Pignon, Charles P. and Spitz, Idan and Sacks, Erik J. and Jørgensen, Uffe and Kørup, Kirsten and Long, Stephen P. (2019) Siberian Miscanthus sacchariflorus accessions surpass the exceptional chilling tolerance of the most widely cultivated clone of Miscanthus x giganteus. GCB Bioenergy, 11 (7). pp. 883-894. ISSN 1757-1693
Full text not available from this repository.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. © 2019 The Authors. GCB Bioenergy Published by John Wiley & Sons Ltd.