Irrigation methods affect wheat flag leaf senescence and chlorophyll fluorescence in the North China Plain

Document Type: Research Paper

Authors

1 Key Laboratory of Crop Ecophysiology and Farming System, Ministry of Agriculture, College of Agronomy, Shandong Agricultural University, Tai’an, Shandong, 271018, P.R. China

2 Key Laboratory of Crop Ecophysiology and Farming System, Ministry of Agriculture, College of Agronomy, Shandong Agricultural University, Tai’an, Shandong, 271018, P.R. China.

3 Agricultural Information Institute of Chinese Academy of Agricultural Sciences, Zhongguancun south Street No. 12, Beijing, 100081, PR China

Abstract

The water resource shortage in North China Plain is an increasing threat to the sustainability
of wheat (
Triticum aestivum L.) production. A two-year field experiment was conducted to
examine the effects of two supplemental irrigation (SI) methods on wheat flag leaf senescence,
chlorophyll fluorescence and grain yield. The following field treatments were conducted:
no irrigation (W
0); SI with 60 mm of water at jointing and anthesis stages (local quota SI, Wck);
SI based on the relative soil water content (SWC) of 0–40 cm soil layers with 65% field
capacity (FC) at jointing stage and 70% FC at anthesis stage (W
1); SI based on SWC of same
soil layers with 70% FC at the jointing and anthesis stage (W
2); and SI based on the SWC of
same soil layers with 75% FC at jointing stage and 70% FC at anthesis stage (W
3). Results
showed that W
0 accelerated flag leaf senescence and had reduced grain yield. Among irrigation
treatments, W
2 (and W3 in 2013-2014) significantly increased flag leaf water potential from
7 to 28 days after anthesis (DAA) compared with W
ck and W1. Superoxide dismutase activity,
catalase activity of W
2 increased by 15.41% and 14.96% compared with those in Wck, resulting
in the significantly decreased concentration of malondialdehyde and increased concentration of
soluble protein at 14–28 DAA. The F
v/Fm at 21–28 DAA and the ΦPSII, qP and NPQ at 14–28
DAA for W
2 (and W3 in 2013–2014) were also significantly higher than those of Wck and W1.
Eventually, grain yield, water use efficiency and irrigation benefit of W
2 were 8704.54 kg ha-1,
20.86 kg ha
-1 mm-1 and 31.44 kg ha-1 mm-1, respectively, which were the highest among those
of all the treatments. These values increased by 5.82%, 9.65% and 6.00%, respectively, relative
to those of W
ck. In conclusion, the SI based on 0–40 cm soil layer and use of an appropriate
relative SWC (both 70% FC at the jointing and anthesis stages) can reduce irrigation amount,
delay leaf senescence and improve grain yield and water use efficiency.

Keywords