| 小麦/玉米/大豆三熟套作体系中小麦根系分泌特性及氮素吸收研究 |
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| 引用本文： | 雍太文,陈小容,杨文钰,向达兵,樊高琼.小麦/玉米/大豆三熟套作体系中小麦根系分泌特性及氮素吸收研究[J].作物学报,2010,36(3):477-485. |
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| 作者姓名： | 雍太文 陈小容 杨文钰 向达兵 樊高琼 |
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| 作者单位： | 四川农业大学农学院，四川雅安625014 |
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| 基金项目： | 本研究由国家公益性行业（农业）科研专项（nyhyzx07-004-10，200803028）和国家粮食丰产科技工程专项（2006BAD02A05）资助。 |
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| 摘 要： | 为探讨小麦/玉米/大豆多熟套作体系下小麦根系分泌物的分泌特性及其对根系生长环境和植株氮素吸收的影响，2006—2008年连续两个生长季采用田间定位试验，研究了小麦-大豆、小麦-甘薯、小麦/玉米/大豆和小麦/玉米/甘薯4种种植模式下小麦根系分泌物的数量与种类、小麦根系生长、土壤水分、土壤氮含量及植株吸氮量的变化特性。结果表明，与小麦-大豆和小麦-甘薯两种净作模式及小麦/玉米/甘薯套作模式相比，小麦/玉米/大豆套作降低了开花期和成熟期小麦生长区的土壤湿度、pH值及NO3--N和NH4+-N的含量，提高了小麦植株地上部总吸氮量、根系活力、根干重及土壤总氮含量，并且，开花期小麦根系分泌有机酸总量和可溶性糖含量增加，表现为套作>净作，大豆茬口>甘薯茬口，边行>中行，其中以小麦边行处理的分泌量最高。拔节期根系分泌的有机酸，净作处理以乙酸含量较高，占总量的47.8%~51.6%，套作处理以柠檬酸含量较高，占总量的31.7%~55.1%；开花期根系分泌的有机酸，净作和套作处理均以乙酸含量较高，占总量的33.3%~78.3%。小麦/玉米/大豆套作对小麦根系分泌有机酸和可溶性糖有促进作用，从而改善了根系生长环境，提高了小麦对氮素的吸收。
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| 关 键 词： | 小麦 种植模式 根系分泌物}氮素吸收 套作 |
| 收稿时间： | 2009-08-26 |
| 修稿时间： | 2009-12-08 |
Root Exudates and Nitrogen Uptake of Wheat in Wheat/Maize/Soybean Relay Cropping System |
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| YONG Tai-Wen,CHEN Xiao-Rong,YANG Wen-Yu,XIANG Da-Bing,FAN Gao-Qiong.Root Exudates and Nitrogen Uptake of Wheat in Wheat/Maize/Soybean Relay Cropping System[J].Acta Agronomica Sinica,2010,36(3):477-485. |
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| Authors: | YONG Tai-Wen CHEN Xiao-Rong YANG Wen-Yu XIANG Da-Bing FAN Gao-Qiong |
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| Institution: | College of Agronomy, Sichuan Agricultural University, Ya’an 625014, China |
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| Abstract: | Root exudates play a role in adjusting physical and chemical characteristics of soil, improving soil fertility, and facilitating nutrient uptake. Thus, they are used to explaining the mechanism of high nutrient utilization efficiency for plants. In the relay cropping system of wheat/maize/soybean, nitrogen use efficiency appears higher than that in the cropping system of wheat/maize/sweet potato. For explaining the relationship between the high use efficiency of nitrogen and the effects of rhizosphere microenvironment in the wheat/maize/soybean cropping system, the characteristics of wheat root exudates as well as its effects on wheat roots, wheat rhizosphere soil, and nitrogen uptake in wheat were studied in a two-year continuous experiment from 2006 to 2008 with four cropping systems, including two sole cropping systems (wheat–soybean and wheat–sweet potato) and two rely cropping systems (wheat/maize/soybean and wheat/maize/sweet potato). In the wheat/maize/soybean system, the soil moisture, soil pH and soil quick-acting N (NO3−-N and NH4+-N) content at wheat rhizosphere reduced at both flowering and maturity stages, and the total nitrogen uptake in shoots, root activity, root dry matter weight and soil total nitrogen content of wheat increased. At flowering stage, the total amount of organic acids and the content of soluble sugar of wheat rhizosphere increased in the wheat/maize/soybean system. The total amount of organic acid and the content of soluble sugar of wheat were higher in relay cropping system than in sole cropping system. In the two sole cropping systems, the wheat–soybean mode had higher amount of organic acid and higher content of soluble sugar than wheat–sweet potato. Wheat plants from fringe rows could exude organic acids and higher soluble sugar content than those from central rows, and the amount of root exudates in fringe rows was the highest among all the cropping systems. At jointing stage, the content of acetic acid in the sole cropping systems increased, which accounted for 47.8% to 51.6% of the total of organic acid. The content of citric acid in the relay cropping systems increased from 31.7% to 55.1% of total organic acid. At flowering stage, the content of acetic acid in sole and relay cropping systems was also promoted from 33.3% to 78.3% of the total organic acid. The root exudates were in favor of improving root growth condition, activating soil nutrition, enhancing nitrogen uptake and increasing nitrogen use efficiency in the wheat/maize/soybean relay cropping system. |
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| Keywords: | Wheat Cropping system Root wxudates Nitrogen uptake Relay cropping |
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