Plants

17 pages, 3034 KiB

Open AccessArticle

Developmental Biology and Induction of Phi Thickenings by Abiotic Stress in Roots of the Brassicaceae

by Maketalena Aleamotu’a, Yu-Ting Tai, David W. McCurdy and David A. Collings

Plants 2018, 7(2), 47; https://doi.org/10.3390/plants7020047 - 19 Jun 2018

Cited by 7 | Viewed by 4326

Phi thickenings are specialized bands of secondary wall deposited around radial walls of root cortical cells. These structures have been reported in various species from the Brassicaceae, including Brassica oleracea, where previous reports using hydroponics indicated that they can be induced by [...] Read more.

Phi thickenings are specialized bands of secondary wall deposited around radial walls of root cortical cells. These structures have been reported in various species from the Brassicaceae, including Brassica oleracea, where previous reports using hydroponics indicated that they can be induced by exposure to salt. Using roots grown on agar plates, we show that both salt and sucrose can induce the formation of phi thickenings in a diverse range of species within the Brassicaceae. Within the genus Brassica, both B. oleracea and B. napus demonstrated the formation of phi thickenings, but in a strongly cultivar-specific manner. Confocal microscopy of phi thickenings showed that they form a complex network of reinforcement surrounding the inner root cortex, and that a delicate, reticulate network of secondary wall deposition can also variously form on the inner face of the cortical cell layer with phi thickenings adjacent to the endodermal layer. Results presented here indicate that phi thickenings can be induced in response to salt and water stress and that wide variation occurs in these responses even within the same species. Full article

(This article belongs to the Special Issue Plant Cell Wall Dynamics in Plant Growth and Stress Response)

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14 pages, 2150 KiB

Open AccessArticle

Characterization of the Genetic Diversity of Acid Lime (Citrus aurantifolia (Christm.) Swingle) Cultivars of Eastern Nepal Using Inter-Simple Sequence Repeat Markers

by Nabin Narayan Munankarmi, Neesha Rana, Tribikram Bhattarai, Ram Lal Shrestha, Bal Krishna Joshi, Bikash Baral and Sangita Shrestha

Plants 2018, 7(2), 46; https://doi.org/10.3390/plants7020046 - 12 Jun 2018

Cited by 13 | Viewed by 6040

Abstract

Acid lime (Citrus aurantifolia (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases, [...] Read more.

Acid lime (Citrus aurantifolia (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases, and pests, as well as poor management practices might have contributed to its extremely reduced productivity, which necessitates a reliable understanding of genetic diversity in existing cultivars. Hereby, we aim to characterize the genetic diversity of acid lime cultivars cultivated at three different agro-ecological gradients of eastern Nepal, employing PCR-based inter-simple sequence repeat (ISSR) markers. Altogether, 21 polymorphic ISSR markers were used to assess the genetic diversity in 60 acid lime cultivars sampled from different geographical locations. Analysis of binary data matrix was performed on the basis of bands obtained, and principal coordinate analysis and phenogram construction were performed using different computer algorithms. ISSR profiling yielded 234 amplicons, of which 87.18% were polymorphic. The number of amplified fragments ranged from 7–18, with amplicon size ranging from ca. 250–3200 bp. The Numerical Taxonomy and Multivariate System (NTSYS)-based cluster analysis using the unweighted pair group method of arithmetic averages (UPGMA) algorithm and Dice similarity coefficient separated 60 cultivars into two major and three minor clusters. Genetic diversity analysis using Popgene ver. 1.32 revealed the highest percentage of polymorphic bands (PPB), Nei’s genetic diversity (H), and Shannon’s information index (I) for the Terai zone (PPB = 69.66%; H = 0.215; I = 0.325), and the lowest of all three for the high hill zone (PPB = 55.13%; H = 0.173; I = 0.262). Thus, our data indicate that the ISSR marker has been successfully employed for evaluating the genetic diversity of Nepalese acid lime cultivars and has furnished valuable information on intrinsic genetic diversity and the relationship between cultivars that might be useful in acid lime breeding and conservation programs in Nepal. Full article

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22 pages, 868 KiB

Open AccessReview

The Effects of Foliar Sprays with Different Silicon Compounds

by Henk-Maarten Laane

Plants 2018, 7(2), 45; https://doi.org/10.3390/plants7020045 - 07 Jun 2018

Cited by 141 | Viewed by 16488

Abstract

The use of foliar sprays with silicon compounds is relatively new. Initially (in 1990) foliar sprays with silicates were used. In 2003, foliar sprays with (stabilized) silicic acid were introduced, and more recently foliar sprays with silica nanoparticles have also been applied. Foliar [...] Read more.

The use of foliar sprays with silicon compounds is relatively new. Initially (in 1990) foliar sprays with silicates were used. In 2003, foliar sprays with (stabilized) silicic acid were introduced, and more recently foliar sprays with silica nanoparticles have also been applied. Foliar sprays with silicates are effective as pesticides, while (stabilized) silicic acid sprays increase growth and yield and decrease biotic and abiotic stresses. The limited data on foliar silica-nano sprays show a tendency to decrease biotic stress and to stimulate a limited increase in growth and yield. Full article

(This article belongs to the Special Issue Practical Use of Si to Influence Plant Production)

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12 pages, 2054 KiB

Open AccessArticle

Biological Activity of the Salvia officinalis L. (Lamiaceae) Essential Oil on Varroa destructor Infested Honeybees

by Leila Bendifallah, Rachida Belguendouz, Latifa Hamoudi and Karim Arab

Plants 2018, 7(2), 44; https://doi.org/10.3390/plants7020044 - 06 Jun 2018

Cited by 18 | Viewed by 6660

Abstract

The present work is conducted as part of the development and the valorization of bioactive natural substances from Algerian medicinal and aromatic spontaneous plants, a clean alternative method in biological control. For this purpose, the bio-acaricidal activity of Salvia officinalis (sage)essential oil (EO)was [...] Read more.

The present work is conducted as part of the development and the valorization of bioactive natural substances from Algerian medicinal and aromatic spontaneous plants, a clean alternative method in biological control. For this purpose, the bio-acaricidal activity of Salvia officinalis (sage)essential oil (EO)was evaluated against the Varroa destructor, a major threat to the honey bee Apis mellifera ssp. intermissa. The aerial parts of S. officinalis L., 1753 were collected from the Chrea mountainous area in Northern Algeria. They were subjected to hydro distillation by a Clevenger apparatus type to obtain the EO, and screened for bio-acaricidal activity against Varroa destructor by the method of strips impregnated with the mixture EO and twin according to three doses. Pre-treatment results revealed infestation rates in the experimental site ranging from 3.76% to 21.22%. This showed the heterogeneity of infestations in hives according to the density of bees. This constituted a difficulty in monitoring the population dynamics of this parasite. After treatment, a difference in the acaricidal effect of Sage essential oil is noticed. It gives a mortality rate of 6.09% by the dose D1: 5%, 2.32% by the dose D2: 15%, and a low mortality rate of 0.9% by the dose D3: 20%. The chemical treatment carried out by Bayvarol gives a result close to that of the essential oil of Sage (9.97%).These results point to the fact that Sage essential oil treatments have a significant effect and good biological activity with regard to harmful species. Full article

(This article belongs to the Special Issue Lamiaceae Species: Biology, Ecology and Practical Uses)

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21 pages, 6168 KiB

Open AccessArticle

DNA Barcoding to Confirm the Morphological Identification of the Coral Trees (Erythrina spp., Fabaceae) in the Ancient Gardens of Naples (Campania, Italy)

by Adriana De Luca, Giancarlo Sibilio, Paolo De Luca and Emanuele Del Guacchio

Plants 2018, 7(2), 43; https://doi.org/10.3390/plants7020043 - 06 Jun 2018

Cited by 7 | Viewed by 12995

Abstract

The coral trees (genus Erythrina) have been fostering great interest among the botanists and gardeners of Naples, since their arrival in Europe in the second half of the 18th century. Numerous species were present in the royal and private botanical gardens of [...] Read more.

The coral trees (genus Erythrina) have been fostering great interest among the botanists and gardeners of Naples, since their arrival in Europe in the second half of the 18th century. Numerous species were present in the royal and private botanical gardens of the region, but their number has decreased today. The purpose of this work was to verify which species occur nowadays in the public areas of Naples and associate them with the historical information about their introduction. The identification was carried out also by molecular methods, by means of sequencing nuclear and chloroplast DNA markers. The comparison of the sequences obtained for the specimens present in Naples with those present in the literature, together with a morphological examination, allowed us to identify with accuracy the species anciently introduced or nowadays cultivated in Naples. Full article

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17 pages, 1759 KiB

Open AccessReview

Exploring the Role of Cell Wall-Related Genes and Polysaccharides during Plant Development

by Matthew R. Tucker, Haoyu Lou, Matthew K. Aubert, Laura G. Wilkinson, Alan Little, Kelly Houston, Sara C. Pinto and Neil J. Shirley

Plants 2018, 7(2), 42; https://doi.org/10.3390/plants7020042 - 31 May 2018

Cited by 49 | Viewed by 8036

Abstract

The majority of organs in plants are not established until after germination, when pluripotent stem cells in the growing apices give rise to daughter cells that proliferate and subsequently differentiate into new tissues and organ primordia. This remarkable capacity is not only restricted [...] Read more.

The majority of organs in plants are not established until after germination, when pluripotent stem cells in the growing apices give rise to daughter cells that proliferate and subsequently differentiate into new tissues and organ primordia. This remarkable capacity is not only restricted to the meristem, since maturing cells in many organs can also rapidly alter their identity depending on the cues they receive. One general feature of plant cell differentiation is a change in cell wall composition at the cell surface. Historically, this has been viewed as a downstream response to primary cues controlling differentiation, but a closer inspection of the wall suggests that it may play a much more active role. Specific polymers within the wall can act as substrates for modifications that impact receptor binding, signal mobility, and cell flexibility. Therefore, far from being a static barrier, the cell wall and its constituent polysaccharides can dictate signal transmission and perception, and directly contribute to a cell’s capacity to differentiate. In this review, we re-visit the role of plant cell wall-related genes and polysaccharides during various stages of development, with a particular focus on how changes in cell wall machinery accompany the exit of cells from the stem cell niche. Full article

(This article belongs to the Special Issue Plant Cell Wall Dynamics in Plant Growth and Stress Response)

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16 pages, 1097 KiB

Open AccessArticle

Silicon Influences Soil Availability and Accumulation of Mineral Nutrients in Various Plant Species

by Maria Greger, Tommy Landberg and Marek Vaculík

Plants 2018, 7(2), 41; https://doi.org/10.3390/plants7020041 - 19 May 2018

Cited by 167 | Viewed by 10330

Abstract

Silicon (Si) effects on mineral nutrient status in plants are not well investigated. It is known that Si has a beneficial effect on plants under stressed conditions. The aim was to make a state of the art investigation of the Si influence: (1) [...] Read more.

Silicon (Si) effects on mineral nutrient status in plants are not well investigated. It is known that Si has a beneficial effect on plants under stressed conditions. The aim was to make a state of the art investigation of the Si influence: (1) on nutrient availability in four different soil types, namely clayish, sandy, alum shale and submerged soil; and (2) on accumulation of various nutrients in maize, lettuce, pea, carrot and wheat growing in hydroponics. Soil was treated with K₂SiO₃ corresponding to 80 and 1000 kg Si ha⁻¹ and the nutrient medium with 100, 500, 1000 and 5000 μM Si. In general, Si effects were similar in all analyzed plant species and in all soil types tested. Results showed that, in soil, Si increased the availability of Ca, P, S, Mn, Zn, Cu and Mo and that of Cl and Fe tended to increase. The availability of K and Mg was not much affected by Si. Uptake from solution of S, Mg, Ca, B, Fe, and Mn increased; N, Cu, Zn and K decreased; P decreased/increased; and Cl and Mo was not influenced. Translocation to shoot of Mg, Ca, S, Mn, and Mo increased; Fe, Cu and Zn decreased; and K, P, N, Cl and B was not affected. It was concluded that, if plants had been cultivated in soil, Si-maintained increased availability of nutrients in the soil solution would probably compensate for the decrease in tissue concentration of those nutrient elements. The study shows that Si also influences the nutrient uptake in non-stressed plants. Full article

(This article belongs to the Special Issue Role of Silicon in Plants)

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18 pages, 580 KiB

Open AccessArticle

Allelopathic Responses of Rice Seedlings under Some Different Stresses

by Tran Dang Khanh, La Hoang Anh, La Tuan Nghia, Khuat Huu Trung, Pham Bich Hien, Do Minh Trung and Tran Dang Xuan

Plants 2018, 7(2), 40; https://doi.org/10.3390/plants7020040 - 08 May 2018

Cited by 14 | Viewed by 4951

Abstract

The objective of this study was to evaluate the allelopathic responses of rice seedlings under submergence stress at different temperatures (10, 25, 32, and 37 °C). The results showed that a wide range of allelopathic responses of rice seedlings depended on varieties and [...] Read more.

The objective of this study was to evaluate the allelopathic responses of rice seedlings under submergence stress at different temperatures (10, 25, 32, and 37 °C). The results showed that a wide range of allelopathic responses of rice seedlings depended on varieties and stress conditions, with temperature was being a key factor. It showed that the extracts of rice seedlings induced significant suppression on lettuce and radish seedling germination, but had negligible allelopathic effects on growth of barnyardgrass, whilst the emergence and growth of natural weeds was stimulated. In contrast, the root exudates of Koshihikari rice seedlings (K32) at 32 °C reduced the number of total weeds by ≈60.0% and the total dry weight of weeds by 93.0%; i.e., to a greater extent than other root exudates. Among the 13 identified phenolic acids, p-hydroxybenzoic, vanillic, syringic, sinapic and benzoic acids—at concentrations of 0.360, 0.045, 3.052, 1.309 and 5.543 μg/mL might be involved in allelopathic responses of K32, inhibiting the growth of barnyardgrass and natural weeds. Findings of the present study may provide useful information on allelopathic responses of rice under environmental stresses and thus further understand of the competitive relationships between rice and weeds under natural conditions. Full article

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14 pages, 1336 KiB

Open AccessArticle

Phenotypic and Physiological Evaluation of Two and Six Rows Barley under Different Environmental Conditions

by Mahmoud Naser, Mohamed Badran, Hanaa Abouzied, Heba Ali and Ibrahim Elbasyoni

Plants 2018, 7(2), 39; https://doi.org/10.3390/plants7020039 - 04 May 2018

Cited by 5 | Viewed by 4550

Abstract

In recent years, barley has attracted more interest as a food and feed source because of its high soluble dietary fiber and β-glucan content compared with other small grains. Twenty-five barley genotypes (20 imported genotypes and five check cultivars) were grown in three [...] Read more.

In recent years, barley has attracted more interest as a food and feed source because of its high soluble dietary fiber and β-glucan content compared with other small grains. Twenty-five barley genotypes (20 imported genotypes and five check cultivars) were grown in three environments for two successive seasons: 2015/2016 and 2016/2017. The first environment was in El-Nubaria, Alexandria, Egypt during 2015/2016, while the second and third environments were in El-Bostan, Elbhera, Egypt during 2015/2016 and 2016/2017. The experiments were conducted in a randomized complete block design with the three replicates. The primary objectives of the current study were to evaluate the performance of 20 imported barley genotypes under several environmental conditions. The imported materials were superior to the local commercial cultivars for several traits, including grain yield. Therefore, the superior genotypes will be further evaluated and used in barley breeding programs. Our future work will focus on creating several crosses among the selected superior genotypes to improve yield and other important traits, while applying marker-assisted selection. Full article

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11 pages, 2269 KiB

Open AccessCommunication

Examination of S-Locus Regulated Differential Expression in Primula vulgaris Floral Development

by Benjamin Burrows and Andrew McCubbin

Plants 2018, 7(2), 38; https://doi.org/10.3390/plants7020038 - 02 May 2018

Cited by 7 | Viewed by 4044

Abstract

Recent findings on the molecular basis of heteromorphic self-incompatibility in Primula have shown that the controlling self-incompatibility (S)-locus is not allelic, but is instead a small hemizygous region of only a few genes in the thrum genotype. How these genes alter [...] Read more.

Recent findings on the molecular basis of heteromorphic self-incompatibility in Primula have shown that the controlling self-incompatibility (S)-locus is not allelic, but is instead a small hemizygous region of only a few genes in the thrum genotype. How these genes alter the development of floral morphology and the specificity of self-incompatibility is still not completely clear. In order to start to identify genes regulated by the S-locus and elucidate the large-scale biological processes affected, we used RNA-seq data from floral buds of heteromorphic P. vulgaris pin (long style, short anthers) and thrum (short style, long anthers) morphs at early and late developmental time points. Differential expression between the two morphs was assessed at both time points and Gene Ontology term analyses of these gene sets were conducted. Our findings suggest that the S-locus regulates a large number of genes outside its physical bounds and likely sets up a cascade of expression changes. Additionally, we found evidence to suggest that there may be a timing difference in pollen development between the morphs, with pin pollen development proceeding earlier than thrum pollen development. This finding provides insight into how morphological differences in pollen between the morphs may be established, but intriguingly, could also be related to the self-incompatibility phenotype. Full article

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16 pages, 1777 KiB

Open AccessArticle

Assessment of Sulfur Deficiency under Field Conditions by Single Measurements of Sulfur, Chloride and Phosphorus in Mature Leaves

by Philippe Etienne, Elise Sorin, Anne Maillard, Karine Gallardo, Mustapha Arkoun, Jérôme Guerrand, Florence Cruz, Jean-Claude Yvin and Alain Ourry

Plants 2018, 7(2), 37; https://doi.org/10.3390/plants7020037 - 28 Apr 2018

Cited by 23 | Viewed by 4742

Abstract

Determination of S status is very important to detect S deficiency and prevent losses of yield and seed quality. The aim of this study was to investigate the possibility of using the ([Cl⁻]+[NO₃⁻]+[PO₄³⁻]):[SO₄²⁻ [...] Read more.

Determination of S status is very important to detect S deficiency and prevent losses of yield and seed quality. The aim of this study was to investigate the possibility of using the ([Cl⁻]+[NO₃⁻]+[PO₄³⁻]):[SO₄²⁻] ratio as an indicator of S nutrition under field conditions in Brassica napus and whether this could be applied to other species. Different S and nitrogen (N) fertilizations were applied on a S deficient field of oilseed rape to harvest mature leaves and analyze their anion and element contents in order to evaluate a new S nutrition indicator and useful threshold values. Large sets of commercial varieties were then used to test S deficiency scenarios. As main results, this study shown that, under field conditions, leaf ([Cl⁻]+[NO₃⁻]+[PO₄³⁻]):[SO₄²⁻] ratio was increased by lowering S fertilization, indicating S deficiency. The usefulness of this ratio was also found for other species grown under controlled conditions and it could be simplified by using the elemental ([Cl]+[P]):[S] ratio. Threshold values were determined and used for the clustering of commercial varieties within three groups: S deficient, at risk of S deficiency and S sufficient. The ([Cl]+[P]):[S] ratio quantified under field conditions, can be used as an early and accurate diagnostic tool to manage S fertilization. Full article

(This article belongs to the Special Issue Advances in Plant Sulfur Research)

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14 pages, 5122 KiB

Open AccessArticle

Treatment of Anaerobic Digester Effluent Using Acorus calamus: Effects on Plant Growth and Tissue Composition

by Tararag Pincam, Hans Brix and Arunothai Jampeetong

Plants 2018, 7(2), 36; https://doi.org/10.3390/plants7020036 - 20 Apr 2018

Cited by 7 | Viewed by 5163

Abstract

The responses of Acorus calamus under greenhouse conditions for 56 days when exposed to three dilutions (25%, 50%, and undiluted) of anaerobic digester effluent from a swine farm were determined. Plant growth, morphology, pigments, and minerals in plant tissues as well as water [...] Read more.

The responses of Acorus calamus under greenhouse conditions for 56 days when exposed to three dilutions (25%, 50%, and undiluted) of anaerobic digester effluent from a swine farm were determined. Plant growth, morphology, pigments, and minerals in plant tissues as well as water quality were investigated. The plants grew well in all concentrations of anaerobic digester effluent with no statistically significant effects on plant growth and morphology, and without any toxicity symptoms. The NH₄⁺ concentrations in leaves and roots and the NO₃⁻ concentrations in leaves as well as the nitrogen, phosphorus, and potassium concentrations in the plant tissues increased with increasing effluent concentration. The nutrients in the anaerobic digester effluent were removed effectively (NH₄-N > 99% removal; PO₄-P > 80% removal), with highest removal rates in the undiluted digester effluent. The removal of total suspended solids (>80% in 42 days) and chemical oxygen demand (37–53%) were lower. The dissolved oxygen concentration in the anaerobic digester effluent increased overtime, probably because of root oxygen release. It is concluded that Acorus calamus could be a promising species for treating high-strength wastewater with high nutrient concentrations, such as effluents from anaerobic digesters as well as other types of agricultural wastewaters. Full article

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50 pages, 27184 KiB

Open AccessArticle

Seed Dormancy Involves a Transcriptional Program That Supports Early Plastid Functionality during Imbibition

by Alberto Gianinetti, Franca Finocchiaro, Paolo Bagnaresi, Antonella Zechini, Primetta Faccioli, Luigi Cattivelli, Giampiero Valè and Chiara Biselli

Plants 2018, 7(2), 35; https://doi.org/10.3390/plants7020035 - 19 Apr 2018

Cited by 15 | Viewed by 6768

Abstract

Red rice fully dormant seeds do not germinate even under favorable germination conditions. In several species, including rice, seed dormancy can be removed by dry-afterripening (warm storage); thus, dormant and non-dormant seeds can be compared for the same genotype. A weedy (red) rice [...] Read more.

Red rice fully dormant seeds do not germinate even under favorable germination conditions. In several species, including rice, seed dormancy can be removed by dry-afterripening (warm storage); thus, dormant and non-dormant seeds can be compared for the same genotype. A weedy (red) rice genotype with strong dormancy was used for mRNA expression profiling, by RNA-Seq, of dormant and non-dormant dehulled caryopses (here addressed as seeds) at two temperatures (30 °C and 10 °C) and two durations of incubation in water (8 h and 8 days). Aim of the study was to highlight the differences in the transcriptome of dormant and non-dormant imbibed seeds. Transcript data suggested important differences between these seeds (at least, as inferred by expression-based metabolism reconstruction): dry-afterripening seems to impose a respiratory impairment onto non-dormant seeds, thus glycolysis is deduced to be preferentially directed to alcoholic fermentation in non-dormant seeds but to alanine production in dormant ones; phosphoenolpyruvate carboxykinase, pyruvate phosphate dikinase and alanine aminotransferase pathways appear to have an important gluconeogenetic role associated with the restoration of plastid functions in the dormant seed following imbibition; correspondingly, co-expression analysis pointed out a commitment to guarantee plastid functionality in dormant seeds. At 8 h of imbibition, as inferred by gene expression, dormant seeds appear to preferentially use carbon and nitrogen resources for biosynthetic processes in the plastid, including starch and proanthocyanidins accumulation. Chromatin modification appears to be a possible mechanism involved in the transition from dormancy to germination. Non-dormant seeds show higher expression of genes related to cell wall modification, suggesting they prepare for acrospire/radicle elongation. Full article

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11 pages, 20593 KiB

Open AccessCommunication

TUNEL Assay and DAPI Staining Revealed Few Alterations of Cellular Morphology in Naturally and Artificially Aged Seeds of Cultivated Flax

by Yong-Bi Fu, Zaheer Ahmed, Hui Yang and Carolee Horbach

Plants 2018, 7(2), 34; https://doi.org/10.3390/plants7020034 - 13 Apr 2018

Cited by 8 | Viewed by 12211

Abstract

In a search for useful seed aging signals as biomarkers for seed viability prediction, we conducted an experiment using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining to analyze morphological and molecular changes in naturally aged (NA) [...] Read more.

In a search for useful seed aging signals as biomarkers for seed viability prediction, we conducted an experiment using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining to analyze morphological and molecular changes in naturally aged (NA) and artificially aged (AA) flax (Linum usitatissimum L.) seeds. A total of 2546 sections were performed from 112 seeds of 12 NA and AA seed samples with variable germination rates. Analyzing 1384 micrographs generated from TUNEL assay and DAPI staining revealed few alterations of the cellular morphology of the NA and AA seeds. Also, the revealed DNA degradations in the aged flax seeds appeared to be associated with seed samples of low germination rates. These results suggest that oily flax seed aging may alter the cellular morphology differently than starchy wheat seed aging. The results also imply that the TUNEL assay and DAPI staining may not yield informative assessments on cellular alterations and DNA degradation after the aging of oily seeds. Full article

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11 pages, 9732 KiB

Open AccessReview

Silicon and Mechanisms of Plant Resistance to Insect Pests

by Fadi Alhousari and Maria Greger

Plants 2018, 7(2), 33; https://doi.org/10.3390/plants7020033 - 13 Apr 2018

Cited by 100 | Viewed by 17285

Abstract

This paper reviews the most recent progress in exploring silicon-mediated resistance to herbivorous insects and the mechanisms involved. The aim is to determine whether any mechanism seems more common than the others as well as whether the mechanisms are more pronounced in silicon-accumulating [...] Read more.

This paper reviews the most recent progress in exploring silicon-mediated resistance to herbivorous insects and the mechanisms involved. The aim is to determine whether any mechanism seems more common than the others as well as whether the mechanisms are more pronounced in silicon-accumulating than non-silicon-accumulating species or in monocots than eudicots. Two types of mechanisms counter insect pest attacks: physical or mechanical barriers and biochemical/molecular mechanisms (in which Si can upregulate and prime plant defence pathways against insects). Although most studies have examined high Si accumulators, both accumulators and non-accumulators of silicon as well as monocots and eudicots display similar Si defence mechanisms against insects. Full article

(This article belongs to the Special Issue Role of Silicon in Plants)

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22 pages, 6616 KiB

Open AccessArticle

Transcriptome and Metabolome Analyses Reveal That Nitrate Strongly Promotes Nitrogen and Carbon Metabolism in Soybean Roots, but Tends to Repress It in Nodules

by Shinji Ishikawa, Yuki Ono, Norikuni Ohtake, Kuni Sueyoshi, Sayuri Tanabata and Takuji Ohyama

Plants 2018, 7(2), 32; https://doi.org/10.3390/plants7020032 - 12 Apr 2018

Cited by 18 | Viewed by 5388

Abstract

Leguminous plants form root nodules with rhizobia that fix atmospheric dinitrogen (N₂) for the nitrogen (N) nutrient. Combined nitrogen sources, particular nitrate, severely repress nodule growth and nitrogen fixation activity in soybeans (Glycine max [L.] Merr.). A microarray-based transcriptome analysis [...] Read more.

Leguminous plants form root nodules with rhizobia that fix atmospheric dinitrogen (N₂) for the nitrogen (N) nutrient. Combined nitrogen sources, particular nitrate, severely repress nodule growth and nitrogen fixation activity in soybeans (Glycine max [L.] Merr.). A microarray-based transcriptome analysis and the metabolome analysis were carried out for the roots and nodules of hydroponically grown soybean plants treated with 5 mM of nitrate for 24 h and compared with control without nitrate. Gene expression ratios of nitrate vs. the control were highly enhanced for those probesets related to nitrate transport and assimilation and carbon metabolism in the roots, but much less so in the nodules, except for the nitrate transport and asparagine synthetase. From the metabolome analysis, the concentration ratios of metabolites for the nitrate treatment vs. the control indicated that most of the amino acids, phosphorous-compounds and organic acids in roots were increased about twofold in the roots, whereas in the nodules most of the concentrations of the amino acids, P-compounds and organic acids were decreased while asparagine increased exceptionally. These results may support the hypothesis that nitrate primarily promotes nitrogen and carbon metabolism in the roots, but mainly represses this metabolism in the nodules. Full article

(This article belongs to the Special Issue Advances in Plant Nitrogen Metabolism)

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9 pages, 1382 KiB

Open AccessArticle

Separation, Identification, and Antidiabetic Activity of Catechin Isolated from Arbutus unedo L. Plant Roots

by Hanae Naceiri Mrabti, Nidal Jaradat, Ismail Fichtali, Wessal Ouedrhiri, Shehdeh Jodeh, Samar Ayesh, Yahia Cherrah and My El Abbes Faouzi

Plants 2018, 7(2), 31; https://doi.org/10.3390/plants7020031 - 12 Apr 2018

Cited by 31 | Viewed by 5543

Abstract

Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used [...] Read more.

Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used widely in the traditional medicine as an antidiabetic agent. The current study aimed to isolate the pharmacologically active compound from A. unedo roots using accelerated solvent extraction technology, to determine its chemical structure using different instrumental analytical methods, and also to evaluate the α-glucosidase inhibitory activity. The roots of A. unedo were exhaustively extracted by high-pressure static extraction using the Zippertex^® technology (Dionex-ASE, Paris, France), and the extract was mixed with XAD-16 resin to reach quantifiable amounts of active compounds which were identified by high-pressure liquid chromatography (HPLC), ¹H NMR (300 MHz), and ¹³C NMR. The antidiabetic activity of the isolated compound was evaluated using the α-glucosidase inhibitory assay. The active compound was isolated, and its structure was identified as catechin using instrumental analysis.The results revealed that the isolated compound has potential α-glucosidase inhibitory activity with an IC₅₀ value of 87.55 ± 2.23 μg/mL greater than acarbose. This was used as a positive control, which has an IC₅₀ value of 199.53 ± 1.12 μg/mL. According to the results achieved, the roots of A. unedo were considered the best source of catechin and the Zippertex^® technology method of extraction is the best method for isolation of this therapeutic active compound. In addition, the α-glucosidase inhibitory activity results confirmed the traditional use of A. unedo roots as an antidiabetic agent. Future clinical trials and investigations of antidiabetic and other pharmacological effects such as anticancer are required. Full article

(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)

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3 pages, 194 KiB

Open AccessEditorial

Flavonoid Functions in Plants and Their Interactions with Other Organisms

by Ulrike Mathesius

Plants 2018, 7(2), 30; https://doi.org/10.3390/plants7020030 - 03 Apr 2018

Cited by 149 | Viewed by 9752

Abstract

Flavonoids are structurally diverse secondary metabolites in plants, with a multitude of functions. These span from functions in regulating plant development, pigmentation, and UV protection, to an array of roles in defence and signalling between plants and microorganisms. Because of their prevalence in [...] Read more.

Flavonoids are structurally diverse secondary metabolites in plants, with a multitude of functions. These span from functions in regulating plant development, pigmentation, and UV protection, to an array of roles in defence and signalling between plants and microorganisms. Because of their prevalence in the human diet, many flavonoids constitute important components of medicinal plants and are used in the control of inflammation and cancer prevention. Advances in the elucidation of flavonoid biosynthesis and its regulation have led to an increasing number of studies aimed at engineering the flavonoid pathway for enhancing nutritional value and plant defences against pathogens and herbivores, as well as modifying the feeding value of pastures. Many future opportunities await for the exploitation of this colourful pathway in crops, pastures, and medicinal plants. Full article

(This article belongs to the Special Issue Plant Flavonoids)

14 pages, 4763 KiB

Open AccessArticle

Effect of Silicon on the Tolerance of Wheat (Triticum aestivum L.) to Salt Stress at Different Growth Stages: Case Study for the Management of Irrigation Water

by Daoud A.M., Hemada M.M., Saber N., El-Araby A.A. and Moussa L.

Plants 2018, 7(2), 29; https://doi.org/10.3390/plants7020029 - 03 Apr 2018

Cited by 27 | Viewed by 5973

Abstract

This paper aims to determine the most tolerant growth stage(s) of wheat to salinity stress with the addition of silicon. The aim was to investigate whether saline water could be used instead of good quality water for irrigation without implicating a greater risk [...] Read more.

This paper aims to determine the most tolerant growth stage(s) of wheat to salinity stress with the addition of silicon. The aim was to investigate whether saline water could be used instead of good quality water for irrigation without implicating a greater risk to crop production. Local wheat cv. Gimmiza 11 was germinated and grown in sand cultures. Four different NaCl salinity levels were used as treatments: 0, 60, 90 and 120 mM. This was in the presence of 0 and 0.78 mM Si which added as sodium meta- silicate (Na₂SiO₃·9H₂O). Both the NaCl and Si treatments were carried out using a full strength nutrient solution that was adjusted at pH 6.0 and used for irrigation in four replications. The application of Si with the saline nutrient media significantly enhanced superoxide dismutase (SOD) and catalase (CAT) activities in plant leaves at the booting stage compared to the other stages. This was associated with a marked decline in the H₂O₂ content. At the booting stage, the Si treatment promoted CAT activity in 120 mM NaCl-stressed leaves compared to the leaves treated with only 120 mM NaCl solution. SOD showed greater prevalence at the booting stage when Si was added into the saline media, and it also revealed maximum activity at the milky stage with salinity stress. This was associated with a smaller reduction in shoot fresh and dry weights, greater reduction in the leaf Na⁺ content and an increase in the K⁺ content, which ultimately increased the cytosolic K⁺/Na⁺ ratio. Chlorophyll a and b and carotenoid (total photosynthetic pigments) were also higher at the booting stage of salt-stressed plants treated with Si compared to other stages. Accordingly, Si application enhanced the salt tolerance of wheat and reduced the inhibitory effect of Na⁺ and oxidative stress damage as growth proceeded towards maturity, particularly at the booting stage. This shows that saline water can be used for wheat irrigation at the booting stage (much water is consumed) when good quality water is not available for supplemental irrigation. A field study is needed to confirm the greenhouse results. Full article

(This article belongs to the Special Issue Role of Silicon in Plants)

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16 pages, 4339 KiB

Open AccessArticle

Effects of Drought on Nutrient Uptake and the Levels of Nutrient-Uptake Proteins in Roots of Drought-Sensitive and -Tolerant Grasses

by Deepesh R. Bista, Scott A. Heckathorn, Dileepa M. Jayawardena, Sasmita Mishra and Jennifer K. Boldt

Plants 2018, 7(2), 28; https://doi.org/10.3390/plants7020028 - 30 Mar 2018

Cited by 168 | Viewed by 10732

Abstract

Climate change will increase drought in many regions of the world. Besides decreasing productivity, drought also decreases the concentration (%) of nitrogen (N) and phosphorous (P) in plants. We investigated if decreases in nutrient status during drought are correlated with decreases in levels [...] Read more.

Climate change will increase drought in many regions of the world. Besides decreasing productivity, drought also decreases the concentration (%) of nitrogen (N) and phosphorous (P) in plants. We investigated if decreases in nutrient status during drought are correlated with decreases in levels of nutrient-uptake proteins in roots, which has not been quantified. Drought-sensitive (Hordeum vulgare, Zea mays) and -tolerant grasses (Andropogon gerardii) were harvested at mid and late drought, when we measured biomass, plant %N and P, root N- and P-uptake rates, and concentrations of major nutrient-uptake proteins in roots (NRT1 for NO₃, AMT1 for NH₄, and PHT1 for P). Drought reduced %N and P, indicating that it reduced nutrient acquisition more than growth. Decreases in P uptake with drought were correlated with decreases in both concentration and activity of P-uptake proteins, but decreases in N uptake were weakly correlated with levels of N-uptake proteins. Nutrient-uptake proteins per gram root decreased despite increases per gram total protein, because of the larger decreases in total protein per gram. Thus, drought-related decreases in nutrient concentration, especially %P, were likely caused, at least partly, by decreases in the concentration of root nutrient-uptake proteins in both drought-sensitive and -tolerant species. Full article

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19 pages, 35977 KiB

Open AccessArticle

Identification of Leaf Promoters for Use in Transgenic Wheat

by Saqer S. Alotaibi, Caroline A. Sparks, Martin A. J. Parry, Andrew J. Simkin and Christine A. Raines

Plants 2018, 7(2), 27; https://doi.org/10.3390/plants7020027 - 28 Mar 2018

Cited by 13 | Viewed by 7551

Abstract

Wheat yields have plateaued in recent years and given the growing global population there is a pressing need to develop higher yielding varieties to meet future demand. Genetic manipulation of photosynthesis in elite wheat varieties offers the opportunity to significantly increase yields. However, [...] Read more.

Wheat yields have plateaued in recent years and given the growing global population there is a pressing need to develop higher yielding varieties to meet future demand. Genetic manipulation of photosynthesis in elite wheat varieties offers the opportunity to significantly increase yields. However, the absence of a well-defined molecular tool-box of promoters to manipulate leaf processes in wheat hinders advancements in this area. Two promoters, one driving the expression of sedoheptulose-1,7-bisphosphatase (SBPase) and the other fructose-1,6-bisphosphate aldolase (FBPA) from Brachypodium distachyon were identified and cloned into a vector in front of the GUS reporter gene. Both promoters were shown to be functionally active in wheat in both transient assays and in stably transformed wheat plants. Analysis of the stable transformants of wheat (cv. Cadenza) showed that both promoters controlled gus expression throughout leaf development as well as in other green tissues. The availability of these promoters provides new tools for the expression of genes in transgenic wheat leaves and also paves the way for multigene manipulation of photosynthesis to improve yields. Full article

(This article belongs to the Special Issue Crop Enhancement for Global Food Security)

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13 pages, 9806 KiB

Open AccessArticle

Potential of Silicon Amendment for Improved Wheat Production

by Olga S. Walsh, Sanaz Shafian, Jordan R. McClintick-Chess, Kelli M. Belmont and Steven M. Blanscet

Plants 2018, 7(2), 26; https://doi.org/10.3390/plants7020026 - 28 Mar 2018

Cited by 22 | Viewed by 6833

Abstract

Many studies throughout the world have shown positive responses of various crops to silicon (Si) application in terms of plant health, nutrient uptake, yield, and quality. Although not considered an essential element for plant growth, Si has been recently recognized as a “beneficial [...] Read more.

Many studies throughout the world have shown positive responses of various crops to silicon (Si) application in terms of plant health, nutrient uptake, yield, and quality. Although not considered an essential element for plant growth, Si has been recently recognized as a “beneficial substance” or “quasi-essential” due to its important role in plant nutrition, especially notable under stressed conditions. The goal of this study was to evaluate the effect of Si on wheat plant height, grain yield (GY), and grain protein content (GP). The experiment was conducted during two consecutive growing seasons in Idaho. A split-plot experimental design was used with three Si fertilization rates (140, 280, and 560 kg Si ha⁻¹) corresponding to 100, 50, and 25% of manufacturer-recommended rates and two application times—at planting and tillering (Feekes 5). MontanaGrow^TM (0-0-5) by MontanaGrow Inc. (Bonner, MT, USA) used in this study is a Si product sourced from a high-energy amorphous (non-crystalized) volcanic tuff. There was no significant effect of Si rate and application time on plant height, nutrient uptake, GY, or GP of irrigated winter wheat grown in non-stressed conditions. These results could be directly related to the Si fertilizer source used in the study. We are planning to further evaluate Si’s effect on growth and grain production of wheat grown in non-stressed vs. stressed conditions utilizing several different Si sources and application methods. Full article

(This article belongs to the Special Issue Practical Use of Si to Influence Plant Production)

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30 pages, 1154 KiB

Open AccessReview

Qualitative and Quantitative Analysis of Polyphenols in Lamiaceae Plants—A Review

by Katerina Tzima, Nigel P. Brunton and Dilip K. Rai

Plants 2018, 7(2), 25; https://doi.org/10.3390/plants7020025 - 26 Mar 2018

Cited by 58 | Viewed by 9772

Abstract

Lamiaceae species are promising potential sources of natural antioxidants, owing to their high polyphenol content. In addition, increasing scientific and epidemiological evidence have associated consumption of foods rich in polyphenols with health benefits such as decreased risk of cardiovascular diseases mediated through anti-inflammatory [...] Read more.

Lamiaceae species are promising potential sources of natural antioxidants, owing to their high polyphenol content. In addition, increasing scientific and epidemiological evidence have associated consumption of foods rich in polyphenols with health benefits such as decreased risk of cardiovascular diseases mediated through anti-inflammatory effects. The complex and diverse nature of polyphenols and the huge variation in their levels in commonly consumed herbs make their analysis challenging. Innovative robust analytical tools are constantly developing to meet these challenges. In this review, we present advances in the state of the art for the identification and quantification of polyphenols in Lamiaceae species. Novel chromatographic techniques that have been employed in the past decades are discussed, ranging from ultra-high-pressure liquid chromatography to hyphenated spectroscopic methods, whereas performance characteristics such as selectivity and specificity are also summarized. Full article

(This article belongs to the Special Issue Lamiaceae Species: Biology, Ecology and Practical Uses)

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11 pages, 267 KiB

Open AccessArticle

Response of Weeping Lantana (Lantana montevidensis) to Compost-Based Growing Media and Electrical Conductivity Level in Soilless Culture: First Evidence

by Giuseppe Cristiano, Gjok Vuksani, Vincenzo Tufarelli and Barbara De Lucia

Plants 2018, 7(2), 24; https://doi.org/10.3390/plants7020024 - 22 Mar 2018

Cited by 5 | Viewed by 4084

Abstract

The most common substrate for potted ornamental plants is prepared with Sphagnum peat; however, the cost and declining availability of high-quality peat, due to environmental constraints, make it necessary to investigate for alternative organic materials. The present study aimed to determine the effects [...] Read more.

The most common substrate for potted ornamental plants is prepared with Sphagnum peat; however, the cost and declining availability of high-quality peat, due to environmental constraints, make it necessary to investigate for alternative organic materials. The present study aimed to determine the effects of partial compost replacement with peat and the optimum electrical conductivity (EC) level of the nutrient solution in potted weeping lantana [L. montevidensis (Spreng.) Briq.] under a recirculating soilless system. Three compost-based substrates were prepared by mixing peat (Pe) with sewage sludge-based compost (Co.) at a rate of 0% (Pe90Co0Pu10, control), 30% (Pe60Co30Pu10), or 60% (Pe30Co60Pu10), respectively. The soilless recirculated closed system was equipped with two different EC levels (high and low) of nutrient solution. Growing media main characteristics and plant bio-morphometric parameters were evaluated. Our first evidence clearly demonstrates that the replacement of peat with compost at doses of 30% and 60% gave the poorest results for plant diameter, shoots, leaves, flowers, and fresh and dry mass, probably indicating that the physical characteristics of the compost based substrates may be the major factor governing plant growth rate. Compost media pH and EC values, too, showed negative effects on plant growth. Considering the effect of EC level, all morphological traits were significantly improved by high EC compared to low EC in weeping lantana. Thus, based on first evidence, further research is needed on organic materials for the establishment of ecological substrates with optimal physicochemical characteristics for the growth of weeping lantana. Full article

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Plants, Volume 7, Issue 2 (June 2018) – 24 articles

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