Noncompetitive effects of Kochia scoparia on grain sorghum and soybeans

1982 ◽  
Vol 60 (12) ◽  
pp. 2923-2930 ◽  
Author(s):  
Frank A. Einhellig ◽  
Mary K. Schon
Keyword(s):  
Water Potential ◽  
Nutrient Solution ◽  
Grain Sorghum ◽  
Water Metabolism ◽  
Kochia Scoparia ◽  
Soybean Seedling ◽  
Allelopathic Potential ◽  
Diffusive Resistance ◽  
Leaf Resistance ◽  
Production Losses

The allelopathic potential of Kochia scoparia (L.) Schrad., a common weed in cultivated fields, was demonstrated on grain sorghum and soybeans. Growth of sorghum seedlings was reduced when the nutrient medium contained an extract equivalent of 1 g fresh weight of Kochia in 60 mL of nutrient solution, or higher quantities. Soybean seedling growth was depressed by as little as 1 g of Kochia in 240 mL of nutrient solution. Treatments with Kochia extracts that reduced growth also caused seedlings to have either an increase in leaf diffusive resistance, a decrease in water potential, or both. The addition of dried Kochia to soil pots in which seedlings were germinated and grown showed that 0.5 g of debris per 80 g of soil resulted in a significant reduction in sorghum growth, and seedlings grown with 2.0-g additions also had an increase in leaf resistance and decrease in water potential. Effects on water metabolism are indicated as one mechanism of action of allelochemicals from Kochia. It is suggested that biochemical interference from Kochia weeds in sorghum and soybean fields can contribute to production losses.

Irrigation of Geraniums with an Automatic Controlled Water Table System

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 522d-522 ◽  
Author(s):  
J.W. Buxton ◽  
D.L. Ingram ◽  
Wenwei Jia
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Water Table ◽  
Nutrient Solution ◽  
Irrigation System ◽  
Central Area ◽  
Dry Weight ◽  
Trickle Irrigation ◽  
Run Off ◽  
Optimum Water

Geraniums in 15-cm pots were irrigated automatically for 8 weeks with a Controlled Water Table (CWT) irrigation system. Plants were irrigated with a nutrient solution supplied by a capillary mat with one end of the mat suspended in a trough below the bottom of the pot. The nutrient solution remained at a constant level in the trough. Nutrient solution removed from the trough was immediately replaced from a larger reservoir. The vertical distance from the surface of the nutrient solution and the bottom of the pot determined the water/air ratio and water potential in the growing media. Treatments consisted of placing pots at 0, 2, 4, and 6 cm above the nutrient solution. Control plants were irrigated as needed with a trickle irrigation system. Geraniums grown at 0,2 and 4 CWT were ≈25% larger than the control plants and those grown at 6 CWT as measured by dry weight and leaf area. Roots of plants grown at 0 CWT were concentrated in the central area of the root ball; whereas roots of plants in other treatments were located more near the bottom of the pot. Advantages of the CWT system include: Plant controlled automatic irrigation; no run off; optimum water/air ratio.

Use of a Hydraulic Press for Estimation of Leaf Water Potential in Grain Sorghum 1

1986 ◽  
Vol 78 (4) ◽  
pp. 749-751 ◽  
Author(s):  
S. K. Hicks ◽  
R. J. Lascano ◽  
C. W. Wendt ◽  
A. B. Onken
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Grain Sorghum ◽  
Hydraulic Press ◽  
Leaf Water

Assessment of the Allelopathic Potential of Cumin Accessions in Different Soil Water Potential

2018 ◽  
Vol 21 (3) ◽  
pp. 249-260 ◽  
Author(s):  
Zahra Ghafari ◽  
Hassan Karimmojeni ◽  
Mohammad M. Majidi ◽  
Bahare Naderi
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Allelopathic Potential

Anomalous Water Relations in Copper-Deficient Wheat Plants

1976 ◽  
Vol 3 (2) ◽  
pp. 229 ◽  
Author(s):  
RD Graham
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Copper Deficiency ◽  
Water Status ◽  
Specific Effect ◽  
Water Levels ◽  
Leaf Water ◽  
Diffusive Resistance ◽  
Effect Of Copper

Leaf water potential, diffusive resistance, relative water content, weekly water use, yields and head bending were measured on wheat plants subjected to four copper levels (0, 0.4, 0.8 or 4.0 mg Cu per pot) and two water levels (6 or 12% soil water content). Severe copper deficiency (Cu 0) resulted in no grain yield, wilting, increased leaf diffusive resistance and, at the same time, increased leaf water potential relative to plants receiving 4.0 mg Cu (Cu 4.0). Water supply effects were observed but there was no interaction between copper and water treatments. Mild copper deficiency (Cu 0.4, Cu 0.8) resulted in small yield decreases, relative to Cu 4.0, and increased head bending towards maturity. It is concluded that wilting, characteristic of copper-deficient plants, is due to structural weakness (decreased lignification) and not to the water status of the plants; also, increased leaf diffusive resistance is due to a specific effect of copper deficiency on guard cells and not to decreased leaf water potential.

Internal Water Balance of Brigalow (Acacia harpophylla F. Muell.) Under Natural Conditions

1975 ◽  
Vol 2 (4) ◽  
pp. 489 ◽  
Author(s):  
BR Tunstall ◽  
DJ Connor
Keyword(s):  
Water Potential ◽  
Water Status ◽  
Carbon Uptake ◽  
Diurnal Changes ◽  
Plant Water ◽  
Litter Fall ◽  
Tissue Water ◽  
Diffusive Resistance ◽  
Plant Water Potential ◽  
Water Contents

On one day each month over a period of 2½ years, diurnal measurements of plant water status, leaf diffusive resistance, carbon uptake, irradiance, ambient temperature and humidity were made in a brigalow community. Diurnal changes in leaf diffusive resistance, osmotic potential, plant water potential, and carbon uptake are shown to follow general patterns and the changes in plant water potential were related to the dawn value of plant water potential. The data suggest the development of negative turgor in brigalow and demonstrate the capacity of the plant to maintain high tissue water contents at low water potentials. Measurements of shoot extension and litter fall showed that litter fall occurred principally following shoot extension.

scholarly journals Modifications in vapor diffusion resistence of leaves and water relations in barbados cherry plants under water stress

2001 ◽  
Vol 13 (1) ◽  
pp. 75-87 ◽  
Author(s):  
REJANE J. MANSUR C. NOGUEIRA ◽  
JOSÉ ANTÔNIO P. V. DE MORAES ◽  
HÉLIO ALMEIDA BURITY ◽  
EGÍDIO BEZERRA NETO
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Temperature ◽  
Diffusive Resistance ◽  
Severe Water Stress ◽  
Relative Water ◽  
Proline Concentration ◽  
Prolonged Stress

Young sexually and assexually propagated Barbados cherry plants were submitted to water deficit (20 days without irrigation). During this period the accumulation of proline, water potential of branches, osmotic potential, the relative water content of leaves, the leaf diffusive resistance, the transpiration rate and leaf temperature in the cuvette were determined. In addition, photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) were measured in the porometer cuvette. The concentration of proline for both types of plants began to increase on the fifth day without watering, and reached 38.1 times the concentration in the control plants grown from seeds and 26.4 times the concentration in grafted plants on the tenth day without watering. The lowest levels of leaf water potential in the plants suffering from severe water stress varied from -4.5 to -5.7 MPa, the lowest values being observed in the sexually propagated plants. These plants also showed the highest values for transpiration (0.9 mmol.m-2.s-1) and proline concentration (20.42 mg.g-1 DM), the lowest for relative water content of the leaves (38.4%) and diffusive resistance (940 s.m-1) at the end of the experiment. The Barbados cherry plants developed strategies for surviving drought, with differences between various characteristics, resulting from prolonged stress, which significantly influenced the parameters evaluated, with the exception of leaf temperature.

THE EFFECT OF WATER DEFICIT ON N2(C2H2) FIXATION BY WHITE BEAN AND SOYBEAN

1988 ◽  
Vol 68 (4) ◽  
pp. 957-967 ◽  
Author(s):  
D. L. SMITH ◽  
M. DIJAK ◽  
D. J. HUME
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Acetylene Reduction ◽  
Physiological Responses ◽  
Plant Water ◽  
Diffusive Resistance ◽  
Drought Conditions ◽  
Plant Water Potential ◽  
White Bean

White bean (Phaseolus vulgaris L.) is generally reported to fix less N than soybean (Glycine max Merrill [L.]). Recent work has shown that in soybean the onset of physiological responses that conserve plant and soil water occurs at greater water deficits than in some other legumes. Little is known about water use regulation in white bean. Research was conducted to compare the responses of these two species to water deficit, particularly its effects on N2 fixation, in both controlled environment and field conditions. In the growth room, plant water potential, leaf diffusive resistance, acetylene reduction and nodule mass per plant were measured for both species during progressive drought, and compared to watered controls. In the field, the leaf diffusive resistance of irrigated and unirrigated plants of both species was measured, as was the soil water potential in plots where these crops were grown. Under conditions of increasing water deficit white bean reacts to conserve plant and soil water sooner than soybean: closing its stomates earlier under drought conditions and maintaining higher plant water potentials. White bean acetylene reduction declined more rapidly over time and over plant water potential levels, but not over changes in leaf diffusive resistance, than that of soybean, as the droughting progressed. In the field, under drought conditions, white bean root nodules senesced, while soybean nodules did not, and white bean was observed to exhibit more parahelionasty than soybean. The onset of physiological responses that conserve plant and soil water occurred at lesser water deficits in white bean than soybean, and this was reflected in more extreme effects on N2 fixation by white bean.Key words: White bean, soybean, water deficit, acetylene reduction, nitrogen fixation, nodulation

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