连续3年对滨海盐土进行咸水结冰灌溉和地膜覆盖基础上的土壤水盐动态监测，并在以上基础上，针对不同地膜覆盖时间，设置了结冰灌溉条件下融冰入渗后覆膜（MI）、播种覆膜（SI）和无覆膜（NI），以及灌前秋季覆膜（无结冰灌溉，AN）和对照（无结冰灌溉无覆膜，CK）5个处理，以研究咸水结冰灌溉条件下土壤水盐动态规律，以及覆膜时期对土壤水盐动态和棉花生长的影响。结果表明：咸水结冰灌溉后，随着咸水冰层的融化，地表冰层含盐量和钠吸附比（SAR）均逐渐降低。相同土壤深度土壤含盐量随灌溉年限的延长而逐年降低，如2006—2008年冬灌前土壤表层（0～20 cm）盐分含量分别为19.8、15.4和12.4 g kg-1。结冰灌溉融水入渗完成后，0～40cm土层的土壤含盐量均被淋洗至4kg-1以下。融水入渗后9 d内进行地膜覆盖效果较好。咸水结冰灌溉结合地膜覆盖（MI）土壤脱盐效果最好，其棉花出苗率和籽棉产量也最高，分别为63.78%和3 200 kg hm-2，其次为AN、SI、NI和CK处理。经过长期（3年）结冰灌溉后，秋季进行覆膜依然可获得较高产量，其棉花出苗率和产量分别为59.63%和2 600 kg hm-2。但如果没有覆膜措施或覆膜较晚，依然不能获得理想的产量。
The North China Plain(NCP)is a severe water shortage region,especially during the wheat growing season.Understanding the response of grain yield and water availability in winter wheat cultivars(Triticum aestivum L.)is important to adjust planting structure under groundwater reducible exploitation in rainfed dry years of NCP.Field experiments were conducted at the Luancheng Agroecosystem Experiment Station of the Chinese Academy of Sciences,Hebei,China.Two different drought resistant winter wheat cultivars(Jinmai47 and Shiluan02-1)were grown under rainfed conditions during four years of 2010-2011,2011-2012,2012-2013 and 2013-2014.Grain yield and its components,aboveground biomass(AB),dry matter accumulation translocation efficiency,water consumption,water use efficiency at field scale,and photosynthetic characteristics were measured.The results showed that Jinmai47 rapidly accumulated AB by higher tiller and photosynthetic potential comparing with those of Shiluan02-1.Its grain yield was 16.49%higher than that of the drought-sensitive winter wheat variety Shiluan02-1 during the four rainfed years.However,the dry matter remobilization efficiency(DMRE)and contribution of dry matter remobilization from heading stage to maturity stage to grain(CDMRE)of Shiluan02-1 was higher than those of Jinmai47.The average water use efficiency at grain yield level(WUEy),WUE at aboveground biomass level(WUEab),and WUE at grain yield under rainy conditions(WUEr)of Jinmai47 were 11.08%,16.41%,and 17.21%higher than those of Shiluan02-1.There was a significant difference in the WUEab and WUEr between the two wheat cultivars.The two wheat varieties under drought condition have different growing strategies.Jinmai47 has more tiller number,earlier vigor,and higher AB than Shiluan02-1,helping it to adapt to the fluctuations in the environment.
Baodi DongHong YangYunzhou QiaoMingming ZhangYakai WangLele JinMengyu Liu
本研究以耐盐性不同的8个冬小麦品种为材料,分别在室温（20℃/25℃）和接近小麦生产的低温（10℃/15℃）条件下采用溶液培养,并在苗期进行盐胁迫处理（150 mmol·L-1 Na Cl）,研究温度和盐胁迫交互作用对耐盐性不同的小麦抗氧化机制的影响。结果表明,对室温培养的幼苗进行盐胁迫后,耐盐强的小麦幼苗超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化酶（APX）活性均显著升高,并且高于2个耐盐性弱的品种;而耐盐性弱的小麦幼苗盐处理后仅APX活性显著升高,其活性氧（ROS）累积量和叶片相对电导率均高于耐盐小麦;抗旱小麦以上指标介于耐盐品种和耐盐性弱的品种中间。低温培养下进行盐胁迫,谷胱甘肽还原酶（GR）在所有供试品种中均显著升高2-3倍;耐盐品种仅CAT和APX活性升高,抗旱品种SOD、POD和APX以及耐盐性弱的品种SOD和POD活性显著提高。由此得出与室温盐胁迫下小麦抗氧化机制的响应不同,低温盐胁迫条件下,耐盐小麦SOD和POD酶活性受到抑制,主要通过提高抗坏血酸-谷胱甘肽循环的两个关键酶APX和GR活性增加对ROS的清除能力,而抗旱品种和耐盐性弱的品种除GR酶活性显著提高外,SOD和POD对ROS的清除能力均显著增强。在各种抗氧化酶的共同作用下,耐盐性不同的小麦品种之间ROS累积量和叶片电导率等受伤害指标的差异程度与室温盐胁迫相比减弱。
