Ethylene, Water Relations and Tolerance to Waterlogging of Three Eucalyptus Species

1981 ◽  
Vol 8 (6) ◽  
pp. 497 ◽  
Author(s):  
TJ Blake ◽  
DM Reid
Keyword(s):  
Water Relations ◽  
Ethylene Production ◽  
Stomatal Closure ◽  
Initial Increase ◽  
Flood Tolerance ◽  
Eucalyptus Species ◽  
Aerenchyma Formation ◽  
Subsequent Increase ◽  
Exogenous Ethylene ◽  
Lower Stem

Effects of flooding of the roots on ethylene levels and water relations of flood-tolerant and flood-susceptible eucalypts were studied in an attempt to shed light on mechanisms of adaptation to waterlogging. The order of most flood tolerant to least tolerant were Eucalyptus camaldulensis Dehnh., E. globulus Labill., and E. obliqua L'Hérit. Tolerance of flooding in E. camaldulensis was associated with an initial increase in ethylene production by the roots, a subsequent increase in ethylene evolution by the lower stem, and basal stem thickening and aerenchyma formation in response to flooding. In addition, exogenous ethylene gas (500 �ll-1) increased stem thickening in E. camaldulensis seedlings compared with untreated controls. Although treatment of the flood-susceptible E. obliqua with ethylene gas resulted in stem hypertrophy, flooding did not induce either the stem thickening response nor did it stimulate ethylene production. Eucalyptus globulus was intermediate as regards flood tolerance and basal stem thickening; ethylene production by the roots increased but it did not show marked hypertrophy of the unflooded lower stem and was unresponsive to exogenous ethylene gas. Water stress was not associated with flooding damage in eucalypts. Early stomatal closure as shown by high leaf stomatal resistances occurred in both the flood-tolerant and the flood-susceptible species and leaf water potential did not decrease in any of the three species in response to flooding. The results suggest that the high degree of flood-tolerance in E. camaldulensis may be due to (1) increased ethylene production which results in (2) tissue hypertrophy and basal stem thickening. Such tissue hypertrophy would permit the plant to eliminate the build-up of the potentially toxic gas ethylene and could also enhance the transport of oxygen to the roots. The other species lacked one or other of these adaptive mechanisms and exhibited a lesser degree of flood tolerance.

Changes in Water Relations Associated With Infection by Phytophthora cinnamomi

1982 ◽  
Vol 30 (4) ◽  
pp. 393 ◽  
Author(s):  
P Dawson ◽  
G Weste
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Relative Water Content ◽  
Phytophthora Cinnamomi ◽  
Stomatal Closure ◽  
Leaf Conductance ◽  
Eucalyptus Species ◽  
Significant Difference ◽  
Relative Water

Changes in water relations associated with infection by Phytophthora cinnamomi were measured for three native species from the Brisbane Ranges forest. Measurements included leaf conductance, stomatal aperture, transpiration, water potential and relative water content in container-grown plants of Isopogon ceratophyllus (highly susceptible), Eucalyptus macrorhyncha (field-susceptible) and E. goniocalyx (field-resistant) maintained in a glasshouse. I. Ceratophyllus showed a large and highly significant difference in water relations between infected and control plants. Infection was associated with stomatal closure, reduced transpiration, reduced relative water content and leaf water potential. These reactions to infection were not observed for either of the glasshouse-reared Eucalyptus species. In the forest diseased E. macrorhyncha showed significant differences in leaf conductance compared with healthy trees, whereas E. goniocalyx forest trees showed less infection-associated variation. This variation in leaf conductance was not associated with water stress.

Nitrate increases ethylene production and aerenchyma formation in roots of lowland rice plants under water stress

2017 ◽  
Vol 44 (4) ◽  
pp. 430 ◽  
Author(s):  
Cuimin Gao ◽  
Lei Ding ◽  
Yingrui Li ◽  
Yupei Chen ◽  
Jingwen Zhu ◽  
...  
Keyword(s):  
Water Stress ◽  
Ethylene Production ◽  
Oryza Sativa L ◽  
Acc Synthase ◽  
Ethylene Biosynthesis ◽  
Lowland Rice ◽  
Shoot Biomass ◽  
Aerenchyma Formation ◽  
Exogenous Ethylene ◽  
Root Cortical Aerenchyma

Ethylene increases root cortical aerenchyma formation in maize (Zea mays L.), rice (Oryza sativa L.) and other species. To further investigate the effects of nitrate, ammonium and water stress on ethylene production and aerenchyma formation in roots, two lowland rice cultivars (Shanyou 63, hybrid indica, and Yangdao 6, inbred indica) were cultured hydroponically with 10% (w/v) polyethylene glycol to simulate water stress. Water stress decreased shoot biomass, stomatal conductivity and leaf water potential in cultivars fed with nitrate but not with ammonium. Water stress induced more aerenchyma formation in cultivars fed with nitrate rather than ammonium, and increased cortical aerenchyma was found in Yangdao 6. Endogenous ethylene production by roots increased significantly under water stress in plants fed with nitrate rather than ammonium. Exogenous ethylene stimulated root cortical aerenchyma formation. Expression of the ethylene biosynthesis gene 1-aminocyclo-propane-1-carboxylic acid (ACC) synthase (ACS5) was greater in roots fed with nitrate rather than ammonium in the presence and absence of water stress. The expression of ethylene signalling pathway genes involved in programmed cell death (lesion-simulating disease (L.S.D.)1.1 and L.S.D.2; enhanced disease susceptibility (EDS) and phytoalexin-deficient (PAD4)) were regulated by the N form and water stress. In plants of cultivars fed with ammonium, L.S.D.1.1 expression increased under water stress, whereas L.S.D.2, EDS and PAD4 expression decreased. In conclusion, nitrate increases ethylene production and cortical aerenchyma formation in roots of water-stressed lowland rice. However, ammonium increased L.S.D.1.1 expression in water-stressed roots, and decreased ACS5, EDS and PAD4 expression, which would inhibit ethylene production and aerenchyma formation.

Influence of cold hardening on water relations of three Eucalyptus species

1990 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
R. Valentini ◽  
G. S. Mugnozza ◽  
E. Giordano ◽  
E. Kuzminsky
Keyword(s):  
Water Relations ◽  
Cold Hardening ◽  
Eucalyptus Species

Comparative Water Relations, Photosynthesis, and Growth of Soybean (Glycine max) and Seven Associated Weeds

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 318-323 ◽  
Author(s):  
David T. Patterson ◽  
Elizabeth P. Flint
Keyword(s):  
Glycine Max ◽  
Water Relations ◽  
Dry Matter ◽  
Stomatal Closure ◽  
Growth Dynamics ◽  
Dry Matter Production ◽  
Matter Production ◽  
Net Assimilation ◽  
Prickly Sida ◽  
Smooth Pigweed

Growth dynamics, water relations, and photosynthesis of soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), jimsonweed (Datura stramoniumL.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), smooth pigweed (Amaranthus hybridusL.), spurred anoda [Anoda cristata(L.) Schlect.], and velvetleaf (Abutilon theophrastiMedic.) were compared in a controlled-environment greenhouse programmed for 32C day and 23C night temperatures. Net photosynthetic rates, net assimilation rates, and water-use efficiency on a whole-plant or single-leaf basis were greatest in the C4-plant, smooth pigweed. Total dry-matter production at 29 days after planting was greatest in common cocklebur and least in jimsonweed. Interspecific differences in dry-matter production were highly positively correlated with leaf area duration and negatively correlated with net assimilation rate. Threshold leaf water-potential levels causing stomatal closure varied among species. The stomata of jimsonweed were the most sensitive to water stress and those of prickly sida were the least sensitive.

scholarly journals Inhibition of Ethylene Production in Banana Fruit Tissue by Ethylene Treatment

1971 ◽  
Vol 24 (4) ◽  
pp. 885 ◽  
Author(s):  
M Vendrell ◽  
WB Mcglasson
Keyword(s):  
Ethylene Production ◽  
Banana Fruit ◽  
Duration Of Treatment ◽  
Fruit Tissue ◽  
Ethylene Treatment ◽  
Chlorophyll Breakdown ◽  
Endogenous Ethylene ◽  
Exogenous Ethylene

A temporary ethylene treatment, sufficient to stimulate ripening in banana fruit tissue, partly suppresses endogenous ethylene production and the evolution of ethylene from methionine. The production of endogenous ethylene does not return to rates normal for naturally ripening fruit after the exogenous ethylene is removed. The extent of inhibition is related to the concentration of applied ethylene up to 5-10 p.p.m., and to the duration of treatment within the period 12 hI' to 3 days. Other characteristics of ripening appear to develop normally, except in the shorter treatments, where respiration shows a lower climacteric peak and chlorophyll breakdown is delayed.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. II. Root and Shoot Water Relations of Lupin During Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 415 ◽  
Author(s):  
CR Jensen ◽  
IE Henson ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Transport ◽  
Water Uptake ◽  
Water Relations ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Water Uptake ◽  
Leaf Conductance

Plants of Lupinus cosentinii Guss. cv. Eregulla were grown in a sandy soil in large containers in a glasshouse and exposed to drought by withholding water. Under these conditions stomatal closure had previously been shown to be initiated before a significant reduction in leaf water potential was detected. In the experiments reported here, no significant changes were found in water potential or turgor pressure of roots or leaves when a small reduction in soil water potential was induced which led to a 60% reduction in leaf conductance. The decrease in leaf conductance and root water uptake closely paralleled the fraction of roots in wet soil. By applying observed data of soil water and root characteristics, and root water uptake for whole pots in a single-root model, the average water potential at the root surface was calculated. Potential differences for water transport in the soil-plant system, and the resistances to water flow were estimated using the 'Ohm's Law' analogy for water transport. Soil resistance was negligible or minor, whereas the root resistance accounted for 61-72% and the shoot resistance accounted for about 30% of the total resistance. The validity of the measurements and calculations is discussed and the possible role of root- to-shoot communication raised.

scholarly journals Water relations, photosynthesis, xylem embolism and accumulation of carbohydrates and cyclitols in two Eucalyptus species (E. camaldulensis and E. torquata) subjected to dehydration–rehydration cycle

Trees ◽  
2020 ◽  
Vol 34 (6) ◽  
pp. 1439-1452
Author(s):  
Samira Souden ◽  
Mustapha Ennajeh ◽  
Sarra Ouledali ◽  
Nooman Massoudi ◽  
Hervé Cochard ◽  
...  
Keyword(s):  
Water Relations ◽  
Eucalyptus Species ◽  
Xylem Embolism

Turgor-Volume Regulation and Cellular Water Relations of Nicotiana tabacum Roots Grown in High Salinities

1989 ◽  
Vol 16 (6) ◽  
pp. 517 ◽  
Author(s):  
SD Tyerman ◽  
P Oats ◽  
J Gibbs ◽  
M Dracup ◽  
H Greenway
Keyword(s):  
Nicotiana Tabacum ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Volume Regulation ◽  
Turgor Pressure ◽  
Root Hairs ◽  
Solution Culture ◽  
Pressure Probe ◽  
Initial Increase ◽  
Solute Permeability

Nicotiana tabacum plants were grown in solution culture with salinity treatments of 1, 100 and 200 mol m-3 [NaCl], in Hoagland solution. After several weeks, solute concentrations and osmotic pressure of cell sap from the roots were measured. Increases in cellular [Na+] and [Cl-] and a smaller reduction in [K+] accounted for the difference in sap osmotic pressure between the 200 mol m-3 and 1 mol m-3 treatments. Turgor pressure (P) of fully expanded cortex cells measured with the pressure probe were 0.48 MPa in 1 mol m-3, 0.24 MPa in 100 mol m-3, 0.20 MPa in 200 mol m-3, and these values agreed with those calculated by difference between internal and external osmotic pressure. Low values of volumetric elastic modulus (ε), ranging from 1.2 MPa to 3.0 MPa at P = 0.42 MPa were obtained, which accounted for long equilibration times to changes in water potential. There was no effect of high salinities on ε after accounting for the fact that ε was a function of P and neither was there an effect on hydraulic conductivity (Lp), which ranged between 1.9 × 10-8 and 24.1 × 10-8 m s-1 Mpa-1. At 200 mol m-3 [NaCl]o, and to a lesser degree at 100 mol m-3 [NaCl]o, root hairs became deformed to resemble spherical bladders (mean diameter = 88 �m) which displayed similar P and water relations to other epidermal cells and cortex cells. In other experiments the response to a sudden reduction in [NaCl], from 200 to 1 mol m-3 was studied. P of cortex cells first rapidly increased from about 0.15 MPa to 0.53 MPa and then slowly declined with a half time of about 35 min to a new steady state of 0.3 MPa. This level was maintained in intact roots for at least 48 h. The rate of the initial increase in P is limited by water flow into the cells while the slow decline is limited by solute efflux from the cells with water following osmotically. The efflux was mainly in response to reduced external osmotic pressure rather than [NaCl]o. Efflux of Na+, K+ and Cl- accounted for the decrease in internal osmotic pressure but it is possible that the membrane also became more permeable to sugars. With the exception of bladder hairs, the overall integrity of the cell membrane was maintained since Lp did not increase and P declined smoothly to the new level with no evidence of rupture and resealing of the membrane. It is argued that the loss of solutes after the step down in external osmotic pressure consists of turgor or volume regulation in which solute permeability increases steeply as turgor or volume goes above a threshold.

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