Rainfall, maximum, minimum and mean temperatures (°C) recorded during the growing season (March to June) in 2010–2011 (<i>A</i>) and 2011–2012 (<i>B</i>).

<p>Rainfall, maximum, minimum and mean temperatures (°C) recorded during the growing season (March to June) in 2010–2011 (<i>A</i>) and 2011–2012 (<i>B</i>).</p

Effects of row spacing on <i>F</i>_v/<i>F</i>_m (<i>A</i>,<i>B</i>,<i>C</i>,<i>D</i>) and <i>Φ</i>_PSII (<i>E</i>,<i>F</i>,<i>G</i>,<i>H</i>)of the flag, penultimate and third leaves of two spike types of wheat under high plant density over a two-year period (2011 and 2012).

<p>R₀, R₁, R₂ and R₃ refer to 5-cm row spacing, 15-cm row spacing, 25-cm row spacing and 35-cm row spacing, respectively. Numbers 1, 2 and 3 refer to the flag, penultimate and third leaves, respectively. The data are means ± standard error (SE; n = 3). Vertical bars indicate SE.</p

Effects of row spacing on photosynthetic rate (<i>P</i>_N) of flag (<i>A</i>,<i>B</i>,<i>C</i>,<i>D</i>), penultimate (<i>E</i>,<i>F</i>,<i>G</i>,<i>H</i>) and third leaves (<i>I</i>,<i>J</i>,<i>K</i>,<i>L</i>) of two spike types of wheat under high planting density over a two-year period (2011 and 2012).

<p>R₀, R₁, R₂ and R₃ refer to 5-cm row spacing, 15-cm row spacing, 25-cm row spacing and 35-cm row spacing, respectively. Data are means ± standard error (SE; n = 3). Vertical bars indicate the SE.</p

Effects of row spacing on leaf area index (LAI) of two spike types of wheat under high plant density over a two-year period (2011 and 2012).

<p>R₀, R₁, R₂ and R₃ refer to 5-cm row spacing, 15-cm row spacing, 25-cm row spacing and 35-cm row spacing, respectively. The data are means ± standard error (SE; n = 3). Different small letters in each group indicate significant differences at <i>P</i><0.05.</p

Relationships between LAI (<i>A</i>), CAP (<i>B</i>) at mid-grain filling stage and yield of two spike types of wheat under high plant density.

<p>Correlation coefficients (R) were calculated, and asterisks (**) represent the significance at the 0.01 probability level (n = 24).</p

Ridge-furrow mulched with plastic film improves the anti-oxidative defence system and photosynthesis in leaves of winter wheat under deficit irrigation

<div><p>In semi-arid areas of China, the ridge-furrow mulched with plastic film (RF) cultivation system is a common water-saving agricultural technique where the shortage of water resources has become a serious problem. Therefore, we aimed to explore whether this cultivation is actually an improvement over the traditional flat planting (TF) method while testing two deficit irrigation (150, 75 mm) levels to grow winter wheat. Furthermore, we examined the responses of the anti-oxidative defence system and photosynthetic capacity of winter wheat flag leaves under three simulated rainfall (275, 200 and 125 mm) conditions. The results showed that the RF system with 150 mm deficit irrigation and 200 mm simulated rainfall condition (RF2₁₅₀) treatment raised soil water content (%) at the jointing and flowering stages and achieved higher net photosynthesis rates (Pn) in flag leaves. Furthermore, such improvements were due to the reduction of malondialdehyde (MDA) content and oxidative damage during different growth stages of winter wheat. The RF2₁₅₀ treatment significantly increased the activities of superoxide dismutase (SOD); peroxidise (POD), catalase (CAT) and ascorbate peroxidase (APX) and the content of soluble protein (SP) during different growth stages of winter wheat. Furthermore, RF2₁₅₀ treatment attained the highest value at the flowering stage, while also exhibiting significant declines in contents of proline, MDA, H₂O₂ and O₂ in flag leaves. The higher free H₂O₂ and O₂ scavenging capacity and better anti-oxidative enzyme activities under the RF2₁₅₀ treatment were due to the lower level of lipid peroxidation, which effectively protected the photosynthetic machinery. The net photosynthetic rate of flag leaves was positively correlated with SOD, POD, CAT, APX and SP activities, and negatively correlated with proline, MDA, H₂O₂ and O₂ contents. We concluded that the RF2₁₅₀ treatment was the better water-saving management strategy because it significantly delayed flag leaf senescence and caused the increases in SWC, WUE, Pn, antioxidant enzyme activities and grain yield of winter wheat grown in semi-arid regions of China.</p></div

Effects of different cultivation models and deficit irrigation on average soil water content (%) at the depth of 0–100 cm soil layers under simulated rainfall conditions at different growth stages of winter wheat during 2015–2017.

<p>Note: R₁₅₀: ridges covered with plastic film mulch and 150 mm deficit irrigation; R₇₅: ridges covered with plastic film mulch and 75 mm deficit irrigation; F₁₅₀: traditional flat cultivation and 150 mm deficit irrigation; F₇₅: traditional flat cultivation and 75 mm deficit irrigation. Three different simulated rainfall concentrations 275 mm, 200 mm and 125 mm were used. ST: sowing time; JS: jointing stage; FS: flowering stage; GFS: grain filling stage; MS: maturing stage. Bars represent the LSD at p = 0.05 (n = 3).</p

Malondialdehyde (MDA) content (μmol g^-1 FW) in winter wheat leaves of different treatments^a during 2015–2016 and 2016–2017^b.

<p>Malondialdehyde (MDA) content (μmol g^-1 FW) in winter wheat leaves of different treatments<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200277#t004fn001" target="_blank">^a</a> during 2015–2016 and 2016–2017<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200277#t004fn002" target="_blank">^b</a>.</p