scholarly journals Physiological characteristics and RNA sequencing in two root zones with contrasting nitrate assimilation of Populus × canescens

2020 ◽  
Vol 40 (10) ◽  
pp. 1392-1404
Author(s):  
Jing Zhou ◽  
Yan Lu ◽  
Wen-Guang Shi ◽  
Shu-Rong Deng ◽  
Zhi-Bin Luo
Keyword(s):  
Root Zone ◽  
Reductase Activity ◽  
Nitrate Assimilation ◽  
Root Apex ◽  
Root Zones ◽  
Uptake Rates ◽  
Element Binding Protein ◽  
No3 Uptake Rates ◽  
Zone Ii ◽  
Populus Species

Abstract Different root zones have distinct capacities for nitrate (NO3−) uptake in Populus species, but the underlying physiological and microRNA (miRNA) regulatory mechanisms remain largely unknown. To address this question, two root zones of Populus × canescens (Ait.) Smith. with contrasting capacities for NO3− uptake were investigated. The region of 0–40 mm (root zone I) to the root apex displayed net influxes, whereas the region of 40–80 mm (root zone II) exhibited net effluxes. Concentrations of NO3− and ammonium (NH4+) as well as nitrate reductase activity were lower in zone II than in zone I. Forty one upregulated and twenty three downregulated miRNAs, and 576 targets of these miRNAs were identified in zone II in comparison with zone I. Particularly, growth-regulating factor 4 (GRF4), a target of upregulated ptc-miR396g-5p and ptc-miR396f_L + 1R-1, was downregulated in zone II in comparison with zone I, probably contributing to lower NO3− uptake rates and assimilation in zone II. Furthermore, several miRNAs and their targets, members of C2H2 zinc finger family and APETALA2/ethylene-responsive element binding protein family, were found in root zones, which probably play important roles in regulating NO3− uptake. These results indicate that differentially expressed miRNA–target pairs play key roles in regulation of distinct NO3− uptake rates and assimilation in different root zones of poplars.

Use of artificial wetland for the treatment of surface and wastewater

1996 ◽  
Vol 33 (4-5) ◽  
pp. 309-313
Author(s):  
Jan Šálek ◽  
František Marcián ◽  
Iman Elazizy
Keyword(s):  
Water Level ◽  
Root Zone ◽  
Artificial Wetland ◽  
Root Zones ◽  
Different Types ◽  
Water Media ◽  
Inlet Zone

Vegetative root zone methods are based on self-purifying processes that take place in the soil, wetland and vegetation containing water media. Our studies are concentrated on the course of puryfying in relation with the length of the filtration bed and on the progress of eliminating the ammoniacal pollution. The research proved that the essential part of the puryfying process takes place within the inlet zone (Figs 1 and 2). The decomposition of ammonia proceeds very slowly. The process of nitrification is affected by the lack of oxygen in the filtration media. To improve the effectiveness of vegetative root zone methods we suggest specific steps: an adjustment of the inlet zone, a system of cascades, a water level pulsation system and combinations of different types and arrangements of vegetative root zones.

scholarly journals Comparative Proteomics of Root Apex and Root Elongation Zones Provides Insights into Molecular Mechanisms for Drought Stress and Recovery Adjustment in Switchgrass

Proteomes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
Zhujia Ye ◽  
Sasikiran Reddy Sangireddy ◽  
Chih-Li Yu ◽  
Dafeng Hui ◽  
Kevin Howe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drought Stress ◽  
Molecular Mechanisms ◽  
Root Zone ◽  
Root Apex ◽  
Root Tip ◽  
Leaf Water Content ◽  
Severe Drought ◽  
Proteomics Data ◽  
Drought Treatment

Switchgrass plants were grown in a Sandwich tube system to induce gradual drought stress by withholding watering. After 29 days, the leaf photosynthetic rate decreased significantly, compared to the control plants which were watered regularly. The drought-treated plants recovered to the same leaf water content after three days of re-watering. The root tip (1cm basal fragment, designated as RT1 hereafter) and the elongation/maturation zone (the next upper 1 cm tissue, designated as RT2 hereafter) tissues were collected at the 29th day of drought stress treatment, (named SDT for severe drought treated), after one (D1W) and three days (D3W) of re-watering. The tandem mass tags mass spectrometry-based quantitative proteomics analysis was performed to identify the proteomes, and drought-induced differentially accumulated proteins (DAPs). From RT1 tissues, 6156, 7687, and 7699 proteins were quantified, and 296, 535, and 384 DAPs were identified in the SDT, D1W, and D3W samples, respectively. From RT2 tissues, 7382, 7255, and 6883 proteins were quantified, and 393, 587, and 321 proteins DAPs were identified in the SDT, D1W, and D3W samples. Between RT1 and RT2 tissues, very few DAPs overlapped at SDT, but the number of such proteins increased during the recovery phase. A large number of hydrophilic proteins and stress-responsive proteins were induced during SDT and remained at a higher level during the recovery stages. A large number of DAPs in RT1 tissues maintained the same expression pattern throughout drought treatment and the recovery phases. The DAPs in RT1 tissues were classified in cell proliferation, mitotic cell division, and chromatin modification, and those in RT2 were placed in cell wall remodeling and cell expansion processes. This study provided information pertaining to root zone-specific proteome changes during drought and recover phases, which will allow us to select proteins (genes) as better defined targets for developing drought tolerant plants. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD017441.

Early signalling processes in roots play a crucial role in the differential salt tolerance in contrasting Chenopodium quinoa accessions

2021 ◽  
Author(s):  
Nadia Bazihizina ◽  
Federico Vita ◽  
Raffaella Balestrini ◽  
Claudia Kiferle ◽  
Stefania Caparrotta ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Root Zone ◽  
Regulatory Protein ◽  
Membrane Integrity ◽  
Chenopodium Quinoa ◽  
Root Apex ◽  
Tolerance Mechanisms ◽  
Bladder Cell ◽  
Receptor Kinases ◽  
Root Plasma Membrane

Abstract Significant variation in epidermal bladder cell (EBC) density and salt tolerance (ST) exists amongst quinoa accessions, suggesting that salt sequestration in EBCs is not the only mechanism conferring ST in this halophyte. In order to reveal other traits that may operate in tandem with salt sequestration in EBCs and whether these additional tolerance mechanisms acted mainly at the root or shoot level, two quinoa (Chenopodium quinoa) accessions with contrasting ST and EBC densities (Q30, low ST with high EBC density versus Q68, with high ST and low EBC density) were studied. The results indicate that responses in roots, rather than in shoots, contributed to the greater ST in the accession with low EBC density. In particular, the tolerant accession had improved root plasma membrane integrity and K+ retention in the mature root zone in response to salt. Furthermore, superior ST in the tolerant Q68 was associated with faster and root-specific H2O2 accumulation and reactive oxygen species-induced K+ and Ca2+ fluxes in the root apex within 30 min after NaCl application. This was found to be associated with the constitutive up-regulation of the membrane-localized receptor kinases regulatory protein FERONIA in the tolerant accession. Taken together, this study shows that differential root signalling events upon salt exposure are essential for the halophytic quinoa; the failure to do this limits quinoa adaptation to salinity, independently of salt sequestration in EBCs.

Rhythmic patterns of nutrient acquisition by wheat roots

2002 ◽  
Vol 29 (5) ◽  
pp. 595 ◽  
Author(s):  
Sergey Shabala ◽  
Andrew Knowles
Keyword(s):  
Root Zone ◽  
Root Hairs ◽  
Rhythmic Activity ◽  
Root Apex ◽  
Root Surface ◽  
Ion Flux ◽  
Nutrient Acquisition ◽  
Wheat Roots ◽  
Non Invasive ◽  
Functional Zone

Oscillatory patterns in H+, K+, Ca2+ and Cl- uptake were observed at different regions of the root surface, including root hairs, using a non-invasive ion flux measuring technique (the MIFE™ technique). To our knowledge, this is the first report of ultradian oscillations in nutrient acquisition in the mature root zone. Oscillations of the largest magnitude were usually measured in the elongation region, 2–4 mm from the root apex. There were usually at least two oscillatory components present for each ion measured: fast, with periods of several minutes; and slow, with periods of 50–80 min. Even within the same functional zone, the periods of ion flux oscillations were significantly different, suggesting that they are driven by some internal mechanisms located in each cell rather than originating from one ‘central clock pacemaker’. There were also significant changes in the oscillatory characteristics (both periods and amplitudes) of fluxes from a single small cluster of cells over time. Analysis of phase shifts between oscillations in different ions suggested that rhythmic activity of a plasma membrane H+-pump may be central to observed rhythmic nutrient acquisition by plant roots. We discuss the possible adaptive significance of such an oscillatory strategy for root nutrient acquisition.

scholarly journals Role of different planting techniques in improving the water logging tolerance and productivity of sesame (Sesamum indicum L.)

2015 ◽  
Vol 50 (3) ◽  
pp. 193-198
Author(s):  
M Aslam ◽  
HM Nasrullah ◽  
M Akhtar ◽  
B Ali ◽  
M Akram ◽  
...  
Keyword(s):  
Grain Yield ◽  
Root Zone ◽  
Research Area ◽  
Climatic Conditions ◽  
Semiarid Region ◽  
Research Station ◽  
Root Zones ◽  
Water Logging ◽  
Arid And Semiarid

Sesame is a well known oil seed crop in arid and semiarid region of Pakistan and its productivity is affected due to sensitiveness to water logging in the root zones. The experiment was conducted at research area of Agronomic Research Station, Bahawalpur during the year 2010 and 2011. The crop was sown by three different planting techniques i.e. flat sowing with 45cm apart rows, ridge sowing with 45cm apart, bed sowing with 60/30 cm i.e. 60 cm wide beds with 30 cm furrow between the beds. The data revealed that maximum number of plants wilted in flat planting as compared to other methods of planting were taken in this experiment. It was also recorded that bed planting at 90cm apart beds gave maximum grain yield of 843 kg ha-1 followed by ridge planting (seed spreading by broadcast and with augmented furrows) with a grain yield of 811 kg ha-1. The lowest yield was obtained from conventional method of sowing which gave 349 kg ha-1 grain yield. Water logging stress in the root zone can successfully be avoided by planting sesame on beds or ridges under climatic conditions of Bahawalpur.Bangladesh J. Sci. Ind. Res. 50(3), 193-198, 2015

Nitrate Reductase from a Mutant Strain of Chlamydomonas reinhardii Incapable of Nitrate Assimilation

1983 ◽  
Vol 38 (5-6) ◽  
pp. 439-445 ◽  
Author(s):  
Emilio Fernández ◽  
Jacobo Cárdenas
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Wild Strain ◽  
Nitrate Assimilation ◽  
Pyridine Nucleotide ◽  
Spectral Studies ◽  
Binding Region ◽  
Chlamydomonas Reinhardii ◽  
Blue Sepharose

Nitrate reductase from mutant 305 of Chlamydomonas reinhardii has been purified about 90-fold and biochemically characterized. The enzyme can use reduced flavins and viologens as electron donors to reduce nitrate but, unlike the nitrate reductase complex from its parental wild strain, lacks NAD(P)H-nitrate reductase and NAD(P)H-cytochrome c reductase activities, does not bind to Blue-Agarose or Blue-Sepharose and exhibits a significantly lower molecular weight (177.000 vs. 241.000), whereas its kinetic characteristics and its sensitivity against several inhibitors and treatments are very similar to those of the terminal nitrate reductase activity of the wild strain complex. Spectral studies and antagonistic experiments with tungstate show the presence of cytochrome b557 and molybdenum. These facts lead us to propose that nitrate reductase from mutant 305 has a protein deletion which affects the pyridine nucleotide binding region of the diaphorase protein but without any effect on the terminal nitrate reductase activity.

scholarly journals Polychlorinated Biphenyl (PCB)-Degrading Bacteria Associated with Trees in a PCB-Contaminated Site

2006 ◽  
Vol 72 (4) ◽  
pp. 2331-2342 ◽  
Author(s):  
Mary Beth Leigh ◽  
Petra Prouzová ◽  
Martina Macková ◽  
Tomáš Macek ◽  
David P. Nagle ◽  
...  
Keyword(s):  
Plant Species ◽  
Polychlorinated Biphenyl ◽  
Root Zone ◽  
Pinus Nigra ◽  
Contaminated Site ◽  
Rrna Gene ◽  
Mature Trees ◽  
Salix Caprea ◽  
Root Zones ◽  
Degrading Bacteria

ABSTRACT The abundance, identities, and degradation abilities of indigenous polychlorinated biphenyl (PCB)-degrading bacteria associated with five species of mature trees growing naturally in a contaminated site were investigated to identify plants that enhance the microbial PCB degradation potential in soil. Culturable PCB degraders were associated with every plant species examined in both the rhizosphere and root zone, which was defined as the bulk soil in which the plant was rooted. Significantly higher numbers of PCB degraders (2.7- to 56.7-fold-higher means) were detected in the root zones of Austrian pine (Pinus nigra) and goat willow (Salix caprea) than in the root zones of other plants or non-root-containing soil in certain seasons and at certain soil depths. The majority of culturable PCB degraders throughout the site and the majority of culturable PCB degraders associated with plants were identified as members of the genus Rhodococcus by 16S rRNA gene sequence analysis. Other taxa of PCB-degrading bacteria included members of the genera Luteibacter and Williamsia, which have not previously been shown to include PCB degraders. PCB degradation assays revealed that some isolates from the site have broad congener specificities; these isolates included one Rhodococcus strain that exhibited degradation abilities similar to those of Burkholderia xenovorans LB400. Isolates with broad congener specificity were widespread at the site, including in the biostimulated root zone of willow. The apparent association of certain plant species with increased abundance of indigenous PCB degraders, including organisms with outstanding degradation abilities, throughout the root zone supports the notion that biostimulation through rhizoremediation is a promising strategy for enhancing PCB degradation in situ.

scholarly journals Aflatoxin Contamination of Peanuts from Plants Drought Stressed In Pod or Root Zones1

1993 ◽  
Vol 20 (1) ◽  
pp. 5-8 ◽  
Author(s):  
T. H. Sanders ◽  
R. J. Cole ◽  
P. D. Blankenship ◽  
J. W. Dorner
Keyword(s):  
Drought Stress ◽  
Moisture Content ◽  
Root Zone ◽  
Aflatoxin Contamination ◽  
Stress Conditions ◽  
Root Zones ◽  
Moisture Contents ◽  
Root Stress

Abstract Studies were conducted to investigate the separate roles of root stress and pod stress in pre-harvest aflatoxin contamination of peanuts. Pod and root zones were separated by a polystyrene barrier in a unique design and drought type conditions were applied either above or below the barriers. In the three year study, aflatoxin was consistently found in peanuts when pods were exposed to drought stress although roots of those plants were well watered. Generally, aflatoxin was not found in peanuts when pods were well watered although roots were subjected to drought stress conditions. Moisture content of Pod Maturity Profile classes was generally lower in root zone stress conditions especially in the immature classes. Moisture contents of mustard-colored pods in all classes were extremely low (< 26%).

Seasonal variation in nitrate reductase activity in needles of high-elevation red spruce trees

1992 ◽  
Vol 22 (3) ◽  
pp. 375-380 ◽  
Author(s):  
M.G. Tjoelker ◽  
S.B. McLaughlin ◽  
R.J. DiCosty ◽  
S.E. Lindberg ◽  
R.J. Norby
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Nitrate Assimilation ◽  
High Elevation ◽  
Preliminary Evidence ◽  
Air Pollutant ◽  
Red Spruce ◽  
Acid Vapor ◽  
Assimilation Capacity

To assess seasonal and site variation in foliar nitrate reductase activity and its utility as a biochemical marker for the uptake of nitrogen oxide pollutants in high-elevation forests, we measured nitrate reductase activity in current-year needles of red spruce (Picearubens Sarg.) saplings at two high-elevation stands (1935 and 1720 m) in the Great Smoky Mountains, North Carolina. Measurements spanned two growing seasons between September 1987 and September 1988. Nitrate reductase activity peaked near 60 nmol•g−1•h−1 at both sites in September and October 1987 and August 1988 and declined 80% in November 1987 and 65% in September 1988. Although nitrate reductase activity was 30% greater in saplings at the higher site relative to the lower site in September and October 1987, activity dropped to approximately 10 nmol•g−1•h−1 at both sites in November 1987. No differences among sites were evident the following year. Comparing deposition of nitric acid vapor at a nearby site to nitrate reductase activity suggests that needle nitrate reductase activity is not an unequivocal marker for foliar uptake of nitrogen oxides during air pollutant episodes. The changes in soil nitrate levels in this system provide preliminary evidence that foliar nitrate assimilation may, in part, include nitrate taken up from the soil, as the highest activity occurred during periods of higher A-horizon nitrate concentrations in 1988. These measurements of nitrate reductase activity suggest that red spruce are capable of assimilating nitrate in foliage in the field and that the nitrate assimilation capacity varies throughout the year.

INFLUENCE DE LA TEMPERATURE DU SUBSTRAT ET DE LA FERTILISATION AZOTEE SUR LA CROISSANCE, LE DEVELOPPEMENT, LA TENEUR EN AZOTE ET L’ACTIVITE DE LA NITRATE REDUCTASE CHEZ LA TOMATE

1984 ◽  
Vol 64 (1) ◽  
pp. 181-191 ◽  
Author(s):  
ANDRÉ GOSSELIN ◽  
FRANÇOIS-P. CHALIFOUR ◽  
MARC J. TRUDEL ◽  
GHISLAIN GENDRON
Keyword(s):  
Lycopersicon Esculentum ◽  
Nitrate Reductase ◽  
Nitrogen Content ◽  
Nitrate Reductase Activity ◽  
Root Zone ◽  
Reductase Activity ◽  
Dry Weight ◽  
Fruit Weight ◽  
Root Zone Temperature ◽  
Lycopersicon Esculentum Mill

We measured the effects of five root temperatures (12, 18, 24, 30 and 36 °C) and five rates of nitrogen fertilization (0, 2.5, 7.5, 22.5 and 67.5 meq N∙L−1) on growth, development, nitrogen content and nitrate reductase activity of tomato plants (Lycopersicon esculentum Mill. ’Vendor’). The greatest root dry weight was obtained at 18 °C and 2.5 meq N∙L−1 and the highest shoot dry weight at 24 °C and 22.5 meq N∙L−1. Total fruit weight was maximum at 24 °C and 2.5 meq N∙L−1. High root temperatures and high levels of fertilization increased the number of aborted flowers and the nitrogen content of shoots, but reduced tomato yields. Nitrate reductase activity (NRA) was higher in leaves than in roots and with plants receiving 22.5 meq N∙L−1 as compared to 2.5 meq. NRA in roots decreased as temperature increased.Key words: Lycopersicon esculentum Mill., root zone temperature, nitrate reductase, nitrogen

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