Table 5 Contributions of γ-PGA-N to the nitrogen (N) pools of plant-soil system at different sampling days.

From: Effects of poly-γ-glutamic acid (γ-PGA) on plant growth and its distribution in a controlled plant-soil system

N (%)

Day

Shoot

Root

Plant

NH4 +-N

NO3 −-N

Soil

Plant-Soil

1

0.78 ± 0.065a

2.60 ± 0.079a

0.81 ± 0.064a

1.87 ± 0.15bc

4.06 ± 0.17c

2.30 ± 0.023a

2.28 ± 0.022a

3

1.98 ± 0.010b

3.65 ± 0.015b

2.02 ± 0.010b

3.52 ± 0.030a

5.42 ± 0.01b

2.22 ± 0.008b

2.21 ± 0.008ab

7

2.98 ± 0.019c

4.63 ± 0.094c

3.03 ± 0.020c

2.18 ± 0.07b

6.62 ± 0.36a

2.17 ± 0.025b

2.20 ± 0.024b

15

6.61 ± 0.063g

6.66 ± 0.036f

6.61 ± 0.062 g

3.54 ± 0.63a

6.58 ± 0.36a

1.87 ± 0.030c

2.24 ± 0.032ab

30

6.06 ± 0.030e

6.17 ± 0.179e

6.06 ± 0.023e

1.18 ± 0.02cd

3.62 ± 0.05cd

1.59 ± 0.009d

2.08 ± 0.008c

45

6.27 ± 0.123f

6.06 ± 0.081ed

6.26 ± 0.116f

0.49 ± 0.02d

3.23 ± 0.06d

1.51 ± 0.007e

2.09 ± 0.021c

60

5.61 ± 0.004d

5.88 ± 0.012d

5.64 ± 0.002d

0.40 ± 0.01d

2.19 ± 0.33e

1.50 ± 0.011e

1.99 ± 0.014d

  1. Means followed by the different letters in the same column are significantly different (p = 0.05); Contribution of γ-PGA-N to the N pool in plant-soil system was calculated as the percentage of the recovered γ-PGA-N to the total N in each N pool.
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