Effect of heat wave on N₂ fixation and N remobilisation of lentil (Lens culinaris MEDIK) grown under free air CO₂ enrichment in a mediterranean‐type environment

Abstract

The stimulatory effect of elevated [CO 2 ] (e[CO 2 ]) on crop production in future climates is likely to be cancelled out by predicted increases in average temperatures. This effect may become stronger through more frequent and severe heat waves, which are predicted to increase in most climate change scenarios. Whilst the growth and yield response of some legumes grown under the interactive effect of e[CO 2 ] and heat waves has been studied, little is known about how N 2 fixation and overall N metabolism is affected by this combination.• To address these knowledge gaps, two lentil genotypes were grown under ambient [CO 2 ] (a[CO 2 ],~400 µmolÁmol À1 ) and e[CO 2 ] (~550 µmolÁmol À1 ) in the Australian Grains Free Air CO 2 Enrichment facility and exposed to a simulated heat wave (3-day periods of high temperatures~40°C) at flat pod stage. Nodulation and concentrations of water-soluble carbohydrates (WSC), total free amino acids, N and N 2 fixation were assessed following the imposition of the heat wave until crop maturity.• Elevated [CO 2 ] stimulated N 2 fixation so that total N 2 fixation in e[CO 2 ]-grown plants was always higher than in a[CO 2 ], non-stressed control plants. Heat wave triggered a significant decrease in active nodules and WSC concentrations, but e[CO 2 ] had the opposite effect. Leaf N remobilization and grain N improved under interaction of e[CO 2 ] and heat wave.• These results suggested that larger WSC pools and nodulation under e[CO 2 ] can support post-heat wave recovery of N 2 fixation. Elevated [CO 2 ]-induced accelerated leaf N remobilisation might contribute to restore grain N concentration following a heat wave.

Carbon sink strength of nodules but not other organs modulates photosynthesis of faba bean (Vicia faba) grown under elevated [CO2] and different water supply

“…Direct effects of [CO 2 ] on plants aside, e[CO 2 ]‐driven climate change predictions include changes in precipitation patterns, which are anticipated to cause more severe drought events in many regions (Knapp et al , 2015). Such drought events may modify C‐uptake capacity and will become more significant in Mediterranean dry‐land environments (Parvin et al , 2018, 2019b, 2020). Legumes are frequently cultivated in such drought‐prone agro‐ecosystems, and their nodule C sink activity is likely to be more threatened by frequent and severe episode of droughts (Leport et al , 1999; Peoples et al , 2001; Maalouf et al , 2015).…”

Plant functioning in a changing global atmosphere

“…For example, Cochrane () studied seed responses to warming in 20 woody perennials from the biodiverse Greenstone Belt of southern Western Australia, while Dewan et al () investigated the phenological and growth responses of seedlings of two key temperate tree species ( Fagus sylvatica and Quercus robur ) to temperature variation in the parental versus offspring generation. Heat‐wave effects in combination with increasing atmospheric CO 2 on lentil ( Lens culinaris ) are investigated in Parvin et al (). The role of small non‐coding (snc)RNA in association with tolerance to low temperatures in a potato species ( Solanum commersonii ) is investigated in Esposito et al (), providing useful information for a strategic use of genomic resources in potato breeding.…”