Details

Autor(en) / Beteiligte

• Tränkner, Merle
• Jákli, Bálint
• Tavakol, Ershad
• Geilfus, Christoph-Martin
• Cakmak, Ismail
• Dittert, Klaus
• Senbayram, Mehmet

Titel

Magnesium deficiency decreases biomass water-use efficiency and increases leaf water-use efficiency and oxidative stress in barley plants

Ist Teil von

• Plant and soil, 2016-09, Vol.406 (1/2), p.409-423

Ort / Verlag

Cham: Springer

Erscheinungsjahr

2016

Quelle

SpringerNature Journals

Beschreibungen/Notizen

• Aims In water-scarce agro-environments a clear understanding of how plant nutrients like magnesium (Mg) affect plant traits related to water-use efficiency (WUE) is of great importance. Magnesium plays a crucial role in photosynthesis and is thus a major determinant of biomass formation. This study investigated the effect of Mg deficiency on leaf and whole plant water-use efficiency, δ¹³C composition, hydrogen peroxide (H₂O₂) production and the activity of key enzymes involved in ROS scavenging in barley. Methods Barley (Hordeum vulgäre) was grown in hydroponic culture under three different levels of Mg supply (0.01, 0.1, 0.4 mM Mg). WUE was determined on the leaf-level (leaf-WUE), the biomass-level (biomass-WUE) and via carbon isotope discrimination (δ¹³C). Additionally, concentrations of Mg, chlorophyll and H₂O₂, and the activities of three antioxidative enzymes (ascorbate peroxidase, glutathione reductase and Superoxide dismutase) in youngest fully expanded leaves were analyzed. Results Dry matter production was significantly decreased (by 34 % compared to control) in Mg deficient barley plants. Mg deficiency also markedly reduced leaf Mg concentrations and chlorophyll concentrations, but increased H₂O₂ concentrations (up to 55 % compared to control) and the activity of antioxidative enzymes. Severe Mg deficiency decreased biomass-WUE by 20 %, which was not reflected regarding leaf-WUE. In line with leaf-WUE data, discrimination against ¹³C (indicating time-integrated WUE) was significantly reduced under Mg deficiency. Conclusions Mg deficiency increased oxidative stress indicating impairment in carbon gain and decreased biomass-WUE. Our study suggests that biomass-WUE was not primarily affected by photosynthesis-related processes, but might be dependent on effects of Mg on night-time transpiration, respiration or root exudation.