Foliar treatment of barley by sodium selenium in controlled conditions

The effects of various selenium concentrations on crop formation, grain quality, and nitrogen and selenium accumulation in spring barley grown on sod–podzolic soil were studied in experiments on vegetation. Optimal amounts of the element were established taking into account different levels of mineral nutrition (NPK) for enriching barley production. Positive effects of selenium on yield, grain quality, and other features of its action on plants were noted. The key role of mineral fertilizers in the effectiveness of foliar treatment of barley was studied.     

Foliar application of selenite and selenate to potato (Solanum tuberosum): effect of a ligand agent on selenium content of tubers

The effect of a foliar spray of selenium on potatoes was investigated for 2 years. Amounts of 0, 50, and 150 g of Se ha(-)(1) were applied both as sodium selenate and as sodium selenite in water, either pure or with the addition of 0.15% of soluble leonardite as a source of humic acids (pH 7). Tuber selenium concentration increased with the application levels, both with sodium selenate and with sodium selenite, when only aqueous solutions were used. When humic acids were added, the tuber selenium level rose more markedly after the application of sodium selenate as compared to the case of the aqueous solutions; however, in the case of sodium selenite, the level showed a large increase only after the application of 50 g of Se ha(-)(1). Kinetics showed that humic acids raised the selenate availability, but no differences were found in the distribution of selenium in the tuber fractions. Foliar application of selenium with humic acids was proven to be a good way to increase the selenium content of potatoes, but the assimilation process of selenium was simpler with selenate than with selenite.     

Foliar application and uptake of selenium extracted from ryegrass

In a pot experiment a water extract from ryegrass (Lolium perenne) containing 21 mg/L selenium (Se) was sprayed on ryegrass, and the uptake of Se was compared with the uptake of Se applied as sodium selenite. The amount of Se recovered from the plants (0 to 53 mg/kg) was a linear function of the amount of Se applied (0 to 130 g/ha), both for the Se in the extract and for the sodium selenite. A total of 2.8 times more Se was recovered from the plants sprayed with the extract than from the plants sprayed with sodium selenite. When the plants were washed with Triton X‐100 the difference was still higher: from the ryegrass sprayed with the extract 5.3 times more Se was recovered from the grass sprayed with the extract than from the grass sprayed with sodium selenite.     

水稻品种间吸收和转运硒特性差异机制研究

采用溶液培养试验比较了富硒水稻与非富硒水稻对硒的吸收和运输特征,期望揭示富硒水稻秀水48和非富硒水稻丙9652籽粒硒累积差异部分生理机制。结果表明,两品种水稻根部对硒吸收的Km值差异不大,但富硒水稻秀水48的Vmax是非富硒水稻的1.57倍,两品种水稻根系对硒的共质体吸收皆受载体调控。硒吸收时间动力学试验证实秀水48茎中硒的浓度和含量在各个处理时间段均要高于丙9652,富硒水稻秀水48的木质部汁液中硒的浓度大约是非富硒水稻丙9652的2倍,在相等蒸腾速率的条件下,秀水48地上部硒含量显著高于丙9652,说明两品种水稻向地上部转运硒的能力差异显著,秀水48更易将根中的硒转运到地上部,高效的转运体系是富硒品种地上部硒含量高的关键所在。富硒水稻具备很强的向地上部转运硒的能力,部分原因在于其根部木质部对硒的装载能力较强。     

Responses of anaerobic bacteria to soil amendment with selenite

Soil (Haplic Luvisol) was incubated in anaerobic microcosms with and without addition of a small amount of selenite (2 mg Se kg⁻¹) and straw, and changes in both bacterial populations (fermentative and selenite-respiring) and selenium fractionation were assessed. Selenite caused an initial decrease in CO₂ emission (−98% alone and −60% with straw) but this effect decreased with time. Selenite and straw additions enhanced the dynamics of fermentative and selenite-respiring bacteria but their effect was not cumulative. Selenium became less easily extractable during incubation: the non-extractable fraction of added selenium increased from 22% to 68% (73% with straw).     

Influence of selenium on oxidoreductive enzymes activity in soil and in plants

The aim of this greenhouse experiment was the assessment of the influence of H₂SeO₃ at soil concentrations of 0.05, 0.15 and 0.45 mmol kg⁻¹, on the activity of selected oxidoreductive enzymes in wheat (Triticum aestivum). The wheat plants were grown in 2 dm³ pots filled with dust-silt black soil of pH 7.7. Applied H₂SeO₃ caused activation of plant nitrate reductase at all concentrations, but activation of plant polyphenol oxidase at only two lower concentrations. The highest concentration caused inhibition of polyphenol oxidase and peroxidase. Plant catalase activity decreased under the influence of 0.15 and 0.45 mmol kg⁻¹ concentration. After the final analysis Se was quantified in plants and soil. The amounts in plants were: control (unamended soil) 1.95 mg kg⁻¹; I dose (0.05 mmol kg⁻¹) 18.27 mg kg⁻¹; II dose (0.15 mmol kg⁻¹) 33.20 mg kg⁻¹ and III dose (0.45 mmol kg⁻¹) 38.37 mg kg⁻¹, in soil: 0.265 mg kg⁻¹; 3.61 mg kg⁻¹; 10.53 mg kg⁻¹; 30.53 mg kg⁻¹; respectively. Simultaneously, a laboratory experiment was performed, where the activity of soil catalase and peroxidase were tested after 1, 3, 7, 14, 28, 56, and 112 days after Se treatment. Peroxidase activity in soil decreased with increasing Se content, over the whole experiment. The lowest dose of Se caused activation a significant 10% increase in catalase activity, but the influence of others doses was unclear.     

Effects of different application methods of selenite and selenate on selenium distribution within wheat

Abstract

The objective of this sand culture experiment was to determine how fertilization methods (i.e., fertigation rates of 0.5, 1, and 2?mg Se·pot^?1, foliar rates of 5, 10, and 20?mg Se· L^?1) and fertilizer type (i.e., selenate or selenite) affected wheat Se concentrations. The results showed that the fertigation and foliar treatments both increased wheat Se content. In the fertigation and foliar treatment total Se content of wheat was greatest in the selenate treatments. In the fertigation treatment, the Selenite had mainly accumulated in the roots, while the Selenate was majority transported to shoot. In the foliar treatment, we found that most of Se was transported to grain. In addition, the organic Se concentration was the most than other Se fractions. In conclusion, selenate was more effective than selenite in both the fertigated and the foliar application treatments. And the foliar application was better than fertigation.     

不同浓度硒肥对籼稻硒含量和产量的影响

发展富硒水稻经济效益显著。为了进一步理解籼稻组合富硒能力和产量变化规律,本研究以安康市农科所选育的优势较好的籼稻后代组合(MR、ME、MI、ML)为材料,在苗期、孕穗期和齐穗期连续喷施不同浓度的硒肥。结果表明:随着硒肥浓度增加,4个籼稻材料硒含量均出现快速增长,但后期增速减缓,富硒能力依次为:MLMRMEMI;产量随着硒肥浓度增加而增加,但是浓度过高,产量则下降,在最适硒肥浓度下,籼稻产量大小依次为:MRMLMIME。因此,籼稻后代材料MR和ML富硒能力较好,可以作为后续育种工作的重点材料。     

The effects of pressure trunk injections of potassium on the mineral content,growth, yield and fruit quality of sweet cherry (Prunus avlum L.) and mineral content of prune (Prunus domestica L.)

Abstract

Fall trunk injections of 200 g K in K₂SO₄ solution or up to 300 g K in K₂HPO₄ solution had no effect on sweet cherry mid‐shoot leaf K in August. Phosphorus content was significantly increased in buds in March and midshoot leaves in August one year by fall injection of K₂HPO₄ (79.2 g P).

Spring trunk injections of 12.5 g K (K₂S04 or K₂HPO₄) in prune increased leaf K within four days and K levels remained higher than controls for at least 22 days with K₂SO₄ Leaf P was increased within four days by K₂HPO₄ and was higher than controls in August.

Fruit set in sweet cherry was significantly lower on trees injected with 200 g K (K₂S0₄) and 300 g K (K₂HPO₄). Yield was significantly lower for all injection treatments and was probably caused at least in part by reduced fruit set. Fruit quality was not affected by K injections.     

2008—2018年功能农业的理论发展与实践

功能农业作为高产农业、绿色农业之后,农业发展的新阶段,是“调优供给”、“调强农业产业”的重要支撑性技术,加强功能农业研究是构建生态高值农业产业体系的重要内容,是我国农业供给侧结构性改革的主要举措之一,对我国农业发展和乡村振兴战略具有重要意义。功能农业从2008年提出至今已有十年时间,本文对有关功能农业的定义、学科的发展、应用实践,进行了系统回顾,对于未来发展进行了展望。     

Efficiency of foliar selenium application on oilseed rape (Brassica napus L.) as influenced by rainfall and soil characteristics

The Czech Republic is characterized by a low Se soil content, resulting in Se deficiency in crops, humans, and animals. This study investigated the response of oilseed rape to foliar application of selenate solution in a microscale field experiment conducted at two locations differing in soil and climatic conditions but with comparable total Se contents. Sodium selenate (Na₂SeO₄) was applied at two rates (25 and 50 g Se ha^?1). The potential effect of Se application on the uptake of essential elements was also evaluated. The foliar Se application resulted in an effective stepwise increase in the Se contents of all the plant components studied (leaves > stems > roots > siliques ~ seeds), as expected. No significant influence of Se fortification on the other investigated macro- and microelements was observed. However, the soil and climatic conditions influenced the Se uptake, such that a higher Se content was observed in plants grown in the most acidic location (Cambisol soil) that had a higher oxidizable carbon content and higher average annual rainfall compared to the less acidic location (Luvisol soil). These observations indicated the necessity to optimize the Se application for the particular soil and climatic conditions to achieve a maximum biofortification effect.     

Effect of selenite additions on microbial activity and dynamics in three soils incubated under aerobic conditions

Three soils were incubated for 4-day periods with selenite (0-5 mg Se kg⁻¹) and the effect of straw amendment was also studied for one of these soils. The same soil was also incubated for up to 6 weeks, with and without straw and selenite (0-2 mg Se kg⁻¹). Changes in microbial activity (oxygen respiration) and dynamics (total, fungal biomass; bacterial density number) were assessed. Selenium fractionation and volatilization were also quantified. Selenium addition had no marked effect on respiratory activity, total and fungal biomass whatever the incubation period, but inhibited the growth of heterotrophic bacteria in the longer term. When straw was added, the same trend was observed with more variability. The volatilization losses of Se differed between soils but did not vary significantly over the 6-week period and were not affected by straw addition. Freshly added Se was more easily extracted than native soil Se and its extractability decreased with time, whereas no change in the fractionation of native Se was observed. This study shows that moderate additions of Se may influence microbial dynamics in aerated soil but could not establish a causal link with changes in Se fractionation.     

土壤施硒对茶树叶片硒及矿质元素含量的影响

以茶树为试材,亚硒酸钠和硒酸钠为硒源,采用土壤沟施的方式,进行田间试验,研究茶树叶片总硒、有机硒及K、Ca、Mg、Zn、Fe含量变化规律。结果表明,土壤施硒可显著提高叶片总硒和有机硒含量,叶片总硒含量随着施肥浓度增加显著升高,随着采样时间延长,先升高后降低,在施肥后5个月达到最大值。茶树对Se(VI)的吸收和转运能力远高于Se(IV),硒酸钠处理叶片总硒含量是亚硒酸钠处理的10.4~25.3倍。茶树吸收无机硒后大部分都转化为较为安全的有机硒,有机硒占总硒比例为91.6%~96.2%。土施不同浓度硒肥,叶片K、Ca、Mg、Zn、Fe含量呈现出波动式升降变化的特点,施硒显著提高嫩叶Zn含量,并显著降低老叶Ca、Fe含量,对叶片K、Mg含量无显著影响。     

土壤Se的分级与Se的植物有效性的关系

Nine soils with distinct properties and Se levels were selected to test a fractionation procedure of soil Se based on sequential extraction. Soil Se was fractionated into readily available Se (fraction Ⅰ, extracted by 0.5 M NaHCO₃), slowly available Se (fraction Ⅱ, extracted by 0.1 M NaOH-0.1 M Na₄P₂O₇), amorphous oxide-occluded Se (fraction Ⅲ, extracted by acid ammonium oxalate), free oxide-occluded Se (fraction Ⅵ, extracted by dithionite-citrate-bicarbonate buffer solution) and residual Se (fraction Ⅴ, determined by HNO₃-HClO₄ digestion of the final soil residue). The recovery of soil Se (the sum of all fractions over total soil Se determined independently) by this procedure was from 88.1% to 110.9%, mean 99.2%±6.4% for the test soils. The sum of fractions Ⅰ and Ⅱ, provided a good measure of available Se in soils and the percentage of fraction Ⅰ plus Ⅱ over the total soil Se, tentatively defined as Se availability index, could be used to indicate soil Se status and predict Se deficiency.     

Foliar application of silicon at different growth stages alters growth and yield of selected wheat cultivars

To evaluate the response of some selected wheat cultivars to silicon application at different growth stages under drought stress, an experiment was carried out in the greenhouse of College of Agriculture, Shiraz University, Iran, during 2012 using a completely randomized factorial design with four replications. Experimental treatments included drought stress (100% F.C. as control and 40% F.C. as drought) and foliar application of 6 mM sodium silicate (control, application at mid tillering stage, at anthesis stage, and application at tillering + anthesis stages) and wheat cultivars (Sirvan and Chamran, relatively drought-tolerant, and Shiraz and Marvdasht, drought-sensitive cultivars). Drought stress significantly reduced chlorophyll content, leaf area, relative water content, grains per spike, 1000-grain weight, grain yield and biomass of all wheat cultivars. Furthermore, drought stress increased electrolyte leakage of the flag leaves of all cultivars. In contrast, foliar-applied silicon significantly increased these parameters and reduced electrolyte leakage. Furthermore, highest positive influence of silicon application was observed at combined use of silicon both at the tillering + anthesis stages in wheat plants under both stress and non-stress conditions. Significant differences were found in physiological responses among wheat cultivars. The drought tolerant cultivars (Sirvan and Chamran) had significantly higher growth and yield than those of drought sensitive cvs. Shiraz and Marvdasht under drought stress. In conclusion, foliar application of silicon especially at the tillering + anthesis stages was very effective in promoting resistance in wheat plants to drought conditions by maintaining cellular membrane integrity and relative water content, and increasing chlorophyll content.     

Foliar ammonium accumulation as an index of stress in plants

Abstract

Foliar ethylene evolution is used as a bioassay to index physiological stress in plants. Accumulation of uncombined ammonium frequently precedes or coincides with ethylene evolution by stressed plants and also may serve as an index of stress. The objective of this research was to assess the relationship between ethylene evolution and ammonium in plants stressed by toxicity. Ethylene evolution and ammonium accumulation by tomato (Lycopersicon esculentum Mill.) foliage were measured for plants grown in a greenhouse with nutrition from ammonium‐ or nitrate‐based nutrient solutions. Foliar symptoms of stress from ammonium toxicity appeared on plants growing on ammonium‐based solutions. Ethylene evolution increased in response to a progressive array of foliar ammonium accumulation, which varied with source of N and duration of the treatments. Above a threshold of about 0.2 mg NH₄‐N g^‐1 fresh weight, ethylene evolution rose sharply and linearly with ammonium accumulation. Ammonium accumulation in foliage is suggested as an index to assess environmentally induced stresses in plants.     

南宁市土壤硒分布特征及其影响因素探讨

以南宁市土壤为对象,系统采集了2 767个表层土壤(0～20 cm)和711个母质样(150～200 cm)。用AFS原子荧光光谱法进行了样品全硒含量质量分数分析;研究了南宁市土壤全硒含量的分布特征及其与成土母质、土壤类型和土壤理化性质的关系。结果表明,南宁市土壤全硒含量变幅为0.09～1.34 mg kg-1,算术平均值为0.57 mg kg-1。土壤类型中,新积土全硒含量最高,平均为0.89 mg kg-1;紫色土全硒含量最低,平均为0.37 mg kg-1。成土母质中,全硒含量以二叠系碳酸盐岩母质发育土壤为最高,平均为0.79 mg kg-1;以下白垩系紫红色碎屑岩母质发育土壤为最低,平均为0.39 mg kg-1。影响南宁市土壤硒含量的主要因素是成土母质,土壤pH、有机碳及铁和铝的含量对土壤全硒含量的富集与分布也有一定影响。     

施硒对药用菊花主要有效成分和花中硒含量的影响

采用砂培盆栽试验探讨施Se对药用菊花花中总黄酮、绿原酸和Se含量的影响。结果表明,在施Se量不超过2.0mg/kg时能促进药菊的生长,提高药菊花中总黄酮、绿原酸的含量,药菊花、茎叶和根的干重和花中的总黄酮、绿原酸含量均随施Se量的增加而增加;其中以施Se量为2.0mg/kg处理的效果最佳,该施Se量处理药菊花干重、根干重、花中绿原酸含量与施Se量分别为0、0.25、0.5、1.0mg/kg各处理以上各相应指标的差异均达到显著水平,该施Se量处理药菊花中总黄酮含量高于其他所有5处理,并与施Se量为0mg/kg和0.25mg/kg两处理药菊花中总黄酮含量的差异达到显著水平。过量施Se(4.0mg/kg)对药菊的生长表现出一定抑制作用,其药菊各部位生物量和花中总黄酮、绿原酸含量均低于施Se量2.0mg/kg的处理。药菊花、茎叶和根中的Se含量均随施Se量的增加而增加,菊花茎叶和根中的Se含量与施Se量呈线性相关关系,而菊花花中的Se含量(y)与施Se量(x)符合一元二次回归方程:y=-0.8175x2+6.0045x+0.1363。施用适量的Se既能显著提高药菊花中总黄酮和绿原酸含量,又能大幅提高花中的Se含量,这为富Se菊花及其系列产品的研发提供了理论依据。     

Determination of selenium concentration of rice in china and effect of fertilization of selenite and selenate on selenium content of rice

A method of hydride generation atomic fluorescence spectrometry was applied to the determination of the selenium concentration of regular polished rice in China and selenium-enriched polished rice obtained by foliar application of selenium-enriched fertilizer in the forms of selenite and selenate. The average selenium content of regular rice was 0.025 +/- 0.011 microg g(-)(1). On the basis of a daily dietary rice intake of 300-500 g suggested by the China Nutrition Society, the total selenium intake from regular rice was calculated to be 7.5-12.5 microg per person per day for an adult. The selenium contents of rice were significantly increased to 0.471-0.640 microg g(-)(1) by foliar application of selenium-enriched fertilizer at rate of 20 g of Se ha(-)(1) in the forms of sodium selenite and sodium selenate. The selenium content of rice by application of a fertilizer of selenate was 35.9% higher than that by a fertilizer of selenite, which showed that Se-enriched fertilizer in selenate exhibited greater efficiency in increasing Se content in rice products. The Se-enriched rice products can increase daily Se intake on average by 100-200 microg of Se per day by the consumption of 400 g of rice products if the Se level of rice products is controlled at 0.3-0.5 microg of Se g(-)(1). Because rice is a staple food in China, selenium-enriched rice obtained by bioenrichment of selenium to increase the Se content of rice could be a good selenium source for the population in selenium-deficient regions.     

土壤含硒量对玉米农艺性状、产量及籽粒硒含量的影响

在2个硒含量的土壤背景下,种植8个不同遗传背景的玉米品种,研究土壤硒含量对玉米品种的农艺性状、产量及硒含量的差异,结果表明:(1)土壤硒含量对玉米的株高、穗位、可见叶片数有增加效应,富硒区玉米的3个指标高于非富硒区,但富硒区的单产未能表现高于非富硒区。(2)供试品种的产量依次为康农玉108(7 822.6 kg/hm2)华玉11号(7 302.11 kg/hm2)双玉919(6940.47 kg/hm2)禾盛玉718(6860.41 kg/hm2)正大999(6 374.98kg/hm2)万玉168(5964.29kg/hm2)恩单804(5889.69kg/hm2)兴农单3号(5692.68kg/hm2)。(3)土壤硒含量对玉米籽粒的硒含量有促进作用,供试品种籽粒硒含量依次为:兴农单3号双玉919万玉168恩单804康农玉108正大999华玉11号禾盛玉718。