|Stier, J. - UNIV. OF WISCONSIN|
|Filiault, D. - UNIV. OF WISCONSIN|
|Palta, J. - UNIV. OF WISCONSIN|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2003
Publication Date: April 1, 2003
Citation: STIER, J.C., FILIAULT, D.L., WISNIEWSKI, M.E., PALTA, J.P. VISUALIZATION OF FREEZING PROGRESSION IN TURFGRASSES USING INFRARED VIDEO THERMOGRAPHY. CROP SCIENCE, April 2003, Vol. 43, pgs. 415-420. Interpretive Summary: Freezing injury can be a significant problem in turfgrasses and developing a better understanding how ice develops and ramifies throughout the plant could assist in the development of improved management or screening processes for cultivar development. In the present study, the freezing process in two species (perennial ryegrass - Lollium perenne and supine bluegrass - Poa supine) of turfgrass were examined using infrared thermography. Plantlets were incubated in either cold acclimating or normal growth temperatures. Plants were then subjected to progressively decreasing freezing temperatures in a growth chamber. Droplets of ice-nucleating-active (INA) bacteria were placed on the plants prior to freezing. An infrared camera was used to view ice initiation and propagation in whole plants in real time. Results indicated that ice was initiated in the root system, propagated rapidly up to the crown and then advanced slowly through the crown. No differences were observed between the two species in the non-acclimated state but in the acclimated state, roots of supine bluegrass froze earlier than the roots of the perennial ryegrass plants. INA bacteria did not induce freezing of the turf tissues. The project demonstrated the utility of using infrared thermography to detect freezing events in whole turfgrass plants. The information gained from the use of this technology should be helpful in identifying freeze-resistant germplasm or evaluating the effects of management practices on frost protection.
Technical Abstract: Freezing injury can be a significant problem in turfgrasses. Understanding how freezing develops and ramifies throughout the plant could assist in the development of improved management or screening processes for cultivar improvemen. The development of freezing injury is not well understand due partly to lack of technology to view freezing origin and progression of whole plants in real time. Perennial ryegrass (Lolium perenne L.) and supina bluegrass (Poa supina Schrad.) plants were incubated in either cold-acclimating or non-cold-acclimating temperatures. Droplets containing ice-nucleating bacteria (Pseudomonas syringae) were placed on turf leaves, crowns, and roots. Plants were then subjected to progressively decreasing freezing temperatures in a controlled environment. An infrared thermal imaging radiometer (camera) was used to view ice initiation and propagation in whole plants in real time. Freezing always originated in roots, spreading acropetally and basipetally throughout connecting root tissues until it contacted the crown. Freezing was slow in the crown, then occurred rapidly upwards into shoots, and then into the leaves. The time required for freezing was similar between the two species of non-acclimated plants. In acclimated plants, supina bluegrass roots froze earlier than roots of perennial ryegrass, though freezing times were similar for crown and leaf tissues. Ice-nucleating bacteria did not incite freezing of turf tissues. The project demonstrated the utility of infrared imaging for detecting freezing events in whole turfgrass plants. Results suggest that root tissue in the vicinity of the crown can be a source of ice which propagates into the crown and kills the plant.