Stomatal aperture rather than nitrogen nutrition determined water use efficiency of tomato plants under nitrogen fertigation
Research output: Contribution to journal › Journal article › Research › peer-review
Fertigation can improve water use efficiency (WUE) compared with conventional separate supply of water and fertilizers to plants. Yet the mechanisms underlying the improved WUE under fertigation remain largely elusive. Therefore, the impact of water and nitrogen (N) on leaf gas exchange, plant water relations, ABA signaling and WUE as well as leaf δ 13C and δ 18O were investigated in order to unravel how water and N modulate plant WUE. Results showed that reduced soil water regimes under N fertigation caused partial closure of stomata via decreased plant water status and intensified root-to-shoot ABA signaling, resulting in improved intrinsic WUE (WUE i). Decreased soil water regimes increased plant WUE (WUE p) and leaf δ 13C, and the increased leaf δ 13C was due to reduced g s and/or higher specific leaf N content enhanced photosynthetic capacity. Leaf δ 18O and δ 13C further indicated that the significant increase in leaf δ 13C under the reduced water regimes was caused primarily by reductions in g s compared with N nutrition. Therefore, g s rather than N nutrition predominated regulation of plant WUE under fertigation. Moderate soil water regimes with sufficient N supply are recommended for fertigation in terms of achieving high fresh fruit yield, WUE and nutrient uptake.
|Journal||Agricultural Water Management|
|Number of pages||8|
|Publication status||Published - 2018|
- Abscisic acid, Carbon isotopic composition, Irrigation, Nitrogen, Oxygen isotopic composition, Physiology