【作者】 程汉亭；

【导师】 胡景江； 慕自新；

【作者基本信息】 西北农林科技大学 ， 植物学， 2009， 硕士

【摘要】 本研究以高产、稳产、多抗玉米新品种郑单958为试验材料,采用PEG6000处理模拟干旱胁迫-复水的方法,研究了干旱胁迫-复水后玉米侧根发育的可塑性和调控机制,得出以下主要结论:1、在三个水势梯度（-0.4MPa、-0.8MPa、-1.2MPa）和两个时间梯度（干旱胁迫12h后复水和干旱胁迫24h后复水）下研究干旱胁迫对侧根发育的影响,发现轻度（-0.4MPa）胁迫能够促进玉米侧根的发生和延伸生长,而中、重度（-0.8MPa和-1.2MPa）胁迫使侧根生长发育受到不同程度的抑制,水势越低,胁迫时间越长抑制效果越显著;复水后玉米侧根出现了不同程度的补偿生长现象,尤其在-0.8MPa干旱胁迫-复水条件下玉米侧根补偿生长最显著。2、在-0.8MPa水势梯度下研究了干旱胁迫-复水诱导玉米侧根补偿生长的机制。发现（Ⅰ）干旱胁迫下玉米根系中水孔蛋白表达量比正常水分条件下低,复水后玉米根系中水孔蛋白表达量急剧增加,而且表达量超过了正常生长条件下的表达量;正常生长条件下水孔蛋白均匀分布在根皮层组织上,干旱胁迫以及干旱胁迫复水后水孔蛋白主要分布在根的外皮层和内皮层细胞上,而且胁迫程度越大,复水后表现越明显。用水孔蛋白抑制剂HgCl2初步证明了水孔蛋白介导了此过程中侧根的发生。（Ⅱ）干旱胁迫下玉米根系中NO含量低于正常生长条件下的含量,复水后NO含量高于正常条件下的含量,其含量的变化与侧根发育规律相一致,进一步用药理学试验证明了NO与干旱胁迫-复水诱导玉米侧根的发育有着密切的关系。（Ⅲ）H₂O₂能够在一定程度上促进玉米侧根的生长发育,由此可见干旱-复水过程中玉米侧根发育的可塑性可能受水孔蛋白、NO和H₂O₂等诸多因素的影响和调控。更多还原

【Abstract】 Using Zhengdan-958 new maize variety of high-quality, high-yield and multi-resistance as material, the compensation of lateral roots development and regulation mechanism were studied by re-watering after draught stress in maize. The results were as follows:Under water stress and re-watering, lateral root system dynamic development were studied.Lateral root growth and development was promoted under low-level water stress（-0.4MPa）.Lateral root growth and development was restrain with water potential decreased; lateral roots development of maize have high plasticity with the change of water condition.The effect of lateral roots development were studied with three water potential gradient（-0.4MPa、-0.8MPa、-1.2MPa）and two time gradient（re-watering after draught stress 12h and re-watering after draught stress 12h）.Lateral root growth and development was promoted under low-level （-0.4MPa） water potential （-0.4MPa） but restrained with hight-level（-0.8 MPa） and middle level （-1.2MPa） water potential .This phenomenon was more significant whih the lower of water potential. The compensation growth of lateral roots promoted root water uptake after re-watering especially under re-watering by -0.8MPa.Study on the molecular mechanism of compensatory growth under water stress and re-watering Induced the follow results: （Ⅰ）Aquaporin expression in the roots reduced under water stress. expression of aquaporin which distributed in exodermis and endodermis increased rapidly under water stress. Pharmacological experiment of HgCl2 verified that the increased of aquaporin expression stimulated lateral roots emergence;（Ⅱ）The level of NO expression under water stress lower than normal level in the roots,but the level of NO expression under re-watering higher than normal level. The results showed that the level of NO expression had intimated relationship with compensation growth of lateral root under re-watering;（Ⅲ）Pharmacological experiment of H₂O₂ verified that exterior H₂O₂ stimulated lateral roots emergence,so the exterior H₂O₂ had intimated relationship with compensation growth of lateral root.更多还原