Changes in plant taxonomic and functional diversity patterns following treeline advances in the South Urals

Background: Treeline ecotones represent environmental boundaries that fluctuate in space and time and thus induce changes in plant taxonomic and functional diversity.

Aims: To study changes through time in taxonomic and functional plant diversity patterns along the treeline ecotone.

Methods: In 2002, vegetation was sampled along a gradient from upper montane forest to the treeline–alpine transition in the South Ural Mountains, Russia. In 2014, vegetation was resampled and plant functional traits were collected. We studied spatial and temporal changes in plant species composition, functional composition and functional diversity.

Results: Species composition and diversity changed along the elevational gradient. The functional composition in height, leaf area, specific leaf area and leaf nitrogen content decreased with elevation, whereas functional composition of leaf carbon content increased. We found a temporal shift towards shorter plants with smaller leaves in treeline sites. Functional richness varied in several traits along the elevational gradient, while functional dispersion showed a trend towards increased functional dispersion in height, specific leaf area and leaf nitrogen in the treeline–tundra transition.

Conclusions: Tree encroachment across the treeline ecotone has resulted in a shift in plant species relative abundances and functional diversity, possibly affecting plant community assembly patterns.     

Physiological,biochemical, and fluorescence parameters of senescing sugar beet leaves in the vegetative phase of growth

The phase of vegetative growth of sugar beet (Beta vulgaris L., single-sprout form) was conditionally subdivided into four periods according to leaf number and size (including already withered leaves): (A) 8 ± 1 weeks after seedling emergence (wase) (5–7 leaves); (B) 11 ± 1 wase (10–12 leaves); (C) 14 wase (13–15 leaves); (D) 15 wase (15–18 leaves). It took each next leaf about 1 week to come into view. In the course of leaf senescence, palisade parenchyma became less ordered; cells, vacuoles, and intercellular spaces expanded; leaf area and thickness increased. Chloroplasts became swollen, starch grains (and later osmiophilic globules) accumulated and degraded. In every growth period, the highest levels of soluble carbohydrates (sCH), chlorophyll (Chl (a + b)), soluble protein, and the highest activities of rubisco and soluble carboanhydrase usually preceded the full leaf expansion. In unfolded leaves at the growth period B, the maximum values of biochemical characteristics were as a rule higher than at the growth periods A and C and especially D. The only exception was Chl (a + b) with its peak level somewhat increased with plant age. Occurrence of peak values of individual characteristics depended on plant growth period. These characteristics started diminishing asynchronously, with a minimum in old operational leaves. Only the sCH content in the leaves at the periods C and D was stable. Changes in quantum yield at PSII and nonphotochemical fluorescence quenching reflected the age-associated differences in biochemical characteristics. The results are discussed in the light of the idea that leaf senescence is a normal stage of development directly related to the changes in source-sink relations. Biochemically, this stage comprises the degradation of temporarily stored products and partial utilization of the breakdown products for maintenance of the growth of newly formed leaves and root.     

Micropropagation of selected somaclones ofBegonia andSaintpaulia

Begonia x elatior plantlets which regenerated from leaf disk callus showed variations in plant morphology, number of flowers per plant, and flower size. Variations in flowering period, number of flowers per plant, and flower morphology were observed in Saintpaulia ionantha L. plants directly regenerated from leaf disk explants. The cytokinins, benzylaminopurine and zeatin, tested in the culture medium did not affect the basic plant characteristics including flower colour which remained stable in both species. Micropropagation of selected somaclones having the desirable trait of high number of flowers per plant was stable in the MV2 and MV3 generations.     

长叶红砂叶际细菌和真菌群落对季节变化的响应特征

【背景】植物叶际(phyllosphere)定殖着丰富多样的微生物,叶际微生物通过发挥特定功能在逆境下生存,影响寄主植物的生理生态特性并受环境异质性的影响。【目的】植物叶际微生物群落是动态的,认识季节更替对植物叶际微生物群落结构的影响,对于加深对植物-微生物-环境相互作用的理解具有积极意义。【方法】以鄂尔多斯荒漠草原泌盐盐生植物长叶红砂为研究对象,分别测定春季、秋季植物叶片表面理化特性,并结合叶际细菌、真菌高通量测序结果进行综合分析。【结果】长叶红砂冠下土壤含水率、pH、电导率等指标在季节更替下存在显著差异,叶片表面Na+、K+和电导率值存在显著差异;进一步分析发现,叶际细菌分类操作单元(operational taxonomic unit,OTU)、Shannon、Chao1和ACE (abundance-based coverage estimator)指数与土壤和叶片表面盐分含量呈正相关;春季叶际蓝细菌门和拟杆菌门保持了较高的相对丰度,而秋季叶际变形菌门、放线菌门、子囊菌门的相对丰度则高于春季;其中,叶际Bradyrhizobium、Novosphingobium和Edaphob...     

拮抗菌群对烟草野火病的防治效果及叶际微生物群落多样性的影响

【背景】烟草野火病(Tobacco Wild Fire)是烟草上的主要病害之一,利用拮抗菌防治烟草野火病是具有较好前景的防治手段。【目的】分析烟草叶际微生物群落结构组成和多样性,阐释拮抗菌群施用对烟草野火病的防治效果及对叶际微生物群落的影响。【方法】在烟草上施用3种拮抗菌群,采用16Sr RNA基因高通量测序及生物信息学手段,分析拮抗菌群对烟草叶际微生物群落结构组成和多样性的影响,研究拮抗菌群在叶片上的定殖。【结果】拮抗菌群对烟草野火病的防治效果达到50.44%-68.58%。与对照相比,3种拮抗菌群处理叶际微生物群落结构和组成都产生了明显的变化,群落多样性显著增高。拮抗菌群处理后,烟草叶际微生物泛菌(Pantoea)、寡养单胞菌(Stenotrophomonas)和假单胞菌(Pseudomonas)等菌属所占比例发生显著变化,其中芽孢杆菌属(Bacillus)和寡养单胞菌属相比对照增加分别达到3.9倍和7.02倍,其丰度与病情指数显著负相关。【结论】拮抗菌群对烟草野火病有较好的防治效果,施用拮抗菌群显著影响叶际微生物群落的组成和多样性,假单孢杆菌和寡养单胞菌等优势菌属能够在烟草叶际定殖,起到防治烟草野火病的作用。     

Male Blue Tits Cyanistes caeruleus choose early-leafing tree species during spring dawn chorus

Capsule Blue Tits sang their dawn song in trees that provided greater concealment.

Aims To determine if dawn singing Blue Tits select trees that increase their concealment.

Methods We compared the timing of leaf growth initiation in Blue Tit song-post trees to the average timing of leaf growth initiation for other tree species within 25 m of the song-post.

Results Most Blue Tits (96%, n = 23) sang from tree species that begin leaf growth earlier than the average tree available within 25 m. If males singing in Hawthorns Crataegus monogyna were excluded, 92% (n = 13) sang from earlier leafing trees.

Conclusion Dawn singing Blue Tits select perches that offer greater concealment.     

Regeneration from the Leaf of Atrichum undulatum (Hedw.) P. Beauv.

Abstract

Regeneration of new plants from the leaves of Atrichum undulatum will take place after 6 weeks if they are placed with the abaxial surface in contact with damp filter-paper in a saturated atmosphere.

The new plants arise from the surface cells of the midrib area of the leaf where there is a discontinuity of the photosynthetic filaments. This occurs mainly in the distal third of the leaf.

As the leaf ages it loses it capacity for regeneration. There are two regeneration processes, one which occurs when the leaf is separated from the stem and the only wound is at the point of attachment to the stem, and the second when other wounds are inflicted on the leaf. Regeneration due to wounding is greatest in the distal half of the leaf, mutilations near the base of the leaf having less effect on the percentage of regenerated plants.

There seems to be a potential for regeneration (both normal and as a result of wounding) which is greatest in the distal third of the leaf and decreases towards the base of the leaf of A. undulatum. This is compared with the leaf of Physcomitrium turbinatum, and the greater complexity of the process in the former is considered to be the result of greater differentiation of the leaf.     

Three propaguliferous species of Pohlia (Mielichhoferiaceae,Musci) in China

Abstract

As a result of a literature survey and examination of specimens, we believe that the identification of three species of propaguliferous Pohlia in China, Pohlia flexuosa, Pohlia proligera, and Pohlia leucostoma needs to be clarified. Pohlia flexuosa has two differing types of propagule: one short and oblong and the other long and thread-like; both propagules have inconspicuous leaf primordia, and can occur on the same stem. Propagules of P. proligera are shortly clavate to long vermicular, with one to three unicellular or multicellular prong-like leaf primordia arising at the apex of the propagule, and the leaf primordia are approximately one-fourth of the total length of the propagules. Pohlia leucostoma has long filiform propagules, with two or three short peg-like leaf primordia about one-tenth of total propagule length.     

烤后不同霉变程度烟叶际真菌群落组成与多样性分析

【目的】为了解烤后不同霉变程度烟叶真菌群落组成与多样性。【方法】基于IlluminaMiSeq高通量测序平台对烤后烟叶叶柄和叶片叶际样品的真菌群落组成进行了分析。【结果】霉变重烟叶叶片(BQ)、霉变重烟叶叶柄(BZ)、霉变轻烟叶叶片(JQ)、霉变轻烟叶叶柄(JZ) 4类样品真菌分布于子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、接合菌门(Zygomycota)等7个菌门、27个纲、58个目、104个科、171个属的360个真菌分类单元(OTUs)。不同霉变程度烟叶叶际真菌群落组成、分类单元的相对丰度及优势分类单元皆存在不同程度差异。在属的水平上,霉变重烟叶叶片(BQ)的优势菌属为Aspergillus (89.64%)、Myrothecium (2.54%)、Rhodotorula (2.48%)、Gibberella (1.49%);霉变重烟叶叶柄(BZ)的优势菌属为Aspergillus(96.93%)和Alternaria(1.92%);霉变轻烟叶叶片(JQ)的优势菌属为Aspergillus(40.13%)、Rhodotorula(31.81%)、Alternaria(16.75%);霉变轻烟叶叶柄(JZ)的优势菌属为Aspergillus (62.77%)、Alternaria (9.74%)、Rhodotorula (5.20%)。【结论】霉变轻烟叶叶片样品真菌群落的多样性最高,霉变轻烟叶叶柄的真菌群落丰富度最高。霉变重烟叶样品的叶片部位的真菌群落丰富度和多样性均高于叶柄。烟叶霉烂为烤房常见病害,其病原真菌种类多样,且广泛分布于烟叶和环境中。该研究结果为烤房烟叶霉烂病的防治可根据不同发病程度的不同部位的真菌群落构成特征,制定相应的防治方案提供了参考依据。     

Characterization of a dominant mutation for the liguleless trait: Aegilops tauschii liguleless (Lgt)

Background

Leaves of Poaceae have a unique morphological feature: they consist of a proximal sheath and a distal blade separated by a ligular region. The sheath provides structural support and protects young developing leaves, whereas the main function of the blade is photosynthesis. The auricles allow the blade to tilt back for optimal photosynthesis and determine the angle of a leaf, whereas the ligule protects the stem from the entry of water, microorganisms, and pests. Liguleless variants have an upright leaf blade that wraps around the culm. Research on liguleless mutants of maize and other cereals has led to identification of genes that are involved in leaf patterning and differentiation.

Results

We characterized an induced liguleless mutant (LM) of Aegilops tauschii Coss., a donor of genome D of bread wheat Triticum aestivum L.. The liguleless phenotype of LM is under dominant monogenic control (Lg^t). To determine precise position of Lg^t on the Ae. tauschii genetic map, highly saturated genetic maps were constructed containing 887 single-nucleotide polymorphism (SNP) markers derived via diversity arrays technology (DArT)seq. The Lg^t gene was mapped to chromosome 5DS. Taking into account coordinates of the SNP markers, flanking Lg^t, on the pseudomolecule 5D, a chromosomal region that contains this gene was determined, and a list of candidate genes was identified. Morphological features of the LM phenotype suggest that Lg^t participates in the control of leaf development, mainly, in leaf proximal–distal patterning, and its dominant mutation causes abnormal ligular region but does not affect reproductive development.

Conclusions

Here we report characterization of a liguleless Ae. tauschii mutant, whose phenotype is under control of a dominant mutation of Lg^t. The dominant mode of inheritance of the liguleless trait in a Triticeae species is reported for the first time. The position of the Lg^t locus on chromosome 5DS allowed us to identify a list of candidate genes. This list does not contain Ae. tauschii orthologs of any well-characterized cereal genes whose mutations cause liguleless phenotypes. Thus, the characterized Lg^t mutant represents a new model for further investigation of plant leaf patterning and differentiation.

     

Leaf morphological analyses in four European oak species (Quercus) and their hybrids: A comparison of traditional and geometric morphometric methods

Abstract

In this study, leaf morphology was assessed in a mixed oak stand (western France) using two geometric morphometric (landmark and outline) datasets and one dataset of 19 leaf measures. Adult oaks (817 oaks), comprising four white oak species (Quercus petraea, Q. robur, Q. pubescens and Q. pyrenaica), were sampled for DNA extraction and genetic analysis (nuclear microsatellites). Leaf morphology was assessed on 336 oaks, comprising pure species and hybrids as determined by genetic assignment. This comparative study of oak leaf morphology, based on the use of two free size geometric morphometric methods and a set of leaf measurements, combined with the genetic assignment of individuals to pure species or hybrids, provided information about the differences among species and the intermediate leaf morphology of their hybrids.     

Control of storage rot of cassava tuber caused by Rhizopus oryzae using some plant extracts

Abstract

The potency of Piper nigrum seed and leaf, Aframomum meleguata seed and Ageratum conyzoides leaf extracts in the control of cassava tuber rot caused by Rhizopus oryzae was investigated. Water, ethanol and petroleum ether were used as extracting solvents. These extracts were fungitoxic both in vitro and in vivo against the test pathogen. P. nigrum seed extracts were the best followed by those of A. meleguata seed, A. conyzoides leaf and then P. nigrum leaf. The extracts were more effective in controlling rot development in unwounded than wounded tubers especially when they were applied before inoculation with the test pathogen. Ethanol extracts gave the highest growth inhibition in vivo followed by water and the petroleum ether extract whereas water extracts showed marked superiority over the extracting solvents in checking rot development in cassava tuber. Water and ethanol extracts of P. nigrum seed and leaf, A. meleguata seed and A. conyzoides leaf could be used as pesticide of plant origin in the control of R. oryzae causing cassava tuber rot in storage.     

Altitudinal variation in leaf mass per unit area,leaf tissue density and foliar nitrogen and phosphorus content along an Amazon-Andes gradient in Peru

Background: Leaf traits are important in determining the capacity for a plant to acquire carbon, but few data are available for montane cloud forests in the Andes.

Aims: To investigate the changes in leaf traits along a large altitudinal transect (220–3600 m) from lowland to montane cloud forest in Peru.

Methods: We determined leaf mass per area (LMA, g m^?2), leaf tissue density (L _d, g cm^?3), and foliar nitrogen (N) and phosphorus (P) content, both on a mass (N _m and P _m, %) and area (N _a and P _a, g m^?2) basis for the most abundant species locally.

Results: LMA increased with altitude (62.8–169.4 g m^?2), though overall, LMA was lower than in comparable tropical elevation gradients. N _m declined significantly with altitude (2.39–1.25 %, P < 0.05), but N _m contents were higher than in comparable studies. The relatively high N _m and low LMA values are consistent with published global leaf trait datasets. No altitudinal trend for P _m was found; rather, our data highlighted the spatial variability in P _m (and P _a) within and among sites at different elevations. Foliar N:P ratios did not show a trend with altitude and did not indicate N limitation except at 3000 m altitude.

Conclusions: Though leaf traits showed altitudinal trends similar to other studies, contrary to the general hypothesis, our data suggest that the tropical montane forests presented here are not N limited.     

Acaulon eremicola,a new moss from the Australian arid zone

Abstract

A new species, Acaulon eremicola is described from aridcentral Australia. It differs from A. muticum and A. integrifolium in the leaf with longer cells and longer usually downwardly curved acuminate apex with twisted arista, the strongly incurled leaf margins when dry, and different spore pattern.     

A comparison of Dichodontium flavescens (Dicks.) Lindb. and D. pellucidum (Hedw.) Lindb. (Bryopsida)

Abstract

Fifty-three herbarium samples of the genus Dichodontium, originating from 15 countries in Europe and North America, were examined to critically assess new distinguishing characters between D. flavescens and D. pellucidum. The examination, including SEM, revealed some new characteristics in the gametophyte, notably leaf shape, leaf length: width ratio, and width of the nerve, permitting accurate determinations even on sterile material. D. flavescens is recognized here as a distinct species.     

Effects of pH and bicarbonate on the nutrient status and growth of three Lupinus species

Aims

High pH, and high bicarbonate (HCO₃⁻) and calcium (Ca) availability characterise calcareous soils. High [Ca] only partially explains why some Lupinus species are calcifuge, so we explored high [HCO₃⁻] and high pH.

Methods

We grew six Lupinus genotypes in hydroponics with pH 5, 6.5 and 8^a (adjusted by KOH), and 8^b (adjusted by KHCO₃). Leaf symptoms and areas, root appearance and biomass were recorded; whole leaf and root nutrient concentrations, and leaf cellular phosphorus (P), Ca and potassium (K) concentrations were determined using elemental X-ray microanalysis.

Results

Chlorosis was observed in young leaves at high pH for L. angustifolius and L. cosentinii, and P deficiency at high pH for all genotypes. High pH decreased iron (Fe) and zinc (Zn) uptake in all genotypes. It also decreased lateral root growth, the uptake of P, K, Ca, and manganese (Mn) by all sensitive species; and translocation of P, Fe, Zn, Mn, and Ca to leaves in most sensitive species. However, leaf [Ca], leaf [K], [K] within each measured cell type, and translocation of K and Ca to leaves of L. pilosus and L. cosentinii at pH 8 were greater than at pH 5 and 6.5. Compared with pH 8^a, all L. angustifolius genotypes translocated more P, Fe, Zn, Mn and K from roots to leaves at pH 8^b. High pH did not affect the leaf cell types that accumulated P and Ca, but decreased the leaf cellular [P].

Conclusions

Lupinus angustifolius and L. cosentinii were sensitive to high [HCO₃⁻] and/or high pH; L. pilosus was relatively tolerant. High pH decreased lateral root growth and nutrient uptake, inhibiting growth of sensitive species. High [HCO₃⁻] diminished the negative effect of pH 8 on nutrient translocation to leaves in most L. angustifolius genotypes. This knowledge provides critical insights into the habits of Lupinus species to guide breeding of calcicole plants.

     

Leaf yield loss assessment due to Macrophomina root rot disease in mulberry gardens of south India

Abstract

Leaf yield loss in mulberry due to Macrophomina root rot disease was assessed in three different states of south India at field level. The highest leaf yield loss recorded was in V-1 variety (34.74%), whereas the lowest leaf yield loss was in K-2 variety (28.54%). However, the leaf yields losses in other varieties viz., MR-2 (32.90%), S-36 (32.06%), RFS-175 (31.75%) and S-13 (29.0%) recorded were medium. The average leaf yield loss was 31.49% due to root rot disease caused by M. phaseolina in mulberry.     

An Outline of the Bryophytes of County Laois (Queen's County)

Abstract

Scapania lingulata is reported from five vice-counties in Scotland and from one in Ireland, two gatherings bearing ♂ shoots and one with perianths. It differs from S. scandica in its larger gemmae, from S. praetervisa in its broadly rounded postical leaf lobes, and from both species in its larger leaf cells, more numerous oil bodies and polyploid chromosome complement. Usually it grows on base-deficient earthy banks but also on base-rich rock ledges.     

Revision of <Emphasis Type="Italic">Heterosavia</Emphasis>, stat. nov., with notes on <Emphasis Type="Italic">Gonatogyne</Emphasis> and <Emphasis Type="Italic">Savia</Emphasis> (Phyllanthaceae)

Heterosavia (Phyllanthaceae) is segregated from Savia (tribe Bridelieae), recognized at generic rank, and placed in tribe Phyllantheae. Floral, fruit, leaf anatomical, leaf venation, and pollen characters of the neotropical taxa previously united as Savia including Gonatogyne are discussed and illustrated. Keys to the three genera and to the species of Heterosavia are presented. Four species (all new combinations), Heterosavia bahamensis, H. erythroxyloides, H. laurifolia, and H. maculata, are recognized. The new combinations Heterosavia laurifolia var. intermedia and H. maculata var. clementis are proposed. The names Heterosavia, H. erythroxyloides, H. laurifolia, Savia clementis, S. clusiifolia, S. clusiifolia var. fallax, and S. longipes are lectotypified. Distribution maps and conservation assessments (IUCN ratings) of Heterosavia species and varieties are provided.