Copper nutrition of greenhouse roses relative to supplementary irradiation and growing medium 1

‘Samantha’ roses (Rosa hybrida L.) potted in sand or soil mixture were grown under natural or HPS supplementary irradiation and fertilized with 0.05, 0.25, 0.5, 2.5 or 5.0 ppm Cu in each irrigation. Foliar and root Cu contents increased relative to the Cu level in solution while leaf and root Fe contents were reduce with higher concentration of Cu applied. Growing medium influenced the pattern of foliar content response to Cu concentration. In sand, the effect of Cu level in solution was evident from the beginning of the experiment whereas in soil mixture the effect was observed only after six months. Plant growth and flower production was reduced only in plants grown in sand and fertilized with 2.5 and 5.0 ppm Cu. No Cu deficiency symptoms were observed even though leaf content in plants grown in soil mixture was as low as 2.2 ppm. High Cu level in solution induced Fe deficiency symptoms, especially in plants grown in sand. Supplementary irradiation did not influence the effect of Cu fertilization level on foliar content or flower production. Most of the Cu applied was retained in the upper 5 cm layer of soil mixture reducing its availability for plant uptake.     

Chemical transformation of copper in some sludge-amended soils

In a laboratory incubation study, the periodic changes in different chemical fractions of copper (Cu) in three sludge-amended soil types (acidic sandy clay loam, neutral clay loam and alkaline clay loam) of varying soil reaction were monitored under field capacity and flooding moisture regime over 16 months. The water soluble and exchangeable fraction of Cu was very low (≤1% of total Cu) in all three soil types. At the end of incubation (16 months), the sodium acetate extractable (carbonate sorbed)- and residual-Cu fractions transformed into Fe-Mn oxide fraction, irrespective of moisture regime in all three soil types. However, the extent of transformation varied among soils.     

Loading behavior analysis of an aluminum alloy roof structure system under wind loads

The numerical analysis of a conventional aluminum alloy roof system taken from an actual international airport under wind uplift is conducted. A two-step simulation analysis approach is proposed, which effectively overcomes the computational difficulties brought by the contact between panels and supports. Through numerical analysis of roof components, the failure mode of the roof connection and the load bearing capacity of the roof are obtained. And the efficiency of material strength in each component is evaluated as well. It can provide reference for the design and application of aluminum alloy roof structure.     

Effect of phytic acid modification AZ31 magnesium alloy on the cell surface adhesion property

Phytic acid coatings on the surface of AZ31 magnesium alloys are prepared by immersion method. Then cell culture and detection of cell survival rate on treated or untreated AZ31 magnesium alloy with phytic acid is carried out by the direct method and the indirect method respectively,and surface morphology and chemical composition of coatings are studied by scanning electron microscopy with energy dispersive spectrometer. The results show that uniform phytic acid coating forms on the surface of magnesium alloy,and there is a similar cell survival rate on the treated or untreated AZ31 magnesium alloy surface. But the adhesive ability of cells on the surface of phytic acid modification magnesium alloy is significantly different. Phytic acid modification can effectively improve the cell adhesion properties of AZ31 magnesium alloy.     

Management of Soil Micronutrient Deficiencies in the Rice-Wheat Cropping System

Summary

Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains.     

Zinc chromate poisoning in calves

Extract

Losses in dairy cattle have occurred recently in which the clinical symptoms and general postmortem picture would suggest that an irritant poison was the cause of death. In these particular cases, zinc chromate paste* * A paste used by the State Hydro-electric Department for joining sections of steel-cored aluminium power conductors on cross-country transmission lines. had been used in the vicinity of the stock concerned just prior to the first mortalities. It was therefore reasonable to suggest that, in addition to the more common stock poisons, tests for zinc chromate should be made on the specimens submitted for toxicological examination.     

A field study of the association between periodontal disease and body condition in sheep

Three farms with a high prevalence of periodontal disease (PD) were selected using data from a December 1983/January 1984 survey. On each of these farms in August 1984, the incisor condition and body condition score of about 50 ewes were noted. Two of the farms and an additional farm with a high prevalence of PD were visited again in August 1985, and on each, incisor condition and body weights of about 150 ewes were recorded.

On one farm only was there a significant association between PD and body condition or weight, and it occurred in both years.     

三向位移作用下面板堆石坝周边缝“W”型铜止水变形特性研究

为提高面板堆石坝周边缝的防渗性能、探究“W”型铜止水的变形规律,采用自制的加载平台,对“W”型铜止水分别进行了不同张开、沉降位移下的剪切试验,拟合得到了铜止水变形量与剪切失效位移间的关系式,揭示了施加张开、沉降位移越大铜止水越早出现屈曲失稳现象的基本变形规律;同时结合有限元分析深入探讨了铜止水在不同位移下的变形特点,研究了止水结构长度对铜止水剪切失效位移的影响,得出在张开位移和沉降位移较小时铜止水鼻子折曲长度越长铜止水适应变形能力越强的结论。     

铜处理对菠菜幼苗体内氧化应激反应和矿质元素吸收的影响

【目的】研究不同浓度Cu处理对菠菜幼苗氧化应激反应、矿质营养吸收的影响,分析菠菜的耐Cu机理,为筛选强耐Cu性植物提供理论依据。【方法】以菠菜幼苗为材料,设置6组Cu处理浓度,处理7 d后,采样测试植物生物量、抗氧化物酶活性、大量元素和微量元素含量等指标的影响。【结果】低浓度Cu处理(50 mg/kg Cu浓度)时,菠菜幼苗体内Cu含量增加,但是并没有对植物的生长生理活动造成影响,主要表现为植物生物量显著增加,叶部K、Ca、Mg、Fe、Mn、Ni元素含量,以及根部N、P、K、Ca、Mg、Fe、Mn、Zn、Mo、Ni含量均达到最大值,其原因可能是植物能够主动提升自身抗氧化能力(SOD、APX活性和脯氨酸含量增加),将膜质过氧化伤害降至最低,避免Cu²⁺积累对植物产生的伤害。而高浓度Cu胁迫(1 000 mg/kg Cu浓度)时,菠菜幼苗体内的Cu含量增至最大值,SOD、CAT活性虽有增加但是也无法抵御高浓度Cu对膜质过氧化的严重伤害,幼苗叶部的N、P、K、Ca、Mg、Fe、Mn、Mo、Ni含量,以及根部P、K、Mg、Fe、Mn、Zn、Mo、Ni含量显著下降,生物量降至最低,高浓度Cu胁迫已超过了植物抵御胁迫伤害的能力,严重抑制了植物生长和矿质元素吸收。【结论】菠菜幼苗能够表现出较强的耐Cu性,将其作为Cu污染土壤修复的备选植物。     

铜对土壤脲酶活性特征的影响

铜是土壤中的"双重元素",为了从土壤酶角度探讨其生态毒理,采用模拟方法较为系统地研究了铜对土壤脲酶活性及酶促反应参数的影响。结果表明,(1)土壤肥力水平越高,脲酶活性越大,铜的加入导致土壤脲酶活性降低越大,除5号土样外,铜的质量浓度与土壤脲酶活性达显著或极显著负相关,表明土壤脲酶活性可作为土壤铜污染程度的监测指标之一;供试土壤铜轻微和严重污染时,铜质量浓度分别为94.00~151.75和470.40~759.28mg/kg;尿素浓度对土壤生态剂量值影响不大,生态剂量总体呈现土娄土大于红壤。(2)除4号土样外,土壤脲酶最大反应速度(Vmax)、最大反应速度/米氏常数(Vmax/Km)和反应速度常数(k)值,随铜质量浓度的增加呈显著或极显著降低,Km值则略有增加,说明铜对土壤脲酶的作用机理为混合型抑制,其中包含微弱的竞争性抑制,但以非竞争性抑制为主。可见,土壤脲酶及其参数在一定程度可表示土壤铜的污染程度。