scholarly journals Effect of Soil Physical Conditions on Emission of Allyl Isothiocyanate and Subsequent Microbial Inhibition in Response to Brassicaceae Seed Meal Amendment

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 846-852 ◽  
Author(s):  
Likun Wang ◽  
Mark Mazzola
Keyword(s):  
Growth Inhibition ◽  
Soil Water ◽  
Plant Pathogens ◽  
Soil Water Potential ◽  
Allyl Isothiocyanate ◽  
Pythium Ultimum ◽  
Seed Meal ◽  
Soilborne Disease ◽  
Physical Conditions ◽  
Orchard Soils

Generation of allyl isothiocyanate (AITC) in soil treated with residues of specific Brassicaceae species yields direct and indirect suppression of soilborne plant pathogens. Soil physical conditions demonstrably affected the quantity of AITC generated in response to soil incorporation of a Brassica juncea/Sinapis alba seed meal (SM) formulation. The concentration of AITC generated in SM-amended soil increased with an increase in temperature from 10 to 30°C. AITC emission was also elevated with an increase in soil water potential from −1,000 kPa through −40 kPa; however, a significant decrease in AITC emission was observed in a saturated soil environment (0 kPa). Peak AITC emission was obtained 2 to 3 h after SM amendment under optimal conditions but the peak was delayed in soils incubated at low temperature or in extreme moisture environments. Although AITC production varied significantly across different orchard soils, all three orchard soils yielded the same pattern of AITC release in response to SM amendment over the spectrum of soil water potentials examined in this study. Mycelial growth inhibition in fungi and oomycetes isolated from apple roots was dependent on both AITC concentration and exposure time. Pythium ultimum exhibited sensitivity to AITC at concentrations ranging from 0.01 to 0.22 µg g−1 of soil, whereas Hypocrea lixii was insensitive to AITC. Exposure to AITC at a concentration of 0.22 µg g−1 of soil for a period of 2 h restricted hyphal growth of Rhizoctonia solani AG-5, Ilyonectria destructans, and Mortierella alpina. R. solani AG-5 exhibited significant growth inhibition when incubated at AITC concentrations of 0.008 to 0.011 µg g−1 of soil for 10 h. These findings provide information that will be useful in the management of appropriate soil variables to obtain optimal yields of AITC in response to SM soil amendments and indicate that a standard soil moisture prescription may be suitable for use when applying this SM formulation for soilborne disease control.

Vegetative Growth Distribution During Water Deficits in Vitis vinifera L

1988 ◽  
Vol 15 (5) ◽  
pp. 641 ◽  
Author(s):  
HR Schultz ◽  
MA Matthews
Keyword(s):  
Growth Inhibition ◽  
Vitis Vinifera ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Vitis Vinifera L ◽  
Initial Growth ◽  
Growth Responses ◽  
Time Duration ◽  
Water Deficits

The expansion of plant organs is inhibited by water deficits but the effect of ontogeny on growth sensitivity is not known. Therefore, growth responses of shoot organs (internodes, leaves, tendrils) of Vitis vinifera L. cv. White Riesling to developing water deficit were investigated under controlled environmental conditions. Growth of organs at a node position was asynchronous, with internode growth being more restricted than leaf and tendril growth in time (duration of growth) and space (number of node positions at which growth occurred). The timing of initial growth inhibition and final growth cessation caused by soil water deficits was identical in internodes, leaves, and tendrils. The degree of growth inhibition at low water potential was similar among organs, whether linear or volume changes were considered and whether the most rapidly expanding organs or organs of similar developmental stage were compared. In addition, the relative partitioning of growth among internodes, leaves, and tendrils along single shoots was unaltered when growth was inhibited by water deficits. Growth of each organ was inhibited initially at soil water potential of -0.065 MPa and ceased completely at -0.54 MPa. Therefore, it was concluded that the sensitivity of growth to water deficits did not differ among shoot organs. The region along the shoot in which organs expanded was reduced during water deficits. Similarly, the regions within organs in which growth occurred diminished as water deficits developed. Although growth was inhibited in all tissues, inhibition was complete in older tissues when some growth was maintained in younger tissues. Therefore, it was concluded that sensitivity of growth to water deficits increased with ontogeny.

Inhibition of Fungal Growth by Macerated Plant Tissues in a Closed Environment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476e-476
Author(s):  
Craig S. Charron ◽  
Catherine O. Chardonnet ◽  
Carl E. Sams
Keyword(s):  
Radial Growth ◽  
Fungal Pathogens ◽  
Solid Phase ◽  
Indian Mustard ◽  
Fungal Growth ◽  
Allyl Isothiocyanate ◽  
Pythium Ultimum ◽  
Alternative Methods ◽  
Gas Chromatography Mass Spectrometry ◽  
Clean Air

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.

Effect of Soil Water Potential of Two Soils on Soybean Emergence 1

1979 ◽  
Vol 71 (6) ◽  
pp. 980-982 ◽  
Author(s):  
L. G. Heatherly ◽  
W. J. Russell
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential

scholarly journals A Data-Driven Method for the Temporal Estimation of Soil Water Potential and Its Application for Shallow Landslides Prediction

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1208
Author(s):  
Massimiliano Bordoni ◽  
Fabrizio Inzaghi ◽  
Valerio Vivaldi ◽  
Roberto Valentino ◽  
Marco Bittelli ◽  
...  
Keyword(s):  
Machine Learning ◽  
Water Potential ◽  
Soil Water ◽  
Temporal Trends ◽  
Soil Water Potential ◽  
Shallow Landslides ◽  
Water Dynamics ◽  
Data Driven ◽  
Machine Learning Techniques ◽  
Physically Based

Soil water potential is a key factor to study water dynamics in soil and for estimating the occurrence of natural hazards, as landslides. This parameter can be measured in field or estimated through physically-based models, limited by the availability of effective input soil properties and preliminary calibrations. Data-driven models, based on machine learning techniques, could overcome these gaps. The aim of this paper is then to develop an innovative machine learning methodology to assess soil water potential trends and to implement them in models to predict shallow landslides. Monitoring data since 2012 from test-sites slopes in Oltrepò Pavese (northern Italy) were used to build the models. Within the tested techniques, Random Forest models allowed an outstanding reconstruction of measured soil water potential temporal trends. Each model is sensitive to meteorological and hydrological characteristics according to soil depths and features. Reliability of the proposed models was confirmed by correct estimation of days when shallow landslides were triggered in the study areas in December 2020, after implementing the modeled trends on a slope stability model, and by the correct choice of physically-based rainfall thresholds. These results confirm the potential application of the developed methodology to estimate hydrological scenarios that could be used for decision-making purposes.

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

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