Phosphorus effects on radial oxygen loss, root porosity and iron plaque in two mangrove seedlings under cadmium stress

2017 ◽  
Vol 119 (1) ◽  
pp. 262-269 ◽  
Author(s):  
Minyue Dai ◽  
Jingchun Liu ◽  
Wenwen Liu ◽  
Haoliang Lu ◽  
Hui Jia ◽  
...  
Keyword(s):  
Cadmium Stress ◽  
Iron Plaque ◽  
Radial Oxygen Loss ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Mangrove Seedlings

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.

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.

The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

2010 ◽  
Vol 158 (5) ◽  
pp. 1189-1196 ◽  
Author(s):  
H. Cheng ◽  
Y. Liu ◽  
N.F.Y. Tam ◽  
X. Wang ◽  
S.Y. Li ◽  
...  
Keyword(s):  
Zinc Uptake ◽  
Root Anatomy ◽  
Radial Oxygen Loss ◽  
Oxygen Loss ◽  
Mangrove Seedlings

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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