Arimad- instrument for plant water potential measurement

Transcription

1 Arimad- instrument for plant water potential measurement

2 Table of contents WHAT IS PLANT WATER POTENTIAL? 2 PLANT WATER STRESS IS INFLUENCED BY 4 ENVIRONMENTAL CONDITIONS 2 PRESSURE CHAMBER (ΨW MEASUREMENT) 3 APPLICATIONS OF ARIMAD IN AGRICULTURE 4 WINE GRAPES 4 HIGH STRESS CROPS 4 STONE FRUIT 4 LOW STRESS CROPS 4 MEDIUM STRESS CROPS: 4 HIGH STRESS CROPS 4 ARIMAD- TECHNICAL SPECIFICATIONS 5 MEASURING PROCEDURE: 5 MRC LTD. CONTACT DETAILS 6 1

3 What is plant water potential? ARIMAD keeps you in touch with your crop s water status! Plant scientists have expended considerable effort in devising accurate and reliable methods for evaluating the water status of a plant. Four instruments that have been used extensively to measure Ψw, Ψs, and Ψp are described here: psychrometer, pressure chamber, cryoscopic osmometer, and pressure probe. Plant water potential Provides Indication of Prevailing soil moisture stress. Influence of environmental changes-heat load, humidity, wind, salinity etc. Plant moisture stress. Pressure chamber method demonstrating the plant s reaction to moisture excess or defficiency. Changes in growth, proteins & photosynthesis. Plant water stress is influenced by 4 environmental conditions Soil moisture Humidity Wind Direct sunlight or heat load. While most monitoring systems only monitor one of these influences, the ARIMAD Pressure Chamber takes all four into consideration when taking a direct plant based measurement. Enables wise adjustments of irrigation schedule. 2

4 Pressure chamber (Ψw measurement) A relatively quick method for estimating the water potential of large pieces of tissues, such as leaves and small shoots, is by use of the pressure chamber. This method was pioneered by Henry Dixon at Trinity College, Dublin, at the beginning of the twentieth century, but it did not come into widespread use until P. Scholander and coworkers at the Scripps Institution of Oceanography improved the instrument design and showed its practical use (Scholander et al. 1965). In this technique, the organ to be measured is excised from the plant and is partly sealed in a pressure chamber (Web Figure 3.6.C). Before excision, the water column in the xylem is under tension. When the water column is broken by excision of the organ (i.e., its tension is relieved allowing its Ψp to rise to zero), water is pulled rapidly from the xylem into the surrounding living cells by osmosis. The cut surface consequently appears dull and dry. To make a measurement, the investigator pressurizes the chamber with compressed gas until the distribution of water between the living cells and the xylem conduits is returned to its initial, pre-excision, state. This can be detected visually by observing when the water returns to the open ends of the xylem conduits that can be seen in the cut surface. The pressure needed to bring the water back to its initial distribution is called the balance pressure and is readily detected by the change in the appearance of the cut surface, which becomes wet and shiny when this pressure is attained. Pressure chamber measurements provide a quick and accurate way of measuring leaf water potential. Because the pressure chamber method does not require delicate instrumentation or temperature control, it has been used extensively under field conditions (Tyree and Hammel 1972). For a more complete description of the theory and operation of the pressure chamber see Boyer, [Redirected from plant physiology online, chapter 3: Water and plant cells topic 3.6: Measuring water potential] 3

5 Applications of ARIMAD in Agriculture The pressure chamber can be used in various fields of agriculture Wine Grapes The pressure chamber method introduced by ARIMAD is widely used in the wine industry within the past decades. Understanding the significance of the quality of grapes for producing premium wine, agronomists nowadays seek for ways to improve the quality of their grapes. Among woody plants, grapevines are often described as highly vulnerable to water-stress. Vine's physiological characteristics are highly influenced by the irrigation regime applied towards them; for example, deficit irrigation, which means deliberately withholding irrigation to cause stress, is known to improve the grapes quality. But how can we distinguish between well-irrigated and water stressed vines on the spot. The ARIMAD pressure chamber allows you to control and monitor the vine's water status so that you can stress the vine just to the appropriate level. Details For more details about Plant-based Approach to Deficit Irrigation in Trees and Vines High stress crops: Cotton, Olive, Walnut Trees: Almonds, Oaks, Walnuts. Stone fruit: Peaches, Prunes, Apples, Pistachio, Nectarines. Low stress crops: Melon, Tomato, Lettuce, Spuach, Celery, Bean, Radish, Carrot, Rice, Coffee, Tobacco, Pea Medium stress crops: Alfalfa, Sugar beet, Grape, Oats, Barley, Wheat, Corn, Peach, Almond, Green pepper, Pasture grasses, Soy been, Citrus, Berries, Apricot, Mint, Potato, Avocado Details Plant physiology and proteomics reveals the leaf response to drought in alfalfa (Medicago sativa L.) Effects of environment, leaf characteristics & measuring methodology on stem water potential in avocado trees High stress crops :Cotton, Olive, Walnut Details 4

6 Whole tree water balance & indicators for short-term drought stress in non-bearing Barnea' olives ARIMAD- technical specifications Accuracy: ±1% full scale. Size: W355 x D280 x H175mm. Weight: 7kg. Battery: 9V. Data hold. Memory record-max./min. RS-232 output for datalogger option. Applicable software windows version. Certified under ISO-9001, CE, IEC-1010 regulations. Internal Gas Inlet Can cooperate with various sensors for different plant species (5,10,20,35,70bar). ARIMAD-3000 Measuring procedure: Simple & Short Procedure of 4 Steps: 1. Selecting a representative leaf. 2. Preparing the instrument. 3. Inserting pressured gas in the chamber. 4. Reading the plant s water potential. 5