Siberian Miscanthus sacchariflorus accessions surpass the exceptional chilling tolerance of the most widely cultivated clone of Miscanthus x giganteus

Charles P. Pignon, Idan Spitz, Erik J. Sacks, Uffe Jørgensen, Kirsten Kørup, Stephen P. Long

Research output: Contribution to journalArticle

Abstract

Chilling temperatures (0–15°C) inhibit photosynthesis in most C4 grasses, yet photosynthesis is chilling tolerant in the ‘Illinois’ clone of the C4 grass Miscanthus x giganteus, a candidate cellulosic bioenergy crop. M. x giganteus is a hybrid between Miscanthus sacchariflorus and Miscanthus sinensis; therefore chilling-tolerant parent lines might produce hybrids superior to the current clone. Recently a collection of M. sacchariflorus from Siberia, the apparent low temperature limit of natural distribution, became available, which may be a source for chilling tolerance. The collection was screened for chilling tolerance of photosynthesis by measuring dark-adapted maximum quantum yield of PSII photochemistry (Fv/Fm) on plants in the field in cool weather. Superior accessions were selected for further phenotyping: plants were grown at 25°C, transferred to 10°C (chilling) for 15 days, and returned to 25°C for 7 days (recovery). Two experiments assessed: (a) light-saturated net photosynthetic rate (Asat) and operating quantum yield of PSII photochemistry (ΦPSII), (b) response of net leaf CO2 uptake (A) to intercellular [CO2] (ci). Three accessions showed superior chilling tolerance: RU2012-069 and RU2012-114 achieved Asat up to double that of M. x giganteus prior to and during chilling, due to increased ci - saturated photosynthesis (Vmax). RU2012-069 and RU2012-114 also maintained greater levels of ΦPSII during chilling, indicating reduced photodamage. Additionally, accession RU2012-112 maintained a stable Asat throughout the 15-day chilling period, while Asat continuously declined in other accessions; this suggests RU2012-112 could outperform others in lengthy chilling periods. Plants were returned to 25°C after the chilling period; M. x giganteus showed the weakest recovery after 1 day, but a strong recovery after 1 week. This study has therefore identified important genetic resources for the synthesis of improved lines of M. x giganteus, which could facilitate the displacement of fossil fuels by cellulosic bioenergy.

Original languageEnglish (US)
Pages (from-to)883-894
Number of pages12
JournalGCB Bioenergy
Volume11
Issue number7
DOIs
StatePublished - Jul 2019

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Keywords

  • Miscanthus sacchariflorus
  • Miscanthus x giganteus
  • Siberia
  • bioenergy
  • biomass
  • chilling tolerance
  • cold tolerance
  • photosynthesis
  • photosystem II

ASJC Scopus subject areas

  • Forestry
  • Renewable Energy, Sustainability and the Environment
  • Agronomy and Crop Science
  • Waste Management and Disposal

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