Slight shading after anthesis increases photosynthetic productivity and grain yield of winter wheat (Triticum aestivum L.) due to the delaying of leaf senescence

Abstract

The solar radiation intensity and duration are continuously decreasing in the major wheat planting area of China. As a consequence, leaf senescence, photosynthesis, grain filling and thus wheat yield shall be affected by light deficiency. Therefore, two winter wheat (Triticum aestivum L.) cultivars, Tainong18 (a large-spike cultivar) and Jinan17 (a multiple-spike cultivar), were subjected to shading during anthesis and maturity under field condition in 2010-2011 and 2011-2012. Under the slight shading treatment (S1), leaf senescence was delayed, net photosynthesis rate (P n) and canopy apparent photosynthesis rate (CAP) were improved, and thus thousand kernel weight (TKW) and grain yield were higher as compared with the control. However, heavy-intensity shading (S2 and S3) led to negative effects on these traits substantially. Moreover, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity in flag leaf were significantly greater under slight shading than in other treatments, while the malondialdehyde (MDA) content was less than under other treatments. In addition, the multiple-spike cultivar is more tolerant to shading than large-spike cultivar. In conclusion, slight shading after anthesis delayed leaf senescence, enhance photosynthesis and grain filling, and thus resulted in higher grain yield.

Slight Shading Stress at Seedling Stage Does not Reduce Lignin Biosynthesis or Affect Lodging Resistance of Soybean Stems

“…The same results were obtained in wheat. Research of Xu et al showed that slight shade did not significantly affect photosynthetic product accumulation in wheat [34]. A study on sweet potato showed that slight shade has little effect on plant growth and photosynthesis, and even has some positive effects [35].…”

Effects of Shading Stress on Grain Number, Yield, and Photosynthesis during Early Reproductive Growth in Wheat

“…Multiple studies have shown that shading stress causes yield loss (Liu et al, 2015b;Xu et al, 2016). When grain number decreases, a limited supply from the source could have positive effects on grain weight.…”

“…In the present study, this was evident mainly after 1, 2, and 3 d of shading stress. Multiple studies have shown that shading stress causes yield loss (Liu et al, 2015b;Xu et al, 2016). This is mainly caused by reduction in grain number and grain weight.…”

“…Previous studies have indicated that shading reduces grain yield by the reduction of leaf area index and Pn in leaves (Kemp and Whingwiri, 1980;Mu et al, 2010). The most shade-tolerant cultivars suffer a lower reduction in grain yield and biomass (Li et al, 2010a) because of their higher tillering capacity and, consequently, larger plant population (Xu et al, 2016). showed that the shade-tolerant wheat cultivars could delay the onset of leaf senescence and maintain higher Pn, which contributed to the mechanism of closing a portion of the active center of Photosystem II.…”

“…Muleo et al (2006) proposed that shade-tolerant cultivars increased shoot dry weight, and that the root system also changed under shading conditions. The most shade-tolerant cultivars suffer a lower reduction in grain yield and biomass (Li et al, 2010a) because of their higher tillering capacity and, consequently, larger plant population (Xu et al, 2016). However, there is a lack of knowledge of cultivar differences in shading stress tolerance at the YM stage.…”