Influence of temperature and water potential on growth of Botrytis allii

1984 ◽  
Vol 62 (8) ◽  
pp. 1567-1570 ◽  
Author(s):  
S. C. Alderman ◽  
M. L. Lacy
Keyword(s):  
Water Potential ◽  
Growth Rates ◽  
Radial Growth ◽  
Leaf Tissue ◽  
Dead Leaf ◽  
Salt Solutions ◽  
Influence Of Temperature ◽  
Water Potentials ◽  
Botrytis Allii ◽  
Peg 8000

Water potentials for optimum growth varied with temperature and with the material used to alter water potential. On prune extract – lactose – yeast extract (PLY) agar adjusted with KCl, sucrose, NaCl, or polyethylene glycol (PEG) 8000, growth rates were optimal at 20 or 25 °C and at water potentials of −5 to −10 bars (1 bar = 100 kPa). At 30 °C growth rates were optimal at −35 to −45 bars in the presence of KCl or sucrose and at −10 to −20 bars with NaCl or PEG 8000. Radial growth rates in dried onion leaves, adjusted to various water potentials over salt solutions in sealed chambers, corresponded to those on PLY media adjusted to the same water potentials with KCl or sucrose. Growth was halted at water potentials below −95 to −100 bars in onion leaves or in PLY agar containing KCl or sucrose osmotica, but it was halted at −50 to −60 bars in the presence of NaCl or PEG 8000. Growth of Botrytis allii in onion bulb tissue was optimal at 20 °C. Extent of bulb colonization increased linearly with the logarithm of increasing inoculum concentrations applied to small wounds in bulbs. Survival of B. allii in dead leaf tissue declined rapidly after 3 and 9 days at 37 and 32 °C, respectively.

scholarly journals `Ben Lear' and `Stevens' Cranberry Root and Shoot Growth Response to Soil Water Potential

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Area ◽  
Growth Rates ◽  
Soil Water Potential ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Water Potentials ◽  
Whole Plant

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.

Some notes concerning the measurement of water potentials of leaf tissue with specific reference to Tsuga canadensis and Picea abies

1975 ◽  
Vol 53 (8) ◽  
pp. 784-788 ◽  
Author(s):  
A. J. B. Talbot ◽  
M. T. Tyree ◽  
J. Dainty
Keyword(s):  
Picea Abies ◽  
Water Potential ◽  
Leaf Tissue ◽  
Tsuga Canadensis ◽  
Specific Reference ◽  
Wound Area ◽  
Tissue Volume ◽  
Water Potentials ◽  
Detached Leaves ◽  
Pressure Bomb

Psychrometric measurements of the water potentials of leaves of Tsuga canadensis (L.) Carr. and Picea abies L. are compared with the water potentials of the shoots from which they came as measured by the pressure-bomb technique. Agreement between the two techniques is good when whole leaves are used in the psychrometer chamber, but deviations occur when bisected leaves are used in which the wound area to tissue volume is very small (1 to 2 cm2/cm3 of leaf tissue). Psychrometer determinations of water potential of these detached leaves are much more sensitive to cutting than in other species, e.g., sunflower and pepper (2). A more reliable means of measuring turgor and osmotic pressures in leaves is proposed.

NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS

1988 ◽  
Vol 68 (3) ◽  
pp. 569-576 ◽  
Author(s):  
YADVINDER SINGH ◽  
E. G. BEAUCHAMP
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Incubation Period ◽  
Relative Rate ◽  
Soil Water Potential ◽  
Nitrification Inhibitor ◽  
Silt Loam ◽  
Nitrogen Transformations ◽  
Water Potentials ◽  
Initial Soil

Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production

Photosynthesis Response of Sunlit and Shade Pepper (Capsicum annuum) Leaves at Different Positions in the Canopy Under Two Water Regimes

1994 ◽  
Vol 21 (3) ◽  
pp. 377 ◽  
Author(s):  
A Alvino ◽  
M Centritto ◽  
FD Lorenzi
Keyword(s):  
Water Potential ◽  
Capsicum Annuum ◽  
Leaf Water Potential ◽  
Co2 Exchange ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Water Regimes ◽  
Water Potentials ◽  
Sun And Shade ◽  
Shade Leaves

Pepper (Capsicum annuum L.) plants were grown in 1 m2 lysimeters under two different water regimes in order to investigate differences in the spatial arrangements of the leaves and to relate this to daily assimilation rates of leaves of the canopy. The control regime (well-watered (W) treatment) was irrigated whenever the accumulated 'A' pan evaporation reached 4 cm, whereas the water-stressed (S) treatment was watered whenever the predawn leaf water potential fell below -1 MPa. During the growing cycle, equal numbers of sun and shade leaves were chosen from the apical, middle and basal parts of the canopy, corresponding to groups of leaves of increasing age. The CO2 exchange rate (CER) was measured at 0830, 1230 and 1530 hours on 8 days along the crop cycle, on leaves in their natural inclination and orientation. Leaf water potentials were measured on apical leaves before dawn and concurrently with gas exchange measurements. Control plants maintained predawn leaf water potential at -0.3 MPa, but S plants reached values lower than -1.2 MPa. Midday leaf water potentials were about twice as low in the S plants as in the controls. Water stress reduced LA1 during the period of crop growth, and dry matter production at harvest. Stressed apical leaves appeared to reduce stress by changing their inclination. They were paraheliotropic around midday and diaheliotropic at 0830 and 1530 hours. The CER values of the S treatment were significantly lower than those of the W treatment in apical and middle leaves, whereas the CER of basal leaves did not differ in either treatments. In the S treatment, reduction in the CER values of sunlit apical leaves was more evident in the afternoon than at midday or early in the morning, whereas basal leaves were less affected by water than basal stress leaves if sunlit, and negligibly in shaded conditions.

scholarly journals Dehydration of Macromolecules I. Effect of Dehydration-Rehydration on Indoleacetic Acid Oxidase, Ribonuclease, Ribulosediphosphate Carboxylase, and Ketose-1-Phosphate Aldolase

1973 ◽  
Vol 26 (3) ◽  
pp. 591 ◽  
Author(s):  
B Darbyshire ◽  
BT Steer
Keyword(s):  
Water Potential ◽  
Indoleacetic Acid ◽  
Acid Oxidase ◽  
Enzyme Preparations ◽  
Water Potentials ◽  
Membrane Technique ◽  
Indoleacetic Acid Oxidase

A pressure-membrane technique has been developed to physically manipulate the water potential of in vitro enzyme preparations. Enzyme preparations were subjected to a range of water potentials using this technique.

scholarly journals Effects of Matric and Osmotic Priming Treatments on Broccoli Seed Germination

1996 ◽  
Vol 121 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Lewis W. Jett ◽  
Gregory E. Welbaum ◽  
Ronald D. Morse
Keyword(s):  
Polyethylene Glycol ◽  
Seed Germination ◽  
Root Growth ◽  
Growth Rates ◽  
Germination Rate ◽  
Membrane Integrity ◽  
Seed Vigor ◽  
Radicle Emergence ◽  
The Mean ◽  
Peg 8000

Priming, a controlled-hydration treatment followed by redrying, improves the germination and emergence of seeds from many species. We compared osmotic and matric priming to determine which was the most effective treatment for improving broccoli seed germination and to gain a greater understanding of how seed vigor is enhanced by priming. Broccoli (Brassica oleracea L. var. italica) seeds were osmotically primed in polyethylene glycol (PEG 8000) at -1.1 MPa or matrically primed in a ratio of 1.0 g seed:0.8 g synthetic calcium silicate (Micro-Cel E):1.8 ml water at -1.2 MPa. In the laboratory, germination rates and root lengths were recorded from 5 to 42C and 10 to 35C, respectively. Broccoli seeds germinated poorly at >35C. Root growth after germination was more sensitive to temperatures >30C and <15C than radicle emergence. Matric and osmotic priming increased germination rate in the laboratory, greenhouse, and field. However, matric priming had a greater effect on germination and root growth rates from 15 to 30C. Neither priming treatment affected minimum or maximum germination or root growth temperatures. Both priming treatments decreased the mean thermal time for germination by >35%. The greater germination performance of matrically primed seeds was most likely the result of increased oxygen availability during priming, increased seed Ca content, or improved membrane integrity.

Determination of growth and maintenance coefficients by calorespirometry

2004 ◽  
Vol 31 (9) ◽  
pp. 929 ◽  
Author(s):  
Sannali Matheson ◽  
Derek J. Ellingson ◽  
V. Wallace McCarlie ◽  
Bruce N. Smith ◽  
Richard S. Criddle ◽  
...  
Keyword(s):  
Growth Rates ◽  
Leaf Age ◽  
Leaf Tissue ◽  
Heat Rate ◽  
Regulation Of Respiration ◽  
Convolvulus Arvensis ◽  
Verbascum Thapsus ◽  
Mature Leaves ◽  
Substrate Variation ◽  
Maintenance Coefficients

This study describes a calorespirometric method for determining the coefficients of the correlation of specific respiration and growth rates. To validate the calorespirometric method, coefficients obtained from calorespirometric data are compared with coefficients obtained from mass and elongation growth rates measured at three temperatures on oat (Avena sativa L.) shoots. Calorespirometric measurements were also made on leaf tissue of varying age from Verbascum thapsus L., Convolvulus arvensis L., and Helianthus tuberosus Nutt. Measurements on A. sativa, C. arvensis and H. tuberosus at several temperatures show maintenance coefficients generally increase with temperature, but, in disagreement with accepted theory, growth coefficients for C. arvensis and A. sativa vary with temperature. A comparison of rates expressed as intensive and extensive quantities showed that the decline in specific respiration and growth rates with age is caused by dilution-by-growth, not down-regulation of respiration rate by reduced demand. The ratio of heat rate to CO2 rate increases with leaf age, and, for fully mature leaves, exceeds the maximum possible value for carbohydrates. This shows that the catabolic substrate may vary with leaf age in immature leaves and cannot be assumed to consist only of carbohydrates in mature leaves. Dilution-by-growth, substrate variation, and inseparability of the variables in the growth-maintenance model all complicate physiological interpretation of the slope and intercept of plots of specific respiration rates v. specific growth rates.

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