Dehydration tolerance of five bur oak (Quercusmacrocarpa) seed sources from Texas, Nebraska, Minnesota, and New York

1993 ◽  
Vol 23 (3) ◽  
pp. 387-393 ◽  
Author(s):  
Michael R. Kuhns ◽  
Walter W. Stroup ◽  
G. Michael Gebre
Keyword(s):  
New York ◽  
Water Potential ◽  
Electrolyte Leakage ◽  
Dry Period ◽  
Membrane Injury ◽  
North Central ◽  
Dehydration Tolerance ◽  
Seed Sources ◽  
Water Potentials ◽  
Bur Oak

Dehydration tolerance was studied in saplings of five widely distributed sources of Quercusmacrocarpa Michx. growing together in an outdoor plot in Lincoln, Nebraska. Membrane electrolyte leakage, expressed as percent injury, was used as a measure of dehydration tolerance. Leaves were excised from several plants of each source on July 16 after a long dry period and on August 26 after a long moist period. Leaves were allowed to dry for various times in a laboratory, their water potential was measured, and membrane injury was determined. Regressions were calculated for percent injury versus leaf water potential, so sources could be compared at selected water potentials. All sources showed increased leakage at lower water potentials, with most leakage occurring below a water potential of −3 MPa. A source from Texas had the highest leakage, 23% at −6 MPa in August, while a source from a more xeric site in north central Nebraska generally had the lowest leakage. Stress preconditioning appeared to affect leakage, with leakage often significantly lower in July than in August.

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.

PUBLIC HEALTH, NURSING AND MEDICAL SOCIAL WORK

PEDIATRICS ◽  
1949 ◽  
Vol 3 (6) ◽  
pp. 865-865
Keyword(s):  
Public Health ◽  
New York ◽  
New England ◽  
Central Area ◽  
General Distribution ◽  
North Central ◽  
Medical Social Work ◽  
South Central ◽  
Health Nursing ◽  
West North Central

A "Measles Year" ACCORDING to the reports of the U.S. Public Health Service, this is a measles year. For example, a total of 15,266 cases were reported for the week of January 29, 1949, compared to a five year median of 6,712. Increases were reported in all geographic divisions except New England and the West North Central area. The largest increases were in the East South Central and South Atlantic areas. Of the total that week, an aggregate of 10,522 cases occurred in the following 12 states: Massachusetts, New York, Pennsylvania, Michigan, Wisconsin, Maryland, Virginia, Kentucky, Alabama, Texas, Oregon, and California. In contrast to measles, the influenza incidence picture shows an unusually low number of cases. For example, in the week of January 29, 1949, a total of 4,534 cases was reported, compared to a five year median of 14,253. List of Publications Under date of March 1948 the Children's Bureau has published a list of its publications. The list includes all publications of the Children's Bureau issued since 1945 that are available for general distribution; earlier publications of the Bureau that are still available and of current value; some reprints of material published elsewhere but reproduced by or for the Bureau. Pediatricians will find some of these reprints of particular interest. Single copies of the list and of most of the publications can be obtained free from the Children's Bureau, Washington 25, D.C.

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 Characteristics of patients with acute heart failure in North Central Nigeria

2021 ◽  
Vol 9 (3) ◽  
pp. 221-235
Author(s):  
J.A. Ogunmodede ◽  
P.M. Kolo ◽  
M.O. Bojuwoye ◽  
B.F. Dele-Ojo ◽  
A.J. Ogunmodede ◽  
...  
Keyword(s):  
Heart Failure ◽  
New York ◽  
Heart Association ◽  
Public Health Education ◽  
Sub Saharan Africa ◽  
Aetiological Factor ◽  
Cross Sectional ◽  
Early Presentation ◽  
North Central ◽  
Sub Saharan

Objectives: Heart failure (HF) is an important cause of hospital admission in Nigeria. HF is increasingly prevalent because the population is aging and HF epidemiology is changing. We aimed at profiling the socio-demographic, clinical and echocardiographic (Echo)  characteristics of patients admitted for acute HF. This is one of the largest cohorts of HF patients profiled in Nigeria so far. Methods: Cross sectional design. Socio-demographic, clinical and Echo data were collected from 455 patients admitted for AHF at University of Ilorin Teaching Hospital, North central, Nigeria. Results: Mean age of patients was 58.9± 15.7years, (men were older than women, P= 0.006). 265(58.2%) were males, most patients were aged >60 years, 4.8% had pre-existing Type2 Diabetes mellitus. 53.2% of patients presented in New York Heart Association Stages III and IV. Median duration of admission was 11days (IQR, 6-17), intrahospital mortality- 11.6%. Hypertension was the commonest aetiological factor (62.4%), followed by dilated cardiomyopathy 17.6%, rheumatic heart disease (6.6%), Peripartum cardiomyopathy (5.3%), and others. Conclusion: AHF patients in our study are older than those in previous studies in Nigeria and sub-Saharan Africa. Hypertension is main driver of AHF, and patients largely present with clinically advanced disease necessitating stronger public health education about risk factors and early presentation.  

Lamottia (Favositida, Tabulata) from the Decorah Formation (Kirkfieldian, Ordovician) of Iowa

1988 ◽  
Vol 62 (3) ◽  
pp. 424-426
Author(s):  
Jeffrey C. Edwards
Keyword(s):  
New York ◽  
Thin Section ◽  
Geographic Range ◽  
Upper Ordovician ◽  
North Central ◽  
The North ◽  
Tabulate Coral ◽  
Longitudinal Pattern ◽  
Stratigraphic Range ◽  
Diagenetic Feature

The early tabulate coral Lamottia heroensis has been identified from the Ion Member of the Decorah Formation (Upper Ordovician) in northeast Iowa. This extends the stratigraphic range of this species upward from Lower Chazyan to Kirkfieldian, and extends the geographic range from the Vermont-New York border area to include the north-central Midcontinent. Thin section and SEM studies strongly support the contention that the longitudinal pattern of alternating light and dark bands observed in corallite walls reflects a primary structural grain rather than a secondary diagenetic feature.

Corrigenda - Measurement of the total water potential of aqueous solutions of polyethylene glycol - A comparison between osmometer, thermocouple psychrometer and equilibrated soil cores

Soil Research ◽  
1993 ◽  
Vol 31 (1) ◽  
pp. 1
Author(s):  
IM Wood ◽  
IK Dart ◽  
HB So
Keyword(s):  
Polyethylene Glycol ◽  
Water Potential ◽  
Close Correlation ◽  
Ease Of Use ◽  
Effect Of Temperature ◽  
Soil Cores ◽  
Total Water ◽  
Matric Potential ◽  
Thermocouple Psychrometer ◽  
Water Potentials

This study examined two polyethylene glycol (PEG) polymers (PEG 6000 and PEG 10000) and compared measurements of water potential obtained with a thermocouple osmometer and thermocouple psychrometers at three temperatures (15, 25 and 35�C) and five osmdalities (50, 100, 200, 300 and 400 g/1000 g water). These were then compared with estimates of matric potential of three soils brought to equilibrium with PEG solutions of the same osmolalities. At the same osmolality and temperature the two PEG polymers gave essentially the same water potential. There was a significant effect of temperature on water potential which corresponded closely with changes in specific gravity of the PEG solution. There was a close correlation between the measurements of water potential of the PEG solutions obtained with the osmometer and the psychrometers (R = 0.99). However, the psychrometer gave increasingly lower values than the osmometer as water potential decreased. The differences in the measurements between the two methods are thought to be the result of design and calibration differences. The ease of use of the osmometer is such that it is recommended for routine use. The water potentials of the soil cores brought to equilibrium with the PEG 10 000 solution were linearly related to the water potentials of the PEG solutions estimated from both the osmometer and psychrometers (R2 = 0.84). However, there were clear deviations from a 1:l relationship. It was concluded that the results from the soil cores could not be used to determine which of the two instruments gave the more accurate measurement of water potential of PEG solutions.

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