Root to leaf electrical signaling in avocado in response to light and soil water content

Electrical signaling, stomatal conductance, ABA and Ethylene content in avocado trees in response to root hypoxia

“…In a previous study of avocado trees, adding water to the soil resulted in an increase in ΔV L-S , but this increase was not significantly different from that of control (baseline) plants. 18 However, drought resulted in a significant increase in ΔV L-S which was correlated with reduced gs in avocado. 18 In a recent study 30 two similar experiments with avocado plants were conducted, one in a laboratory to determine the electrical response to an osmotic shock when roots were in a hydroponic medium (simulating short-term drought) and another experiment conducted in a greenhouse to determine the effects of long-term drought on root to leaf electrical signaling.…”

“…18 However, drought resulted in a significant increase in ΔV L-S which was correlated with reduced gs in avocado. 18 In a recent study 30 two similar experiments with avocado plants were conducted, one in a laboratory to determine the electrical response to an osmotic shock when roots were in a hydroponic medium (simulating short-term drought) and another experiment conducted in a greenhouse to determine the effects of long-term drought on root to leaf electrical signaling. Both experiments were conducted under the same conditions and with same plant material described for Experiments 1 and 2 in the present study.…”

“…15,16 It has been postulated that occurrence of electrical signals may be a communication mechanism between roots and shoots. 17,18 Stimulation of roots of Salix viminalis by the application of nutrients, hormones or changes in pH caused changes in the electrical potential difference between the roots and leaves. These changes were followed by a modification of leaf respiration and photosynthetic rates within 3 minutes after treatments were applied, indicating that changes in the electrical signals may reflect or be a direct mechanism of communication between roots and the leaves.…”

“…For short-term electrical measurement, the surface electrode technique was used. 17,18 Surface contact electrodes were placed on the stem, 5 cm above the hydroponic solution surface and in the petiole of a leaf located in the upper half of the plant canopy. The electrodes consisted of a thick cotton thread absorbed with KCl 0.1 M dipped in a 2.0 mL Eppendorf tube containing KCl 0.1 M. The Ag/AgCl electrodes (0.4 mm in diameter) were immersed in the Eppendorf tubes and were connected to an amplifier with an input impedance of 10 11 Ω and DC-1 kHz bandwidth (M-707 Microprobe System; World Precision Instruments, Sarasota, Florida, USA).…”

“…A root to leaf electrical signal conducted through the phloem was measured and correlated with gs in avocado trees subjected to soil drying and rewatering. 18 The electrical potential differences between the base of the stem and the petiole of a leaf located in the lower third of the canopy in avocado trees suggested that voltage changes play a role in root to shoot communication triggered by changes in soil water content.…”