A novel, non-invasive, online-monitoring, versatile and easy plant-based probe for measuring leaf water status

Abstract

A high-precision pressure probe is described which allows non-invasive online-monitoring of the water relations of intact leaves. Real-time recording of the leaf water status occurred by data transfer to an Internet server. The leaf patch clamp pressure probe measures the attenuated pressure, Pp, of a leaf patch in response to a constant clamp pressure, Pclamp. Pp is sensed by a miniaturized silicone pressure sensor integrated into the device. The magnitude of Pp is dictated by the transfer function of the leaf, Tf, which is a function of leaf patch volume and ultimately of cell turgor pressure, Pc, as shown theoretically. The power function Tf=f(Pc) theoretically derived was experimentally confirmed by concomitant Pp and Pc measurements on intact leaflets of the liana Tetrastigma voinierianum under greenhouse conditions. Simultaneous Pp recordings on leaflets up to 10 m height above ground demonstrated that changes in Tf induced by Pc changes due to changes of microclimate and/or of the irrigation regime were sensitively reflected in corresponding changes of Pp. Analysis of the data show that transpirational water loss during the morning hours was associated with a transient rise in turgor pressure gradients within the leaflets. Subsequent recovery of turgescence during the afternoon was much faster than the preceding transpiration-induced water loss if the plants were well irrigated. Our data show the enormous potential of the leaf patch clamp pressure probe for leaf water studies including unravelling of the hydraulic communication between neighbouring leaves and over long distances within tall plants (trees).

Sap Flow Response to Olive Water Stress: A Comparative Study With Trunk Diameter Variations and Leaf Turgor Pressure

“…Probes were clamped on leaves of the east side of the canopy, at about 1.5 m above ground. The output pressure (P p ) sensed by the probe is inversely proportional to the leaf turgor pressure (P c ) (Zimmermann et al, 2008). In the control plot we instrumented one representative tree only.…”

Distribution and function of epistomatal mucilage plugs

“…turgor pressure) was measured online using the non-invasive leaf patch clamp pressure probe. The principle of the probe and the theoretical background of the parameter measured by the probe are described in details elsewhere (Zimmermann et al 2008;Westhoff et al 2009). Briefly, the leaf is positioned in the space between the two planar circular pads of the probe.…”

“…A miniaturised, temperature-independent pressure sensor chip is integrated in one of the pads. A constantly kept, external clamp pressure (up to 250 kPa) is applied by a spring (Zimmermann et al 2008) or a magnet (Westhoff et al 2008) to the clamped leaf patch. Physics shows that the output pressure P P measured by the sensor is dictated by the pressure transfer function of the clamped leaf patch.…”

“…In other words, P p measured by the pressure sensor is inversely correlated to turgor pressure. This was shown by calibration of the patch clamp pressure probe against the cell turgor pressure probe (Zimmermann et al 2008).…”

The Effect of Soil Moisture on the Reflectance Spectra Correlations in Beech and Sessile Oak Foliage/ Talajnedvesség hatása bükk és kocsánytalan tölgy lombozat reflexiós spektrumainak korrelációira.

“…by leaf sampling and a pressure bomb (Scholander et al 1965), stem psychrometer (Dixon -Tyree 1984) or the recently developed leaf patch clamp (Zimmermann et al 2008). These methods are able to describe the instantaneous turgor pressure but reveal less about the long term effects of the drought stress, and may be very sensitive to the sampling time and conditions.…”