Hu Dan Dan, Zhang Ji Wang, Liu Peng, Zhao Bin, Dong Shu Ting
State Key Laboratory of Crop Biology/College of Agronomy, Shandong Agricultural University, Tai' an 271018, Shandong, China.
Ying Yong Sheng Tai Xue Bao. 2018 Oct;29(10):3229-3236. doi: 10.13287/j.1001-9332.201810.021.
To explore the effects of different densities of mixed-cropping on C-photosynthate distribution and grain yield of maize, we measured photosynthetic characteristics, C-photosynthate distribution, dry matter accumulation, and grain yield under different planting densities (LD, 67500 plants·hm and HD, 97500 plants·hm) under mixed-cropping (M, 1:1, 2:2) and monoculture of Zhengdan958 (ZD) and Denghai605 (DH). The results showed that with the increases of planting density, grain yield, C-photosynthate allocation to grain, dry matter accumulation, and leaf area index (LAI) increased, but the chlorophyll content and net photosynthetic rate decreased. No significant difference was observed between the monoculture and mixed-cropping at the density of 67500 plants·hm. However, at 97500 plants·hm, LAI, chlorophyll content, net photosynthetic rate and dry matter accumulation in mixed-cropping were higher than that in monoculture. Mixed-cropping promoted the transport of dry matter from the vegetative organs such as stem to the grain and the distribution of C-photosynthates to grain. Grain yield of summer maize significantly increased in mixed-cropping due to the increase of 1000-grain mass. Under high plant density, the mixed-cropping could enlarge photosynthetic area, maintain higher net photosynthetic rate, increase dry matter accumulation, improve the distribution of dry matter, promote the distribution of C-photosynthates to grains and thus increase the grain yield. Our results indicated that mixed-cropping could significantly increase the yield of close planting summer maize in Huang-Huai-Hai Plain.
为探究不同混作密度对玉米碳同化物分配及籽粒产量的影响，我们测定了郑单958（ZD）和登海605（DH）在混作（M，1:1、2:2）及单作条件下，不同种植密度（低密度，67500株·hm；高密度，97500株·hm）下的光合特性、碳同化物分配、干物质积累及籽粒产量。结果表明，随着种植密度增加，籽粒产量、碳同化物向籽粒的分配、干物质积累及叶面积指数（LAI）增加，但叶绿素含量和净光合速率降低。在67500株·hm密度下，单作和混作间未观察到显著差异。然而，在97500株·hm时，混作的LAI、叶绿素含量、净光合速率及干物质积累高于单作。混作促进了干物质从茎等营养器官向籽粒的转运以及碳同化物向籽粒的分配。由于千粒重增加，夏玉米混作时籽粒产量显著提高。在高种植密度下，混作可扩大光合面积，维持较高的净光合速率，增加干物质积累，改善干物质分配，促进碳同化物向籽粒的分配，从而提高籽粒产量。我们的结果表明，混作可显著提高黄淮海平原密植夏玉米的产量。
