弹簧垫圈断裂原因分析

通过宏观检验观察、化学成分分析、硬度测试、金相检验和断口分析等方法对弹簧垫圈的断裂原因进行分析。结果表明:该弹簧垫圈热处理时产生淬火裂纹,镀锌时氢原子在裂纹尖端偏聚,这两种因素的共同作用导致弹簧垫圈在装配预紧过程中发生脆性断裂。     

锌胁迫对虞美人种子萌发的影响

[目的]研究水培条件下重金属锌胁迫对虞美人种子萌发的影响。[方法]用浓度为05、01、00、1502、002、50、3003、50、400 mg/L的硫酸锌溶液对虞美人种子进行胁迫处理,测定锌胁迫对虞美人种子的发芽势、发芽率、发芽指数等发芽指标的影响。[结果]在锌胁迫条件下,虞美人种子的发芽指标随着锌浓度的增加均表现出先升高后降低的变化趋势。发芽势、发芽率、发芽指数均在锌浓度为200 mg/L时达到最大;种子活力指数在锌浓度为150 mg/L时达到最大。[结论]浓度为200 mg/L的锌可以更好地促进虞美人种子的萌发。     

施磷量及磷锌配施对夏玉米生长发育及籽粒产量的影响

为更好探索小麦/玉米一年两熟种植制度下,夏玉米施肥制度,实现夏玉米抗逆高产丰产。于2010年采用裂区设计,对施磷量及磷锌配施对夏玉米生长发育及籽粒产量的影响进行研究。结果表明：单施磷肥或磷锌配施促进夏玉米生长发育,增加干物质积累和次生根数,降低秃尖、改善穗部性状、提高抗病能,且配施效果优于单施磷肥。单施磷较对照增产幅度为7.70%~31.21%,配施增产15.99%~40.34%,磷锌配施较单施磷肥增产幅度达4.03%~8.73%。其中以施P2O5量在180 kg/hm2时配施15 kg/hm2硫酸锌,产量最高达9581.2 kg/hm2。经回归拟合,单施磷肥和磷锌配施的最佳施P2O5量分别为178.65 kg/hm2和203.49 kg/hm2,籽粒产量可达8823.0 kg/hm2和9499.61 kg/hm2。因此,在施氮基础上,配施磷或磷锌可促进夏玉米生长发育,实现高产抗逆高效栽培。     

锌对小麦抗氧化酶活性的影响

[目的]探讨内源抗氧化酶系统在作物抵抗外源重金属胁迫中的作用。[方法]用不同浓度锌溶液处理盆栽小麦幼苗,至幼苗生长缓慢时取材测定过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、丙二醛（MDA）等指标。[结果]20、50、100、200、400和800mg/L锌溶液处理的小麦POD活性分别比对照组提高了54.8%、58.2%、115.2%、157.8%、408.5%和564.0%。200、400和800mg/L锌溶液处理的小麦SOD活性分别是对照组的77.1%、68.4%和61.2%。20、50、100、200和400mg/L锌溶液处理的小麦CAT活性分别比对照组提高了1.7%、4.0%、13.2%、16.3%和22.8%。20和50mg/L锌溶液处理的小麦的丙二醛含量分别为对照的96.4%和97.5%。100、200、400和800mg/L锌溶液处理的小麦的丙二醛含量分别比对照组提高了57.7%、92.7%、235.4%和464.4%。[结论]在锌胁迫下的小麦活性氧清除系统中,POD是关键的抗氧化酶。     

锌对不同基因型玉米产量及氮磷钾锌吸收与分配的影响

[目的]研究锌对不同基因型五米产量及氮磷钾锌吸收与分配的影响。[方法]以四单19和牡丹9 2种不同基因型玉米为材料,以EDTA-Zn为锌肥料,采用盆栽方法研究锌对不同基因型玉米产量及氮磷钾锌吸收与分配的影响。[结果]适量供锌可以提高玉米的穗粒数;在低锌处理下（Zn0、Zn1）各器官锌含量相差较小,随着施锌水平的提高,锌在叶片、茎秆、叶鞘中含量迅速增加,而在子粒和苞叶中增加幅度较小;玉米吸收的多余的锌主要集中在下部器官,以减轻过量的锌对植株造成的伤害。不同的供锌水平对低锌不敏感品种牡丹9氮、磷、钾的吸收与转运影响较小;相对而言,低锌敏感品种四单19氮、磷、钾的吸收与转运更易受到外界供锌量的影响。[结论]适量供锌可以提高玉米产量和对氮、钾的利用率降,低磷的吸收和利用。     

硫磺、硫酸锌、硼砂施用量与玉米淀粉含量关系的研究

采用二次回归通用旋转组合试验设计,分析硫磺、硫酸锌、硼砂不同施用量对高淀粉玉米淀粉含量的影响。结果表明：硫磺、硫酸锌与玉米淀粉含量的关系符合二次曲线,硼砂与淀粉含量为正的线性关系;单独施用时,硫磺和硫酸锌降低淀粉含量,硼砂增加淀粉含量;硫磺与硫酸锌存在正向互作,与硼砂存在负向互作;硫酸锌与硼砂不存在互作。淀粉含量高于76.39%的施肥方案是硫磺、硫酸锌、硼砂用量分别为6.39～31.56、8.2～32.0、22.4～28.5 kg/hm2。     

氮磷钾与锌肥配施对小麦和玉米锌含量的影响

采用大田定位试验,研究了氮磷钾与锌肥配施对小麦和玉米产量及Zn含量的影响。结果表明：在土壤有效Zn含量高于1.20 mg/kg的土壤上施用Zn肥,小麦和玉米增产效果不明显。不同施肥处理的小麦和玉米植株的Zn含量及Zn吸收量存在明显差异。土施Zn肥能显著提高小麦和玉米籽粒的Zn含量及Zn吸收量。与氮磷钾配施相比,氮磷钾配施锌肥小麦籽粒的Zn含量和Zn吸收量分别提高25.0%和25.7%,玉米籽粒的Zn含量和Zn吸收量分别提高12.0%和13.0%。     

Evaluation of selected metal nanoparticles on hatching and survival of larvae and fry of Indian major carp,rohu (Labeo rohita)

Different laboratory synthesized metal nanoparticles viz. Copper oxide (CuO), Zinc oxide (ZnO) and silver doped titanium dioxide (Ag‐TiO₂) were studied for their effect on hatching and survival of larvae and fry of Indian major carp, rohu, Labeo rohita both in direct application in tank water & coated onto tanks. Among these nanoparticles, CuO and ZnO nanoparticles exhibited highest percentage of hatching in both direct addition (78.0 ± 3.1% and 78.05 ± 4.2%, respectively) and coating onto tanks (58.6 ± 2.1% and 61.2 ± 2.7%, respectively) at 1 mg mL^?1 while least percentage of hatching was recorded in Ag‐TiO₂ nanoparticles irrespective of its concentration & mode of supplementation. Highest survival of L. rohita fry (50.13 ± 2.2%) was observed after 15 days post hatching in CuO coated tanks followed by ZnO coated tanks (38.6 ± 2.8%) while least was recorded in Ag‐TiO₂ coated tanks (22.53 ± 3.0%). However in control tanks coated with Poly‐Urethane base with hardener and uncoated control tanks, the survival was 42.4 ± 1.2% and 41.36 ± 1.8% respectively. Further, significantly lower microbial load of water was recorded in CuO nanoparticles coated tanks (1.5 × 10¹⁰ CFU L^?1) as compared to uncoated control tanks (1.1 × 10¹⁶ CFU L^?1) without affecting water quality parameters. On the other hand, in Ag‐TiO₂ coated tanks, significantly lower microbial load (1.0 × 10⁶ CFU L^?1) as compared to uncoated control tanks at 15 days post hatching was recorded. However, Ag‐TiO₂ was toxic to L. rohita larvae & fry both in direct application and coating onto tanks. Considering the beneficial effects of CuO nanoparticle application, it has the scope of being used in a more eco‐friendly way in hatchery operations.     

The influence op soil treatments on elemental composition of corn and on zinc soil tests on two Missouri soils

Abstract

Corn (Zea mays L) was grown at three locations on soil treated with Zn at two levels of soil fertility. Corn leaves were sampled at 2 stages of growth and analyzed for several elements. Yields were measured and soils were analyzed for O.lN HCl and DTPA extractable Zn and by standard testing methods for other components.

Zinc at 10 and 20 lb/A did not affect corn grain yields. The Zn treatments significantly increased leaf Zn concentrations. The influence of leaf sampling time differed between locations. The DTPA and O.lN HCl extractable soil Zn both reflected the Zn soil treatments. The DTPA appeared to extract a more soluble component of soil Zn which became more un‐extractable with time. In general, the extractable soil Zn was poorly correlated with Zn concentrations in the corn leaves. Under the conditions of the experiment the soil Zn levels as measured by the 2 extractants were a poor predictor of plant Zn when soil Zn levels were adequate.     

Estimation of critical limit for zinc in rice soils

Abstract

Twenty surface soil samples wore collectod from Nalnltal Tarai (foot‐ hills of Himalya) where ‘Khaira’ disease (Zn deficiency disease of rice) was prevalent. Rice (Oryza sativa L. variety IR ‐ 8) was grown in pots for 8 weeks after transplanting. Experiments were carried out to find the suitability of five soil Zn extractants viz. dilute acid (HC1 ‐ H₂SO₄) mixture, DTPA‐ (NH₄) ₂CO₃, pH 7.3, dithizono, NH₄ ‐ Ac, pH 4.6 and MgCl₂. Critical limits of available Zn in soils were established for rice crop by old and new Cate and Nelson procedures.

Zn extracted from the soil with NH₄ ‐ Ac, pH 4.6, dithlzono, MgCl₂, and DTPA‐(NH₄) ₂CO₃, pH 7.3 was significantly correlated with the uptake of Zn by the rice plants. The correlation of Zn uptake with dilute acid mixture extractable Zn was not significant. The extractant which extracted more Zn gave higher values of critical limit and vice versa. It is concluded that all extracting solutions except dilute acid mixture were found to be suitable for predicting available Zn in rice soils of Taral.