experimental study of laser fluorescence method for remote plant stress sensing in situations induced by mechanical injury of plant root system

Stress situations of plants can be caused by a lack of nutrients; mechanical injuries; diseases; low or high temperatures; a lack of illumination; insufficient or excess humidity of the soil; soil salinization; soil pollution by the oil products or heavy metals; increased soil acidity; use of pesticides, herbicides, insecticides, etc.

At the early stages to detect stress situations caused by adverse external factors by plants appearance is often difficult. However, the fluorescent analysis potentially allows us to detect stress situations of plants by the spectra distortion of the laser induced fluorescence.

The conducted experiments allows us to study a capability of the laser fluorescent method to control plants behavior in the stress situations caused by the mechanical root system injury with the exciting fluorescence wavelength being of 532 nm,.

Researches of fluorescence spectra were conducted on the created laboratory installation. As a source of the fluorescence radiation excitement the second harmonic of YAG:Nd laser is used. The subsystem to record fluorescence radiation is designed using a polychromator and highly sensitive matrix detector with the amplifier of brightness.

Experimental studies were aimed at the lawn grass.

Experimental studies of laser induced fluorescence specra of plants for the excitement wavelength of 532 nm show that the effect of the stress factors, caused by mechanical root system injury, on the plant significantly distorts a fluorescence spectrum of plants. Influence of a stress factor is shown in the changing form of the fluorescence spectrum. Thus, the identifying factor is a ratio between the fluorescent intensities at two wavelengths of 685 and 740 nm. This can serve the basis for a laser method to control state of plants.