海河低平原深松播种对夏玉米根系生理的影响及其节水增产效应

Effects of Subsoiling-Seeding on Root Physiological Indices, Water-Saving and Yield-Increasing Behaviors in Summer Maize(Zea mays L.) in Haihe Lowland Plain of China

于2012-2013年在河北省农林科学院旱作农业研究所深州试验站，以郑单958为供试品种，设置夏玉米深松播种和免耕播种两个处理，从玉米出苗开始，根据生育进程定期观察玉米根系形态、生理指标及微观结构、玉米冠层光合特性和叶面积指数，成熟期测定产量，计算水分利用效率和2m土体水分储蓄情况。结果表明，0～60cm土层，深松播种处理可提高玉米根系干物质积累、表面积、根长和活跃吸收面积比例，全生育期分别比免耕播种处理提高30．5％、24．6％、29．7％和56．3％。0～60cm土层，深松播种处理玉米根系脯氨酸含量、硝酸还原酶活性和根系活力分别比免耕处理高140．0％、37．0％和36．5％。全生育期，深松播种处理根系伤流液总量比免耕播种处理提高15．2％。0～40cm土层，深松播种处理单根和整株根系导水率分别提高15．8％和17．0％。0～40cm土层，深松播种处理玉米根系中柱导管直径增大，中柱鞘细胞壁及中柱内薄壁细胞的细胞壁增厚栓化，髓细胞数量增多但整体在髓腔横切面积中所占比例偏小，后生木质部导管直径增大、数量增多，皮层厚度降低；O～20cm土层，深松播种处理根系皮层中部细胞虽也较大但层数较少，相当于免耕处理的86．2％。深松播种处理可提高玉米叶面积指数，全生育期平均比免耕处理高12．5％：深松播种处理还可提高叶片光合速率和光合势。深松播种处理玉米籽粒灌浆速率全生育期平均比免耕播种处理高5．0％。与免耕处理相比，深松播种处理2年平均穗粒数、千粒重和产量分别比免耕播种处理提高2．4％、3．9％和8．2％，耗水量降低9．1％，产量和水分利用效率分别比免耕处理高8．2％和14．4％，2m土体贮水量提高31．7％。

The study was carried out in Shenzhou Experimental Station, Arid Farming Research Institute, Hebei Academy of Agri- cultural and Forestry Sciences in 2012-2013. The maize variety Zhengdan 958 was used in this experiment with two treatments including sub-soiling seeding （SRT） and no-tillage seeding （NT）. From seedling emergence to maturity, the root morphology, physiological parameters and microstructure, canopy photosynthetic characteristics, and leaf area index were regularly measured. At maturity, the yields and the water use efficiency and water storage in 2 m soil layer were investigated. The results showed that SRT increased the root dry mass, surface area, length and active absoiling area ratio in 0~50 cm soil layer, with the increase of 30.5%, 24.6%, 29.7%, and 56.3%, respectively, in comparison with NT. In addition, SRT also increased the proline content, nitrate reduetase activity and activity of roots compared with NT in this soil layer, with the increase of 140.0%, 37.0%, and 36.5%, respectively. The total root bleeding sap in SRT increased by 15.2% compared with NT in the whole growth stage. In 0-40 cm soil layer, the hydraulic conductivity in single root and the roots per plant around whole growth stage in SRT increased by 15.8% and 17.0% respectively, in comparison with NT. In SRT, the diameter of stele vessel was increased, cell walls of pericycle and stele parenchyma were thickened, and the number of pith cells were increased, but its section area ratio in stale decreased compared with NT. Moreover, the numbers and diameter of xylem vessel in SRT increased, but the cortical thickness in roots decreased. In 0-20 cm soil layer, although the middle cortical cells of root in SRT were larger than those of NT, but there number was only 86.2% ofNT. SRT also increased the LAI and photosynthetic rate. The grain-filling rate in SRT treatment was also increased, with 5.0% higher than in NT. In two growth seasons, compared with NT, the spike kernels, 1000-grain weight, and yield in SRT treat- ment were increased by 2.4%, 3.9%, and 8.2%, respectively, whereas the water consumption was reduced by 9.1%, the water use efficiency was increased by 14.4%, and the water storage amount in 2 m soil layer was increased by 31.7%.