Interactions among Flooding, Freezing, and Ice Encasement in Winter Wheat

Abstract

Exposure of winter wheat ( Triticwn aestivum L.) to various combitions of flooding and freezing stresses induces much greater damage than the individual stresses. Cold-hardened plants flooded for 1 week or exposed to -6°C for 1 week show 100% survival, while survival of plants exposed to both stresses simultaneously is reduced by 20 to 30%, and cold hardiness decreases by several degrees. The level of nonstructural carbohydrates increases in crown tissue during cold acclimation, but decreases when the plants are exposed to flooding or to -6°C for 1 week. The respiratory capacity of crown tissue segments declines when the plants are sbessed. Uptake of MRb by the roots of intact seedlns declines after exposure to either freezing or flooding, whereas passive efflux of amino acids is observed after freezing but not folowing flooding. This study has shown that detectable stress-induced metabolic changes occur in winter wheat before the applied stress is severe enough to reduce survival.The precise nature of overwintering damage to winter cereals is not well understood. Overwintering cereals are frequently exposed to a number of adverse environmental stresses, including subfreezing temperatures, low-temperature flooding, and ice encasement, which singly or in combination may be lethal. In geographical areas where mid-winter temperatures are extremely low and snow cover is sparse, plants may be killed directly by low temperature. In areas where winter rains or unseasonable thaws occur, refreezing of fully hydrated plants may cause severe injury (15). The damaging effect of ice encasement (2, 18) and flooding at low temperature (19) on survival of winter cereals also has been well documented. Recent studies (5), however, have demonstrated that icing tolerance of winter wheat is increased significantly by a flooding pretreatment at low temperature.Exposure of winter cereals to various low-temperature environmental stresses results in major changes in physiological and metabolic processes. Metabolites of anaerobic respiration, such as ethanol, CO2, and lactic acid accumulate in tissues of winter cereals during ice encasement (1,4,18,21) and flooding at low temperature (7,19). 02 consumption of tissue segments and mitochondria from ice-encased seedlings declines more slowly than the decline in seedling viability (3,18 'To whom reprint requests should be forwarded.flooding (19). Membrane permeability to amino acids and salts increases markedly during ice encasement or exposure to CO2 and ethanol at -1°C (4).These studies have greatly increased our knowledge of the effects of individual stresses on physiological and biochemical processes in winter cereals, but little is known about many of the interactions among these stresses. This paper reports the effect of various combinations of low temperature flooding, freezing, and icing on stress resistance and cellular processes of Fredrick winter wheat. After 4 and 7 weeks of cold acclimation, groups of flats were removed from the growth cabinet and the leaves were trimmed...

Effect of Soil Water Content on the Winter Survival of Winter Wheat, Rye and Triticale

“…This conclusion was reached with long-term drought stress in the greenhouse with unheated air but with some soil temperature control. However, confirming previous repofts, total ice encasement reduced survival (Andrews and Pomeroy 1975,1911Gao et al 1983;Hope et al 1984) For personal use only.…”

Effects of Ice Cover on Annual Bluegrass and Creeping Bentgrass Putting Greens

“…In contrast, Gudleifsson et al (1986) reported significant differences between ice injury and cold hardiness in pasture grasses. Flooding may increase tolerance to ice injury but reduce freezing tolerance as a result of crown hydration (Gao et al, 1983). Therefore, in determining whether or not to remove an ice sheet from a putting green, it is important to determine the relative importance of factors such as length of time of the ice cover vs. potential for cold temperature injury resulting from crown hydration when the ice melts.…”

Relationships Among Freezing, Low Temperature Flooding, and Ice Encasement Tolerance in Alfalfa

“…Many variables influence the winter survival of plants and the relationships among these factors are complex (Steponkus 1978). These factors include freezing, heaving, ice sheet formation, flooding, desiccation, diseases and nutritional status (Steponkus 1978;Paquin and Mehuys 1980; Gao et al 1983). …”