Authors:Seyed Ahmad Shafiei Darabi; Abbas Almodares; Mansour Ebrahimi Abstract: Human exposure to arsenic has increased rapidly with the expansion of industrial activity and its toxicity raises concerns for public health. Arsenic remediation by plants is regarded as suitable avenue to a safer environment. Transporters facilitate remediation by transporting negative ions, but the contribution of cationic transporters to anionic remediation has not been fully studied. To determine which transporter is involved in anion and cation toxicity, the P1B ATPase gene family and arsenic and cadmium expression network relations were navigated using text mining software. The extracted pathways were tested and analyzed in silico and by gene expression detection. The results show that many putative pathways exist between arsenic and cadmium and P1B ATPases to stimulate expression or inhibition of this family. This study showed that arsenic stimulates expression of the P1B ATPase transporter through the abscisic acid signaling pathway. This cascade, as the end section of the arsenic stimulation pathway on P1B ATPase, was improved and investigated. The experimental results show that expression of P1B ATPase increased in response to arsenic exposure in Sorghum bicolor. The putative network contained abscisic acid- and glucose-related pathways for arsenic and ZIP8-related pathways for cadmium. PubDate: 2017-07-19 DOI: 10.1007/s11738-017-2472-z Issue No:Vol. 39, No. 8 (2017)
Authors:Shengyang Niu; Fengge Hao; Haizhen Mo; Jianfu Jiang; Chonghuai Liu; Hua Wang Abstract: The Chinese wild grapevine, Vitis davidii, is disease resistant, matures late, and is the only Vitis species with white-fruit type native to China, and is ideal for grape breeding programs. To uncover the molecular mechanisms responsible for the V. davidii white-fruit phenotype and the relationship between accessions with white and pigmented fruits, the SSR markers, DNA sequencing and qRT-PCR were used. We found a high coefficient of genetic similarity between the two phenotypes; 12 markers, in particular, revealed that the white-skinned V. davidii “Baiciputao” evolved from the pigmented “Hunanci”. The MybA1 gene sequence analysis results revealed that “Baiciputao” harbored only MybA1a at the MybA1 locus, and in “Hunanci”, both MybA1a and MybA1c alleles were detected. This was also linked to grape skin color of the control cultivars, which were Pinot blanc and Pinot noir, Muscat blanc and Muscat rouge. To verify our conclusions, the elementary composition of the anthocyanin profiles of V. davidii and V. vinifera were analyzed using high-performance liquid chromatography and electrospray ionization mass spectrometry (HPLC–ESI–MS/MS), revealing divergent chemical profiles. The main cyanidin derivative in V. davidii was 3-O-glucoside-5-O-glucoside, whereas it was 3-O-glucoside in V. vinifera. The qRT-PCR results indicated that the total anthocyanin content in V. davidii grape skins was not solely determined by UFGT or MYB-related expression levels. These data support the conclusion that the molecular mechanism leading to the white-skinned V. davidii phenotype is the MybA1 gene mutation. PubDate: 2017-07-18 DOI: 10.1007/s11738-017-2473-y Issue No:Vol. 39, No. 8 (2017)
Authors:Qingxu Ma; Jinzhao Ma; Yan Sun; Jianqiu Chen; Lianghuan Wu Abstract: Sucrose is crucial for plant growth, but research about the effect of sucrose on the uptake of different nitrogen (N) and the metabolism of glycine is lacking. The uptake of glycine by pakchoi, when it was in a mixture of glycine, nitrate, and ammonium or acted as the single N source under different sucrose levels were detected in a sterilized environment. The optimal sucrose level for pakchoi growth varied with N supply; it was 6 μM in the single N source of glycine, while it was 15 μM in the mixture. The N contribution of glycine increased under the optimal sucrose, while the N contribution of ammonium decreased. The effect of exogenously supplied sucrose on the uptake and metabolism of glycine is dependent on the N supply. With the single N source, the metabolism of glycine to serine in roots rather than uptake was the limiting step under a high sucrose level (300 μM). In the mixed nitrogen, active uptake and the metabolism of glycine to serine are the limiting steps under high sucrose level. Externally supplied sucrose affects the absorption and metabolism of glycine by pakchoi greatly, and this effect varied with nitrogen supply. PubDate: 2017-07-17 DOI: 10.1007/s11738-017-2459-9 Issue No:Vol. 39, No. 8 (2017)
Authors:Ting-ting Zheng; Zhi-ke Zhang; Muhammad Qasim Shahid; Wei-ling Wei; Faheem Shehzad Baloch; Jin-cheng Wu; Shun-quan Lin; Xiang-hui Yang Abstract: Loquat (Eriobotrya japonica Lindl.) cultivars can be classified as yellow- and white-fleshed based on fruit color. The pulps of yellow-fleshed cultivars appear yellow because of high contents of carotenoids, while the pulps of white-fleshed cultivars appear ivory white due to the lack of carotenoid accumulation. To elucidate the genes associated with the carotenoid accumulation, de novo assembly of the fruit transcriptome in three loquat cultivars having different pulp colors, including ‘Golden nugget’ (yellow pulp), ‘Jiefangzhong’ (yellow pulp), and ‘Baiyu’ (white pulp), at breaker stage, was conducted in this study. By RNA-seq, a total of 11.92 Gb clean data was obtained, and 51,934 unigenes were assembled and annotated. Based on BLAST search, 26,447 unigenes had a hit in at least one of the protein and nucleotide databases used in the present study. Swiss-Port annotation and Clusters of Orthologous Group were assigned for 16,679 and 13,986 unigenes, respectively. Moreover, Gene Ontology enrichment analysis classified 18,842 unigenes into 53 functional groups, which largely detected in biological process category, followed by cellular component category and molecular function category. We detected 3438 differentially expressed genes using Reads Per kb per Million reads method. Of these genes, six were identified as carotenoid accumulation-related genes. Our study revealed a certain relationship between carotenoid accumulation and expression patterns of carotenogenic genes. PubDate: 2017-07-14 DOI: 10.1007/s11738-017-2463-0 Issue No:Vol. 39, No. 8 (2017)
Authors:Gang Zhang; Biaobiao Sun; Zhen Li; Bao Di; Diying Xiang; Yu Meng Abstract: The present study evaluated the influence of delayed soil thawing on the growth and frost hardiness of Pinus sylvestris var. mongolica saplings between September 2011 and August 2012 in Northern China (41°35′N, 116°32′E). The saplings were randomly divided into three treatments: control, snow removal, and snow removal + insulation. The control saplings were grown under natural conditions. Snow cover was removed from the saplings in the snow removal treatment. For the snow removal + insulation treatment, snow cover was removed and soil surface was covered with a layer of hay (15 cm). The bud break, current-year shoot elongation and diameter as well as current-year needle elongation were measured and compared among the three treatments. The frost hardiness of previous-year stems and needles was assessed using the electrical impedance spectroscopy method. The saplings in the snow removal + insulation treatment exhibited delayed bud break, needle and shoot growth, as well as cessation of needle and shoot growth compared to the other treatments. In contrast, the growth of shoots and needles was generally higher in the snow removal treatment. A linear relationship was observed between plant growth, especially needle elongation, and temperature sum at soil depth of 20 cm. During dehardening, there were no differences in frost hardiness for both stems and needles among the treatments. In conclusion, snow removal + insulation delayed growth, whereas snow removal accelerated the growth. The frost hardiness of saplings during dehardening did not differ among treatments significantly. The possible reduction of snow cover and increase of soil freezing under warming climate would not have negative impacts on saplings in terms of frost hardiness during dehardening. Nevertheless, increased soil freezing would have unfavorable influences in terms of shoot and needle growth. PubDate: 2017-07-14 DOI: 10.1007/s11738-017-2470-1 Issue No:Vol. 39, No. 8 (2017)
Authors:Wenyuan Hao; Feiwu Li; Wei Yan; Congcong Li; Dongyun Hao Abstract: We compared metabolic changes in transgenic maize lines (differing in genetic backgrounds and exogenous genes insertion) with non-transgenic counterparts. At the corn seedling stage, entirely expanding leaves were obtained from maize lines 1 (transgenic maize SK12-5; overexpressing cry1Ab/cry2Aj; parental maize ZD958), 2 (transgenic maize IE034; overexpressing cry1Ie; parental maize ZD958), 3 (transgenic maize Bt799; overexpressing cry1Ac-M; parental maize Z58), 4 (transgenic maize Bt799; overexpressing cry1Ac-M; parental maize ZD958), 5 (non-transgenic maize Z58), and 6 (non-transgenic maize ZD958). For each line, six biological replicates were prepared; each contained an entirely expanded leaf at the top of the plant. Metabolites were identified with high-performance liquid chromatography mass spectrometry in three comparison groups (4 transgenic maize lines vs. their corresponding controls, line 3 vs. 4, and transgenic vs. non-transgenic maize). Top 200 cationic and top 200 anionic metabolites with higher variable importance in projection value were chosen for principal component analysis, followed by pathway enrichment analysis. Annotation was possible for 227 of 400 metabolites. Twelve up- and 26 down-regulated overlapping metabolites were identified in line 1 vs. 6, line 2 vs. 6, and line 4 vs. 6 comparison groups. Altered metabolites significantly enriched in purine and glutathione metabolism pathways, but no pathways were enriched in line 3 vs. 4. Comparing transgenic and non-transgenic maize lines revealed 59 up- and 37 down-regulated metabolites, which were also significantly enriched in purine and glutathione metabolism pathways. Therefore, transgenic Bt maize differed metabolically from non-transgenic maize. Additionally, purine and glutathione metabolism pathways may be important in the transgenic maize metabolism. PubDate: 2017-07-14 DOI: 10.1007/s11738-017-2468-8 Issue No:Vol. 39, No. 8 (2017)
Authors:M. Libik-Konieczny; M. Kozieradzka-Kiszkurno; Ż. Michalec-Warzecha; Z. Miszalski; J. Bizan; R. Konieczny Abstract: The enrichment with antioxidants (glutathione or ascorbate) or prooxidants (alloxan, methylviologen, hydrogen peroxide) of root inducing medium significantly decreased rhizogenesis frequency (alloxan, hydrogen peroxide) or inhibited roots regeneration (ascorbate, methylviologen) during the in vitro culture of Mesembryanthemum crystallinum L. hypocotyls. The adventitious roots morphology, root hairs length and density, was also influenced. Changes in the rhizogenesis course were related to the differences in hydrogen peroxide concentration during following days of culture between explants exhibiting morphogenic potential and those without the ability to form adventitious roots. In explants with morphogenic potential, rhizogenesis induction was always accompanied by a high level of hydrogen peroxide followed by the decrease in H2O2 content in following days. In contrast, in the explants without regeneration potential, the level of hydrogen peroxide was increasing during the culture period. Activity patterns of superoxide dismutase (SOD) and guaiacol peroxidase (POX) in the following days of culture were similar in the explants exhibiting regeneration potential cultured on different media. Total activity of SOD decreased during initial days of culture and then increased due to the activation of additional SOD isoform described as MnSODII. The activity of POX was low during the rhizogenesis induction, and then increased during following days of culture; the increase was correlated with the decrease in hydrogen peroxide content. In the explants without the ability to regenerate roots, the total activity of SOD was low throughout the whole culture period, whereas the POX activity was significantly higher than in hypocotyls with regeneration potential. It might be concluded that the increase in hydrogen peroxide during initial stages of rhizogenesis and the induction of MnSODII are prerequisites for adventitious roots formation from hypocotyls of M. crystallinum, independently in the presence of anti- or prooxidant in the culture medium. PubDate: 2017-07-13 DOI: 10.1007/s11738-017-2466-x Issue No:Vol. 39, No. 8 (2017)
Authors:Gonzalo G. Lucho-Constantino; Fabiola Zaragoza-Martínez; Teresa Ponce-Noyola; Carlos M. Cerda-García-Rojas; Gabriela Trejo-Tapia; Fernando Esparza-García; Ana C. Ramos-Valdivia Abstract: Jatropha curcas has significant potential for production of biodiesel and secondary metabolites with medical applications. The effect of jasmonic acid (JA) on flavonoid production and antioxidant responses in two Mexican J. curcas plants (accessions I-64 and I-52), growing under controlled environmental conditions, was studied. Foliar application of JA (0.25, 0.5, and 1.0 mM) increased flavonoid content by 3.3-fold (445.6 ± 62.2 µg QE g−1 DW) at 1.0 mM in the I-64 accession after 120 h. At this time, individual flavonoid levels of kaempferol, apigenin, and vitexin were 6.8 (106.8 ± 18.6 µg g−1 DW), 4.4 (15.5 ± 1.5 µg g−1 DW), and 8.1 (6.27 ± 1.3 µg g−1 DW) times higher than in the controls, while for the I-52 specimens, the highest increase of flavonoids occurred at 24 h. In treated I-52 plants, enhancement of 58% (74.7 ± 9.2 µg g−1 DW) in anthocyanins occurred after 120 h, while in I-64 plants, they remained similar to controls. Phenylalanine ammonia lyase showed a peak of activity after 120 h in treated I-64 plants, while the I-52 accession showed peaks at 24 and 120 h. Elicited I-64 plants presented H2O2 levels similar to controls with a 30.6% increase in catalase (CAT) and 3.3-fold in ascorbate peroxidase (APX) activities. In elicited I-52 plants, a 2.4-fold increase in H2O2 concentration was related to a 65.6% decrease of CAT and a 1.8-fold increase of APX activities. Therefore, under JA elicitation, J. curcas plants increased antioxidant responses including flavonoid and anthocyanin production to maintain cell redox balance. PubDate: 2017-07-12 DOI: 10.1007/s11738-017-2461-2 Issue No:Vol. 39, No. 8 (2017)
Authors:Myeong Ja Kwak; Seong Han Lee; Inkyin Khaine; Sun Mi Je; Tae Yoon Lee; Ha Na You; Hyun Kyung Lee; Ji Hwi Jang; Iereh Kim; Su Young Woo Abstract: Yellow poplar (Liriodendron tulipifera L.) is a widespread hardwood tree of great ecological and economic value. Light pollution caused by excessive and indiscriminate exposure to artificial night light has emerged as a new risk factor due to its adverse effects related to energy waste, sleep disorders, anthropogenic habitat disturbance, and perceptual disorder of daily and seasonal rhythms in wildlife. However, it remains unknown how associations between artificial night light and stomatal behaviors controlled by internal signals are established. After continuous exposure to artificial light at night over 3 years, leaves in the experimental set-up were measured for stomatal movements, starch turnover, endogenous abscisic acid (ABA) levels, and chloroplast ultrastructure during the growing season. Yellow poplar showed dynamic changes in stomatal movement, starch turnover, and endogenous ABA levels in response to day/artificial night light cycle, resulting in reduction of circadian phase-shifting capacity at both dusk and dawn and normal chloroplast development as compared with natural night. Nighttime light exposure may act as a major factor for disorder of circadian and circannual rhythms as well as physiological and ultrastructural repressor in plants, via a modification of the perceived photoperiod. Our study suggests that these dynamic responses can provide advantageous insights that complement the current knowledge on light pollution. PubDate: 2017-07-11 DOI: 10.1007/s11738-017-2465-y Issue No:Vol. 39, No. 8 (2017)
Authors:Katya Georgieva; Ádam Solti; Ilona Mészáros; Áron Keresztes; Éva Sárvári Abstract: Haberlea rhodopensis belongs to the group of homoiochlorophyllous desiccation-tolerant plants which preserve their chlorophyll content during dehydration. It is a typical shade adapted plant and it is proved to be very sensitive to light intensity higher than the natural during drought stress. To reveal the reasons of their light sensitivity, we compared the damages and protective mechanisms of shade plants during desiccation either simulating their natural light conditions (30 μmol photons m−2 s−1, LL) or at a moderately higher light intensity (100 μmol photons m−2 s−1, ML). In the desiccated stage, no damage could be discovered in terms of thylakoid membrane quantity or integrity either at LL or ML. Nevertheless, the altered structure and localization of chloroplasts did not restore in plants desiccated and rehydrated at ML, where no starch could be re-synthesized, but a number of plastoglobuli appeared. The PSII activity and the amount of β-carotene and lutein decreased more strongly in ML leaves in agreement with their higher MDA production. Lack of recovery of ML plants may be connected with the very high number of damaged PSII reaction centres caused by the loss of the subtle balance between ROS production and scavenging. In addition, because of the impaired starch re-synthesis, there is no sink for the water-replacing sugars and water cannot be taken up which proved to be lethal to ML plants. PubDate: 2017-07-11 DOI: 10.1007/s11738-017-2457-y Issue No:Vol. 39, No. 8 (2017)
Authors:Yahan Zhou; Jiani Xu; Jiao Xie; Shixiang Yao; Lili Deng; Kaifang Zeng Abstract: Navel oranges (Citrus sinensis L. Osbeck) were treated with pure orange oil to simulate the natural cause of oleocellosis and to elucidate the mechanism involving in fruit injury caused by orange oil. Results showed that no injury was found on the rind surface of control fruits during storage. By contrast, application of exogenous orange oil onto the surface of fruits could rapidly induce peel injury. Moreover, the severity of injury increased during storage. At the end of the storage time, the collapse and discolouration scores were 17.3 and 16.7 times higher than those at 4 h after treatment. Oil treatment caused fruit membrane degradation by increasing the activities of phospholipase D and lipoxygenase, reducing the ratio of unsaturated/saturated fatty acids and enhancing the levels of hydrogen peroxide, superoxide anion, malonaldehyde, and electrolyte leakage. In addition, the treatment reduced the activities of superoxide dismutase and catalase, as well as suppressed the ascorbate acid–glutathione cycle, which led to the efficiency loss of the reactive oxygen species scavenging system. PubDate: 2017-07-11 DOI: 10.1007/s11738-017-2464-z Issue No:Vol. 39, No. 8 (2017)
Authors:Zohreh Elmi Anaraki; Mansour Shariati; Sayed Ali Hosseini Tafreshi Abstract: In this work, we investigated the importance of phytoene desaturase (PDS) during salt stress in plants. For this aim, we transiently suppressed the corresponding gene of Nicotiana benthamiana using a Tobacco Rattle Virus silencing system. After salinity stress, the silenced plants were assayed for different growth and physiological parameters. The silenced plants were found to be induced more stunted and feeble shoots and roots than the negative controls. The results indicated that the concurrent incidence of salinity stress and viral infection did not have an additive influences on the plant growth and physiological parameters. Importantly, our results showed a more detrimental influence of salinity on plant growth and physiology after PDS silencing. Compared to the control, salt-stressed plants contained more proline, and malondialdehyde, less amount of photosynthetic pigments, higher Na+/K+ ratios in shoots and roots and lower relative water content after PDS silencing. The activity of antioxidant enzymes were also decreased in the plants coped with salinity or Tobacco Rattle Virus. It was also represented that simultaneous silencing of the PDS gene and salinity treatment resulted in a significant decrease of the performance index (PIABS) and an increase of dissipation per active reaction center (DIo/RC) reflecting severe injuries in photosynthetic machinery under such a condition. Overall results suggested that PDS silencing could increase the sensitivity of plants to salinity. PubDate: 2017-07-10 DOI: 10.1007/s11738-017-2460-3 Issue No:Vol. 39, No. 8 (2017)
Authors:Jianqing Hao; Ning Yue; Caixia Zheng Abstract: Populus euphratica Oliv. is well-adapted to extreme desert environments and possess the characteristic of heterophylly. On the same tree, the lanceolate, broad-ovate, and dentate broad-ovate leaves distribute in the different tiers of the canopy. The lanceolate leaves distribute on the lower canopy, broad-ovate leaves on the middle canopy, and dentate broad-ovate leaves on the upper canopy. The leaf structure was found to be xeromorphic. The stomatal densities of the three typical leaves were different and decreased in value from dentate broad-ovate, to broad-ovate, and to lanceolate leaves. The osmotic potentials at full and zero turgor were lowest in dentate broad-ovate leaves. In an appropriate growth environment, the chlorophyll fluorescence parameters of the three leaf types were almost the same and significantly changed upon exposure to short-term water stress. These results showed that dentate broad-ovate leaves can maintain their normal size and shape under arid and hot conditions because of their relatively thick cell wall and high mechanical strength. Moreover, dentate broad-ovate leaves had more developed vascular bundles in the main vein than the other types and thus more efficiently transported water and salts. These results suggested that dentate broad-ovate leaves can efficiently adapt to changing conditions, with more obvious xeromorphic characteristics and a relatively higher photosynthesis rate under drought conditions, compared with the others leaf types. PubDate: 2017-07-10 DOI: 10.1007/s11738-017-2467-9 Issue No:Vol. 39, No. 8 (2017)
Authors:D. Tekdal; S. J. Lucas; S. Cetiner Abstract: Thermopsis turcica Kit Tan, Vural & Küçüködük is an herbaceous perennial, endemic and listed as endangered species by IUCN in Turkey. This plant is noted for its unusual floral structure characterized by a 2–4 carpellary ovary. In this study, a DPD (NADP+)-like gene was partially sequenced for the first time in T. turcica. Since there is no previous molecular genetic information available for T. turcica, RT-PCR was performed using degenerate primers targeted to conserved sequences of WUS protein homologues from related legume species. Amplified cDNAs of the expected size were sequenced and analyzed using bioinformatics tools. The analysis strongly suggested that a 283 bp PCR product was part of a dihydropyrimidine dehydrogenase (NADP+)-like coding sequence with a Flavin mononucleotide binding domain. The putative gene was named Tt-DPD and the partial CDS submitted to the NCBI database (accession number KT182937). This gene has not been identified previously in T. turcica. The DPD (NADP+) enzyme is the rate-limiting step in pyrimidine degradation, which is essential for the biosynthesis of beta-alanine and pantothenates in plants; it has also been shown to be required for normal seed development in Arabidopsis. Expression of Tt-DPD was monitored by both endpoint and real-time RT-PCR. High expression of the identified gene was observed in the mid-developmental stage of the pistil of T. turcica. The findings presented here provide a starting point for understanding the roles of this gene in pyrimidine catabolism in T. turcica. PubDate: 2017-07-08 DOI: 10.1007/s11738-017-2458-x Issue No:Vol. 39, No. 8 (2017)
Authors:Barbara Swarcewicz; Aneta Sawikowska; Łukasz Marczak; Magdalena Łuczak; Danuta Ciesiołka; Karolina Krystkowiak; Anetta Kuczyńska; Mariola Piślewska-Bednarek; Paweł Krajewski; Maciej Stobiecki Abstract: Drought stress is perhaps one of the most common abiotic factors which crop plants have to cope with. To survive, plants have to adapt to periods of water deficit that may occur during their vegetation. This can be achieved by triggering various changes in the plant genome, transcriptome, proteome, and metabolome, leading to different physiological and biochemical reactions of plants. We have compared changes in barley leaf and root metabolomes in response to drought in recombinant inbred line (RIL) population derived from hybrids between two spring genotypes: German variety Maresi and Syrian breeding line Cam/B1//CI08887/CI05761. Response of plants to drought of the studied barley lines was rather conservative; most barley genotypes changed their metabolome composition independently in leaf and root. Based on analysis of variance, metabolites were classified with respect to significance of difference between lines, drought effect (understood as the difference between metabolite level in drought and control plants), and line × drought interaction. The revealed changes in accumulation of some metabolites, e.g., proline and other amino acids, carbohydrates or carboxylic acids have been regarded to be a basic plant strategy for acquiring drought stress tolerance. It was possible to draw some general inferences from obtained results: changes of metabolites involved in barley response to drought were rather similar qualitatively but varied quantitatively among the studied RILs. Compatible solutes and osmolytes were the major group of compounds accumulated under drought. We have also observed significant organ specificity between leaf and root response to drought at the metabolome level in all recognized metabolites classes. Moreover, we have found metabolites which differentiated tested genotypes under drought—and these compounds might be considered as potential biomarkers associated with drought tolerance in barley. PubDate: 2017-07-06 DOI: 10.1007/s11738-017-2449-y Issue No:Vol. 39, No. 8 (2017)
Authors:Jozef Kováčik; Petr Babula Abstract: Various fluorescence reagents are often used for the detection of oxidative stress, but more extensive comparison in the same study is rather rare. We tested five ROS-related and two non-ROS-related reagents in the roots of Zea mays germinated and growing in 1 or 100 µM cadmium-enriched solution. Namely, “general” ROS (CellROX Deep Red reagent and 2′,7′-dichlorodihydrofluorescein diacetate), hydrogen peroxide (Amplex UltraRed), superoxide radical (dihydroethidium), hydroxyl radical/peroxynitrite (aminophenyl fluorescein), nitric oxide (1,2-diaminoanthraquinone), and glutathione/-SH (monochlorobimane) indicators were tested. Both Cd doses stimulated signal of various ROS often extensively compared to control and mainly H2O2 differed between 1 and 100 µM Cd. Signal of ROS was clearly visible in exodermis and vascular tissue through which cadmium is transported via transpiration stream. CellROX Deep Red reagent gives bright and clear signal on the root cross sections. The standard spectrophotometry (detection of H2O2 and superoxide) did not reveal differences between control and 1 µM Cd, indicating that fluorescence microscopy is more sensitive to detect low change in oxidative balance. Nitric oxide and glutathione/-SH signal was less different between control and Cd treatments, indicating their contribution to metal tolerance. Cd accumulation and translocation and the use of reagents under the excess of other metals are also discussed. PubDate: 2017-07-03 DOI: 10.1007/s11738-017-2455-0 Issue No:Vol. 39, No. 8 (2017)
Authors:Manrang Zhang; Fengwang Ma; Huairui Shu; Mingyu Han Abstract: Branch bending has been practiced for decades in China to induce flower buds in ‘Fuji’ apple. However, the optimum bending angle is yet to be elucidated. The main objectives of this study were to compare the effect of branch bending angles (70°, 90° and 110°) on the flowering and nutrient accumulation of 1-year-old shoots of ‘Fuji’ and ‘Gala’ apples and to determine the optimum branch bending angle for each cultivar. In both cultivars, the production of spurs and terminal flower buds, and the total sugar concentration and the carbon-to-nitrogen (C/N) ratio in the shoot terminals increased, whereas the N concentration decreased with increasing bending angles. The nutrient concentration was significantly higher in spurs than in medium and long shoots. The distinction between the changing patterns of C and N concentrations in the bent shoots during the growing season in our study suggested the competition of these two nutrients caused by vegetative and reproductive growth at different growing times. In ‘Fuji’ apple, the proportion of flowering buds appeared to increase more rapidly with the increase of bending angle from 70° to 110° than that in ‘Gala’ apple, and particularly a higher proportion of spurs was observed on ‘Fuji’ branches bent at a larger angle. The increase in the total sugar concentration and the C/N ratio in the shoot terminals of the bent branches might be involved in inducing floral buds after bending. The optimum bending angle was about 90° for ‘Gala’ apple and 110° for ‘Fuji’ apple, respectively. Bending could help farmers to reduce the severity of biennial fruiting in ‘Fuji’ apple. PubDate: 2017-06-29 DOI: 10.1007/s11738-017-2450-5 Issue No:Vol. 39, No. 7 (2017)
Authors:K. A. Fayez; B. A. El-Deeb; N. Y. Mostafa Abstract: Silver nanoparticles (AgNPs) were biosynthesized using the cell-free filtrate of bacterium Proteus mirabilis, reacted with 1 mM of AgNO3 solutions at 37 °C. The synthesis of AgNPs was monitored by UV–Vis spectroscopy and transmission electron microscopy (TEM) equipped with selected area electron diffraction (SAED). The results point to formation of spherical to cubical particles of AgNPs ranging in size from 5 to 35 nm with an average of 25 nm in diameter. The toxicity of Ag on barley (Hordeum vulgare L. cv. Gustoe) that was subjected to Ag+ as AgNO3 and AgNPs was explored. The grain germination and seedling growth of barley decreased in the presence of 0.1 mM Ag+ and was inhibited at 1 mM Ag+. In contrast, our results indicated that the AgNPs at low concentration (0.1 mM) could be useful for barley grain germination and seedling growth. However, the higher concentrations of AgNPs (0.5 and 1 mM) reduced grain germination and exhibited a stronger reduction in the root length. A decline in the photosynthetic pigments and disorganization of chloroplast grana thylakoids in Ag+ and AgNPs-treated plants confirmed the leaf chlorosis. An increase of plastoglobuli within chloroplasts was observed in Ag+ and AgNPs-treated leaves. Ag+ caused dense aggregation of nuclear chromatin materials and degeneration of mitochondria. Ag+ and AgNPs increased contents of malondialdehyde, soluble proteins, total phenolic compounds and activity of guaiacol peroxidase in barley leaves; these results point to activation of plant defence mechanisms against oxidative stress in barley. PubDate: 2017-06-27 DOI: 10.1007/s11738-017-2452-3 Issue No:Vol. 39, No. 7 (2017)
Authors:Pooja Bansal; Alka Srivastava Abstract: Desiccation, a major environmental stress, affects water potential and turgor in the plants leading to physiological imbalance. Though bryophytes have the ability to endure desiccation, the adverse environmental conditions may cause them to dry irreversibly. In the present study, desiccation tolerance mechanism of Brachythecium procumbens (Mitt.) A. Jaeger was analysed in terms of its antioxidative response and photosynthetic pigments. Plants of B. procumbens were subjected to desiccation stress for varying durations (24–96 h) along with control (0 h) at room temperature. Monitoring was done using antioxidant enzyme activities, photosynthetic pigments, chlorophyll stability index, as well as, relative water content. The antioxidative enzymes—superoxide dismutase and peroxidase—showed higher activity in desiccated plants as compared to control and increased significantly with duration of desiccation. However, the activity of catalase decreased during desiccation. The amount of chlorophyll increased up to 48 h of desiccation treatment as compared to control, whereas in rehydrated samples, relatively lower value was obtained. Majority of bryophytes may withstand a certain level of desiccation for at least a few days, but some are much more tolerant than that. The bryophyte system studied showed basic difference in enzyme activities and chlorophyll under different periods of desiccation. Hence, drought-tolerant genera need to be identified and propagated so that some pioneer colonizers of the ecosystem are naturally conserved. PubDate: 2017-06-26 DOI: 10.1007/s11738-017-2454-1 Issue No:Vol. 39, No. 7 (2017)
Authors:Izabela Marcińska; Ilona Czyczyło-Mysza; Edyta Skrzypek; Maciej T. Grzesiak; Marzena Popielarska-Konieczna; Marzena Warchoł; Stanisław Grzesiak Abstract: Functionality of the photosynthetic system under water stress is of major importance in drought tolerance. Oat (Avena sativa L.) doubled haploid (DH) lines obtained by pollination of F 1 oat crosses with maize were used to assess the differences in plant genotypic response to soil drought. The investigations were based on the measurements of gas exchange and chlorophyll a fluorescence kinetics. Drought was applied to 17-day-old seedlings by withholding water for 14 days and subsequent plant recovery. Non-stressed optimally watered plants served as controls. Yield components were determined when plants reached full maturity. It was shown differences among the oat lines with respect to drought stress susceptibility (SI) and stress tolerance index mean productivity and drought susceptibility index. Sensitivity to drought of individual DH lines was significantly different, as demonstrated by the correlation between drought susceptibility index and yield components, such as dry weight (GW) or grain number (GN) of the harvested plants. GW and GN were lower in drought-sensitive genotypes exposed to drought stress compared to those resistant to drought. The principal component analysis allow to separate three groups of lines differing in their sensitivity to drought stress and indicated that tolerance to drought in oat has a common genetic background. PubDate: 2017-06-24 DOI: 10.1007/s11738-017-2453-2 Issue No:Vol. 39, No. 7 (2017)
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