【作者】 王立国；

【导师】 施培； 孙学振；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2003， 硕士

【摘要】 棉麦双高产复合群体棉花根系生理与根际微生态特征研究　　协调共生期棉麦资源竞争与互作是影响棉麦两熟产量和效益最关键的环节之一，其中地下部的竞争与互作是研究的热点与难点。本研究选用鲁麦15号和美棉33B，于2001－2002年在山东农业大学泰安实习农场和中国农业科学院棉花研究所探讨了棉麦两熟双高产条件下棉麦复合群体干物质和养分的累积与分配、根系生长的时空动态分布、根系生理特性、根际与非根际土壤养分含量与土壤酶活性及微生物区系数量变化的特征。主要结果如下：1干物质和养分的累积与分配：在棉麦共生期，套作棉养分累积与干物质累积均低于单作棉，小麦收获后，在初蕾期到花铃期这一阶段，套作棉吸收的氮磷钾增长最快，增长速度比单作棉约快5倍。干物质累积也是如此，说明解除小麦的竞争后，套作棉在养分累积与干物质累积上有一个加速阶段。套作棉氮磷钾绝对量各时期均低于单作棉，在营养器官的分配比重高于单作棉，在生殖器官的分配比重则相反。棉麦自然根系和纱网隔根复合群体单株总氮、磷、钾累积均低于棉麦塑膜隔根复合群体，棉麦自然根系复合群体单株总氮总钾累积量低于棉麦纱网隔根复合群体；棉麦自然根系群体中棉花单株干物重最弱。小麦收获后，棉麦自然根系复合群体中棉花干物质与养分累积仍弱于棉麦纱网隔根和塑膜隔根复合群体。2根系生长的时空动态分布：套作棉和单作棉根长和根长密度、根表面积以及根系平均直径均随生育时期的延后呈先上升后下降趋势。根长、根长密度、根表面积最大值的出现时期差异较小，但套作棉花铃期后40cm土层以下根长和根长密度、根表面积的衰退速率明显低于单作棉；根系平均直径差异较小，套作棉花铃期前浅层根干重低于单作棉，花铃期后深层根干重明显高于单作棉，并在根系总量上超过单作棉。在空间分布上，在距棉花25cm的范围内，0-20cm土层的根长和根长密度、根总表面积最大，并随土层加深而递减。单作棉浅层根长密度表现为距棉花8.75-16.25cm处较高，套作棉则以距棉花0－7.5cm处较大，并<WP=7>随距棉花距离的增加而降低。根表面积的空间分布规律与密度一致。各土层水平方向最大根干重位点随土层深度增加,单作棉呈弓背形分布，而套作棉呈逐渐偏离棉花主根趋势。3棉花叶片生理特征及根干物质累积：棉麦自然根系和塑膜隔根复合群体降低了棉麦共生期棉花叶片硝酸还原酶活性，棉麦纱网隔根复合群体对棉花叶片硝酸还原酶活性的影响较小。棉麦套作降低了棉麦共生期棉花叶片内源保护酶活性，棉花根系干物质累积量减少；棉麦共生期隔根对距棉花12.5cm以内的根干重累积影响较小；棉花蕾期，棉麦塑膜隔根显著提高了棉花叶片硝酸还原酶活性；棉麦塑膜隔根复合群体在40-70cm土层的根干重高于单作棉，表明塑膜隔根在抑制根系横向生长的同时促进了根系的纵向生长。小麦收获后，棉麦套作对棉花叶片内源保护酶活性的影响作用仍然存在。4棉花根系生理特性的变化：在距离棉花12.5cm以内，0－20cm土层内棉麦自然根系和纱网隔根复合群体降低了棉麦共生期棉花的根系活力，棉麦塑膜隔根提高了根系活力；棉麦套作可提高棉花根系的硝酸还原酶活性，降低棉麦共生期内的棉花根系内源保护酶活性及可溶性蛋白含量；解除小麦遮荫后，棉麦复合群体根系内源保护酶活性和可溶性蛋白含量均较共生期有不同程度的改善，与棉麦自然根系复合群体相比，棉麦隔根降低了棉花根系内源保护酶活性及可溶性蛋白含量。5棉花根际与非根际土壤养分、pH值和土壤酶活性：在棉麦共生末期，套作棉根际与非根际pH值均高于单作棉，根际与非根际全氮、有效磷、速效钾含量均高于单作棉，而铵态氮、有机质含量低于单作棉，除过氧化氢酶外，余土壤酶活性均高于单作棉。小麦收获后，套作棉根际与非根际土壤养分含量及土壤酶活性高于单作棉，且根际养分含量与土壤酶活性多高于非根际。套作棉根际与非根际土壤pH值在初花期后已明显低于单作棉，套作棉根际与非根际土壤养分含量与土壤酶活性具有一定的相关性，蔗糖酶活性与土壤全氮、有机质、有效磷和速效钾含量均呈极显著正相关。蛋白酶活性与铵态氮、硝态氮含量呈显著或极显著负相关，脲酶活性与土壤全氮、有机质、有效磷和速效钾的含量均呈极显著正相关；过氧化氢酶与土壤养分含量及pH值相关性均不显著。<WP=8>6棉花根际非根际土壤微生物数量：棉麦自然根系群体有利于棉花根际非根际土壤细菌和氨化细菌的增殖；棉麦纱网隔根复合群体对根际土壤真菌增殖有利；棉麦塑膜隔根复合群体对棉花根际土壤固氮菌和纤维分解菌增殖有利，对非根际土壤真菌、固氮菌和纤维分解菌增殖有利；棉麦套作不同复合根系群体对放线菌和氨化细菌的影响随生育期的延后而有所变动。更多还原

【Abstract】 The balances of competition and interaction of resources between cotton and wheat during the intergrowth period are of importance to determining yield and benefit in cotton-wheat double cropping system, and the competition and interaction of resources between underground organs are paid much attentions by many scientists in this field. At the experimental station of Shandong Agricultural University and the Cotton Research Institute of Chinese Agricultural Academy of Science in the growth season of 2001-2002, wheat variety Lumai 15 and cotton variety Meimian 33B were planted as the cotton-wheat double cropping systems. Total four treatments were implemented, i.e. monocultural system as CK, cotton-wheat double cropping system in which the roots of cotton and wheat mixed (DSRM), DS in which the roots of wheat and cotton were separated with nylon net (DSRN), and DS in which roots of wheat and cotton were separated with plastic film (DSRP). The characteristics of accumulation and distribution of nutrient and dry matter, growth and temporal and spatial distributionof root, root physiology, soil nutrient contents, soil enzyme activities, changes in species and number of microbe in the rhizosphere and non-rhizosphere zones of cotton were studied. The results were as follows: 1 Accumulation and distribution of dry matter and nutrientOver the intergrowth period, accumulation of dry matter and nutrients in cotton with cotton-wheat double cropping system (DS) were lower than than that with monoculture (CK). After harvest of wheat, absorbing of N, P and K<WP=10>between early-bud and bolling stage increased quickly, and was about 5 times higher in cotton plants with DS than that with CK. The accumulation of dry matter showed the same tendency. This indicated that the accumulation of dry matter and nutrients expressed a speedup when the competition between cotton and wheat dismissed after the harvest of wheat. Compared with CK, contents of N, P and K in cotton plant with DS was lower，and the nutrients distributed to vegetative organs were higher, while those to reproductive organs were lower.Accumulation of N, P and K in cotton plants with cotton-wheat double cropping system in which the roots of cotton and wheat mixed (DSRM) and DS in which the roots of wheat and cotton were separated with nylon net (DSRN) were lower than that with DS in which roots of wheat and cotton were separated with plastic film (DSRP). Total accumulation of N and K in cotton with DSRM was lower than that with DSRN.Dry matter of cotton plants with DSRM was the lowest, indicating that the accumulation of dry matter and nutrients was strongly impacted by wheat. After harvest of wheat, the accumulation of nutrients and dry matter in cotton plants with DSRM was still lower than those with DSRN and DSRP. 2 Temporal and spatial distribution of root growthThe changes of root length, root length density, root area and root average diameter of cotton plants showed a single-peak curve with the developmental stages. The stages of the highest root length, root length density and root area showed little difference between cotton plants with interplant systems and single crop system. After bolling stage, however, the decline speed of root area, root length and root length density in soil layers below 40 cm of cotton plants with interplant systems were obviously lower than that with single crop system. The average root diameter showed little difference between cottons with interplant and single crop systems. The dry weights of root in the top soil layers were lower of plants with interplant systems before bolling, while obviously higher after bolling, compared with those of single crop<WP=11>system.Within the observed area of 0-25cm apart from cotton, root length, root length density and root area were the highest in the 0-20cm soil layer, and descending with soil layer. In the topsoil layers, root density was the highest at the locations of about 12.5 and 0-7.5cm away from cotton plant with single crop system and interplant systems, res更多还原