Soil sodicity is more detrimental than salinity for quinoa (Chenopodium quinoa Willd.): A multivariate comparison of physiological,biochemical and nutritional quality attributes

Soil salinization is a serious environmental problem worldwide. To explore the comparative effects of soil salinity and sodicity on physiological, biochemical and nutritional quality attributes of four quinoa genotypes (A1, A7, Puno, Vikinga), pot and field experiments were performed on non‐saline soil and two types of salt‐affected soils designated as SS1 (saline) and SS2 (saline‐sodic). The results of both the experiments showed similar reduction pattern in biomass (11%–44%), chlorophyll content (10%–36%), stomatal conductance (18%–32%) and grain yield (30%–47%) of four genotypes on SS2 compared with SS1. Higher sodicity level of SS2 resulted in more Na accumulation (23%–40%) and oxidative damage (12%–35% decrease in membrane stability) leading to an increase in the activities of antioxidant enzymes (SOD, POD, CAT) in all the genotypes. Grain mineral contents (except Na and Mg) were decreased more in SS2 than SS1. Multivariate analysis revealed that grain Na content has negative correlation with all the nutritional quality attributes except Mg and fibre contents. Genotypes A1 and A7 were more salt tolerant with better grain nutritional quality than Puno and Vikinga. It is concluded that soil sodicity is more detrimental than salinity, and quinoa genotypes A1 and A7 are better than Puno and Vikinga for cultivation on saline and saline‐sodic soils.     

A Comparative Study of Different Amendments on Amelioration of Saline-Sodic Soils Irrigated with Water Having Different EC: SAR Ratios

Soil degradation affects soil properties such as structure, water retention, porosity, electrical conductivity (EC), sodium adsorption ratio (SAR), and soil flora and fauna. This study was conducted to evaluate the response of contrasting textured soils irrigated with water having different EC:SAR ratios along with amendments: gypsum (G), farm manure (FM), and mulch (M). Water of different qualities viz. EC 0.6 + SAR 6, EC 1.0 + SAR 12, EC 2.0 + SAR 18, and EC 4.0 + SAR 30 was used in different textured soils with G at 100% soil gypsum requirement, FM at 10 Mg ha^?1, and M as wheat straw was added on surface soil at 10 Mg ha^?1. Results revealed that the applied amendments in soils significantly decreased pH_s and electrical conductivity (EC_e) of saturated paste and SAR. Four pore volumes of applied water with leaching fraction 0.75, 0.77, and 0.78 removed salts 3008, 4965, and 5048 kg ha^?1 in loamy sand, silty clay loam, and sandy clay loam soils, respectively. First four irrigations with LF of 0.82, 0.79, 0.75, and 0.71, removed 5682, 5000, 3967, and 2941 kg ha^?1 salts, respectively. The decreasing order for salt removal with amendments was FM > G > M > C with LF = 0.85, 0.84, 0.71, and 0.68, respectively. This study highlights a potential role of soil textures to initiate any mega program for reclamation of saline-sodic soils in the perspective of national development strategies.     

INCREASING SAR OF IRRIGATION WATER AGGRAVATES BORON TOXICITY IN MAIZE (ZEA MAYS L.)

We evaluated the effect of boron (B) application on shoot growth and shoot B concentration and uptake by two maize cultivars (‘FHY-396’ and ‘Sonari’) on a loam soil irrigated with water of different sodium absorption ratio (SAR) values [control, 5 and 15 (mmol_c L^?1)^1/2]. Plants were harvested after forty days of growth. Shoot dry matter decreased significantly (P < 0.05) with B application due to toxicity marked by leaf injury. Toxic effect of B was further aggravated by increasing SAR of irrigation water. In both cultivars concentration and uptake of B was significantly (P < 0.05) increased over control with B application and SAR of irrigation water. Shoot Ca concentration decreased with increasing SAR and B application. The phenomena of B toxicity and low Ca marked by reduction in shoot dry matter of plants irrigated with high SAR water could be important in management of brackish water used for irrigating crops on arid and semiarid region soils.     

提高无控制点星载SAR影像的定位精度研究

针对无控制点情况下星载SAR地面目标高精度定位问题,提出在整个成像条带中任选一景SAR影像,并基于全球DEM数据生成模拟的SAR影像,然后通过自动或半自动匹配方式寻找一个控制点,修正整个条带的轨道参数,从而消除了系统误差的影响,提高了整个SAR条带影像的定位精度。     

水质对土壤水分扩散率的影响

本文实验研究了水质对土壤水分扩散率的影响.实验结果表明,土壤水分扩散率随钠吸附比(SAR)的增大而减小,随着电导率(EC)的增大而增大;SAR对土壤水分扩散率的影响随着EC的增大而减小,EC≥5时,SAR对土壤水分扩散率的影响很小;EC对土壤水分扩散率的影响随着SAR的增大而增大;SAR≤5时,EC对土壤水分扩散率的影...     

施用脱硫石膏对稻田碱土和排水中可溶性盐分的影响

【目的】探讨不同脱硫石膏施用量对稻田碱土和排水中可溶性盐分的影响.【方法】通过田间试验,研究了脱硫石膏3个施用量29.17、16.68和4.17 t·hm-2(分别记为S1、S2、S3)对水田排水中可溶性盐分浓度的影响和苏打碱土的改良效果.【结果和结论】除碳酸根外,水稻分蘖期后水田排水中可溶性盐分的浓度趋于稳定,pH、电导率和残余碳酸钠含量(RSC)基本不变;0~20 cm耕层土壤电导率随着石膏施入量的增加而升高,S1和S2处理10~20 cm土壤的电导率存在显著差异(P0.05),pH和钠吸附比(SAR)则呈相反的变化趋势;0~40 cm土壤S1处理的脱盐效果好于S2和S3处理.     

植物转基因沉默及其克服方法研究进展

转基因沉默可分为转录水平的基因沉默和转录后水平的基因沉默，前者是因为启动子失活，不能起邕，而后者是因为mRNA被被解，或mRNA的加工被干扰，其原因包括多种因素，如转基因的拷贝数和构型，基因的甲基化，异染色质化，RNA依赖的RNA聚合酶等，涉及DNA－DNA，DNA－RNA，RNA－RNA三种核酸相互作用。克服转基因沉默的方法包括对外源基因进行改造，采用具有特殊功能的启动子与增强子，构建细胞核骨架附着区载体，以及筛选单拷贝转基因子代植株。     

基于变差函数的中高分辨率SAR影像农村建筑区提取

目的 基于中高分辨率影像进行大范围的农村建筑区提取时,由于影像分辨率的限制以及农村建筑区规划自身规划特点等因素,造成了传统变差函数方法的高错分误差。为了准确提取农村建筑区,为后续获取建筑密度和人口密度等工作建立基础,提出了一种基于迭代P参数法的阈值确定方法。方法 通过设定亮度阈值,在变差函数纹理计算中为满足条件的像元点赋以权值。本文方法确保在4个方向都满足条件的像元点(认为是建筑区)获得较大的变差函数值加成,而仅在一个方向或者没有方向满足条件的像元点(认为是非建筑区)获得较小加成或不变,以此改进传统变差函数方法,抑制了农村建筑区与周边非建筑区的混淆。结果 以Radarsat-2的多个极化波段影像为数据源进行了实验,改进变差函数方法在实验区1与实验区2的各个波段平均检测率分别为91.58%和90.11%,平均错分误差分别为19.83%和31.87%。结论 与传统变差函数方法以及最小距离法相比,既保证了较高的检测率,同时显著降低了错分误差,不足之处是在建筑区与非建筑区的边缘处以及与建筑区具有相似纹理特征的非建筑区处出现错分,需要进一步的研究和完善。     

昆虫神经活性物质章鱼胺受体激动剂的设计、合成及其构效关系研究

以章鱼胺能系统为靶标,设计并合成了72个取代苄基亚胺基-2-(口恶)唑烷和取代苯胺基2-(口恶)唑啉化合物。测定了目标化合物对美州大蠊神经索腺苷酸环化酶的活化作用。结果发现配体取代基的变化可引起对章鱼胺受体活性的较大幅度改变。邻氯苄基亚胺基-4-苯基-2-(口恶)唑啉显示与 OA 受体的较高亲和力(V_(max)=33.39,Km=0.33μmol·L~(-1)。应用 Hansch-Fujita 方法、RSA、MFA、药效团分析和分子模型技术等计算机辅助设计方法对它们的结构活性关系进行剖析并建立了一些可信度高的模型。     

InSAR干涉图滤波方法比较

干涉条纹图滤波是合成孔径雷达干涉测量处理中不可缺少的重要环节。对干涉条纹图滤波的一个重要要求是在有效抑制噪声的同时尽可能地保持条纹的纹理信息。首先时干涉合成孔径雷达（InSAR）滤波方法进行分类,然后对基于局部统计自适应滤波中的4种算法：Goldstein滤波、INSAR干涉条纹图的复数空间自适应滤波、鲁棒加权圆周期滤波扣正余弦滤波法滤波进行了研究,每种算法都给出了真实数据的处理结果,以比较各种处理算法的优缺点。并且用5种定量的评价指标比较和评价上述4种滤波方法的优劣。