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Figure 1:
Diagram sketch of an experimental soil-filled column. Each column was comprised of PVC pipe cut into three 4-cm-long sections. Each section had an internal diameter of 4.4 cm and was taped tightly together. A 2-cm-long injection ring was placed at the bottom of each migration column with a hole through which nematode suspensions could be injected. A 15-µm mesh screen was attached to the bottom of each injection ring. A 300-cm3 Styrofoam cup with the bottom removed was taped to the top of each migration column. Each cup had a nylon mesh screen with 35-µm openings taped to the bottom. One-third of the columns had no plant, one-third contained tomato (Solanum lycopersicum), and one-third contained marigold (Tagetes patula) seedlings.
Figure 2:
Experiment step-by-step. A: Soil columns filled with sandy soil; B: Styrofoam cups with either no plant, tomato, or marigold were attached to the columns and then transferred to separate growth chambers, each set at either 20 or 26ºC; C: Injection of suspension of second-stage juveniles of Meloidogyne enterolobii into the hole in the injection ring; D: Dismantling of each column was performed with a spatula to separate the rings; E: The 35-µm mesh screen prevented roots from growing into the columns; F: An example of a tomato plant root system at 12 DAI; G: Soil from each ring was placed in separate cups for centrifugal-flotation extraction of second-stage juveniles; H: Root staining with acid fuchsin was used for determining nematode penetration numbers.
Figure 3:
Distribution of recovered second-stage juveniles (J2) of Meloidogyne enterolobii extracted from PVC column sections each 4-cm long × 4.4-cm internal diameter. A. The percentages of second-stage juveniles (J2) migrating in columns containing either tomato, marigold, or no plant untreated control, where bars represent average data pooled from all temperatures and days after inoculation (DAI) (n = 32). B. The percentages of J2 migrating in columns sampled at four dates 3, 6, 9, and 12 DAI, where bars represent average data pooled from all temperatures and stimuli (n = 24). The bars among the different sampling periods are statistically different according to X2 test (P < 0.01).
Figure 4:
Distribution of active second-stage juveniles (J2) of Meloidogyne enterolobii in PVC soil columns (sections were 4-cm long and 4.4-cm internal diameter) over distance migrated (cm) and sampling time (3, 6, 9, and 12 days after inoculation [DAI]) at two different temperatures: 20ºC (A) and 26ºC (B). Each bar represents the average data pooled from all plant stimuli (n = 12). Distribution percentages were statistically different according to X2 test (P < 0.01).
Figure 5:
Penetration of second-stage juveniles (J2) of Meloidogyne enterolobii into tomato and marigold roots (A) and their rates over time for both plant species (B). Bars represent means of J2 compared by LSD test. Different letters indicate statistically different penetration rates at 5% of probability.
Supplementary Figure 1:
Penetration of second-stage juveniles (J2) of Meloidogyne enterolobii into tomato and marigold roots across 3, 6, 9, and 12 days after inoculation (DAI). Bars represent the average of J2 per plant for both temperatures (n=8), and error bars represent the standard errors of the mean. There was no interaction between stimulus and time; therefore, no statistical analysis was performed for this data.
Repeated measure MANOVA summary of second-stage juveniles (J2) of Meloidogyne enterolobii inside roots after migrating through sandy soil-filled PVC columns.
Source
df
J2 inside roots
SS
MS
F
p-value
Block
3
2.96
0.99
2.99
0.0409
Temperature (Temp)
1
0.02
0.02
0.05
0.8333
Stimulus (Stim)
1
7.48
7.48
22.69
<0.0001
Temp×Stim
1
0.02
0.02
0.06
0.8067
Time
3
9.01
3.00
9.10
<0.0001
Time×Temp
3
0.22
0.07
0.22
0.8841
Time×Stim
3
2.74
0.91
2.76
0.0528
Time×Temp×Stim
3
0.07
0.02
0.07
0.9748
Repeated measure MANOVA summary of the effects of temperature, plant stimulus, section, and time on second-stage juveniles (J2) of Meloidogyne enterolobii vertical migration in PVC columns filled with sandy soil.
Source
Recovered J2
Active J2
df
SS
MS
F
p-value
SS
MS
F
p-value
Block
3
16.00
5.50
1.04
0.3755
86.91
28.97
8.37
<0.0001
Temperature (Temp)
1
129.20
129.20
24.62
<0.0001
194.18
194.18
56.13
<0.0001
Stimulus (Stim)
2
78.40
39.20
7.47
0.0007
47.94
23.97
6.93
0.0011
Section (Sec)
4
3884.40
971.10
184.97
<0.0001
628.20
157.05
45.40
<0.0001
Temp×Stim
2
10.80
5.40
1.02
0.3603
1.30
0.65
0.19
0.8276
Temp×Sec
4
4.40
1.10
0.20
0.9380
8.60
2.15
0.62
0.6469
Stim×Sec
8
96.00
12.00
2.29
0.0210
41.12
5.14
1.48
0.1614
Temp×Stim×Sec
8
78.40
9.80
1.86
0.0653
35.44
4.43
1.28
0.2526
Time
3
142.20
47.40
9.03
<0.0001
146.28
48.76
14.09
<0.0001
Time×Temp
3
3.00
1.00
0.19
0.9065
16.98
5.66
1.64
0.1805
Time×Stim
6
45.00
7.50
1.43
0.2021
15.00
2.50
0.72
0.6322
Time×Sec
12
730.80
60.90
11.60
<0.0001
493.68
41.14
11.89
<0.0001
Time×Temp×Stim
6
22.80
3.80
0.71
0.6383
15.72
2.62
0.76
0.6034
Time×Temp×Sec
12
55.20
4.60
0.88
0.5640
82.20
6.85
2.01
0.0228
Time×Stim×Sec
24
193.00
8.04
1.53
0.0547
106.80
4.45
1.29
0.1682
Time×Temp×Stim×Sec
24
64.80
2.70
0.52
0.9711
44.64
1.86
0.54
0.9652
Chemical attributes characterization of the soil used to fill the columns.