Growth response ofFestuca altaica,Festuca hallii, andFestuca campestristo temperature

Abstract

In Alberta, the rough fescue complex consists of Fesruca alraica Trin., Fesrlcca hallii (Vasey) Piper, and Fesruca carr~pesrris Rydb. The potential commercial value of these species for grazing, and their ecological significance, necessitates an increased understanding of their environmental adaptation. This study compared the growth response of the three species at five temperature regimes of 7: 3, 12:8, 17:13, 22: 18, and 27:23"C (1ight:dark; 18-h photoperiod). Seedlings were established and grew for 10 weeks at lS°C before being trimmed to a height of 3.5 cm and randomly assigned (36 pots of each species) to the growing environments. Growth was followed for 12 weeks. Temperature had a significant effect on most plant variables but the response differed among species. The optimal temperature for dry matter accumulation was 17: 13"C, and for tillering 12:s to 17:13"C. Fesriccu hnllii and E canzpesrris exhibited a faster tillering rate than E alraica, which had the heaviest tillers and highest leaf extension rate. The root to shoot ratio declined at temperatures above 17: 13°C. The significance of these observations to the geographical distribution of the species is discussed. Resume : En Alberta, le complexe des fCtuques rugeuses comporte le Fesruca altaica Trin., le Fesrucu hallii (Vasey) Piper, et le Fesruccl carnpesrris Rydb. La valeur commerciale potentielle de ces espkces pour le plturage, ainsi que leur signification Ccologique, nCcessitent une meilleure comprkhension de leur adaptation environnementale. Cette Ctude compare la croissance des trois espkces sous cinq rCgimes de tempCrature 7:3, 12:8, 17:13, 22:18, et 27:23'C (lumikre : obscuritC; photopCriode de 18 h). Les plantules ont Ct C Ctablies et ont poussC pendant 10 semaines B 18°C avant d'ktre ramenCes B une hauteur de 3,5 cm et distribuies au hasard (36 pots pour chaque espkce) sur l'espace de croissance. La croissance a Ct C suivie pendant 12 semaines. La tempCrature exerce un effet significatif sur la plupart des paramktres de croissance, mais les rCactions diffkrent selon les espkces. La tempCrature optimum pour I'accumulation de la matikre skche est de 17: 13"C, et pour le tallage de 12:s B 17: 13°C. Le E hallii et le E campesrris montrent un taux de tallage plus rapide que le E alraicrl, lequel posskde les talles les plus lourds et les taux d'extension foliaire en hauteur les plus grands. Le rapport racine B tige diminue aux temperatures supCrieures B 17: 13°C. Les auteurs discutent les implications de ces observations sur la distribution gkographique de ces espkces.

Stomatal regulation in a changing climate: a field study using Free Air Temperature Increase (FATI) and Free Air CO2 Enrichment (FACE)

“…Other cooltemperate grass species have been reported to respond sitnilarly (e.g. Fe.stuca species; King, Hill & Willms 1995). The tetnperature tesponse in the present experitnent is more negative, but this could be anticipated in view of the hot weather conditions which preceded the tneasutement period (a daily maximum of 7, of on average 37-2 °C).…”

Implications of Precipitation, Warming, and Clipping for Grazing Resources in Canadian Prairies

“…Notably, the decline in accumulated herbage with warming was largely due to graminoids rather than forbs. King et al (1995) also showed that decreases in growth of three Festuca species were due to increased temperature and not changes in soil moisture. That study suggested that this was an adaptation to limit growth to periods of lower temperatures, thus restricting growth to early in the growing season when soil moisture is high.…”

“…There is also evidence that productivity at northern latitudes is increasing due to climate change, although this trend is inconsistent across North America (Zhou et al, 2001). Warming can have negative effects on biomass, however, if plants are optimally adapted to their current (i.e., lower) temperature (King et al, 1995; Bertrand et al, 2008). The response of plant biomass to warming has also been shown to depend on other environmental variables, such as precipitation availability (Hoeppner and Dukes, 2012).…”

Morphological and Physiological Characteristics Associated with Heat Tolerance in Creeping Bentgrass

“…High root‐to‐shoot ratio is an important mechanism in plant adaptation to environmental stresses (King et al, 1995). Higher root‐to‐shoot biomass ratio in heat‐tolerant than in heat‐sensitive cultivars has been reported in various species, including Kentucky bluegrass (Bonos et al, 1995); potato ( Solanum tuberosum ) (Basu and Minhas, 1991); and wheat ( Triticum aestivum ) (Mann et al, 1994).…”