科尔沁沙地不同下垫面风沙流结构与变异特征

对流动、半流动、半固定和固定沙地 4种不同下垫面 0～ 2 0 cm气流层的风沙流结构与变异特征研究表明 :(1 )不同退化沙地在总输沙量及各层输沙量上存在明显的差异 ,在 5月 1 5日的测定中 ,流动沙地的总输沙量是 83 .1g/ cm2 .h,分别是半流动、半固定和固定沙地的 2 .1倍、9.2倍和 33 .9倍 ;而在 5月 1 5日的测定中 ,流动沙地的总输沙量 1 0 5.7g/ cm2 .h,分别是半流动、半固定和固定沙地的 5.6倍、1 4.1倍和 75.6倍。(2 )总输沙量的 60以上分布在 1 0cm的高度内 ,随高度的增加 ,输沙量呈负指数函数下降。(3)风蚀物中粗粒 (粒径 1 .0～ 0 .5mm )与极细颗粒 (粒径0 .1～ 0 .0 5mm)和粉、粘粒 (<0 .0 5mm)的含量均很低 ,而细颗粒 (粒径 0 .2 5～ 0 .1 mm)的含量很高 ,占风蚀物的73 %～ 91 %,说明近地表层沙粒的运动以跃移为主。随高度的增加 ,风蚀物中中颗粒 (粒径 0 .5～ 0 .2 5mm)的含量下降 ,而极细颗粒和粉、粘粒含量增加 ,但其增幅因下垫面不同而异。(4) 0～ 2 0 cm总输沙量及各层输沙量与植被盖度呈显著负相关 ,与植株高度、地表紧实度和地表粗糙度长度呈微弱负相关     

Variations in Content and Molecular Structure of Barley Nonstarch Polysaccharides Associated with Genotypic and Cellular Origin

Barley cell walls are an excellent source of soluble and insoluble dietary fiber. Despite variations due to genetic and environmental factors within cereal grains, generally the content of total dietary fiber in whole barley grain (17.3%) is higher than in other cereal grains. Arabinoxylans and mixed linkage (1→3)(1→4)‐β‐d ‐glucans are the major nonstarch polysaccharides present in various tissues of barley, but other polysaccharides such as cellulose, glucomannans, and arabinogalactans also occur, although in much smaller amounts. Depending on the genotypic or cellular origin, both polymers exhibit variations in molecular features. The molecular structures of β‐glucans and arabinoxylans are important determinants of physicochemical properties and may affect physiological functionality in the gastrointestinal tract. Barley β‐glucans have been associated with lowering plasma cholesterol, reducing glycemic index, and reducing the risk of colon cancer. Furthermore, arabinoxylans offer nutritional benefits of soluble and insoluble fiber and, because of phenolic moieties bound to arabinoxylans, they may also have some antioxidant properties.     

油料作物种子维生素E含量和组分改良的分子育种研究

作为重要的脂溶性天然抗氧化剂,维生素E的存在对预防油脂多不饱和脂肪酸过氧化、增强油脂营养品质具有重大意义。近十年来,随着人们对高等植物维生素E生物合成途径认识的不断深入,油料作物种子油脂中维生素E品质的多元化改良成为可能。本研究首先简要介绍了天然维生素E的类型和生物合成途径,然后概述了油料作物种子中维生素E和脂肪酸之间相互关系的研究进展以及油料作物种子维生素E品质改良的分子育种研究进展,最后展望了油料作物种子油脂脂肪酸和维生素E综合品质改良育种的前景。     

利用分子标记筛选源于野生多毛番茄的高可溶性固形物的基因

TA1218是野生多毛番茄(Lycopersicoum hirsutum)LA1777的一个近等基因系,带有LA1777第1染色体的含高可溶性固形物基因(QTL)的长1.2cM的染色体片段。研究以TA1218与栽培番茄(L.esculentum)骨干系9706、F1代及回交一代(BC1)为材料,对该染色体片段进行了AFLP分析,并对QTL附近的4个RFLP标记进行了CAPS标记的转化研究,共获得了2个CAPS标记TG161和TG237。对BC1群体进行遗传鉴定、可溶性固形物含量和其它农艺性状的综合分析,获得了8个比TA1218中的外源染色体片段更短的番茄材料,其中3个含TG161的阳性标记的单株和1个含TG237阳性标记的单株的可溶性固形物含量高,而且综合农艺性状优良,可作为新的高可溶性固形物种质用于番茄遗传育种。     

Agronomic Efficiency of Feldspar,Quartz Silica,and Zeolite as Silicon (Si) Fertilizers in Sandy Soil

ABSTRACT

Partial replacement of synthetic chemical fertilizers by naturally occurring alternatives is environmentally recommended. Feldspars (F), quartz silica (S), and zeolites (Z) are silicon (Si)-rich minerals that may be utilized as Si fertilizers. This study aims to assess the agronomic efficiency (AE) of the mentioned minerals as Si fertilizers and to estimate Si-use efficiency (Si-UE) in sandy soil. A field experiment was carried out (summer seasons of 2016 and 2017) in which F, S, and Z were mixed with surface soil in an application rate 500 mg kg^?1 soil with and without potassium humate (K-H, 2 mg kg^?1 soil). Treatments were distributed in a complete randomized block design (CRBD) with three replicates including control before cultivation of soybean (Glycine max L.). Yield (kg ha^?1) of soybean, available Si (mg kg^?1) in soil and uptake (mg kg^?1) of N, P, K, Cu, Fe, Mn, Zn, and Si by soybean seeds and straw were estimated. The most significant increase was by 67.87% followed by 38.69% was recorded for the S and S K-H treatments, compared to the control. Same treatments showed nonsignificant decrease in the available Si (mg kg^?1) that may refer to partial replenishment of plant available Si (PAS) in soil and avoid significant deficiency. Silica treatments resulted in the most significant increase in the uptake (mg kg^?1 soil) of Si, N, P, K, Cu, Fe, Mn, and Zn by seeds and almost by straw. Silica was more efficient agronomically than feldspar and zeolite. Absorption of more biocompatible Si-organo species may depend on Si source.     

Organo-metallic complexes in an Andosol: a comparative study with a Cambisol and Podzol

Current soil-forming processes were studied in a nonallophanic Andosol from the Vosges mountains (north-eastern France). For this purpose, we conducted comparative studies on the organo-metallic fraction dynamics of selected profiles of an Andosol and other typical soils from this region, Cambisol and Podzol. These soils are derived from old volcanic rocks under mesic soil temperature and udic soil moisture regimes. The Andosol profile displayed the characteristics of nonallophanic Andosols: large accumulation of humus, active Al mostly complexed with humus, and low pH. Special attention was given to physical and microbial stability of these organo-metallic associations, respectively by disaggregation tests and incubation experiments. The results indicated that these associations showed a strong resistance against disaggregation by water and against biodegradation. Moreover, the very low concentration of DOC, Al and Fe in soil solutions collected by zero-tension lysimeters, coupled with very low amounts of water-dispersed clays obtained after dispersion tests, suggested that no significant translocations of these components occurred in this Andosol profile. Low mobility together with a strong resistance against mineralization may account for the large accumulation of carbon in this Andosol.     

Retention and release of dissolved organic matter in Podzol B horizons

The main objectives were to study the effects of pH on the retention and release of organic matter in acid soil, and to determine the main differences in results obtained from batch experiments and experiments in columns. We took soil material from the B horizons of a Podzol at Skånes Värsjö (southern Sweden). In batch experiments, soil was equilibrated with solutions varying in pH and concentration of dissolved organic C. In Bh samples, the release of dissolved C gradually increased with increase in pH. In the Bs1 material there was a minimum at pH 4.1, and in the Bs2 soil the minimum occurred at pH 4.6. The ability to retain added dissolved C increased in the order Bh < Bs1 < Bs2. The column experiment was run for 160 days under unsaturated flow conditions. Columns were packed with Bh, Bh + Bs1 or Bh + Bs1 + Bs2 samples to calculate mass balances for each horizon. Solutions either without any dissolved organic C or ones containing 49 mg C dm^?3 with pH of 4.0 or 3.6 were used to leach columns. The pH of input solutions only little affected the concentration of dissolved C in the effluent. Relative proportions of hydrophobic substances decreased with increasing column length and decreasing pH. For input solutions containing dissolved C, near steady state was achieved for both the Bs1 and Bs2 horizons with approximately 25% dissolved organic matter retention. Thus, no maximum sorption capacity for dissolved C could be defined for these horizons. This behaviour could not have been predicted by batch data, showing that column experiments provide useful additional information on interactions between organic compounds and solid soil material.     

平坦沙质地表蚀积量计算模型研究

通过对平坦沙质地表蚀积动态的野外观测,结合同时期区域风况资料,分析了平坦沙质地表蚀积过程。在输沙势和最大可能输沙量计算公式基础上,调整参数提出了平坦沙质地表蚀积量的计算模型,弥补了两者不能直观准确表示区域风沙活动的缺点。通过对比野外实测值与输沙势、模型预测值和最大可能输沙量之间的变化趋势得出它们存在同期波动特征。进一步比较回归方程可知,模型预测值回归方程更加显著,预测值更加接近实测值,能够更好地表示区域风沙活动特征和强度,可为沙漠的扩张和收缩提供量化预测依据。     

秸秆-膨润土-PAM改良材料对沙质土壤团粒结构的影响

为改善沙质土壤团粒结构,以重庆市分布面积较大的冷沙黄泥为研究对象,将作物秸秆、膨润土和聚丙烯酰胺(PAM)按一定比例配制后作为改良材料,研究秸秆改良材料种类、改良材料剂量与配比、土培时间等因素对改良材料改良效应的影响。结果表明:秸秆改良材料可以增加沙质土壤1~5 mm团聚体的含量,不同秸秆改良材料改良效果不同,且随着改良材料剂量、PAM含量(<2%)的增加、土培时间(<60 d)的延长,沙质土壤1~5 mm团聚体含量呈现增加趋势;添加麦秆改良材料(添加量为10 g/kg土,配方中PAM含量为2%)的土样,在培养60 d后,1~5 mm团聚体含量为45.1%,为CK的2.12倍,自然条件下的1.9倍,对沙质土壤团粒结构改良效果最为明显。可见,秸秆改良材料可以改善沙质土壤团粒结构。     

秦皇岛海岸潮间带的石英砂表面结构研究

20世纪80年代后期,通过扫描电镜对秦皇岛现代海岸潮间带的石英砂表面进行研究,发现了该岸带正遭受海水侵蚀并有海水不断进侵的趋势。而该证据与海岸带的地貌第四纪研究的诸手段所获得的结论是一致的。     

砂壤土对中、高分子量PAM吸附行为的研究

选择中分子量(800万)、高分子量(1200万)的聚丙烯酰胺(PAM),通过静态法和淀粉-三碘化物比色法相结合方法针对砂壤土对两种分子量PAM的吸附行为进行研究,并探究了砂壤土对不同分子量PAM在不同液固比和不同吸附时间下吸附量的影响。探究结果表明,两种分子量PAM在砂壤土中吸附的最佳液固比均为25∶1,吸附平衡时间分别为6h、8h。利用Langmiur等温吸附方程对数据进行回归拟合,拟合的相关系数均在0.96以上,故量两种分子量的PAM在砂壤土上的吸附等温线符合Langmiur模型,说明砂壤土对两种分子量PAM的吸附是单分子层吸附。并得到两种分子量PAM在砂壤土中的吸附量为800万分子量1200万分子量,其饱和吸附量分别是1.11 mg g-1、1.04 mg g-1。     

Changes in Retrogradation Properties of Rice Starches with Amylose Content and Molecular Properties

The increases in storage modulus (G′), retrogradation enthalpy change (ΔH) and ΔH‐related Avrami kinetic parameters of gelatinized rice starch dispersions at 25% (w/w) were investigated with respect to storage period, amylose content (AC), and molecular properties. Three high‐AC and five low‐AC rice cultivars were compared for understanding the multiple influences of AC and molecular properties involved. After refining the results of correlation analysis, the G′ of just‐cooled samples changed positively, mainly with AC and additionally with the average chain length of amylose (CL_AM) and the weight ratio of extra‐long plus long chains to short chains of amylopectin (AP) (r_APchain). The developed ΔH on short‐term storage (10 days) elevated with increasing AC and CL_AM and decreasing degree of polymerization of AP (DP_AP), but after long‐term aging for one to three months with increasing r_APchain, especially for the low‐AC cultivars examined. Greater Avrami rate constants for retrogradation could be attributed to the combination of a lower DP_AP and r_APchain or AP chain length and a greater CL_AM. The polynomials using these critical factors to describe the retrogradation parameters were elucidated and could account for 85–99.6% of data deviations.     

沙地土壤pH值、养分含量对微地形变化的响应

[目的]针对浑善达克沙地土壤pH值、碳、氮、磷含量的微地形变异性进行研究,系统分析浑善达克沙地不同微地形条件下土壤营养物质含量的的变化规律,为浑善达克沙地环境建设和合理开发利用提供理论参考。[方法]以内蒙古锡林郭勒盟白音锡勒牧场境内的中国科学院内蒙古草原生态系统定位站长期围封的沙地样地为研究对象,测定坡位对土壤pH值、碳、氮、磷含量。[结果]不同坡位pH值平均值大小顺序为:阳坡坡底阴坡坡顶;有机碳含量平均值大小顺序为:坡底阴坡阳坡坡顶;全磷含量平均值大小顺序为:坡底阴坡坡顶阳坡;土壤含氮量阴坡和坡底显著高于坡顶和阳坡。[结论]不同微地形条件下各层土壤pH值、全碳和全磷含量的变异系数均表现为阳坡和坡顶高于阴坡和坡底;同一坡位不同土层营养物质含量变异系数大小关系没有规律可循,因坡位和土层不同而表现出不同的大小关系。     

围封年限对沙化草地群落结构及物种多样性的影响

[目的]了解围封年限对宁夏回族自治区盐池县沙化草地群落结构及物种多样性的影响,揭示围封沙化草地植被变化规律。[方法]在半干旱区运用空间代替时间法选取不同围封年限区(5,10,20a)和未封育区(对照)的沙化草地为研究对象,进行群落结构及物种多样性的对比研究。[结果]1年和2年生草本是未封育区的优势种。灌木是封育5a区的优势种,而封育10a区的优势种是灌木和多年生草本,在封育20a区,优势种是多年生草本。与未封育区相比,围封5a,10a区植被数量特征值均有显著提高,而围封20a区特征值稍高,但相差不大。[结论]并不是围封时间越长,植被生长状况就越好。小于5a的封育年限可以提高群落的物种多样性,封育年限大于10a,反而使物种多样性下降。围封措施对植被恢复起到了先促进后抑制的作用。     

科尔沁地区不同类型沙地土壤水分变化分析

于2005-2008年5-9月,利用中子水分仪对科尔沁沙地的流动沙丘、固定沙丘和沙质草地的不同深度(0-160 cm)的土壤水分进行了为期4 a的定期观测.采用方差分析和多重比较等方法,并采用变异系数对土壤水分的时空变异进行了分析.结果表明,可将土壤水分剖面的变化划分为3层:土壤水分剧变层(0-40 cm),稳定层(41-130 cm),活跃层(131-160 cm).在0-40 cm土壤层,3种类型沙地土壤水分表现为随深度增加而增加,在41-130 cm土壤层则随深度增加而减小,而在131-160 cm土壤层流动沙丘表现为继续减小,但其它两种沙地的土壤水分则随深度增加而增加.同时土壤水分变异系数表现为:流动沙丘>固定沙丘>沙质草地.土壤水分在不同月份的变化表现为:7月>8月>6月>9月>5月,各月之间总体上差异性显著;各类型沙地土壤水分的年变化为:固定沙丘总体表现出逐年减小的趋势,沙质草地有变化但差异不大,而流动沙丘则随降雨的变化而变化.     

平原高沙土地区土壤侵蚀规律及主要防治措施

研究了平原高沙土地区农田、内三沟及河坡土壤侵蚀的特点，农田土壤侵蚀后就近淤积，内三沟土壤侵蚀量与淤积量基本持平，河坡土壤侵蚀量小于河床淤积量。植被覆盖率与径流量、含沙量、冲刷量及淤积量存在密切相关关系，指出高沙土地区减少土壤侵蚀的主要措施。     

高产、高蛋白与低纤维马棘突变体的筛选鉴定

野生马棘植株低矮,叶片窄小,生物产量低,且可食性较差,但与玉米、苜蓿和高粱等主要饲料作物相比,马棘的饲料应用具有广适性、耐逆性和低种植成本的技术优势.本研究旨在利用诱变方法提高马棘的产量、营养和可食性,采用300Gy的60Co-γ射线诱变马棘干种子,筛选获得了高产、高蛋白质、低纤维含量的突变体MJ-HPLF1.MJ-HPLF1叶片的蛋白质含量显著增加,比野生型平均高30％以上;粗纤维含量明显降低,比野生型平均低20％以上;鲜草和干草产量都为野生型的2倍以上.     

富硒强筋紫粒小麦品种——农大3753的培育

紫色特用小麦(Triticum aestivum)新品种农大3753是由中国农业大学农学与生物技术学院选育的,由组合京冬8号/黑小麦76经系谱法选育而成,系谱号为:97冬加(2)-0-1-1-3-3-0。2006年通过北京市品种审定委员会审定。该品种为冬性,籽粒紫色,产量高,富含微量元素,强筋,营养品质和加工品质俱佳。本文详细介绍了农大3753的特点、选育过程和栽培措施,并初步分析了该品种株高低于双亲、加工品质优于双亲的原因,为该品种的推广种植,以及小麦新品种的培育开展提供必要的信息和借鉴。