Molybdenum-enriched soybean seeds enhance N accumulation, seed yield, and seed protein content in Brazil

High soybean yields require large amounts of nitrogen (N), which can be obtained mainly from symbiotic N₂ fixation. However, the efficiency of this biological process can be limited by micronutrient deficiencies, especially of molybdenum (Mo). In Brazil, soybean generally responds positively to fertilization with Mo in soils of low fertility and in fertile soils depleted of Mo due to long-term cropping. The micronutrient can be supplied by seed treatment, however toxicity of Mo sources to Bradyrhizobium strains applied to seed as inoculant has been observed, resulting in bacterial death and reductions in nodulation, N₂ fixation and grain yield. Therefore, use of seeds enriched in Mo could be a viable alternative to exterior seed treatment, allowing elite inoculant strains of Bradyrhizobium to sustain high rates of biological N₂ fixation. We demonstrated the feasibility of producing Mo-rich seeds of several soybean cultivars, by means of two foliar sprays of 400 g Mo ha⁻¹ each, between the R3 and R5 stages, with a minimum interval of 10 days between sprays. As a result of this method, considerable increases in seed-Mo content were obtained, of as much as 3000%, in comparison to seeds obtained from plants which received no Mo. In field experiments performed in soils with low N content and without any N-fertilizer supply, inoculation of Mo-rich seeds produced plants with increased N and Mo contents in the grain and higher yields of total N and of grain. In most cases, Mo-rich soybean seeds did not require any further application of Mo-fertilizer.     

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。     

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。     

实验室制备六氟合钼和六氟合钨的方法

六氟合钼（MoF6）和六氟合钨（WF6）属于比较重要的氧化剂，因此对它们的制备方法的详细了解对化学工作有着非常重要的意义．虽然关于MoF6和WF6的合成有报道，但对MoF6和WF6在实验室里的制备工作的实验程序和具休步骤缺乏详细介绍。六氟合钼和六氟合钨可以在300～350℃下由单质氟来直接氟化金属单质来合成[1]。本文详细介绍以此方法在实验室里制备MoF6和WF6的具体方法、步骤和所使用的设备。     

Effect of Root Zone Temperature on Accumulation of Molybdenum and Nitrogen Metabolism in Potato Plants

Abstract

Changes in root temperature caused by the application of plastic covers were studied in relation to the uptake and content of molybdenum (Mo) in the different organs of potato (Solanum tuberosum L. var. Spunta) plants (roots, tubers, stems, and leaves) and in relation to nitrogen (N) metabolism. For the semi‐forcing technique of mulching, four different covers were used: T ₁ (transparent polyethylene), T ₂ (white polyethylene), T ₃ (coextruded black and white polyethylene), and T ₄ (black polythylene). The control treatment had no mulch. The results revealed a positive and significant effect of plastic covers on root temperatures: T ₀ = 16°C, T ₁ = 20°C, T ₂ = 24°C, T ₃ = 27°C, T ₄ = 30°C. These thermal differences significantly influenced the Mo concentration, particularly in the T ₂ and T ₃ treatments in the leaves, roots, and tubers. The same temperatures significantly altered N metabolism in both the aerial and underground parts of the plants, and a strong interrelationship was found between Mo and nitrate reductase (NR) activity. The mulching of this crop proved to be a promising technique in phytoremediation.     

钼在石墨炉内石墨探针表面上的原子化机理研究

本文报道了应用Ｘ－射线衍射分析及其它一些实验手段，研究钼在石墨炉内石墨探针表面上的原子化机理。结果表明：钼的原子化源于它的碳化物的热离解。     

硼、钼营养对甘蓝型油菜脂肪酸组分的影响

盆栽试验研究表明:硼、钼及其配合施用使甘蓝型油菜中双6号和中油821的含油量提高4.3%～6.2%,并提高油酸含量,降低芥酸和亚麻酸含量.比较两品种不同施肥处理的效果发现,单施硼肥对提高中油821含油量的效果高于其它处理;单施钼肥对中双6号的含油量及油酸和芥酸含量有显著的影响,而对中油821的影响不显著.综合分析认为,硼、钼配合施用对中油821的品质效应好于中双6号.     

不同钼效率冬小麦品种钼的吸收和分配

 在缺钼酸性黄棕壤上设不施钼（CK，土壤有效钼0.112 mg·kg-1）和施钼两个处理（+Mo，施钼0.13 mg·kg-1），研究钼高效冬小麦品种97003和钼低效冬小麦品种97014钼吸收和分配的差异。结果表明，不施钼时高效品种97003在整个生育期地上部干重和钼累积量均极显著高于97014，表明在相同缺钼逆境下97003吸收钼较多；97003拔节期上部叶、抽穗期穗、成熟期籽粒中分配的钼也多；穗和种子钼含量相对较高，表明97003向繁殖器官输送较多的钼。因而在缺钼逆境下97003对钼的利用效率较高，可获得较高产量。钼的吸收能力和利用能力较高可能是冬小麦品种97003钼高效的重要机理。     

钼对鸡肝肾组织形态学的影响

为研究钼对鸡肝肾组织形态学的影响,选取80只健康2w龄雏公鸡,随机分为5组,每组16只。通过在饮水中添加不同剂量的钼酸钠(以钼离子计),建立试验动物模型:对照组(钼:0mg.L-1)、钼Ⅰ组(钼:12.5mg.L-1)、钼Ⅱ组(钼:25.0mg.L-1)、钼Ⅲ组(钼:50.0mg.L-1)、钼Ⅳ组(钼:100.0mg.L-1)。分别在试验处理第10w,采集鸡的肝脏和肾脏,固定包埋处理后,制得切片,经HE染色分析,用显微镜观察鸡肝肾组织形态学变化。肾脏和肝脏的组织形态学观测结果显示:加钼的各组与对照组相比,细胞数量增多,且有浓染,出现坏死现象,细胞核皱缩加剧,有少量充血。试验低剂量(钼Ⅰ组、钼Ⅱ组)下的钼导致鸡肝肾组织发生不明显的病理形态学变化,而高剂量组(钼Ⅲ组、钼Ⅳ组)发生明显的病理形态学变化。