SOUNDS LEAD TO BETTER IRRIGATION EFFICIENCY Scientists listen as thirsty plants cry out for water SOME PEOPLE talk to their plants, but researchers at the University of Guelph are listening to theirs. The researchers are using the in- audible sounds plants make when they need water to develop more efficient irrigation systems. Their research could also have important spin-offs for the cut-llower in- dustry. About 15 years ago, Scottish researcher Dr. John Milford found that plants) give off inaudible sounds when they need water. He had modified an ordinary record player stylus and placed it in the stem of 2 bean plant which he then allowed to dry. The stylus greatly amplified the sounds made hy the plant (as well as any background noise or nearby vibrations). Milford'’s recordings were noisy, but he did prove that plants give off sounds when they need water. Dr. Michael Dixon, of Guelph's Horticultural Sciences Depart- ment, improsed on Milford ’s technology. He used in ultrasound microphone to pick up the plants’ sounds, then converted them to sounds within the range of human hearing. The result was a ‘‘clip- clop’’ sound. The noises have a physical, rather than a biological, origin. Plant stems contain hundreds of enclosed sundecks aluminum or cedar tiny tubes that move water from the roots to the leaves. When water is in short supply, water molecules are pulled up the stem under great tension. Some of the water molecules may pull away from each other, creating tiny explosions that empty the tubes and make them non- functional. If enough tubes are incapaci- tated, the piant wilts and eventual- Iy dies. The tiny explosions create the sounds the researchers are picking up. While ultrasound monitoring can be used to determine if a plant needs water, Dixon is planning to combine the technique with another system he is working on. “Monitoring plants with ultra- sound gives us qualitative, rather than quantitative, information on a plant’s need for water,*' Dixon explains. It's a measure of the amount of damage being done to the plant's cells rather than a measure of how much water the plant needs."* Dixon's new system consists of a smali air-filled chamber that _ is placed aziinst the plant stem after the skin or cuticle has been remov- ed from that area. The air in the chamber takes on the same relative humidity that exists in the plant stem. Relative humidity is directly relaicd to the suction pressure in the stem, and can be used as a direct measure of how much water the plant needs. patio roofs We also build sundecks best prices in town -~ call for a free estimate today Summer Sale on Patio Roofs (glass or aluminum) 154 off FHP Ca NWA INDUSTRIES CO. LTD. North Shore Owned 472 Riverside Drive 929-3844 North Vancouver 929-3844 “By combining the two systems, we can get more information than we could with either system alone,’ Dixon says. Dixon's research will lead to improvements in irrigation techno- logy in the future, but it could also be good news for florists and greenhouse owners selling cut flowers. Flowers such as roses are usually grown with plenty of water. In these growing conditions, the plants develop tissue that has large water-conducting tubes. Such tissue is fine for plants that always have enough water, bur it makes the plants very susceptible to conditions of drought, such as those encountered when the cut flowers ave moved from the greenhouse to the florist’s, or from the florist's to someane else's home. Hooked up to Dixon's equip- ment, the plants could be ‘toughened’ to withstand drought conditions. ‘By allowing the plamt to reach a critical level of water requirement, then letting it go just a little longer before turning on the irrivation system, we cause the plant to develop water-conducting issue that is more tolerant of drought,”’ he explained. Dixon, Dr. Robert Coffin, of Agriculture Canada, and Dr. Mur- ray Brown, from Guelph's Land Resource Science Department, are carrying out their research on potatoes and roses. (Canadian Science News) 25 - Friday, July 10, 19°7 - North Shore News Yy LUXUR RENOVATIONS BATHROOMS and oad Estimates 987-3055 i ” ey CALL TODAY FOR FREE BROCHURE OR SEND 586.3399 Call today: DOUBLE ‘S’ CEDAR HOMES 14771C 64th AVE., SURREY V3S 1X6 Established 1974 North Van. CPOE A great opportunity to own fine quality home fumishings at great reductions. Our entire gallery stock is on sale. Bedroom, Dining room & occasional tables, sofas, love seats, chairs, 20 - 50% Alt sa'es final KITCHENS —— Pp ereee ie i r ee Showroom 153 W. 3rd Please send me your plan book, spec. sheet, home planner and price list. Enclosed is $3.00. Name Address City —— State/Prov. ___ Zip/P.C. Location of Building Lot Light Oak Display Kitchen Cabinets & Counters As is $2500] 985-9128} OFF Rv aren hers 1) Hours: Mon.-Sat. 9-5. Fri. 9-9 Sun. Noon-5 Debvery extra ——+ 4240 Manor St., Burnaby 435-5566 (172 black west ot Villa Shetaton Hole)