Table 1.
Parameters of spontaneous excitation in Helianthus annuus seedlings under osmotic and salt stresses.
| Hydroponic medium (mM) | Number of studied plants | % of excitable plants | n | SAPs 24 h−1 plant−1 | SAPs velocity (cm min−1) | SAPs direction of propagation % | |
|---|---|---|---|---|---|---|---|
| basipetal | acropetal | ||||||
| Distilled water | 8 | 0 | 0 | lack of SAPs | |||
| Nutrient solution (control) | 12 | 75 | 9 | 3 ± 1 | 14 ± 1 | 75 | 25 |
| 160 mM D-sorbitol | 6 | 0 | 0 | lack of SAPs | |||
| 80 mM KCl | 12 | 100 | 12 | 10 ± 2*** | 14 ± 1 | 77 | 23 |
| 80 mM NaCl | 8 | 62 | 5 | 7 ± 2 | 20 ± 1*** | 71 | 29 |
| 160 mM KCl | 8 | 100 | 8 | 4 ± 1 | 15 ± 1* | 75 | 25 |
| 160 mM NaCl | 8 | 75 | 6 | 4 ± 1 | 12 ± 1 | 80 | 20 |
Propagation velocity of APs was calculated by taking the distance between the electrodes and dividing it by the time necessary for AP to move between the electrodes. Basipetal SAPs are SAPs propagating downwards the stem; acropetal SAPs are SAPs propagating upwards the stem; n—number of seedlings with SAPs.
SAPs 24 h−1 plant−1: data non-normally distributed, unequal variance (Levene's test p = 0.000022), Kruskal-Wallis ANOVA (Chi square = 10.31 df = 4 p = 0.0354). SAP velocity: data non-normally distributed, unequal variance (Levene's test p = 0.000022), Kruskal-Wallis ANOVA (Chi square = 33.66 df = 4 p = 0.0000). Mann-Whitney U-test was used to assess the statistical difference between the control plants and each sunflower group growing in different nutrients. p-value ranges are marked by asterisks:
p < 0.001,
p < 0.05.