The objective of this study was to explore the changes in leaf nitrogen (N) and phosphorus (P) content, physiological processes, growth, and resource-use efficiency in a rapeseed cultivar under drought and (or) high temperatures. The two-wk-old plants were grown under controlled growth chamber conditions and subjected to individual or combined water (well-irrigated, 88% ± 4% field capacity vs. drought, 46% ± 5% field capacity) and temperature (control, 23 °C/17 °C vs. high temperatures, 26 °C/25 °C) regimes for 10 d. The measured response parameters were [N], [P], and their total content in leaves, photosynthetic rate (Asat), stomatal conductance (gs), intercellular CO2 concentration (Ci), mitochondrial respiration (R), intrinsic water use efficiency (WUEi), photosynthetic N use efficiency (PNUE), relative growth rate of the root (RGRr) and shoot (RGRs), leaf area, and dry matter accumulation in the plant. Drought significantly decreased [N], [P], and their total content in leaves, Asat, gs, Ci, RGRr, RGRs, leaf area, dry matter accumulation in the root, shoot, and whole plant, and PNUE, but significantly increased R and WUEi. Drought-induced reduction in growth or Asat was mainly attributed to a decreased Ci due to stomatal closure, while reduction in gs and leaf area appeared to be a drought-adaptive mechanism. High temperature stress alone had no negative impact on physiological and growth parameters, indicating an enhanced thermal stability of the cultivar, which was diminished at combined drought and high temperature stresses. We therefore conclude that the thermal stability of the cultivar in terms of growth was compromised under simultaneous occurrence of drought and high temperature stresses.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.