Diagnosis of nutritional disorders in plants based on the bioelectric potential on leaf surface of tomato plants

摘要

A foliar potential shift is a micropotential that is released from the surface of plant leaves. We have been investigating the relationship between foliar potential and the nutritional status of plants. In foliar potential attributable to different measurement sites were investigated. In experiments on the relationship between foliar potentials and the nutritional status of plants, three test groups were established (complete nutrition, N-deficient, and Mg-deficient groups), and changes in potential were measured at the upper and lower leaves of plants in each group. Measurements were converted into logarithmic values, and were studied statistically by a discriminant analysis. The results showed that potentials at 14 and 16 Hz on upper leaves were greater for the N-deficient group than those for the complete nutrition group. Furthermore, the potential at 19 Hz on the upper leaves was greater for the Mg-deficient plants than that for the complete nutrition group.Experiments on the nycterohemeral characteristics of foliar potential were conducted to identify differences in foliar potentials between night and day . in the past, foliar potentials have only even when measurements are taken during the day, it is difficult to evaluate the effect of conducting experiments in daylight. In the present study, a shield box made using a transparent conductive film was used to allow foliar potentials to be measured during the day. We found that potentials at the same frequencies (11,13-14Hz) were greater at night for both upper and lower leaves. Experiments on the differences in foliar potential attributable to different measurement sites were conducted to clarify the effect of electrode location on test data. Two sets of experiments were performed. In one, an electrode was placed at two different locations on the uppermost leaf. In the other, an electrode was placed on an upper leaf and a lower leaf of the same plant to evaluate differences in data. Data from the same leaf showed a high degree of similarity. Identifiable characteristics in the frequency composition between upper and lower leaves in plants in the N-deficient or Mg-deficient groups. Nevertheless, potential shifts that could distinguish upper and lower leaves could not be confirmed in plants in the complete nutrition group.