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Higher plant population and nitrogen management is an adopted approach for improving crop productivity from limited land resources. Moreover, higher plant density and nitrogen regimes may increase the risk of stalk lodging, which is a consequence of complex interplant competition of individual organs. Here, we aimed to investigate the dynamic change in morphology, chemical compositions and lignin promoting enzymes of the second basal inter-nodes altering lodging risk controlled by planting density and nitrogen levels. A field trial was conducted at the Mengcheng research station (33°9′44″N, 116°32′56″E), Huaibei plain, Anhui province, China. A randomized complete block design was adopted, in which four plant densities, i.e., 180, 240, 300, and 360 × 104 ha−1 and four N levels, i.e., 0, 180, 240, and 300 kg ha−1 were studied. The two popular wheat varieties AnNong0711 and YanNong19 were cultivated. Results revealed that the culm lodging resistance (CLRI) index of the second basal internodes was positively and significantly correlated with light interception, lignin and cellulose content. The lignin and cellulose contents were significantly and positive correlated to light interception. The increased planting density and nitrogen levels declined the lignin and its related enzymes activities. The variety AnNong0711 showed more resistive response to lodging compared to YanNong19. Overall our study found that increased planting densities and nitrogen regimes resulted in poor physical strength and enzymatic activity which enhanced lodging risk in wheat varieties. The current study demonstrated that stem bending strength of the basal internode was significantly positive correlated to grains per spike. The thousand grain weight and grain yield had a positive and significant relationship with stem bending strength of the basal internode. The results suggested that the variety YanNong19 produces higher grain yield (9298 kg ha−1) at density 240 × 104 plants ha−1, and 180 kg ha−1 nitrogen, while AnNong0711 produced higher grain yield (10178.86 kg ha−1) at density 240 × 104 plants ha−1 and with 240 kg ha−1 nitrogen. Moreover, this combination of nitrogen and planting density enhanced the grain yield with better lodging resistance.

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The genetic diversity of 12 Atriplex halimus L. populations collected throughout its natural range in Morocco has been studied by using sequences of nrDNA ITS region. Within-population genetic diversity was high in comparison to others species with similar life histories and ecological traits. Most of genetic variation detected by AMOVA resided within populations (94%), relative to the amount of variation among populations (6%). The level of populations differentiation (FST = 0.06) was low, which corresponds with the high level of gene flow (4.00) revealed between populations. Differentiation among ecological groups of populations accounted only for 1.23% of the total ITS variation, which indicates that climatic conditions did not have an effect of population's structuration or that this differentiation is obviously not related to ITS markers. Furthermore, very low genetic differentiation (FCT = 0.015) was observed between regions (Moroccan populations versus American population). Strangely enough, geographic distances were not correlated to genetic differentiation between the populations (r = 0.06, P = 0.5). The structuration of populations in five groups was not operated according to their bioclimatic type. The data obtained in this assay could play a crucial role to establish efficient strategies for genetic resources conservation and to work out the scheme of breeding programs of Atriplex.

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Authors: Cosme Alvarado-Esquivel, Ángel Osvaldo Alvarado-Félix and Gustavo Alexis Alvarado-Félix

The epidemiology of Toxocara infection in rural Mexico is largely unknown. Therefore, we sought to determine the seroprevalence of Toxocara infection in rural people in a northern Mexican state. We performed a cross-sectional seroprevalence study of 641 people living in rural Durango State including 282 subjects of the general population, 214 subjects of Huichol ethnicity, and 145 subjects of Mennonite ethnicity. Sera of participants were analyzed for the presence of anti-Toxocara immunoglobulin G (IgG) antibodies using a commercially available enzyme immunoassay. Three (0.5%) of the 641 subjects tested were positive for anti-Toxocara IgG antibodies. Of the 3 Toxocara seropositive subjects, two were females, aged 19 and 39 years, and one was male, aged 59 years. They had contacted with dogs, cleaned cat excrement, consumed unwashed raw fruits, contacted soil, or lived in a house with soil floors. Seroprevalence of Toxocara infection was similar among the 3 groups of population studied: 0.4% for the general population, 0.9% for Huicholes, and 0.0% for Mennonites (P = 0.41). In conclusion, the Toxocara seroprevalence found in subjects in rural Durango is low as compared with those reported in people from rural areas in other countries.

Open access
Authors: N. Niu, Y.X. Bai, S. Liu, Q.D. Zhu, Y.L. Song, S.C. Ma, L.J. Ma, X.L. Wang, G.S. Zhang and J.W. Wang

Studies of the pollen abortion mechanism in thermo-sensitive male sterile lines may provide a strong foundation for breeding hybrid wheat and establishing a theoretical basis for marker-assisted selection. To investigate the cause of pollen abortion in Bainong thermo – sensitive male sterile (BNS) lines, we analyzed the properties of pollen grains, changes in the tapetum and microspores in different anther developmental stages, and the distribution and deposition of nutrient substances in microspores. We found that tapetum degraded in the early uninucleate stage in sterile BNS (S-BNS), which was earlier than that of fertile BNS (F-BNS) tapetum. Large amounts of insoluble polysaccharides, lipids, and proteins were deposited until the trinucleate pollen stage in the nutritive cells in F-BNS. At the binucleate stage, the vacuoles disappeared and pollen inclusion increased gradually. At the trinucleate stage, these nutrients would help pollen grains mature and participate in fertilization normally. Therefore, early degradation of the tapetum, which inhibits normal microspore development, and the limited content of nutrient substances in pollen may be the main factors responsible for male sterility in BNS lines.

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The polyamine (PAs), putrescine (Put), spermidine (Spd) and spermine (Spm) are small aliphatic amines that ubiquitous in all living organisms. PA metabolism in higher plants is involved in both biotic and abiotic stress responses, and also influenced by nutrient deficiency. Accumulated evidence suggests that in plants the cellular titers of PAs are affected by various nitrogenous compounds. Therefore, the present study analyzed the effects of different nitrogen levels viz. recommended doses of nitrogen (RDN, 120 kg N/ha), sub-optimal N dose (RDN −25%, 90 kg N/ha) and supra-optimal N dose (RDN +25%, 150 kg N/ha) on PA metabolism in grains of six wheat genotypes at 15 days post anthesis (DPA) and 30 DPA. The activities of polyamine synthesizing enzymes (arginine decarboxylase, ornithine decarboxylase), catabolizing (diamine oxidase, polyamine oxidase) and the PA content were increased at supra-optimal nitrogen dose as compared to RDN. Whereas at sub-optimal nitrogen dose, higher activity of polyamine catabolizing enzymes results in speeding up oxidation of various PAs to cope up with nitrogen deficiency in plant. In relation to PA content, Put was found to be higher at early stage whereas Spd and Spm were found to be higher towards mature stages of grain indicating the use of Put in grain filling process. Highly significant correlation was observed between PA metabolism, yield and nitrogen use efficiency at sub-optimal N dose as compared to supra-optimal dose.

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Authors: M. Sheidai, S. Darini, S. M. Talebi, F. Koohdar and S. Ghasemzadeh-Baraki

The genus Linum L. is an important plant genus as it contains the species with economic values and particularly Linum usitatissimum L. that is source of fibre and linseed oil. This genus contains 230 species throughout the world and has about 22 species in Iran. Little is known about Linum species relationship and phylogeny. Therefore, the aim of present study was molecular phylogenetic investigation of the Linum species growing in Iran and to present data on their biogeography. We used both ITS and chloroplast DNA sequences (psbA-trnHGUG region) for inferring the species phylogeny and relationship. We also used cpDNA for inferring the species time of divergence and with ISSR markers to identify the path of species distribution in the country. The phylogenetic trees obtained for both ITS and cpDNA sequences were almost congruent. NeighborNet diagram and BEAST tree based on Bayesian method separated the outgroup species Hugonia and Anisadenia from the other species studied. The subspecies studied in Linum macronicum were placed close to each other and along with L. corymbulosum comprised a separate clade. The clades obtained showed divergence time between 5–20 mya. The present study revealed that the species of the sect. Linum are monophyletic, while members of the sections Linastrum and Syllinum are intermixed and seem to be paraphyletic.

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Authors: M.Z. Islam, M.A. Siddique, N. Akter, M.F.R.K. Prince, M.R. Islam, M. Anisuzzaman and M.A.K. Mian

Genetic diversity of 28 restorer lines of rice was studied under irrigated condition through Mahalanobis D2 statistics and simple sequence repeat (SSR) banding patterns. The cluster analysis grouped the lines into five clusters. The principal component analysis showed that the first four components with vector values > 1 contributed 76.32% of the total variations. The intra- and inter-cluster distances were the maximum in cluster V (0.86) and between clusters II and V (15.14), respectively. Flag leaf area, plant height, panicle length, five panicle weight, primary branches per panicle and secondary branches per panicle had maximum contribution towards genetic divergence. A total of 24 alleles varied from 2 to 5 with an average of 2.67 alleles per locus were detected for the nine microsatellite markers across 28 lines. The polymorphism information content (PIC) values ranged from 0.12 to 0.71 with an average of 0.29. RM229 was considered as the best markers on the basis of the highest PIC value. Phylogenetic cluster analysis of the SSR data based on distance divided all lines into three groups (A, B and C), whereas the cluster analysis divided these lines into five groups (I, II, III, IV and V). Besides, evaluation of yield contributing traits demonstrated that the restorer lines under the current study possessed a considerable genetic diversity. Potential lines such as BU1IR, China2R, China1R, BHD3R, IR509R and Heera5R can be used as pollen parent in developing new commercial hybrid varieties. Therefore, potential restorer lines need to be conserved in Genebank for future hybrid rice breeding programs.

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Authors: S. Y. Kondratyuk, L. Lőkös, E. Farkas, S.-H. Jang, D. Liu, J. Halda, P.-E. Persson, M. Hansson, I. Kärnefelt, A. Thell, Z. Fačkovcová, Y. Yamamoto and J.-S. Hur

The new for science genus Loekoeslaszloa S. Y. Kondr. et J.-S. Hur, confirmed by three gene phylogeny of the subfamily Teloschistoideae of the Teloschistaceae based on nrITS, nrLSU and mtSSU sequences, and ten new to science species from Eastern Asia, i.e. from South Korea: Bacidina loekoesiana S. Y. Kondr. et J.-S. Hur, Fauriea jejuensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Gyalecta ulleungdoensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Loekoeslaszloa huriana S. Y. Kondr., Orientophila dodongana S. Y. Kondr., L. Lőkös et J.-S. Hur, O. imjadoensis S. Y. Kondr., L. Lőkös et J.-S. Hur, O. incheonensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Oxneriopsis taehaensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Yoshimuria ivanpisutiana S. Y. Kondr., L. Lőkös et J.-S. Hur and Y. seokpoensis S. Y. Kondr., L. Lőkös et J.-S. Hur are described, illustrated and compared with closely related taxa.

Molecular data for the recently described species Flavoplaca laszloana are for the first time provided. Position of Tassiloa magellanica in the subfamily Teloschistoideae as well as Yoshimuria stipitata in the Ikaerioideae ad int. is for the first time illustrated.

An identification key to Fauriea species (including six species, i.e.: F. chujaensis, F. jejuensis, F. orientochinensis, F. patwolseleyae, F. tabidella and F. yonaguniensis), a key to Orientophila species of the Eastern Asian region (of the Orientophila loekoesii and the O. diffluens groups), and a key to Yoshimuria and Loekoeslaszloa species of the Eastern Asian region (including four species, i.e.: Y. galbina, Y. ivanpisutiana, Y. seokpoensis, and Y. spodoplaca, as well as Loekoeslaszloa geumohdoensis and L. huriana) are presented. Seven new combinations, i.e. Fauriea patwolseleyae (basionym: Caloplaca patwolseleyae S. Y. Kondr., U. Jayalal et J.-S. Hur), Fauriea tabidella (basionym: Lecanora tabidella Nyl.), Loekoeslaszloa geumohdoensis (basionym: Mikhtomia geumohdoensis S. Y. Kondr., D. Liu et Hur), Niesslia coarctatae (basionym: Stigmidium coarctatae S. Y. Kondr., L. Lőkös et J.-S. Hur), Opeltia epiphyta (basionym: Caloplaca epiphyta Lynge), Tassiloa magellanica (basionym: Caloplaca magellanica Søchting et Sancho) and Yoshimuria stipitata (basionym: Caloplaca stipitata Wetmore) are proposed. Yoshimuria galbina and Lecanora ussuriensis are for the first time recorded from Japan.

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Zoopsidella grahamii sp. nov., related to the Australasian Z. caledonica, is described from the Andes of Central Peru (Oxapampa Province) and southern Ecuador. It is distinguished from Z. caledonica by the smaller plant size, much lower number of lobe cells and different leaf shape, and by the much more elongate perianth mouth lobes consisting of a row of 6-7 narrowly rectangular cells. Riccardia gradsteinii sp. nov., from the same general area in Peru as Z. grahamii, is unique among all dendroid species of the genus by the broad, frilled wings of the main axis, being split into complicatedly bent and strongly crispate scales.

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Authors: T. Pócs, N.-K.-T. Tram, Q. He, T. Katagiri and T.-T. Luong

After the examination of the Cryptogam collection in the Herbarium of the University of Science, Vietnam National University Ho Chi Minh City (PHH), 25 species proved to be new to Vietnam, including one hornwort and 24 liverworts. Among them, four genera: Denotarisia Grolle, Gongylanthus Nees, Leiomitra Lindb. and Lepicolea Dumort. are new records for the country. Diagnostic characters and illustrations are given for some taxa, as well as locality notes and habitat descriptions are provided for each collecting area.

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