超声波提取——电感耦合等离子体质谱法测定土壤中有效钼

采用超声提取和振荡提取方法对土壤中有效钼进行提取。结果表明:超声提取在较短的时间内就可以达到振荡提取8 h的效果,大大节省了操作时间;超声提取方法检出限为0.016μg/g,准确度在-1.0%～-2.5%之间,精密度在0.046%～0.160%之间,该方法快速、可靠、操作简单,值得推广。     

钼对镉胁迫下小白菜镉含量和生理指标的影响

[目的]探讨了钼对植物的镉吸收累积及生理方面的影响。[方法]以Hoagland营养液为基础,以小白菜为材料,研究了不同钼离子浓度对镉胁迫下小白菜生长、地上部镉累积及全钾、全钠、全氮、全碳及可溶性糖含量的影响。[结果]随着钼离子浓度的增加,小白菜株高、最大叶长、最大叶宽、最大叶面积及地上部鲜重和干重均显著低于对照 地下部鲜重和干重呈逐渐降低趋势,但各处理之间差异不显著。小白菜地上部对镉的累积随钼离子浓度的增加呈降低趋势,且与对照差异达显著水平。随钼离子浓度的增加,全钾含量呈增加趋势,且0.10 mg/L钼离子浓度处理与对照差异达显著水平 全钠和全氮含量各处理间差异均不显著 全碳和可溶性糖含量均以0.05mg/L钼离子浓度处理为最低,且与其他处理差异均达显著水平。[结论]增加钼离子浓度能降低小白菜对镉的吸收累积,但对小白菜的生长有一定的抑制作用。     

硼钼配合施用对花生生长和产量的影响

选用广东省花生主产区的３ 种代表性土壤,采用盆栽试验,探讨硼钼施用对花生生长发育和产量的影响。结果表明：分别采用硼砂０．１％ ～０．２％ 喷施和钼酸铵０．１％ ～０．２％ 喷施,钼酸铵１～２ｇ／ｋｇ 拌种和Ｂ０．５～０．７５ｍ ｇ／ｋｇ基施等施肥方式均能显著或极显著促进花生长长发育并增加产量,其增幅为４．２４％ ～４４．５７％ 。硼基施明显优于喷施,钼拌种明显优于喷施,硼钼配合施用的效果较优,其最佳组合为硼酸按Ｂ０．５ｍ ｇ／ｋｇ 量基施,钼酸按２ｇ／ｋｇ 拌种,并于花生苗期和花期分别用０．１％ 硼砂和０．１％ 钼酸铵喷施     

Improvement of Rice Seedling Establishment in Sulfate-Applied Submerged Soil by Application of Molybdate

Abstract

Sulfide ion generation in strictly reduced soil might be a factor impairing rice seedling establishment. The molybdate ion is known to suppress the microbial transformation of sulfide ions from sulfate ions. I investigated the effect of molybdate on rice establishment in sulfate-applied submerged soil. The establishment of rice seeds sown in sulfate-applied submerged soil was markedly improved by application of potassium molybdate at a rate of 1.5?15 mmol kg-¹ dried soil. The application of potassium molybdate delayed the decline of the sulfur concentration in the soil solution near the seeds and the appearance of circular black stains, or insoluble iron sulfide indicating the generation of sulfide ion, around seeds in the soil. Irrespective of the application of molybdate, the redox potential near the seeds was low enough to allow generation of sulfide ions, implying that molybdate suppresses the generation of sulfide ions with no effect on redox potential. These results suggest that the application of molybdate could improve rice seedling establishment in sulfur-rich submerged soil by suppressing the generation of sulfide ions, that is a possible factor suppressing the establishment of rice seeds sown in sulfur-rich submerged soil.     

钼在茶树中的生理效应

 测定了不同浓度钼处理的水培茶苗体内核酸，可溶性蛋白、游离氨基酸、咖啡碱，儿茶素、钼、磷含量及茶苗的光合强度、根中硝酸还原酶活性，顶梢和根中IAA、GA#-S。（赤霉素1、3、4、7）和ABA（脱落酸）的含量。结果表明，钼有利于茶苗叶中DNA和蛋白质的合成，但RNA含量有所下降；1.00和2.00ppm钼促进茶苗茶氨酸、咖啡碱和儿茶素的合成；钼处理增加茶苗对钼的吸收，但减少对磷的吸收；同时钼促进茶苗的光合强度和根中硝酸还原酸活性，但浓度效应有所不同；钼也影响IAA、GA#-S和ABA的合成和运输。     

氮、磷、钼对木麻黄苗期固氮、生理及生长效应的研究

以细枝木麻黄和沿海防护林内的中性沙土为供试材料,采用三因素五水平二次通用旋转设计方案,进行氮、磷、钼施肥试验。结果表明:细枝木麻黄的叶绿素含量、光合作用指标、硝酸还原酶活性、氨基氮含量、结瘤量、固氮酶活性、苗高生长、生物量积累均随磷的增加而提高;苗木结瘤量和结瘤率、固氮酶活性明显受氮肥制约,随施肥的增加而下降。其他生理指标和生长量在0.4gN/pot·范围内较好,超过此限时略有下降趋势或影响不明显;钼在本试验条件下影响不显著。苗木生物量和固氮酶活性与净光合强度、叶绿素含量、呼吸强度、NRA等指标均呈显著正相关。     

柱花草硼、钼微肥施用效果的研究

在热带地区土壤中硼、钼微量元素缺乏较为普遍.采用田间试验的方法,针对柱花草(Stylosanthes guianensis)喷施硼、钼微肥效果进行研究.结果表明,在土壤缺硼、钼的情况下,适量喷施钼、硼肥均能增加柱花草的产量.其中喷施钼增产效果较明显,其次为硼肥.与对照相比较,喷施钼肥和硼肥柱花草产量分别增加了2 475...     

Effects of dietary Cu, Mo and S on urinary Cu and Zn excretion in Simmental and Angus cattle

This study determined the effects of dietary copper (Cu), molybdenum (Mo) and sulphur (S) on urinary Cu and zinc (Zn) excretion in cattle. Four Simmental and four Angus heifers were fed low (L) or high (H) levels (mg/kg DM) of Cu (5, 40), Mo (1, 10) and S (0.2, 0.5%). Initially two of each breed was fed either LCu or HCu (2 mo). Then all eight animals were fed sequentially LCuHS (1.5 mo), HCuHS, HCuHMo and HCuHMoHS (2 mo each). Simmental had a higher urine flow, increased concentration and total excretion of urinary Cu and Zn compared to Angus, but only total Zn excretion was significantly higher. Urinary Cu excretion was greatest with the HCuHMoHS diet. Urinary Zn excretion significantly increased with HS but not HS in combination with HMo and/or HCu. This study, together with previously reported biliary excretion, allows a direct comparison of urinary and biliary Cu and Zn excretion responses to dietary Cu, Mo and S.     

家蚕中肠碱性磷酸酶活性变化研究

本试验以钼蓝定磷法探讨了各种因素对家蚕中肠碱性磷酸酶活性变化的影响。就家蚕的发育时期来说,酶的活性呈现出规律性的变化,每龄眠中较低,盛食期达最高峰,熟蚕期为五龄的最低值;蚕绝食处理后,中肠碱性磷酸酶活性即下降,绝食后复给桑,酶的活性可恢复到一定水平,大蚕期以不同叶质饲育,此酶活性无论是嫩叶,还是老叶均比适熟叶为低,尤其以基部老叶为最低,不同温度饲育,普通适温区中肠碱性磷酸酶明显高于高温区或低温区;氟化物添食后第二天起,蚕在外表上并无明显的中毒症状,但中肠碱性磷酸酶活性已趋下降。     

Effect of green synthesized molybdenum nanoparticles on nitrate accumulation and nitrate reductase activity in spinach

Abstract

In the present study, the green synthesized Mo nanoparticles (NPs) were firstly prepared using vermicompost extracts and, then, two experiments were separately carried out in a completely randomized design. The first experiment was conducted to investigate the effects of ammonium nitrate (AN) on nitrate (NO₃^?) accumulation rates as well as some other vegetative traits in spinach in four treatments and three replicates and the second experiment was done to investigate the effects of elemental Mo and green synthesized Mo NPs on NO₃^? accumulation, nitrate reductase (NR) activity and some morphological parameters in seven treatments with three replicates. The results of the first experiment indicated that the greatest accumulation of NO₃^? in the aerial parts of the plants was observed in the 3?M AN treatment. That is why the same concentration was utilized in the second experiment to study the effects of elemental Mo and green synthesized Mo NPs on the NR activity, NO₃^? accumulation and the other traits. The results of the second experiment indicated that various concentrations of elemental Mo and green synthesized Mo NPs have significant effects on all measured traits including the fresh and dry weights of the plant, NO₃^? concentration, NR activity, chlorophyll a (Chl a) and chlorophyll b (Chl b) rates, total chlorophyll (Chl a?+?b) and the plant height. Moreover, it was found that the green synthesized Mo NPs, as compared to elemental Mo, have a greater effect on the increase of NR activity and, consequently, significant reduction of NO₃^? accumulation. Abbreviations AN ammonium nitrate

Chl a chlorophyll a

Chl b chlorophyll b

Chl a?+?b the total chlorophylls

M Molar

Mo molybdenum

NPs nanoparticles

NR nitrate reductase

N nitrogen

NO₃^? nitrate