Evaluation of root porosity and radial oxygen loss of disomic addition lines of Hordeum marinum in wheat

2017 ◽  
Vol 44 (4) ◽  
pp. 400 ◽  
Author(s):  
Dennis Konnerup ◽  
A. l. Imran Malik ◽  
A. K. M. R. Islam ◽  
Timothy David Colmer
Keyword(s):  
Triticum Aestivum L ◽  
Radial Oxygen Loss ◽  
Waterlogging Tolerance ◽  
Root Volume ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Chromosome Addition ◽  
Disomic Addition Lines ◽  
Gas Volume ◽  
Root Aeration

Hordeum marinum Huds. is a waterlogging-tolerant wild relative of wheat (Triticum aestivum L.). Greater root porosity (gas volume per root volume) and formation of a barrier to reduce root radial O2 loss (ROL) contribute to the waterlogging tolerance of H. marinum and these traits are evident in some H. marinum–wheat amphiploids. We evaluated root porosity, ROL patterns and tolerance to hypoxic stagnant conditions for 10 various H. marinum (two accessions) disomic chromosome addition (DA) lines in wheat (two varieties), produced from two H. marinum–wheat amphiploids and their recurrent wheat parents. None of the DA lines had a barrier to ROL or higher root porosity than the wheat parents. Lack of a root ROL barrier in the six DA lines for H. marinum accession H21 in Chinese Spring (CS) wheat indicates that the gene(s) for this trait do not reside on one of these six chromosomes; unfortunately, chromosome 3 of H. marinum has not been isolated in CS. Unlike the H21–CS amphiploid, which formed a partial ROL barrier in roots, the H90–Westonia amphiploid and the four derived DA lines available did not. The unaltered root aeration traits in the available DA lines challenge the strategy of using H. marinum as a donor of these traits to wheat.

Anatomical Adaptive Strategies to Flooding and Rhizosphere Oxidation in Mangrove Seedlings

1996 ◽  
Vol 44 (3) ◽  
pp. 297 ◽  
Author(s):  
T Youssef ◽  
P Saenger
Keyword(s):  
Root Surface ◽  
Limited Information ◽  
Ground Tissue ◽  
Radial Oxygen Loss ◽  
Waterlogging Tolerance ◽  
Mangrove Species ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Diffusive Resistance ◽  
Mangrove Seedlings

Limited information exists on the relation between the capacity of mangrove seedlings to oxidise the rhizosphere and their differential waterlogging tolerance. Laboratory experiments were conducted to estimate radial oxygen loss (ROL) by the entire root, the area of oxidising sites (AOS) on the root surface, root porosity (POR), and the internal diffusive resistance in the ground tissue of seedlings of six mangrove species that show a differential response to flooding. Radial oxygen loss was extremely low in all viviparous seedlings (0.7-1.5 μmol O2 per cm2AOS per day). Differential tolerance of species coincided with the degree of porosity (14.8-45.7%) and the ability of seedlings to develop barriers to oxygen leakage on the root surface. The percentage area of lacunae in the ground tissue of seedlings of the four viviparous species revealed a constriction of the air flow path at the hypocotyl junction. These findings suggest that: (i) the differential tolerance to waterlogging in mangrove seedlings is not simply based on their ability to oxidise the rhizosphere; (ii) the high diffusive resistance in the hypocotyl junction is likely to affect root aeration when the plant's access to air is limited by partial or total submergence; and (iii) waterlogging tolerance is probably a function of the strategy by which roots conserve oxygen to maintain aerobic metabolism for longer periods during submergence. Implications of these findings in seedlings are discussed in relation to other anatomical and morphological adaptations to waterlogging in mature mangroves.

Salinity and waterlogging tolerance amongst accessions of messina (Melilotus siculus)

2011 ◽  
Vol 62 (3) ◽  
pp. 225 ◽  
Author(s):  
M. E. Rogers ◽  
T. D. Colmer ◽  
P. G. H. Nichols ◽  
S. J. Hughes ◽  
K. Frost ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Lateral Roots ◽  
Negative Relationship ◽  
Dry Weight ◽  
Waterlogging Tolerance ◽  
Root Volume ◽  
Root Porosity ◽  
Good Tolerance ◽  
Shoot Dry Weight ◽  
Gas Volume

Melilotus siculus (common name messina) has shown potential as a productive annual forage legume in saline and waterlogged areas in temperate Australia. The salt and waterlogging tolerances of 30 M. siculus accessions were evaluated at germination and as established plants. Many accessions germinated at 240 mm NaCl, but germination was <15% at 320 mm NaCl. In vegetative plants, accessions differed in the degree of growth reduction at 300 mm NaCl, with some producing >90%, but others <20%, of non-saline controls. A negative relationship (r = 0.47, P < 0.001) was found between dry weight under non-saline conditions and relative salt tolerance (i.e. salt-treated as % of controls). Concentrations of Cl– and Na+ in shoots of all accessions increased significantly with increasing NaCl in the medium, although these differed among accessions. No relationships were found between shoot Cl–, Na+, or K+ concentrations and relative salt tolerance at 300 mm NaCl, whereas net K+ : Na+ selectivity to shoots was positively correlated with relative salt tolerance (r = 0.30, P = 0.1). All accessions showed good tolerance to stagnant, O2-deficient conditions in the root medium, and shoot growth was not reduced by >20% in any accession. Root porosity (% gas volume/root volume) in both the main and lateral roots increased in all accessions when in stagnant medium, but accessions differed in root porosity. Lateral root porosity was not, however, correlated with either shoot dry weight or root dry weight in stagnant conditions. No single accession of M. siculus had the highest tolerance to saline conditions both at germination and the vegetative stage, but some accessions (e.g. SA 40002 and SA 40004) performed consistently well under saline and waterlogged conditions. Further research and selection is warranted on these accessions with the aim to release a cultivar.

Responses of rice to Fe2+ in aerated and stagnant conditions: growth, root porosity and radial oxygen loss barrier

2014 ◽  
Vol 41 (9) ◽  
pp. 922 ◽  
Author(s):  
Jenjira Mongon ◽  
Dennis Konnerup ◽  
Timothy D. Colmer ◽  
Benjavan Rerkasem
Keyword(s):  
Growth Response ◽  
Oryza Sativa L ◽  
Dry Mass ◽  
Root Surface ◽  
Radial Oxygen Loss ◽  
Root Porosity ◽  
Oxygen Loss ◽  
O2 Transport ◽  
Bulk Medium ◽  
Root Aeration

Lowland rice (Oryza sativa L.) encounters flooded soils that are anaerobic and chemically reduced. Exposure of the roots to high soil Fe2+ concentrations can result in toxicity. Internal aeration delivering O2 to submerged roots via the aerenchyma is well understood, but the effect of Fe2+ on O2 transport in roots is less studied. We aimed to evaluate the effects of Fe2+ on growth and root aeration. O. sativa var. Amaroo was grown in aerobic and deoxygenated solutions with 0 mM, 0.18 mM, 0.36 mM, 0.54 mM or 0.72 mM Fe2+ using FeSO4.7H2O and a control with 0.05 mM Fe-EDTA. The treatments were imposed on 14-day-old plants (28–30 days old when harvested). Dry mass, shoot Fe concentration, root porosity and patterns of radial O2 loss (ROL) along roots were determined. In the aerobic solution, where Fe2+ was oxidised in the bulk medium, root dry mass increased with higher Fe2+; this was not the case in stagnant solutions, which had no significant root growth response, although Fe oxidation near the root surface was visible as a precipitate. In the highest Fe2+ treatment, shoot Fe concentrations in aerobic (667 mg kg–1) and stagnant (433 mg kg–1) solutions were below the level for toxicity (700 mg kg–1). Rice responded to high Fe2+ in aerobic conditions by increasing root porosity and inducing strong barriers to ROL. In stagnant conditions, root porosity was already high and the ROL barrier induced, so these root aeration traits were not further influenced by the Fe2+ concentrations applied.

scholarly journals Improvement of salt and waterlogging tolerance in wheat: comparative physiology of Hordeum marinum-Triticum aestivum amphiploids with their H. marinum and wheat parents

2013 ◽  
Vol 40 (11) ◽  
pp. 1168 ◽  
Author(s):  
Saud A. Alamri ◽  
Edward G. Barrett-Lennard ◽  
Natasha L. Teakle ◽  
Timothy D. Colmer
Keyword(s):  
Triticum Aestivum ◽  
Triticum Aestivum L ◽  
Radial Oxygen Loss ◽  
Waterlogging Tolerance ◽  
Oxygen Loss ◽  
Relative Growth ◽  
Hypoxic Conditions ◽  
Saline Treatment ◽  
Chinese Spring Wheat ◽  
Strong Barrier

Hordeum marinum Huds. is a waterlogging-tolerant halophyte that has been hybridised with bread wheat (Triticum aestivum L.) to produce an amphiploid containing both genomes. This study tested the hypothesis that traits associated with waterlogging and salinity tolerances would be expressed in H. marinum-wheat amphiploids. Four H. marinum accessions were used as parents to produce amphiploids with Chinese Spring wheat, and their responses to hypoxic and 200 mM NaCl were evaluated. Relative growth rate (RGR) in the hypoxic-saline treatment was better maintained in the amphiploids (58–71% of controls) than in wheat (56% of control), but the amphiploids were more affected than H. marinum (68–97% of controls). In hypoxic-saline conditions, leaf Na+ concentrations in the amphiploids were lower than in wheat (30–41% lower) but were 39–47% higher than in the H. marinum parents. A strong barrier to radial oxygen loss formed in basal root zones under hypoxic conditions in two H. marinum accessions; this barrier was moderate in the amphiploids, absent in wheat, and was weaker for the hypoxic-saline treatment. Porosity of adventitious roots increased with the hypoxic treatments; values were 24–38% in H. marinum, 16–27% in the amphiploids and 16% in wheat. Overall, the amphiploids showed greater salt and waterlogging tolerances than wheat, demonstrating the expression of relevant traits from H. marinum in the amphiploids.

The ability of aquatic macrophytes to increase root porosity and radial oxygen loss determines their resistance to sediment anoxia

2012 ◽  
Vol 46 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Damien G. Lemoine ◽  
Florian Mermillod-Blondin ◽  
Marie-Hélène Barrat-Segretain ◽  
Corinne Massé ◽  
Emmanuel Malet
Keyword(s):  
Aquatic Macrophytes ◽  
Radial Oxygen Loss ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Sediment Anoxia

A lack of aerenchyma and high rates of radial oxygen loss from the root base contribute to the waterlogging intolerance of Brassica napus

1999 ◽  
Vol 26 (1) ◽  
pp. 87 ◽  
Author(s):  
L.A.C.J. Voesenek ◽  
W. Armstrong ◽  
G.M. Bögemann ◽  
T.D. Colmer ◽  
M.P. McDonald
Keyword(s):  
Brassica Napus ◽  
Lateral Roots ◽  
Biomass Accumulation ◽  
Radial Oxygen Loss ◽  
Low Oxygen ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Basal Portion ◽  
Pre Treatment ◽  
Oxygen Profiles

The morphology and physiology of the response of two cultivars of Brassica napus to an anaerobic root medium was investigated. The cultivars Chikuzen and Topas showed a large reduction in growth rate when their roots were exposed to a de-oxygenated stagnant nutrient solution containing 0.1% w/v agar. Older seedlings (11 d old) were more sensitive to stagnant agar, expressed as biomass accumulation, than younger ones (5 d old). Brassica napus was characterized by a constitutively low root porosity (3–5%), typical for plant species with a low tolerance to waterlogging. A hypoxia pre- treatment (16 h; 2.25% O2) before exposure to de-oxygenated stagnant agar had no effect on the final number or length of lateral roots and adventitious roots. Brassica napus cv. Chikuzen is characterized by radial oxygen loss being most at the basal portion of the root, when a strong oxygen sink surrounds the root. Oxygen profiles through laterals of Brassica napus cv. Chikuzen show a typical pattern with low oxygen concentrations in the stele and somewhat higher levels in the cortex. Despite the continuum of intercellular air spaces in the root cortical tissue the lack of aerenchyma and therefore low rates of internal oxygen diffusion restricts root growth in anaerobic media and presumably contributes to the sensitivity of Brassica napus to waterlogging.

Growth responses of cool-season grain legumes to transient waterlogging

2007 ◽  
Vol 58 (5) ◽  
pp. 406 ◽  
Author(s):  
Z. Solaiman ◽  
T. D. Colmer ◽  
S. P. Loss ◽  
B. D. Thomson ◽  
K. H. M. Siddique
Keyword(s):  
Faba Bean ◽  
Grain Legumes ◽  
Sand Culture ◽  
Grain Legume ◽  
Growth Responses ◽  
Cool Season ◽  
Waterlogging Tolerance ◽  
Root Porosity ◽  
Root And Shoot Growth ◽  
Gas Volume

Transient waterlogging reduces the yield of cool-season grain legumes in several parts of the world. The tolerance of grain legumes to waterlogging may vary between and within species. This study investigated the effects of 7 days of waterlogging and subsequent recovery (10 days) on plant growth to evaluate the variation in tolerance among 7 cool-season grain legume species, in sand culture in glasshouse experiments. Additionally waterlogging tolerance of 6 faba bean genotypes was also evaluated. Tolerance to waterlogging as indicated by root and shoot growth (as % of drained controls) was ranked as follows: faba bean > yellow lupin > grass pea > narrow-leafed lupin > chickpea > lentil > field pea. Faba bean produced adventitious roots and aerenchyma leading to increased root porosity (9% gas volume per unit root volume). Among the 6 faba bean genotypes screened, accession 794 showed the best waterlogging tolerance, but it was also the slowest growing accession, which might have contributed to apparent tolerance (i.e. growth as % drained control). It is concluded that waterlogging tolerance in grain legumes varied between and within species, with faba bean being the most tolerant. The variation in tolerance identified within the limited set of faba bean genotypes evaluated suggests scope for further genetic improvement of tolerance in this species.

Changes in physiological and morphological traits of roots and shoots of wheat in response to different depths of waterlogging

2001 ◽  
Vol 28 (11) ◽  
pp. 1121 ◽  
Author(s):  
Al Imran Malik ◽  
Timothy D. Colmer ◽  
Hans Lambers ◽  
Marcus Schortemeyer
Keyword(s):  
Water Level ◽  
Adventitious Roots ◽  
Soil Surface ◽  
Net Photosynthesis ◽  
Field Capacity ◽  
Triticum Aestivum L ◽  
Waterlogging Tolerance ◽  
Root Porosity ◽  
Waterlogged Soil ◽  
Different Depths

The growth reduction of wheat (Triticum aestivum L.) during and after waterlogging stress depends on the depth of water from the soil surface. In a pot experiment with 3-week-old plants, soil was waterlogged for 14 d at the surface, or at 100 or 200 mm below the surface, and pots were then drained to assess recovery. A fully drained treatment kept at field capacity served as control. During waterlogging, the relative growth rate of roots decreased more than that of shoots (by 6–27% for shoots, by 15–74% for roots), and plant growth was reduced proportionally as the water level was increased. Light-saturated net photosynthesis was reduced by 70–80% for the two most severe waterlogging treatments, but was little affected for plants in soil waterlogged at 200 mm below the surface. The number of adventitious roots formed per stem in plants grown in waterlogged soil increased up to 1.5 times, but the number of tillers per plant was reduced by 24–62%. The adventitious roots only penetrated 85–116 mm below the water level in all waterlogging treatments. Adventitious root porosity was enhanced up to 10-fold for plants grown in waterlogged soil, depending on water level and position along the roots. Porosity also increased in basal zones of roots above the water level when the younger tissues had penetrated the waterlogged zone. Fourteen days after draining the pots, growth rates of plants where the soil had been waterlogged at 200 mm below the surface had recovered, while those of plants in the more severely waterlogged treatments had only partially recovered. These findings show that the depth of waterlogging has a large impact on the response of wheat both during and after a waterlogging event so that assessment of recovery is essential in evaluating waterlogging tolerance in crops.

Evaluation of root oxygenation and growth in baldcypress in response to short-term soil hypoxia

1994 ◽  
Vol 24 (4) ◽  
pp. 804-809 ◽  
Author(s):  
Hillarius K. Kludze ◽  
S. Reza Pezeshki ◽  
Ronald D. Delaune
Keyword(s):  
Net Photosynthesis ◽  
Soil Conditions ◽  
Growth Responses ◽  
Radial Oxygen Loss ◽  
Short Term ◽  
Aerenchyma Formation ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Soil Redox Potential ◽  
Soil Redox

Seedlings of baldcypress (Taxodiumdistichum (L.) Rich. var. distichum) were grown under laboratory and greenhouse conditions to determine the extent to which short-term soil hypoxia influences root aerenchyma–air space formation (expressed as a percentage of total root volume) and concomitant radial oxygen loss. Subsequent photosynthesis and growth responses were also determined. A colorimetric technique involving the use of Ti3+-citrate, a strong reducing compound, was used to quantify radial oxygen loss from whole root system. Soil redox potential of −250 ± 10 mV resulted in enhancement of both root porosity and radial oxygen loss as much as 3-fold compared with plants under well aerated conditions (515 ± 25 mV). The mean oxygen loss from roots was 1.4 mmol O2•g−1•day−1 in drained plants and 4.6 mmol O2•g−1•d−1 in flooded plants. Mean root porosity was 13.3 and 41.4% in drained and flooded plants, respectively. Stomatal conductance, net photosynthesis, and height growth were adversely affected by reduced soil conditions. Baldcypress exhibited an avoidance mechanism under reduced soil conditions by increasing aerenchyma formation and rhizosphere oxygenation at young ages. This may explain the significance of flooding episodes encountered in young stages in enabling baldcypress saplings and trees to tolerate flooding in later stages of the life cycle.

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