Sulphur Requirement of Rapeseed-Mustard, Groundnut and Wheat: A Comparative Assessment

Two oilseed species, rapeseed-mustard and groundnut, and wheat, a cereal, were compared for their sulphur requirement. Sulphur accumulation pattern in different plant parts at various growth stages indicated a several fold higher requirement of S in rapeseed-mustard as compared to the other two species. A low N: S ratio found in rapeseed-mustard was also an indicative of its higher S requirement. The S requirement of groundnut was found to be similar to that of wheat. The additional S required by rapeseed-mustard may be attributed to the presence of glucosinolates, a characteristic of cruciferous plants. Sulphur fertilization enhanced yield of the oilseed species but not the per cent oil. The role of sulphur in oil biosynthesis is discussed.     

紫色土增施单质硫对大蒜生长发育和硫素营养的影响

对紫色土施用单质硫条件下大蒜生长发育及硫素营养吸收和代谢进行了研究。结果表明,大蒜株高、叶面积、经济产量(蒜头)和经济系数以中等供硫水平最高,而茎粗和生物产量则以高硫水平最大。大蒜能耐高浓度的硫素供应,在0～120kghm-2供硫情况下,其全硫(TS)、水溶性硫(SS)和无机硫(Io-S)含量均随供硫量的增加而上升,小分子水溶性含硫氨基酸含量(Ws-S)以低硫水平最高,而大分子蛋白质硫含量(Wis-S)以中等供硫水平时最高,与大蒜素含量的变化一致。大蒜素含量与不同硫组分比率的关系分析发现,大蒜素含量与Ws-S/TS呈极显著的正相关(r=0.752 ),与Io-S/SS呈显著的正相关(r=0.702 )。全氮含量与全硫含量变化趋势一致,全磷含量以低硫水平时最高,全钾含量以中等供硫水平时最高。     

硫肥的增产效应及其在河南省的应用前景

论述了硫在作物营养平衡中的作用，缺硫原因及其施用硫肥的增产效应。     

不同包装,药剂和硫处理对龙眼贮藏效果的研究

本试验研究了不同包装、药剂和硫处理对石硖龙眼的贮藏效果，结果表明：内包装以０．０２ｍｍ的聚丙烯呈聚乙烯袋为宜，外包装可采用竹篓。普通药剂以特克多５００×１０＾－６加抑霉唑５００×１０＾－６为最佳配方，硫处理中浸泡试验无效。而缓慢放硫处理可使用加二亚硫内或焦亚硫酸风量为６ｇ或８ｋｇ／ｋｇ果；熏硫处理则用３０ｇ硫磺熏蒸３ｋｇ果，时间２０或３０分钟，或者２０ｇ硫磺熏蒸２．５ｋｇ果，时间１５或２５分钟，随     

棉花施用硫肥的产量、品质效应研究

1999～2001年在沿江地区灰潮土上研究了硫磺粉、硫肥95对棉花生长发育、皮棉产量和棉纤维品质的影响。试验结果表明:施用硫肥能提高棉花的株高、果枝数、蕾数、成桃数和茎基粗,还能提高伏桃比例,促进棉花生育后期的生长发育,增加棉花产量,改善棉纤维长度、整齐度、比强度等品质指标。硫肥的适宜用量为45～60kg/hm2。施用硫肥95的增产效果比硫磺粉的要好。     

Labile ester sulphate in organic matter extracted from podzolic soils

Summary We studied the effect of soil pretreatment, molecular-weight fractionation, and K₂SO₄ addition on the concentration and biochemical stability of ester sulphate in soil organic matter. A labile ester sulphate fraction (8.1 g S g^–1 soil) was detected in the organic matter extracted from a sulphate-rich podzolic sandy loam. This fraction was susceptible to loss during soil pretreatment with water and KCl solution and subsequent extraction of organic matter from the soil. The low-sulphate loam was low in labile ester sulphate (0.6 g S g^–1 soil) and the pretreatments had little effect. The addition of K₂SO₄ to the organic matter extracted from the low-sulphate soil resulted in the formation of appreciable amounts of labile ester sulphate. Newly formed ester sulphate tends to be biochemically less stable than indigenous ester sulphate in soil humic polymers and the ester sulphate associated with the low molecular-weight fractoin of soil organic matter appears to be more susceptible to loss by enzymatic hydroylsis. The results were interpreted in terms of steric effect. Ester sulphate groups bound to external surfaces of soil humic polymers may be easily accessible to sulphatase enzyme and thus readily mineralizable during incubation or extraction of soil organic matter at low soluble-sulphate levels. Sulphate groups on inner surfaces of the organic polymers are shielded from the enzyme due to size exclusion and hence more stable.     

Influence of sulphur supply on glucose and ATP concentrations of inoculated broad beans (Vicia faba minor L.)

In the present study, the influence of S supply on S concentrations, N₂ fixation, available amounts of glucose and adenylates of Vicia faba minor L. were weekly investigated, starting 6 weeks after sowing. Glucose was determined photometrically in shoots, roots and nodules and in ATP, ADP and AMP by bioluminescence in roots, mitochondria and bacteroids. Sulphur deficiency resulted in significantly lower S concentrations of shoots, roots and nodules, in a reduced N₂ fixation as well as in significantly lower amounts of glucose in shoots and nodules. In roots and bacteroids, S deficiency resulted in lower ATP concentrations, while the influence of S supply on ADP and AMP was less pronounced. With optimum S supply, the available amounts of glucose and ATP were strongly influenced by flower formation and seed development. Dedicated to Prof. Dr. Dr. h.c. W. Werner on the occasion of his 75th birthday.     

Immobilization of sulphur-35, microbial biomass and arylsulphatase activity in soils from field-grown rape,barley and fallow

Soils under rape, barley and fallow were monitored for S immobilization, microbial biomass and arylsulphatase (ARS) activity. These soils were regularly collected in the field every fortnight from mid-April to the end of June 2001. Then, they were incubated for 1 week at 25°C with carrier-free ³⁵S (Na₂³⁵SO₄). The results showed significant correlation of both immobilized ³⁵S ( r =0.94, P <0.001) and ARS ( r =0.79, P <0.001) with microbial biomass-³⁵S (MB-³⁵S) but not with microbial biomass-C (MB-C). Therefore, only a fraction of MB-C was involved in the immobilization of ³⁵S and hence the release of ARS. In addition, positive correlations appeared between hot water-soluble C (HW-C), ³⁵S immobilization, MB-³⁵S and ARS, indicating the pivotal role of HW-C in regulating S immobilization and turnover. The mean percentage values of immobilized ³⁵S, MB-³⁵S and ARS were higher in soil from the fallow, followed by soils from barley and rape. However, under culture, the mean values of ARS per unit of MB-³⁵S showed the decreasing order: soil from rape (0.58)>soil from barley (0.46)>soil from fallow (0.34). It is concluded that microorganisms under rape were most efficient in producing ARS, a strategy used to cope with the SO₄^2--S limiting conditions.     

MES [2-(N-morpholine)-ethane sulphonic acid] buffer promotes the growth of external hyphae of the arbuscular mycorrhizal fungus Glomus intraradices in an alkaline sand

In this work we investigated the hypothesis, suggested by unpublished experiments carried out previously, that application of MES [2-(N-morpholino)-ethane sulphonic acid] buffer to the substrate of plants hosting the arbuscular mycorrhizal fungus Glomus intraradices might favour the growth of external hyphae. The substrate of Trifolium pratense plants, with or without G. intraradices inoculum, was treated twice weekly, between weeks 5 and 11 of growth, plant with distilled water, P-supplemented 10% Hewitt nutrient solution (H+P), 51mM in H+P or 1mM TRIS-HCl in H+P. MES buffer increased the length of external G. intraradices hyphae and the density of propagules in the substrate, but plant growth was not affected. Although both TRIS-HCl and MES caused substrate pH to fall (from 8.51 to 7.35 and 7.17, respectively), only MES induced a significant increase in external hypha length. We conclude that the effect of MES on external hypha length was not due to plant growth or to substrate pH per se. Received: 10 March 1996