pollen sources for honeybees in Kafrelsheikh province of northern Egypt

This study was conducted at the apiary of the Beekeeping Research Section at the Sakha Agricultural Research Station, ARC, Kafrelsheikh, and other apiaries in Kafrelsheikh province, during two successive years 2015 and 2016. The study aimed to survey nectar and pollen floral resources in Kafrelsheikh province. Ninty seven plant species belonging to 33 families were recorded as nectar sources, and 82 plant species belonging to 36 families were recorded as pollen sources during the whole year. The largest amount of monthly trapped pollen was obtained during May followed by August. It can be concluded that, beekeepers in Kafrelsheikh province can harvest good honey yield at the end of blooming seasons of citrus (Citrus spp.) during March and April, Egyptian clover (Trifolium alexandrinum L.) during May and June, loofah (Luffa aegyptiaca Mill.) during June to October, cotton (Gossypium spp.) during July and August, and banana (Musa spp.) during August and September. They also, could be trapping pollen loads collected from faba bean (Vicia faba L.) and flax (Linum usitatissimum L.) during January to March, date palm (Phoenix dactylifera L.) during March and April, Egyptian clover during May and June, summer seed watermelon (Citrullus lanatus var. colothynthoides L.) during June and July, loofah and maize (Zea mays L.) during June to November.     

Entosthodon mouretii (Corb.) Jelenc new to Europe

Entosthodon mouretii (Corb.) Jelenc, a species related to E. fascicularis (Hedw.) C. Müll., is referred for the first time in Europe, from samples collected in Spain. The Spanish specimens are described and illustrated.     

Ammonium and nitrate uptake by aquatic plants from poorly buffered and acidified waters

In the Netherlands, atmospheric deposition of ammonia compounds, particularly ammonium sulphate, is an important source for the acidification of oligotrophic soft waters. As a consequence, the acidified waters are generally nitrogen enriched, ammonium being the dominant N form. In this study, it is examined how this alteration in the nitrogen household affects the aquatic plant communities in acidifying waters.The uptake of ammonium and nitrate by leaves and roots of two groups of freshwater plants has been studied using glass incubation chambers. The forst group (Littorella uniflora (L.) Aschers.; Lobelia dortmanna L.; Luronium natans (L.) Raf.; Echinodorus ranunculoides (L.) Engelm.) is characteristic of nitrogen-poor soft waters, whereas the second group (Juncus bulbosus L.; Sphagnum flexuosum Dozy & Molk.;Agrostis canina L.; Drepanocladus fluitans (Hedw.) Warnst.) often occurs in dense stands in nitrogen-enriched, acid waters. Both groups have typical adaptations to the nitrogen condition of their aquatic environment. The soft-water species show a nitrate-dominated (63–73%) nitrogen utilization, with the roots as the major (83%) uptake site. Moreover, they are able to survive at very low nitrogen concentrations. The acid-tolerant species have an ammonium-dominated (85–90%) nitrogen utilization, with the leaves as the major (71–82%) uptake site. This group profits from the increased ammonium levels in acid waters. It is concluded that in the case of acidification increased ammonium concentrations additionally account for the suppression of typical soft-water communities by communities dominated by Juncus bulbosus and Sphagnum spp.     

In Vitro and In Vivo Activity of an Organic Tellurium Compound on Leishmania (Leishmania) chagasi

Tellurium compounds have shown several biological properties and recently the leishmanicidal effect of one organotellurane was demonstrated. These findings led us to test the effect of the organotellurium compound RF07 on Leishmania (Leishmania) chagasi, the agent of visceral leishmaniasis in Latin America. In vitro assays were performed in L. (L.) chagasi-infected bone marrow derived macrophages treated with different concentrations of RF07. In in vivo experiments Golden hamsters were infected with L. (L.) chagasi and injected intraperitoneally with RF07 whereas control animals received either Glucantime or PBS. The effect of RF07 on cathepsin B activity of L. (L.) chagasi amastigotes was assayed spectrofluorometrically using fluorogenic substrates. The main findings were: 1) RF07 showed significant leishmanicidal activity against intracellular parasites at submicromolar concentrations (IC50 of 529.7±26.5 nM), and the drug displayed 10-fold less toxicity to macrophages (CC50 of 5,426±272.8 nM); 2) kinetics assays showed an increasing leishmanicidal action of RF07 at longer periods of treatment; 3) one month after intraperitoneal injection of RF07 L. (L.) chagasi-infected hamsters showed a reduction of 99.6% of parasite burden when compared to controls that received PBS; 4) RF07 inhibited the cathepsin B activity of L. (L.) chagasi amastigotes. The present results demonstrated that the tellurium compound RF07 is able to destroy L. (L.) chagasi in vitro and in vivo at concentrations that are non toxic to the host. We believe these findings support further study of the potential of RF07 as a possible alternative for the chemotherapy of visceral leishmaniasis.     

Bacteriophage P1 site-specific recombination. II. Recombination between loxP and the bacterial chromosome

Lipoprotein crystals of hagfish yolk platelets (Myxine glutinosa L.) are, by electron diffraction of embedded specimens, monoclinic (a > 19.8 nm, b > 8.9 nm, c > 9.0 nm, β ~ 105 °; space group C2: 2 dimers per cell). Using sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the four major protein bands in Myxine (molecular weights 30,000; 44,000: 80,000 and 130,000) correspond, with small differences, to similar bands of Xenopus yolk lipoproteins. The symmetric lipovitellin-phosvitin dimer in cyclostomes is unique and probably reflects the lack of diversification of homologous vertebrate protein species.     

The Genome Sequence of Leishmania (Leishmania) amazonensis: Functional Annotation and Extended Analysis of Gene Models

We present the sequencing and annotation of the Leishmania (Leishmania) amazonensis genome, an etiological agent of human cutaneous leishmaniasis in the Amazon region of Brazil. L. (L.) amazonensis shares features with Leishmania (L.) mexicana but also exhibits unique characteristics regarding geographical distribution and clinical manifestations of cutaneous lesions (e.g. borderline disseminated cutaneous leishmaniasis). Predicted genes were scored for orthologous gene families and conserved domains in comparison with other human pathogenic Leishmania spp. Carboxypeptidase, aminotransferase, and 3′-nucleotidase genes and ATPase, thioredoxin, and chaperone-related domains were represented more abundantly in L. (L.) amazonensis and L. (L.) mexicana species. Phylogenetic analysis revealed that these two species share groups of amastin surface proteins unique to the genus that could be related to specific features of disease outcomes and host cell interactions. Additionally, we describe a hypothetical hybrid interactome of potentially secreted L. (L.) amazonensis proteins and host proteins under the assumption that parasite factors mimic their mammalian counterparts. The model predicts an interaction between an L. (L.) amazonensis heat-shock protein and mammalian Toll-like receptor 9, which is implicated in important immune responses such as cytokine and nitric oxide production. The analysis presented here represents valuable information for future studies of leishmaniasis pathogenicity and treatment.     

Like Father,Like Son: Assessment of the Morphological Affinities of A.L. 288–1 (A. afarensis), Sts 7 (A. africanus) and Omo 119–73–2718 (Australopithecus sp.) through a Three-Dimensional Shape Analysis of the Shoulder Joint

The postcranial evidence for the Australopithecus genus indicates that australopiths were able bipeds; however, the morphology of the forelimbs and particularly that of the shoulder girdle suggests that they were partially adapted to an arboreal lifestyle. The nature of such arboreal adaptations is still unclear, as are the kind of arboreal behaviors in which australopiths might have engaged. In this study we analyzed the shape of the shoulder joint (proximal humerus and glenoid cavity of the scapula) of three australopith specimens: A.L. 288–1 (A. afarensis), Sts 7 (A. africanus) and Omo 119–73–2718 (Australopithecus sp.) with three-dimensional geometric morphometrics. The morphology of the specimens was compared with that of a wide array of living anthropoid taxa and some additional fossil hominins (the Homo erectus specimen KNM-WT 15000 and the H. neanderthalensis specimen Tabun 1). Our results indicate that A.L. 288–1 shows mosaic traits resembling H. sapiens and Pongo, whereas the Sts 7 shoulder is most similar to the arboreal apes and does not present affinities with H. sapiens. Omo 119–73–2718 exhibits morphological affinities with the more arboreal and partially suspensory New World monkey Lagothrix. The shoulder of the australopith specimens thus shows a combination of primitive and derived traits (humeral globularity, enhancement of internal and external rotation of the joint), related to use of the arm in overhead positions. The genus Homo specimens show overall affinities with H. sapiens at the shoulder, indicating full correspondence of these hominin shoulders with the modern human morphotype.     

Further notes on European taxa of the lichen genus Leptogium,with emphasis on the small species

Abstract:Leptogium imbricatum P.M. Jørg. sp. nov. and L. intermedium (Arnold) Arnold are established as the correct names for two fairly widespread, small species: L. imbricatum has an arctic-alpine distribution. Leptogium intermedium was previously mostly named L. minutissimum (Flörke) Fr., the type of which is L. subtile (Schrader) Torss., a distinct species usually growing on rotting wood or debris. Leptogium magnussonii Degel. & P.M. Jørg, mainly from maritime rock outcrops in Norway and Sweden, is described as new. The species complexes of L. plicatile (Ach.) Leighton and L. schraderi (Bernh.) Nyl. are discussed. The differences between L. byssinum (Hoffm.) Nyl. and L. biatorinum (Nyl.) Leighton are given, and L. aquale (Arnold) P.M. Jørg. comb. nov., a taxon related to the latter, is considered to be a distinct species growing in mountain brooks in Central Europe. Leptogium rivale Tuck. is recorded as new to Europe, from Romania. Leptogium bellopratense Hy is shown to be a synonym of L. brebissonii Mont. New records for L. coralloideum (Meyen & Flotow) Vainio, L. massiliense Nyl and L. rivulare (Ach.) Mont. are given. A preliminary key to the small European species (north of the Alps) is appended. The following names have been lecto- or neotypified: Collema byssinum Hoffm., Collema pulvinatum Hoffm., Leptogium bellopratense Hy., Leptogium crenulatum Watson, Leptogium massiliense Nyl., Leptogium minutissimum var. intermedium Arnold, Leptogium minutissimum f. plumbeum Zwackh ex Arnold, Leptogium pusillum var. aquale Arnold, Leptogium rivulare var. crenatulum Nyl., Leptogium scotinum var. crenatum Nyl., Lichen byssinus Hoffm., Lichen minutissimus Flörke, Lichen schraderi Bemh., Lichen subtilis Schrader and Parmelia scotina var. lophaea Ach.     

重金属Pb(Ⅱ)对3种藜科植物种子萌发的影响

以珍珠猪毛菜（Salsola passerina Bunge）、地肤（Kochia scoparia(L.)Schrad.）和白藜（Chenopodium album L.）3种藜科植物为研究对象,研究不同浓度（0、50、150、300、600、800、1 000 mg·L^-1）的Pb(Ⅱ)处理对植物种子萌发和幼苗生长的影响。结果表明：当Pb(Ⅱ)浓度为50和150 mg·L^-1时,珍珠猪毛菜和地肤种子的发芽率、发芽势和发芽指数与对照相比差异不显著,Pb(Ⅱ)浓度为150 mg·L^-1时,对白藜种子发芽率、发芽势和发芽指数有明显影响,Pb(Ⅱ)浓度大于300 mg·L^-1对3种植物种子萌发均有抑制作用,对白藜和地肤的抑制大于珍珠猪毛菜。3种植物的种子活力指数除珍珠猪毛菜在50 mg·L^-1时与对照无显著差异,其余各处理均与对照有极显著差异。Pb(Ⅱ)浓度为50 mg·L^-1时,对3种植物的胚根长和胚芽长都影响不大,随着Pb(Ⅱ)浓度的升高,对3种植物的胚根长和胚芽长都有明显的抑制作用,对地肤和白藜的抑制强度更大。地肤和白藜幼苗分别在Pb(Ⅱ)浓度为300和600 mg·L^-1时死亡,当Pb(Ⅱ)浓度达到1 000 mg·L^-1时,珍珠猪毛菜仍可生长,但生长比较缓慢。3种植物幼苗对Pb(Ⅱ)的耐受性为：珍珠猪毛菜＞白藜＞地肤。