). Modern climate models have predicted that mean global temperature will rise by 1.1 °C by the end of this century and intense heat waves will also occur more frequently ( IPCC, 2013 ). Heat stress, caused by elevated temperature, is a major threat for
Heat stress is one of the major limiting factors for cool-season perennial grasses in many regions. As a consequence of climate change and global warming, heat stress may have increasingly negative impact on crop growth and persistence. Plants have
to result in an increase in frequency and intensity of heat waves and drought ( U.S. Global Change Research Program, 2008 ). Leaves function as the primary manufacturer of many metabolites used during plant growth. Both the integrity of the machinery
conditions of CO 2 and O 2 , photosynthesis and the export rates of assimilates in salvia declined as leaf temperature was raised from 25 °C to 40 °C ( Jiao and Grodzinski, 1996 ). Genotypes or lines within species differ in their ability to respond to heat
136 ORAL SESSION 29 (Abstr. 205–210) Stress–Heat and Water
exposed to heat stress during the growing season in temperate regions. During high stress events, kentucky bluegrass can become dormant and lose pigmentation ( Beard, 1973 ; Su et al., 2007 ). Tall fescue has increased heat and drought tolerance, but it
For year-round production, growers in the subtropical areas conventionally divide chrysanthemum cultivars or lines into two groups: heat-tolerant (flowering during the natural summer and fall seasons) and heat-intolerant (flowering during the
High temperature is a major factor limiting growth of cool-season plant species. One of the typical symptoms of heat injury for many plant species is leaf senescence ( Thomas and Stoddart, 1980 ). Leaf senescence is characterized by loss of
”) or 7 °C or less and later negated (counted as “hours”). A later version of the Utah model included a heat accumulation component ( Richardson et al., 1986 ), allowing a prediction of bloom time, in contrast to the previous models, which addressed only
decline, including heat stress (HT) and drought stress (DS). Because this species is often found in nature growing in wetland habitats and areas that do not have high summer temperatures ( Davy, 1980 ; Hagerup, 1939 ), tufted hairgrass may be sensitive to