玉米根系对土壤紧实胁迫和氧胁迫的响应

The root growth and yield of maize are restricted severely by the increasing soil compaction. Actually, the effects of soil compaction on maize root are the co-effects of compaction stress and hypoxia stress. However, the researchers have not made a distinction of the effects on maize root between compaction stress and hypoxia stress, which not only affects the comprehensive understanding of mechanism of soil compaction, but affects the technology establishment to regulate compacted soil. The research is carried out by pool, and the oxygen content in soil is controlled artificially. This research intend to study the growth, microstructure, ultrastructure, activity of ATPase, activities of aerobic respiration enzymes, activities of anaerobic respiration enzymes and contents of respiration matters if maize, analyze the effects of compaction stress, hypoxia stress and their interaction on growth, anatomical structure and physiological function of maize root, and then explain the molecular mechanism how maize root responds to the compaction stress and hypoxia stress. The results will provide a theoretical guide for technology establishment to improve the compacted soil and yield-increasing of maize.

日益加剧的土壤紧实问题严重限制了玉米根系的生长和产量形成。土壤紧实对玉米根系的胁迫效应实际上是紧实和缺氧双重胁迫的结果，但紧实胁迫和氧胁迫对玉米根系的影响尚未明确区分开，不仅不能全面科学理解土壤紧实影响玉米产量的机制，也影响了紧实土壤高产调控技术的制定。本项目采用土壤池栽试验，通过人工控制土壤氧气含量，研究土壤紧实胁迫和氧胁迫条件下玉米根系生长分布、根系显微和超微结构、根系活力、根系ATP酶活性、根系有氧呼吸和无氧呼吸关键酶活性及相关呼吸代谢产物的差异，探讨紧实胁迫、氧胁迫以及二者交互对玉米根系生长分布、解剖结构和生理功能的影响，阐明玉米根系响应土壤紧实胁迫和氧胁迫的内在分子机制，为研发缓解玉米田土壤紧实障碍的调控技术、提升玉米增产潜力提供理论依据。

土壤紧实严重限制了玉米根系的生长和产量形成。为明确土壤紧实存在的紧实胁迫和氧胁迫对玉米根系的影响效应，本项目采用桶栽试验，通过人工控制土壤氧气含量，研究土壤紧实胁迫和氧胁迫条件下玉米根系生长分布、根系显微和超微结构、根系活力、根系ATP酶活性、根系有氧呼吸和无氧呼吸关键酶活性及相关呼吸代谢产物的差异，探讨紧实胁迫和氧胁迫对玉米根系生长分布、解剖结构和生理功能的影响，阐明玉米根系响应土壤紧实胁迫和氧胁迫的内在分子机制。研究结果表明，土壤紧实对玉米根系同时存在紧实胁迫和氧胁迫，土壤容重调控和通氧处理均可以影响玉米根系生长分布、解剖结构、生理功能、基因表达和籽粒产量，但不同土壤质地影响效果不同。壤土进行土壤容重调控，可使玉米根系生物量、根系活力、ATP酶活性、ATP含量、产量分别提高41.7%、43.2%、21.7%、10.3%和19.2%，通氧处理可使玉米根系生物量、根系活力、ATP酶活性、ATP含量、产量分别提高10.0%、16.4%、16.8%、8.5%和12.9%。粘土进行土壤容重调控，可使玉米根系生物量、根系活力、ATP酶活性、ATP含量、产量分别提高23.4%、13.9%、7.8%、17.4%和17.9%，通氧处理可使玉米根系生物量、根系活力、ATP酶活性、ATP含量、产量分别提高9.5%、38.5%、14.0%、19.3%和13.1%。此外，壤土上进行容重调控对玉米根系显微结构、超微结构、有氧呼吸酶活性、无氧呼吸酶活性、代谢产物和根系响应土壤物理阻力piip1基因表达量的影响均大于通氧处理，而通氧处理对粘土玉米根系的影响大于壤土。以上结果表明，土壤紧实对玉米根系同时存在紧实胁迫和氧胁迫，壤土上进行土壤容重调控效果好，而粘土上进行通氧处理效果好，且通氧处理对高容重土壤的调控效果优于适宜容重。该结论为研发缓解玉米田土壤紧实障碍的调控技术、提升玉米增产潜力提供了理论依据。