The effect of temperature and photoperiod on primary floral induction in three lines of alpine bluegrass

Abstract

The effect of temperature and photoperiod on primary floral induction in three lines of alpine bluegrass. Can. J. Plant Sci. 77: 615-622. The effects of temperature and photoperiod on primary floral induction in three lines of alpine bluegrass (Poa alpina L.) were studied in controlled environments. These lines were developed at the Alberta Environmental Centre from single plant accessions collected from the Alberta Rocky Mountains. Plants representing all three lines were subjected to temperatures of 3, 9, and 12°C under dark (0 h), short-day (8 h), and long-day (18 h) photoperiods for durations of 6, 10, and 14 wk. Plants were subsequently transferred to conditions of 22°C/15°C, 18 h photoperiod and heading response was recorded. Primary floral induction was found to be favoured by low temperatures and/or short days with marked inhibition at 12°C. Complete dark conditions were not inductive. Six weeks of primary induction was suboptimal with only 15% of plants flowering. However, 100% of plants flowered after 10 wk of primary induction at 3°C under both long-day and short-day conditions. Differences among lines were significant for number of heading plants, number of heads per plant, time to heading, and critical induction duration. Primary induction in line 907 occurred at longer photoperiods, warmer temperatures, and in shorter durations than the other lines indicating a lesser induction requirement. Possible implications are discussed in the use of alpine bluegrass populations for revegetating disturbed mountain sites. Les différences significatives observées entre les lignées concernaient le nombre de plantes épiant, le nombre de panicules par plantes, le délai de floraison en jour et la durée d'induction critique. Chez la lignée 907, l'induction primaire survenait sous une photopériode plus longue, à des températures plus élevées et en un temps plus court que chez les autres lignées, indiquant que cette lignée aurait de moindres besoins d'induction. Les auteurs examinent la portée éventuelle de ces observations sur l'utilisation du pâturin alpin pour la remise en végétation des sites de montagne perturbés.

Saltgrass Clones' Spike Production Affected by Sampling Time, Nitrogen Fertilization, and Burning

“…Northern switchgrass cultivars showed greater sensitivity to extended photoperiod resulting in a longer vegetative phase as compared with southern cultivars (Van Esbroeck et al, 2003). Our finding is also consistent with results observed in some temperate grasses like kentucky bluegrass (Carlson et al, 1995) and alpine bluegrass (Poa alpina) (Pahl and Darroch, 1997). In both of those studies, genotypes from warmer climates required a shorter time of low temperatures/short daylengths than genotypes from northern areas to maximize flowering.…”

“…The Colorado Front Range is composed of many microenvironments. These heterogeneous microclimates would likely lead to environmental adaptation of important traits (e.g., requirements for flowering) causing within-population variability as similarly observed in blue grama (Bouteloua curtipendula) (Van Esbroeck et al, 2003) and alpine bluegrass (Pahl and Darroch, 1997). Clone A1180 from the Colorado Front Range did not flower with the treatments used.…”

Ex situ conservation storage potential of Saxifraga cernua (Saxifragaceae) bulbils from alpine species

“…For example, some species produce bulbils in place of seeds where the growing season is short (e.g. Pahl and Darroch 1997). This is the case for S. cernua, despite luxuriant flowering, seed set has only rarely been observed (Molau 1992;Brochmann and Håpnes 2001;Kapralov et al 2006).…”