Abstract
Abstract: In order to explore the effect of the frequency of the pulsed electric field on the aged cotton seed vigor, high voltage pulse power supply and arc electrode were used to process aged cotton seeds with different frequency of 1, 5, 10, 20 and 50 Hz at the voltage of 16 and 20 kV, and the treatment time was 40 s. The results showed that the change trends of all indices were consistent for pulsed electric field with different frequency. When the frequency of the electric field increased, the effects increased and reached the maximum at 10 Hz. It could be seen that the electric field frequency had a threshold in this test condition. After 10 Hz, as the electric field frequency increased, the effects began to decrease. Compared with the CK, the germination potential showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5, 20 and 50 Hz, but no significant difference at 1 Hz. The germination rate showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5, 20 and 50 Hz, but no significant difference at 1 Hz. The germination index showed a very significant difference (P<0.01) at 5, 10 and 20 Hz, and a significant difference (P<0.05) at 50 Hz, but no significant difference at 1 Hz. The vigor index showed a very significant difference (P<0.01) at 5, 10, 20 and 50 Hz, but no significant difference at 1 Hz. In conclusion, when the voltage was 16 kV, the treatment effect was better at 10 Hz. The 4 indices of cotton seeds with the 10 Hz treatment were increased by 39%, 54%, 57% and 81% respectively in comparison with that of the CK. In comparison with that of the CK at the voltage of 20 kV, the germination potential showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5 Hz, but no significant difference at 1, 20 and 50 Hz. The germination rate showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5 and 20 Hz, but no significant difference at 50 Hz compared with the CK. The germination index showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5, 20 and 50 Hz. The vigor index showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5, 20 and 50 Hz. In conclusion, when the voltage was 20 kV, the treatment effect was better at 10 Hz. The 4 indices of cotton seeds with the 10 Hz treatment were increased by 28%, 43%, 38% and 62% respectively in comparison with that of the CK. The results showed that when the frequency was 10 Hz, the germination potential, germination rate, germination index and vigor index were significantly improved, and had very significant difference (P<0.01). The treatment condition of 16 kV was better than 20 kV. The results indicated that the effect of electric field frequency on seed vigor index existed, and the influence trend of each index was consistent. It means that there is an optimal frequency range when the electric field strength and processing time are determined. It can increase seed vigor to the maximum.
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