地下水浅埋区重度盐碱地覆膜咸水滴灌水盐动态试验研究

通过在高垄埋设水银负压计,研究土壤水势动态,并在枸杞不同生育期对潜水位以上各土层盐分进行取样分析,研究土壤盐分周年动态变化,为地下水浅埋区重度盐碱地改良利用提供理论依据。结果表明,在覆膜滴灌一个灌溉周期内,土壤水分运动始终为自滴头下方饱和区持续径向向外扩散;雨季降雨使水分从土壤剖面整体向下运动,随着潜水位的升高水分运动逐渐减弱,转为自垄中部向垄坡方向运动。盐分运动受水分运动影响明显,周年盐分动态可以分为春季强烈蒸发—积盐阶段、灌溉淋洗—稳定阶段、雨季淋溶—脱盐阶段、秋季蒸发—积盐阶段和冬季相对稳定阶段五个阶段。剖面土壤电导率(EC1∶5)均值从1.64 dS m-1增长至1.69 dS m-1,土壤未明显积盐,但盐分在剖面分布的周年变化表明滴灌灌溉调控了水分盐分在土壤中的分布,为作物根系生长提供了良好的土壤环境条件。因此,地下水浅埋区重度盐碱地可以通过高垄覆膜咸水滴灌技术加以利用。     

开都河流域下游绿洲土壤盐渍化特征及其光谱分析

以新疆开都河流域下游绿洲为研究区,通过土壤样品化学分析及其光谱反射率的测量,分析了土壤盐渍化特征以及土壤反射光谱曲线与土壤盐渍程度之间的关系;基于统计分析的方法,建立了表征土壤盐渍化特征的因子与其高光谱数据的多元回归模型。研究结果表明:研究区土壤pH值的平均值大于8.0,属于弱碱性土壤;土壤盐分含量呈T型分布;盐渍化土壤的光谱反射率曲线特征在形态上相似,变化平缓;在可见光-近红外波段,盐渍化土壤的光谱反射率曲线形状基本上由五个折线段和四个吸收带组成。     

滨海盐荒地不同高度台田地下水动态变化与脱盐效果

为给大面积滨海盐渍荒地农业开发利用提供高效的技术支撑, 在黄河三角洲滨海盐渍荒地上, 设计135 cm、145 cm和175 cm高度台田处理, 以未做台田处理的盐荒地为对照, 定位监测挖深沟修台田后2年的地下水埋深与矿化度的变化动态, 以及连续种植5年后台田土体含盐量的变化。研究表明: 连续2年3种高度台田均能有效增加地下水的埋深, 盐渍荒地地下水埋深变化为0.65~2.10 m, 3种高度台田地下水埋深变化为2.20~3.63 m。3种高度台田的地下水矿化度同盐渍荒地相比均呈现升高趋势, 表明台田土体盐分通过灌溉和降雨作用淋洗进入地下水中。修建台田前荒地0~30 cm土壤含盐量为4.90~7.33 g·kg^-1, 台田引黄灌溉洗盐后土壤含盐量降低到1.37 g·kg^-1以下, 土壤脱盐率为81.31%~89.05%。连续种植5年后, 不同高度台田0~120 cm土体盐分含量均低于盐荒地, 尤其0~30 cm和30~60 cm土层的盐分含量与盐荒地相比降低显著; 其中135 cm和145 cm台田各土层盐分含量均小于1.62 g·kg^-1。因此, “台田?深沟”模式是改良滨海重度盐渍土的一种有效工程措施, 考虑到开发成本和台田有效面积比, 台田高度可优先选择145 cm。     

硝普钠、24-表油菜素内酯\水杨酸浸种对盐胁迫下玉米种子萌发及幼苗生长的影响

采用营养液水培,以玉米品种天泰16(TT16)、豫玉18(YY18)为材料,探讨外源硝普钠(NO的外源供体SNP)+2,4-表油菜素内酯(EBR)/水杨酸(SA)浸种对盐胁迫下玉米种子萌发及幼苗生长的影响。结果显示,2种外源物组合浸种后,促进了盐胁迫(150mmol/L NaCl溶液)下玉米种子的萌发,以500mg/L 24-表油菜素内酯+硝普钠复合浸种和200mg/L水杨酸+硝普钠复合浸种效果最佳,其发芽率TT16分别比对照增加15%和13%,YY18增加16%和13%;发芽势TT16分别比对照增加24%和22%,YY18增加43%和44%,主根长、芽长及生物量也较对照增加。经外源物质浸种后,盐胁迫下的玉米幼苗长势较好,SOD、POD酶活性相比对照增加显著,MDA含量较少,可溶性糖在200mg/L水杨酸+硝普钠浸种的幼苗中积累最多,分别为对照的4.35倍(TT16)和4.03倍(YY18)。与对照相比,500mg/L EBR+100mmol/L SNP复合浸种和200mg/L SA+100mmol/L SNP复合浸种,玉米种子及幼苗耐盐性增强。     

A COMPREHENSIVE EVALUATION OF SALT TOLERANCE IN CAULIFLOWER （Brassica oleracea L. vat. botrytis L. ） DURING GERMINATION STAGE

以98份花椰菜自交系资源为试材,测定了盐胁迫下种子的发芽率（GP）、发芽势（GR）、发芽指数（GI）、活力指数（VI）、苗高（SH）和根长（RL）等指标的耐盐系数,采用隶属函数法进行了耐盐性的综合评价。结果表明：花椰菜种质材料萌发期的耐盐性强弱评价结果受多个指标的影响。运用模糊数学隶属函数法,并赋予测定指标以相应的权重,计算出种质材料耐盐性强弱的综合评价D值,对98份种质材料耐盐性的强弱进行了综合评价和排序。综合评价D值与GP、GR、GI、VI、SH、RL的耐盐系数隶属函数值的相关性均迭极显著水平（r=0．910^＊＊、0．921^＊＊、0．955^＊＊、0．972^＊＊、0．585^＊＊、0．686^＊＊）,综合评价D值可以全面反映供试种质材料的耐盐性。分别对综合评价D值、GP、GR、GI、VI、SH、RL的隶属函数值进行聚类分析比较,发现GR、GI、VI、RL可以作为花椰菜种质材料萌发期耐盐性筛选的指标,而GP、SH不宜直接作为花椰菜种质材料萌发期耐盐性筛选的指标。基于综合评价D值聚类分析,可以将98份种质材料的耐盐性分为强、中、弱、差四大群类,其中有7份材料属于强耐盐性群类的种质,可供花椰菜耐盐性品种选育改良利用及耐盐性机制、耐盐遗传机理等方面研究。     

EFFECT OF NITRIC OXIDE ON ALFALFA SEED GERMINATION UNDER NaCi STRESS

以甘农4号、阿尔冈金2个品种苜蓿为材料,用一氧化氮（NO）供体硝普钠、NO清除剂c-PTIO、一氧化氮合酶抑制剂N-硝基．L-精氨酸甲脂、硝酸还原酶抑制荆钨酸钾及硝普钠类似物亚铁氰化钠（不产生NO）处理苜蓿种子,研究NO对盐胁迫下苜蓿种子萌发的生理效应。结果表明,盐胁迫显著抑制了2个苜蓿品种的发芽率、胚芽和胚根长及幼苗干重（P〈0．05）,降低种子萌发过程中α、β-淀粉酶、蛋白水解酶活性,抑制淀粉水解和可溶性糖积累（P〈0．05）;盐胁迫下添加外源NO则使2个品种苜蓿α、β淀粉酶、蛋白水解酶活性、种子发芽率显著提高（P〈0．05）,淀粉含量降低,可溶性糖含量升高、胚芽和胚根长及幼苗干重显著增加（P〈0．05）;NO供体SNP的类似物亚铁氰化钠对盐胁迫下苜蓿种子萌发的各项指标无明显影响;施用NO清除剂c-PTIO、硝酸还原酶抑制剂钨酸钾和一氧化氮合酶抑制剂N-硝基-L-精氨酸甲脂具有降低苜蓿种子萌发的效应（P〈0．05）。因此,盐胁迫抑制苜蓿种子的萌发,而添加外源NO是缓解这种抑制作用的有效途径,内源NO也可能参与盐胁迫下苜蓿种子萌发的调节,且通过NOS和NR途径产生的NO在缓解盐胁迫抑制苜蓿种子萌发中可能起关键作用。     

Effect of salinity on nitrogen metabolism in wheat

Objectives of our studies were to quantify effects of salinity on growth and nitrogen metabolism of wheat and to measure variation in response of different cultivars, hybrids, and classes. Methods and criteria for identifying resistance to salinity in wheat, particularly effects on nitrogen metabolism also were tested. Variation in response to salinity was measured by subjecting seedlings of six wheats to one control treatment (‐0.1 bars) and two stress treatments (‐3.5 and ‐10.4 bars) from NaCl, MgSO₄, and MgCl₂ in hydroponic solutions. Both stress treatments retarded growth; wheats significantly varied at ‐3.5 bars but not at ‐10.4 bars. Stress decreased root and shoot nitrate N and total N contents. Studies with one wheat cultivar showed that salinity decreased activity of nitrate reductase enzyme and stimulated accumulation of proline. Salinity more adversely affected vegetative stages than reproductive stages of plants grown to maturity. We concluded that salinity affected wheat by both osmotic effects and antagonism of nitrate metabolism from chloride. Absolute growth and relative growth at different stress levels were superior to differences in nitrogen metabolism as selection criteria for salinity tolerance.     

Effect of nutrient solution salinity and ionic concentration on parsley (Petroselinum crispum Mill.) essential oil yield and content

The growth and essential oil (EO) production of parsley were evaluated in response to salinity and nutrient solution concentrations in a soilless culture. Parsley plants that were 60 days old were potted in a coconut fiber and peat moss medium and were treated with four different nutrient solutions, including T1, T2, T3 and T4. The T1 nutrient solution was the standard, the T2 and T3 solutions contained incremental macronutrient concentrations with an electrical conductivity (EC) of up to 2.2 and 3.2 dS m^?1, respectively, and the T4 solution was the same as T2 but with sodium chloride (NaCl) and an incremental macronutrient concentration with an EC of 3.2 dS m^?1. Next, these plants were grown for 90 days in a greenhouse with natural daylight in Nador, Morocco. Shoot and root growth significant decreased with increasing EC. However, the salinity that resulted from the addition of NaCl did not affect plant growth in the nutrient solutions. The optimum obtained growth and EO production were 1.2 and 2.2 dS m^?1, respectively. Consequently, the optimum EC value (based on the EO production) of parsley in the soilless culture was 1.2–2.2 dS m^?1.     

Fertilizer location modifies root zone salinity,root morphology,and water‐stress resistance of tree seedlings according to the watering regime in a dryland reforestation

There is a direct relationship between soil nutrient concentration in localized zones and root proliferation and elongation under well‐watered conditions. However, in field studies under semiarid conditions this relationship can change due to higher salt accumulation and soil dryness that affect root growth, water stress resistance, and seedling survival. We assessed the effect of different locations of fertilizer placement in the soil profile and water availability on root zone salinity, root development and ecophysiological responses of Quillaja saponaria Mol. after outplanting. A single dose (6 g L^?1) of controlled‐release nitrogen fertilizer (CRF_N) was placed at 0 cm (top layer), 15 cm (middle layer), or 30 cm (bottom layer) depth in the containers in a greenhouse, in addition to an unfertilized treatment (control). After 6 months, seedlings were transplanted to the field and subjected to weekly watering regimes (2 L plant^?1 and unwatered). Morphological and ecophysiological parameters were periodically measured on seedlings, as well as soil electrical conductivity (EC). After 1 year, the shoot : root ratio of unwatered seedlings decreased as a function of CRF_N placement depth, which was attributed to lower shoot growth and not to greater root growth. The root morphology of the bottom layer treatment was negatively affected by high EC in unwatered seedlings. Greater total root length and root volume of the middle layer treatment was found only when well‐watered; however, this did not contribute to improve physiological responses against water stress. The lowest EC and the highest photochemical efficiency, net photosynthesis, and stomatal conductance were shown by unfertilized seedlings, independent of water availability. Our findings suggest that varying depth of CRF_N placement does not contribute significantly to improve root growth under water restriction. Water supplements, independently of the CRF_N location in the substrate, contribute to decrease root zone salinity, and consequently, improve root volume growth.     

适宜无机盐及浓度抑制麦胚脂肪酶存在时油水界面张力

为了探明无机盐稳定化脂肪酶的潜在机理,该文以小麦胚芽脂肪酶为研究对象,基于界面酶学的分析方法,研究添加浓度介于1.0×10-9~1.0×10-2 mol/L的Na~+、K+、Ca~(2+)、Mg~(2+)的氯化物对小麦胚芽脂肪酶存在的油-水界面特性的影响。结果表明,当小麦胚芽脂肪酶体系浓度为1.7×10-6 mol/L时,一价金属中Na~+更有利于抑制油-水界面的表面张力(P0.05),对麦胚脂肪酶存在时的油水界面特性影响也较大;二价金属离子Ca~(2+)对界面张力的影响趋势与一价离子不同,在高浓度时反而增加界面张力;当油水界面上存在脂肪酶的催化底物(三油酸甘油酯)和产物(油酸)时,添加浓度分别为10-6、10-6、10-4和10-9mol/L的Na~+、K~+、Ca~(2+)、Mg~(2+)均可一定程度上降低油水界面张力,从而降低麦胚脂肪酶的作用效果,三油酸甘油酯存在时Mg~(2+)的作用效果最明显(P0.05),油酸存在时Na+的作用效果最明显(P0.05)。综上,无机盐金属离子主要通过影响麦胚脂肪酶在油水界面的聚集行为及底物结构状态起到钝化麦胚脂肪酶的作用,该结果可为麦胚脂肪酶存在时界面的活性调控及麦胚的稳定化处理提供参考。