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Schollander Pressure Bomb

History

50 years ago, plant scientists searched for an independent method for measuring the overall health of a plant. External measurements were an accepted practice measuring the rain levels, rooting depths, gravimetric water contents, air and soil temperatures. How could one measure the direct effects of these exterior influences on plant physiology, and most importantly, how was it affecting the delivery of nutrients and water from roots to leaves?

In the mid-1960's, Dr. Schollander and others surmised that similar to checking ones' blood pressure, wouldn't it be posssible to measure a living plant's sap pressure/tensions? The concept worked and sap measurements using a "pressure bomb", with the rather long name of Plant Water Status Measurements, took hold. As a constant innovator, Soilmoisture Equipment developed the first commercial Plant Water Status (pressure) Consoles for research in 1974. In the intervening years, sap pressure measurements using Soilmoisture's Plant Water Status Consoles have been used in research to help increase the yields of cotton, sorghum, and other crops while minimizing water usage. More recently, vineyards are purposefully inducing a regulated stress to enhance specific fruit colors, tannins, flavors, etc.

PWSC research model 3000

The Model 3000 has been the standard of excellence in plant water status research for over 2 decades. This work horse has all the features needed to make extensive readings in record time. Supplied wthout a bottled gas tank & regulator it is designed for use within the lab where a large air supply tank or mains air supply is available. It has the unique Cam-Lock sealing system and is supplied standard with an 18 cm high vessel, 10 cm long legs, 40 bar gauge and Dicot specimen holder. All parameters can be customised to suit specific research needs.

PWSC research model 3005

The Model 3005 has all the features of the model 3000 but with the added benefit of a field portable pressure supply gas tank and regulator. The model 3005 is designed for both lab and portable field use where an external air supply is not available or cumbersome to provide. Once again it has the unique Cam-Lock sealing system and is supplied standard with an 18 cm high vessel, 10 cm long legs, 40 bar gauge and Dicot specimen holder. All parameters can be customised to suit specific research needs.

How it works

Making Plant Water Measurements is easy and relatively simple:

Step 1: Select a representative sample specimen of the plant with sufficient length to fit into the pressure vessel.
Step 2: Cut the stem close to the plant stalk with a sharp knife or razor.
Step 3: Place the cut leaf into the pressure vessel as quickly as possible to prevent changes due to dehydration, evaporation, etc. Then pressurize the vessel and look for exudation of sap from the petiole. At the first indication of exuding sap, stop pressurization and note the pressure at which sap appeared on the cut surface.

Note: Make Plant Water Status measurements by quickly retrieving specimens from the field and preparing them prior to pressurization in the pressure vessel. Once in the pressure vessel, it's important to maintain consistent pressurization rates from sample to sample.

Proven superior performance

With over 25 years of experience in the design and fabrication of quality Plant Water Status Consoles, only Soilmoisture's consoles have these unique features on all models:

Unique CAM-LOCK sealing
Making a quick measurement is key to accurate readings. Only the PWSC consoles are designed with a unique cam-lock sealing. Just slip the Specimen Holder into the pressure vessel, make a 1/4 turn and you're ready to make a reading! This can only be accomplished because of the strong stainless steel materials used in both the Specimen Holder and the Pressure Vessel.
Wide selection of grommets & specimen holder

Only Soilmoisture plant water status consoles provide the depth of sealing grommets used to gently hold specimens under pressure. There's a grommet to fit almost any size stem. Use one-piece grommets for optimum speed or two-piece grommets for working with a wide selection of stem sizes. We can also provide special grommets for unusual stems such as sorghum. In addition to the widest selection of grommets available, you can choose from two or more Specimen Holders for specific plant types such as round-stemmed plants or thin-bladed grasses.