ORCID Profile
0000-0003-2902-4279
Current Organisations
Nanchang University
,
University of Western Australia
,
Department of Primary Industries and Regional Development
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Publisher: Oxford University Press (OUP)
Date: 22-01-2004
DOI: 10.1093/JXB/ERH041
Publisher: Oxford University Press (OUP)
Date: 11-11-2021
DOI: 10.1093/JXB/ERAA515
Abstract: Very few of the & Proteaceae species in south-western Australia cope with the high calcium (Ca) levels in young, calcareous soils (soil indifferent) most are Ca sensitive and occur on nutrient-impoverished, acidic soils (calcifuge). We assessed possible control points for Ca transport across roots of two soil-indifferent (Hakea prostrata and Banksia prionotes) and two calcifuge (H. incrassata and B. menziesii) Proteaceae. Using quantitative X-ray microanalysis, we investigated cell-specific elemental Ca concentrations at two positions behind the apex in relation to development of apoplastic barriers in roots of plants grown in nutrient solution with low or high Ca supply. In H. prostrata, Ca accumulated in outer cortical cells at 20 mm behind the apex, but [Ca] was low in other cell types. In H. incrassata, [Ca] was low in all cells. Accumulation of Ca in roots of H. prostrata corresponded to development of apoplastic barriers in the endodermis. We found similar [Ca] profiles in roots and similar [Ca] in leaves of two contrasting Banksia species. Soil-indifferent Hakea and Banksia species show different strategies to inhabit calcareous soils: H. prostrata intercepts Ca in roots, reducing transport to shoots, whereas B. prionotes allocates Ca to specific leaf cells.
Publisher: Wiley
Date: 22-03-2016
DOI: 10.1111/PCE.12658
Abstract: Photosynthesis of most seagrass species seems to be limited by present concentrations of dissolved inorganic carbon (DIC). Therefore, the ongoing increase in atmospheric CO2 could enhance seagrass photosynthesis and internal O2 supply, and potentially change species competition through differential responses to increasing CO2 availability among species. We used short-term photosynthetic responses of nine seagrass species from the south-west of Australia to test species-specific responses to enhanced CO2 and changes in HCO3 (-) . Net photosynthesis of all species except Zostera polychlamys were limited at pre-industrial compared to saturating CO2 levels at light saturation, suggesting that enhanced CO2 availability will enhance seagrass performance. Seven out of the nine species were efficient HCO3 (-) users through acidification of diffusive boundary layers, production of extracellular carbonic anhydrase, or uptake and internal conversion of HCO3 (-) . Species responded differently to near saturating CO2 implying that increasing atmospheric CO2 may change competition among seagrass species if co-occurring in mixed beds. Increasing CO2 availability also enhanced internal aeration in the one species assessed. We expect that future increases in atmospheric CO2 will have the strongest impact on seagrass recruits and sparsely vegetated beds, because densely vegetated seagrass beds are most often limited by light and not by inorganic carbon.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/FP13178
Abstract: A barrier to radial O2 loss (ROL) is an adaptive trait of many wetland plants, yet the signal(s) for barrier induction remain uncertain. We assessed the effects of monocarboxylic acids produced in waterlogged soils (acetic, propionic, N-butyric and caproic acids) on barrier formation in adventitious roots of the waterlogging tolerant Hordeum marinum Huds. These acids were applied in nutrient solution either in idually (at 0.4 mM) or as a mixture (‘cocktail’) at various total concentrations (0.1, 0.4 and 2 mM) at pH 6. The barrier to ROL was formed in basal zones of roots exposed to the cocktail at 0.4 mM, but not at 0.1 mM. In idually, only N-butyric and caproic acids invoked a ‘tight’ barrier in subapical positions of the roots. These organic acids accelerated deposition of suberin in the hypodermis/exodermis, but did not affect overall root porosity (% gas space). The organic acids also reduced root extension rate and tissue K+ effects were more pronounced at higher concentrations of the cocktail and as the molecular weight of the organic acid increased. Moreover, the cocktail at 2 mM and caproic acid at 0.4 mM alone induced development of intercellular occlusions, suggesting phytotoxin injury. In summary, even relatively low concentrations of organic acids can promote barrier formation in roots, and the potential toxicity of these compounds was demonstrated by declines in root growth and tissue K+ in the wetland species H. marinum.
Publisher: Oxford University Press (OUP)
Date: 16-12-2009
DOI: 10.1093/JXB/ERN300
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
Publisher: Wiley
Date: 15-09-2020
DOI: 10.1111/PCE.13865
Publisher: Springer Science and Business Media LLC
Date: 23-12-2019
DOI: 10.1038/S41598-019-56202-7
Abstract: Seeds of Australian species of the seagrass genus Posidonia are covered by a membranous wing that we hypothesize plays a fundamental role in seed establishment in sandy, wave swept marine environments. Dimensions of the seed and membrane were quantified under electron microscopy and micro-CT scans, and used to model rotational, drag and lift forces. Seeds maintain contact with the seabed in the presence of strong turbulence: the larger the wing, the more stable the seed. Wing surface area increases from P. sinuosa P. australis P.coriacea correlating with their ability to establish in increasingly energetic environments. This unique seed trait in a marine angiosperm corresponds to adaptive pressures imposed on seagrass species along 7,500 km of Australia’s coastline, from open, high energy coasts to calmer environments in bays and estuaries.
Publisher: Springer Science and Business Media LLC
Date: 30-09-2017
Publisher: Oxford University Press (OUP)
Date: 05-2009
DOI: 10.1093/JXB/ERP089
Abstract: Radial oxygen loss (ROL) and root porosity of rice (Oryza sativa L.) plants grown in either aerated or deoxygenated (stagnant) conditions were combined for the first time with extensive histochemical and biochemical studies of the apoplastic barriers in the roots' peripheral cell layers. Growth in stagnant solution significantly affected structural and, consequently, the physiological features of rice roots. It increased adventitious root porosity by about 20% and decreased the ROL towards the base to zero at a distance of 40 mm from the apex. By contrast, roots of plants grown in aerated solutions revealed the highest rates of ROL at 30 mm from the apex. Differences in the ROL pattern along the root were related to histochemical studies, which showed an early development of Casparian bands and suberin lamellae in the exodermis, and lignified sclerenchyma cells in roots of plants grown in deoxygenated solution. In agreement with anatomical studies, absolute contents of suberin and lignin in the outer part of the roots (OPR) were higher in plants grown in deoxygenated solution. Regardless of growth conditions, the levels of suberin and lignin increased along the roots towards the base. It is concluded that radial oxygen loss can be effectively restricted by the formation of a suberized exodermis and/or lignified sclerenchyma in the OPR. However, the relative contribution of suberin and lignin in the formation of a tight barrier is unclear. Knowing the permeability coefficient across OPR for roots of plants grown in both conditions will allow a more precise understanding of the mechanisms controlling ROL.
Publisher: Wiley
Date: 24-02-2022
DOI: 10.1111/PCE.14279
Abstract: Halophytes accumulate and sequester high concentrations of salt in vacuoles while maintaining lower levels of salt in the cytoplasm. The current data on cellular and subcellular partitioning of salt in halophytes are, however, limited to only a few dicotyledonous C
Publisher: Springer Science and Business Media LLC
Date: 09-02-2019
Publisher: CSIRO Publishing
Date: 2021
DOI: 10.1071/FP20200
Abstract: C4 perennial Urochloa spp. grasses are widely planted in extensive areas in the tropics. These areas are continuously facing waterlogging events, which limits plant growth and production. However, no commercial cultivar combining excellent waterlogging tolerance with superior biomass production and nutritional quality is available. The objective of this study was to identify root traits that can be used for selecting waterlogging tolerant species of Urochloa. Root respiration, root morphological, architectural and anatomical traits were evaluated in eight contrasting Urochloa spp. genotypes grown under aerated or deoxygenated stagnant solutions. Moreover, modelling of internal aeration was used to relate differences in root traits and root growth in waterlogged soils. Increased aerenchyma formation in roots, reduced stele area and development of a fully suberised exodermis are characteristics improving internal aeration of roots and therefore determining waterlogging tolerance in these C4 forage grasses. Waterlogging-tolerant genotypes had steeper root angles and greater root lengths than the waterlogging-sensitive genotypes. In stagnant conditions, waterlogging-tolerant genotypes had a greater proportion of aerenchyma and reduced stele area in root cross-sections, had deeper roots, steeper root angle and larger root biomass, which in turn, allowed for greater shoot biomass. Total root length had the strongest positive influence on shoot dry mass and can therefore be used as proxy for selecting waterlogging tolerant Urochloa genotypes.
Publisher: Wiley
Date: 29-05-2019
DOI: 10.1111/PCE.13562
Abstract: Waterlogged soils contain monocarboxylic acids produced by anaerobic microorganisms. These "organic acids" can accumulate to phytotoxic levels and promote development of a barrier to radial O
Publisher: Springer Science and Business Media LLC
Date: 29-08-2019
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JPLPH.2019.01.009
Abstract: Gibberellins are central to the regulation of plant development and growth. Action of gibberellins involves the degradation of DELLA proteins, which are negative regulators of growth. In barley (Hordeum vulgare), certain mutations affecting genes involved in gibberellin synthesis or coding for the barley DELLA protein (Sln1) confer dwarfism. Recent studies have identified new alleles of Sln1 with the capacity to revert the dwarf phenotype back to the taller phenotypes. While the effect of these overgrowth alleles on shoot phenotypes has been explored, no information is available for roots. Here, we examined aspects of the root phenotypes displayed by plants with various Sln1 gene alleles, and tested responses to growth in an O
Publisher: Oxford University Press (OUP)
Date: 18-05-2019
DOI: 10.1093/JXB/ERZ241
Abstract: Salinity tolerance is associated with Na ‘exclusion’ from, or ‘tissue tolerance’ in, leaves. We investigated whether two contrasting chickpea genotypes, salt-tolerant Genesis836 and salt-sensitive Rupali, differ in leaf tissue tolerance to NaCl. We used X-ray microanalysis to evaluate cellular Na, Cl, and K concentrations in various cell types within leaflets and also in secretory trichomes of the two chickpea genotypes in relation to photosynthesis in control and saline conditions. TEM was used to assess the effects of salinity on the ultrastructure of chloroplasts. Genesis836 maintained net photosynthetic rates (A) for the 21 d of salinity treatment (60 mM NaCl), whereas A in Rupali substantially decreased after 11 d. Leaflet tissue [Na] was low in Genesis836 but had increased markedly in Rupali. In Genesis836, Na was accumulated in epidermal cells but was low in mesophyll cells, whereas in Rupali cellular [Na] was high in both cell types. The excessive accumulation of Na in mesophyll cells of Rupali corresponded to structural damage to the chloroplasts. Maintenance of photosynthesis and thus salinity tolerance in Genesis836 was associated with an ability to ‘exclude’ Na from leaflets and in particular from the photosynthetically active mesophyll cells, and to compartmentalize Na in epidermal cells.
Publisher: Oxford University Press (OUP)
Date: 06-2019
DOI: 10.1093/AOB/MCZ071
Abstract: The perennial C4 grass Urochloa humidicola is widely planted on infertile acidic and waterlogging-prone soils of tropical America. Waterlogging results in soil anoxia, and O2 deficiency can reduce nutrient uptake by roots. Interestingly, both nutrient deficiencies and soil waterlogging can enhance root cortical cell senescence, and the increased gas-filled porosity facilitates internal aeration of roots. We tested the influence of nutrient supply and root-zone O2 on root traits, leaf nutrient concentrations and growth of U. humidicola. Plants were grown in pots in a completely randomized design under aerated or stagnant deoxygenated hydroponic conditions and six nutrient regimes, with low to high concentrations of all essential elements, for 28 d in a controlled-temperature greenhouse. The standard acid solution (SAS) used was previously designed based on infertile acidic soils of the tropical America savannas, and step increases in the concentration of SAS were used in aerated or deoxygenated 0.1 % agar solution, which mimics changes in gas composition in waterlogged soils. Measurements included shoot and root growth, root porosity, root anatomy, radial O2 loss, and leaf tissue nutrient concentrations. Shoot dry mass was reduced for plants in stagnant compared with aerated conditions at high, but not at low, levels of mineral nutrition. In low-nutrition stagnant solution, roots were shorter, of greater porosity and had smaller radial thickness of the stele. Suberized lamellae and lignified sclerenchyma, as well as a strong barrier to radial O2 loss, were documented for roots from all treatments. Leaf nutrient concentrations of K, Mg and Ca (but not N, P and S) were higher in aerated than in stagnant conditions. Under low-nutrient conditions, plant growth in stagnant solution was equal to that in aerated solution, whereas under higher-nutrient regimes growth increased but dry mass in stagnant solution was less than in aerated solution. Slow growth in low-nutrient conditions limited any further response to the low O2 treatment, and greater porosity and smaller stele size in roots would enhance internal O2 movement within roots in the nutrient-limited stagnant conditions. A constitutive barrier to radial O2 loss and aerenchyma facilitates O2 movement to the tips of roots, which presumably contributes to maintaining nutrient uptake and the tolerance of U. humidicola to low O2 in the root-zone.
Publisher: Springer Science and Business Media LLC
Date: 27-02-2012
Abstract: Rice ( Oryza sativa L.), unlike other cereals, can grow well in paddy fields and is highly tolerant of excess water stress, from either submergence (in which part or all of the plant is under water) or waterlogging (in which excess water in soil limits gas diffusion). Rice handles submergence stress by internal aeration and growth controls. A quiescence strategy based on Submergence-1A ( SUB1A ) or an escape strategy based on SNORKEL1 ( SK1 ) and SNORKEL2 ( SK2 ) is used for the growth controls. On the other hand, rice handles waterlogging stress by forming lysigenous aerenchyma and a barrier to radial O 2 loss (ROL) in roots in order to supply O 2 to the root tip. In this article, we summarize recent advances in understanding the mechanisms of responding to excess water stresses ( i.e ., submergence and waterlogging) in rice and other gramineous plants.
Publisher: Wiley
Date: 04-03-2015
DOI: 10.1111/PCE.12506
Abstract: The reproductive phase in chickpea (Cicer arietinum L.) is affected by salinity, but little is known about the underlying cause. We investigated whether high concentrations of Na(+) and Cl(-) in the reproductive structures influence reproductive processes. Chickpea genotypes contrasting in tolerance were subjected to 0, 35 or 50 mm NaCl applied to soil in pots. Flower production and abortion, pod number, percentage of empty pods, seed number and size were evaluated. The concentrations of Na(+) , K(+) and Cl(-) were measured in various plant tissues and, using X-ray microanalysis, in specific cells of developing reproductive structures. Genotypic variation in reproductive success measured as seed yield in saline conditions was associated with better maintenance of flower production and higher numbers of filled pods (and thus seed number), whereas seed size decreased in all genotypes. Despite the variation in reproductive success, the accumulation of Na(+) and Cl(-) in the early reproductive tissues of developing pods did not differ between a tolerant (Genesis836) and a sensitive (Rupali) genotype. Similarly, salinity tolerance was not associated with the accumulation of salt ions in leaves at the time of reproduction or in seeds at maturity.
Publisher: MDPI AG
Date: 14-02-2021
DOI: 10.3390/IJMS22041909
Abstract: Grain legumes are important crops, but they are salt sensitive. This research dissected the responses of four (sub)tropical grain legumes to ionic components (Na+ and/or Cl−) of salt stress. Soybean, mungbean, cowpea, and common bean were subjected to NaCl, Na+ salts (without Cl−), Cl− salts (without Na+), and a “high cation” negative control for 57 days. Growth, leaf gas exchange, and tissue ion concentrations were assessed at different growing stages. For soybean, NaCl and Na+ salts impaired seed dry mass (30% of control), more so than Cl− salts (60% of control). All treatments impaired mungbean growth, with NaCl and Cl− salt treatments affecting seed dry mass the most (2% of control). For cowpea, NaCl had the greatest adverse impact on seed dry mass (20% of control), while Na+ salts and Cl− salts had similar intermediate effects (~45% of control). For common bean, NaCl had the greatest adverse effect on seed dry mass (4% of control), while Na+ salts and Cl− salts impaired seed dry mass to a lesser extent (~45% of control). NaCl and Na+ salts (without Cl−) affected the photosynthesis (Pn) of soybean more than Cl− salts (without Na+) (50% of control), while the reverse was true for mungbean. Na+ salts (without Cl−), Cl− salts (without Na+), and NaCl had similar adverse effects on Pn of cowpea and common bean (~70% of control). In conclusion, salt sensitivity is predominantly determined by Na+ toxicity in soybean, Cl− toxicity in mungbean, and both Na+ and Cl− toxicity in cowpea and common bean.
Publisher: Elsevier BV
Date: 07-2023
Publisher: Frontiers Media SA
Date: 28-04-2021
Abstract: A better understanding of the genetics of salinity tolerance in chickpea would enable breeding of salt tolerant varieties, offering potential to expand chickpea production to marginal, salinity-affected areas. A Recombinant Inbred Line population was developed using accelerated-Single Seed Descent of progeny from a cross between two chickpea varieties, Rupali (salt-sensitive) and Genesis836 (salt-tolerant). The population was screened for salinity tolerance using high-throughput image-based phenotyping in the glasshouse, in hydroponics, and across 2 years of field trials at Merredin, Western Australia. A genetic map was constructed from 628 unique in-silico DArT and SNP markers, spanning 963.5 cM. Markers linked to two flowering loci identified on linkage groups CaLG03 and CaLG05 were used as cofactors during genetic analysis to remove the confounding effects of flowering on salinity response. Forty-two QTL were linked to growth rate, yield, and yield component traits under both control and saline conditions, and leaf tissue ion accumulation under salt stress. Residuals from regressions fitting best linear unbiased predictions from saline conditions onto best linear unbiased predictions from control conditions provided a measure of salinity tolerance per se , independent of yield potential. Six QTL on CaLG04, CaLG05, and CaLG06 were associated with tolerance per se . In total, 21 QTL mapped to two distinct regions on CaLG04. The first distinct region controlled the number of filled pods, leaf necrosis, seed number, and seed yield specifically under salinity, and co-located with four QTL linked to salt tolerance per se . The second distinct region controlled 100-seed weight and growth-related traits, independent of salinity treatment. Positional cloning of the salinity tolerance-specific loci on CaLG04, CaLG05, and CaLG06 will improve our understanding of the key determinants of salinity tolerance in chickpea.
Publisher: Oxford University Press (OUP)
Date: 05-02-2021
DOI: 10.1093/JXB/ERAB043
Abstract: Lack of O2 and high concentrations of iron (Fe) and manganese (Mn) commonly occur in waterlogged soils. The development of a barrier to impede radial O2 loss (ROL) is a key trait improving internal O2 transport and waterlogging tolerance in plants. We evaluated the ability of the barrier to ROL to impede the entry of excess Fe into the roots of the waterlogging-tolerant grass Urochloa humidicola. Plants were grown in aerated or stagnant deoxygenated nutrient solution with 5 µM or 900 µM Fe. Quantitative X-ray microanalysis was used to determine cell-specific Fe concentrations at two positions behind the root apex in relation to ROL and the formation of apoplastic barriers. At a mature zone of the root, Fe was ‘excluded’ at the exodermis where a suberized lamella was evident, a feature also associated with a strong barrier to ROL. In contrast, the potassium (K) concentration was similar in all root cells, indicating that K uptake was not affected by apoplastic barriers. The hypothesis that the formation of a tight barrier to ROL impedes the apoplastic entry of toxic concentrations of Fe into the mature zones of roots was supported by the significantly higher accumulation of Fe on the outer side of the exodermis.
Publisher: Springer Science and Business Media LLC
Date: 29-05-2019
Publisher: Wiley
Date: 18-09-2009
DOI: 10.1111/J.1469-8137.2009.03021.X
Abstract: *Despite the importance of the barrier to oxygen losses of the roots of hygrophytes growing in wet environments devoid of oxygen, there are few data available on permeability coefficients for O(2) across outer root cell layers (P(OPR)) and how they may change in response to low O(2). *A gas perfusion technique was used to measure the P(OPR) of rice (Oryza sativa) plants grown in either aerated or deoxygenated solution. The contributions of the apoplast and of living cells to the overall P(OPR) were characterized either by blocking apoplastic pores with precipitates of brown Cu(2)[Fe(CN)(6)] or by killing cells with 0.1 N HCl. *Compared with that of plants from aerated hydroponics, the P(OPR) of plants grown in deoxygenated medium was smaller by an order of magnitude. Precipitates resulting from CuSO(4)/K(4)[Fe(CN)(6)] treatment only formed in plants grown in aerated solution, where they reduced the P(OPR) by 5-20%. Killing of root segments with HCl increased P(OPR) in plants grown in both conditions by 20-55%. *The results indicated that apoplastic barriers effectively restricted radial O(2) loss. The relative role of the respiratory O(2) consumption of root peripheral layers increased as P(OPR) decreased.
Publisher: Wiley
Date: 22-06-2015
DOI: 10.1111/NPH.13535
Abstract: Oxygen deficiency associated with soil waterlogging adversely impacts root respiration and nutrient acquisition. We investigated the effects of O 2 deficiency and salinity (100 mM NaCl) on radial O 2 concentrations and cell‐specific ion distributions in adventitious roots of barley ( Hordeum vulgare ). Microelectrode profiling measured O 2 concentrations across roots in aerated, aerated saline, stagnant or stagnant saline media. X‐ray microanalysis at two positions behind the apex determined the cell‐specific elemental concentrations of potassium (K), sodium (Na) and chloride (Cl) across roots. Severe O 2 deficiency occurred in the stele and apical regions of roots in stagnant solutions. O 2 deficiency in the stele reduced the concentrations of K, Na and Cl in the pericycle and xylem parenchyma cells at the subapical region. Near the root apex, Na declined across the cortex in roots from the aerated saline solution but was relatively high in all cell types in roots from the stagnant saline solution. Oxygen deficiency has a substantial impact on cellular ion concentrations in roots. Both pericycle and xylem parenchyma cells are involved in energy‐dependent K loading into the xylem and in controlling radial Na and Cl transport. At root tips, accumulation of Na in the outer cell layers likely contributed to reduction of Na in inner cells of the tips.
Publisher: Wiley
Date: 05-2012
DOI: 10.1111/J.1365-3040.2012.02513.X
Abstract: Enhancement of oxygen transport from shoot to root tip by the formation of aerenchyma and also a barrier to radial oxygen loss (ROL) in roots is common in waterlogging-tolerant plants. Zea nicaraguensis (teosinte), a wild relative of maize (Zea mays ssp. mays), grows in waterlogged soils. We investigated the formation of aerenchyma and ROL barrier induction in roots of Z. nicaraguensis, in comparison with roots of maize (inbred line Mi29), in a pot soil system and in hydroponics. Furthermore, depositions of suberin in the exodermis/hypodermis and lignin in the epidermis of adventitious roots of Z. nicaraguensis and maize grown in aerated or stagnant deoxygenated nutrient solution were studied. Growth of maize was more adversely affected by low oxygen in the root zone (waterlogged soil or stagnant deoxygenated nutrient solution) compared with Z. nicaraguensis. In stagnant deoxygenated solution, Z. nicaraguensis was superior to maize in transporting oxygen from shoot base to root tip due to formation of larger aerenchyma and a stronger barrier to ROL in adventitious roots. The relationships between the ROL barrier formation and suberin and lignin depositions in roots are discussed. The ROL barrier, in addition to aerenchyma, would contribute to the waterlogging tolerance of Z. nicaraguensis.
Publisher: Elsevier BV
Date: 02-2018
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/CP19491
Abstract: Increasing the area sown to Ornithopus spp. (serradella) can reduce overall fertiliser requirements in Australian permanent pastures owing to their greater nutrient-acquisition efficiency than that of more widely used pasture legumes such as Trifolium spp. However, uncertainty regarding waterlogging tolerance of Ornithopus spp. may restrict their adoption in the high-rainfall zone of southern Australia. The waterlogging tolerance of cultivars and accessions of three species of Ornithopus (O. compressus, O. sativus and O. pinnatus) was determined by comparing root and shoot growth of plants in deoxygenated, stagnant agar nutrient solution (simulated waterlogging) with growth in aerated nutrient solution. The responses were benchmarked against the known waterlogging-tolerant pasture legume Trifolium michelianum. All Ornithopus cultivars were highly impacted by the deoxygenated stagnant treatment, including those of the anecdotally waterlogging-tolerant O. pinnatus. The 14-day stagnant treatment reduced root dry mass by 32–62% and relative growth rate (RGR) of roots by 36–73%. At the same time, root porosity increased from 1.4% to 8.8%. Following a 14-day recovery period, during which plants were returned to aerated nutrient solution, Ornithopus spp. failed to increase their shoot RGR (particularly for O. sativus cultivars) however, root RGR returned to that of the aerated controls. The stagnant conditions inhibited transport of potassium (K+) to the shoots in all species, as evidenced by lower shoot tissue K+ concentrations, with O. compressus and O. sativus most adversely affected (45% and 48% of the tissue concentration of aerated control plants). We conclude that the suggested area for Ornithopus spp. adaptation should not preclude areas of high rainfall because they have root adaptations that would assist them in coping with transient water excess however, soil types and surface profiles conducive to long-term waterlogging should be avoided to negate significant productivity losses.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Oxford University Press (OUP)
Date: 16-08-2019
DOI: 10.1093/AOB/MCY153
Publisher: Wiley
Date: 28-01-2020
DOI: 10.1111/NPH.16368
Abstract: Roots in flooded soils experience hypoxia, with the least O
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/FP16327
Abstract: A barrier to radial O2 loss (ROL) in roots is an adaptive trait of waterlogging-tolerant plants. Hordeum marinum Huds. is a waterlogging-tolerant species that, in contrast to its waterlogging-sensitive cultivated relatives, forms a tight barrier to ROL in basal root zones. To evaluate the nature of the barrier to ROL in roots, we combined measurements of ROL with histochemical and biochemical studies of two contrasting H. marinum accessions. H21 formed greater aerenchyma (up to 38% of cross-sectional area) and a tight barrier to ROL when grown under deoxygenated stagnant conditions, whereas the barrier was only partially formed in roots of H90 and aerenchyma was up to 26%. A tight barrier to ROL in roots of H21 corresponded with strong suberisation of the exodermis. In agreement with anatomical studies, almost all aliphatic suberin quantities were greater in roots of H21 grown under stagnant conditions compared with roots from aerated controls, and also to those in H90. By contrast to suberin, no differences in root lignification were observed between the two accessions raised in either aerated or stagnant conditions. These findings show that in adventitious roots of H. marinum, suberisation rather than lignification restricts ROL from the basal root zones.
Location: Australia
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