Wang Ying, Zhou Zhiguo, Chen Binglin, Meng Yali, Shu Hongmei
Key Laboratory of Crop Growth Regulation of Agriculture Ministry, Nanjing Agricultural University, Nanjing 210095, China.
Ying Yong Sheng Tai Xue Bao. 2006 Dec;17(12):2341-6.
By the methods of 15N-foliar feeding and 15N dilution, a pot experiment of double-cropping wheat and cotton was conducted to study the nitrogen absorption and allocation in cotton plant under effects of wheat and cotton root mass. Three treatments were installed, i.e., no separation of wheat and cotton roots (treatment I), separation with nylon net (treatment II), and separation with plastic film (treatment III). The results showed that both the competition of 15N absorption between wheat and cotton root, and the translocation of absorbed 15N from wheat root to cotton were existed in the wheat-cotton double-cropping system. The absorbed 15N by cotton root was mostly allocated in aboveground part, and less in root. The aboveground part of cotton had the highest N utilization rate (NUR) in treatment I and the lowest one in treatment III, but the Ndff was lower in treatment I than in treatments II and III. At the early flowering stage of cotton when wheat was harvested and its straw was amended in situ, the absorbed nitrogen by cotton was mainly from the applied 15N, but not from the amended wheat straw. The allocation of absorbed 15N in different organs of cotton was quite different, being much higher in reproductive organs than in other organs. The biomass of cotton plant was also higher in treatment I than in treatments II and III.
采用¹⁵N叶面喷施和¹⁵N稀释法，进行了小麦-棉花套作盆栽试验，研究小麦和棉花根系质量对棉花植株氮素吸收与分配的影响。设置了3个处理，即小麦与棉花根系不隔离（处理Ⅰ）、用尼龙网隔离（处理Ⅱ）、用塑料薄膜隔离（处理Ⅲ）。结果表明，在小麦-棉花套作体系中，小麦与棉花根系之间存在¹⁵N吸收竞争，且存在吸收的¹⁵N从小麦根系向棉花的转移。棉花根系吸收的¹⁵N大多分配到地上部分，分配到根系的较少。棉花地上部分的氮素利用率（NUR）在处理Ⅰ中最高，在处理Ⅲ中最低，但处理Ⅰ中的Ndff低于处理Ⅱ和Ⅲ。在棉花初花期小麦收获并就地还田时，棉花吸收的氮素主要来自施用的¹⁵N，而非还田的小麦秸秆。棉花吸收的¹⁵N在不同器官中的分配差异较大，生殖器官中的分配远高于其他器官。棉花植株生物量在处理Ⅰ中也高于处理Ⅱ和Ⅲ。
