Gao Jia, Zhao Bin, Dong Shuting, Liu Peng, Ren Baizhao, Zhang Jiwang
State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, China.
Front Plant Sci. 2017 Oct 26;8:1821. doi: 10.3389/fpls.2017.01821. eCollection 2017.
Maize is one of the most important crops globally that provides food, feed, and bioenergy. However, shading stress threatens maize production. In this study, we investigated the effects of shading on photosynthate accumulation and distribution of summer maize in the field. Zhengdan958 (ZD958) and Denghai 605 (DH605) were used as experimental materials in a field experiment running from 2013 to 2015. Shading treatments were applied over different growth stages: from the tassel stage (VT) to physiological maturity (R6) (S1), from the six-leaf stage (V6) to VT (S2), and from emergence stage (VE) to R6 (S3). The effects of shading on plant photosynthesis, photosynthate accumulation and distribution, and yield were evaluated in comparison to ambient sunlight. Shading significantly decreased the leaf area, SPAD value, net photosynthetic rate, dry matter accumulation, and grain yield. During the 3-year experimental period, grain yields of ZD958 and DH605 were reduced by 83.4%, 34.2%, 53.1% and 79.3%, 24.2%, 57.6% as compared to the CK by treatments S3, S2, and S1, respectively. CO stable isotope tracing revealed that shading differentially affected the photosynthate transfer rate in different stages; photosynthates were transferred from top to bottom plant parts, in the order control > S2 > S1 > S3. We conclude that shading clearly disrupted photosynthate metabolism, and reduced the photosynthate accumulation in the grain, resulting in a yield reduction.
玉米是全球最重要的作物之一，可提供食物、饲料和生物能源。然而，遮荫胁迫威胁着玉米生产。在本研究中，我们调查了田间遮荫对夏玉米光合产物积累和分配的影响。以郑单958（ZD958）和登海605（DH605）为试验材料，于2013年至2015年进行了田间试验。在不同生长阶段进行遮荫处理：从抽雄期（VT）至生理成熟期（R6）（S1）、从六叶期（V6）至VT（S2）以及从出苗期（VE）至R6（S3）。与自然光照相比，评估了遮荫对植物光合作用、光合产物积累与分配以及产量的影响。遮荫显著降低了叶面积、SPAD值、净光合速率、干物质积累和籽粒产量。在3年试验期内，与对照相比，ZD958和DH605的籽粒产量分别因S3、S2和S1处理而降低了83.4%、34.2%、53.1%以及79.3%、24.2%、57.6%。CO稳定同位素示踪表明，遮荫在不同阶段对光合产物转运速率的影响不同；光合产物从植株上部向下部转运，顺序为对照>S2>S1>S3。我们得出结论，遮荫明显扰乱了光合产物代谢，减少了籽粒中光合产物的积累，导致产量降低。
