Manganese-phosphate reactions in aqueous systems and the effects of applications of monocalcium phosphate,on the availability of manganese to oats in an alkaline fen soil

Summary Electrometric titrations and chemical analyses of aqueous systems containing manganese sulphate and phosphoric acid showed that the compositions of manganese phosphates formed at various pH values depended on initial manganese concentrations and Mn : P molar ratios. The results show how phosphate benefits crops on soils containing toxic levesl of manganese.A pot experiment measured the effects of monocalcium phosphate, in the presence or absence of extra manganese, on the availability to oats of manganese in an alkaline manganese-deficient soil. On such a soil, phosphate equivalent to 750 or 1500 pounds of superphosphate per acre is unlikely to enhance manganese availability; such dressings may lessen grain yields considerably.Neutral and alkaline manganese-deficient fen soils were incubated with monocalcium-phosphate with and without added manganese salts. The phosphate dressings had only small effects on soil pH and on exchangeable and readily reducible manganese.     

Adsorption by soil of water-soluble phosphate from earthworm casts

Summary The equilibrium solution phosphate concentrations of mixtures of surface wormcasts and soil obtained from different depths were measured and from these concentrations, indices of the immobilization, by soil, of soluble phosphate from the wormcasts were derived. These were found to correlate with the nett P-adsorption capacity of soil taken from the same depths. It is suggested that the decrease in availability of soluble phosphate from wormcasts with increase in depth may result from an increase in adsorptive capacity for phosphate by the surrounding soil.     

Nutrient content of the moist tropical forest of Ghana

Summary The total weight of vegetation on an area of just over 1 acre of old secondary forest in the moist forest zone of Ghana has been determined, and found to be equivalent to roughly 150 tons per acre dry weight. The nutrient content of each component of the vegetation was also determined and showed that the amounts of the major nutrients immobilised in the vegetation were: N, 1,800 lb./acre; P, 120 lb./acre; K, 800 1b./acre; Ca, 2,400 lb./acre; Mg, 350 lb./acre. The corresponding amounts of nutrients in the top foot of soil supporting the vegetation were: total N, 4,100 lb./acre; available P, 11 lb./acre; exchangeable K, 580 lb./acre; exchangeable Ca, 2,300 lb./acre; exchangeable Mg, 330 lb./acre. About half the nutrients stored in the vegetation were contained in readily combustible material, and except for N would be released to the soil if the forest were cleared and burnt for cultivation. The quantity of roots and the amounts of nutrients contained in them were not sufficiently great to make an important addítion to the nutrient supply in the soil during subsequent cultivation. Of the total quantity of roots supporting the vegetation 85.5 per cent by weight were within 1 foot of the soil surface.     

Effect of certain chemical fertilizers on the rhizosphere myco-flora of Oryza sativa - I

In the present study an attempt has been made to understand the effect of Ammonium nitrate and Urea on the rhizosphere mycoflora ofOryza sativa. The fertilizers' application to pot-soil planted with the paddy increased the microfungal population both in rhoizsphere and nonrhizosphere regions. Certain fungal species were stimulated by the fertilizers. 80 lbs/acre of amm. nitrate was most favourable for rhizosphere fungi where as 60 lbs/acre of urea proved the best.     

Efficiency of Extraction of Nematodes by Flotation-Sieving Using Molasses and Sugar and by Elutriation

Blackstrap molasses was studied as an economical substitute for sucrose in the preparation of an extracting solution for removal of nematodes from soil by the flotation-sieving technique. The maximal number of nematodes extracted from soil was obtained with molasses solutions with specific gravity values in the range 1.000-1.073. Results of studies on the relation between size of soil sample and the amount of extracting solution are presented. In paired comparisons, a molasses solution with sp. gr. = 1.100 at 27 C extracted greater numbers of plant parasitic, dorylaimoid, mononchoid, and other soil nematodes than did the standard 1.0 M sucrose solution (sp. gr. = 1.100); the superiority of the molasses solution is attributed to its higher viscosity. The molasses method also was superior or equal in efficiency to the elutriation technique.     

THE PHYTOTOXIC EFFECTS OF D.D.T., B.H.C., PARATHION AND TOXAPHENE ON TOBACCO

No phytotoxic effect was seen following a pre-sowing spray of tobacco seed-beds with 27 lb./acre technical D.D.T. or after an application of the same material at 75.6 lb./acre to 3-week-old tobacco seedlings.
A pre-sowing application of parathion (diethyl para nitrophenyl thiophosphate) (2 % dust) at 1–8 lb. parathion per acre had no harmful effect. Used on 3-week-old tobacco seedlings at the excessive rate of 22.7 lb./acre it caused serious stunting and many deaths.
Toxaphene (chlorinated camphene: empirical formula C₁₀H₁₀Cl₈), applied as a 25 % wettable powder in a pre-sowing spray at 6-4 lb. toxaphene per acre, did not injure tobacco seedlings.
No residual phytotoxic effects appeared in beds re-sown 4 months after being treated with parathion or toxaphene at the pre-sowing doses given above.
Benzene hexachloride, applied before sowing at doses above 1.6 lb. technical B.H.C. per acre, suppressed root development in newly germinated tobacco seedlings. B.H.C. dusts used on n-day-old seedlings at 2–25 lb. technical B.H.C. per acre caused temporary distortion and stunting. Up to 11 lb./acre these symptoms were transitory: at 37.5 lb./acre many plants were killed and the remainder severely stunted. Resistance to these phytotoxic effects increased with age of plant, but 3-week-old tobacco seedlings showed considerable mortality after the application of 75.6 lb./acre of technical B.H.C.
Beds re-sown 4 months after the application of 6-4 and 12.8 lb. respectively of technical B.H.C. per acre showed no phytotoxic effect, but, as tobacco seed is sown on the soil surface, the effect of the B.H.C. may have been merely masked, and it is not safe to assume that there was no residual effect. The actual persistence of B.H.C. in the soil was not determined.
The possible mechanism of action of the B.H.C. effect is discussed.     

Transformation of inorganic phosphorus in flooded soils under rice cropping

Summary The concentrations of water soluble and ammonium acetate extractable phosphorus in all the soils under investigation first increased and then decreased with time of submergence under rice cropping. The increase in soluble phosphorus in the three acid soils of Luisiana, Casiguran and Guadalupe was related to decrease in the concentration of iron, calcium and reductant soluble phosphates, while in slightly acidic Maahas clay, the increase was associated with decrease in iron and aluminium phosphates. But in the calcareous soil, the increase was due to decrease in the concentration of aluminium and reductant soluble phosphates. The decrease was due to the re-formation of insoluble aluminium, iron and calcium phosphates in Luisiana and Guadalupe clays, to the formation of aluminium and calcium phosphates in Maahas and to the formation of calcium phosphate only in Casiguran fine sand. The application of phosphorus at the rate of 100 pounds per acre produced better tillering, more penicles and higher straw and grain productions in Luisiana, Casiguran and Guadalupe only where the level of soluble phosphate was very low in pots where no phosphorus was applied. This study, thus, indicated the necessity of phosphorus fertilization in low land rice for soils which are low in phosphorus and high in active iron and aluminium.     

Chemical Restraint of Exotic Animals in a Disease Regulatory Program

The African red tick (Rhipicephalus evertsi Neuman) is widely distributed in Africa but had never been identified in North America until September 1960 when it was found in a wild animal compound in Florida. The red tick is a vector of cattle fever (piroplasmosis) and several other exotic diseases including the highly fatal East Coast fever. The 130 acre compound contained more than 300 African and Asian animals, including giraffes, camels, zebras, elands, nilghais, blackbuck, aoudads, ostriches and Abyssinian asses. To determine the extent of the infestation, representative numbers of animals were immobilized with succinylcholine chloride for visual and manual examination. The grounds were treated with 2 lbs. of DDT per acre at three week intervals for six weeks and another group of animals were immobilized to determine the efficacy of the program. In all more than 50 wild animals were successfully immobilized with succinylcholine.     

玉米淀粉渣中玉米黄色素的提取及性质测定

利用玉米生产葡萄糖工艺中的淀粉渣提取的玉米黄色素 ,主要成分是一种脂溶性色素和少量的极性较大的色素 ,呈血红色 ,其稀释液呈柠檬黄色。高醇和石油醚提取色素液在 2 41nm和 2 80～ 32 7nm之间有最大吸收值 ,水提色素液在 2 13nm有最大吸收值。通过不同的方法进行了对比提取 ,并作了酸碱和热等稳定性的测定     

Investigations on the role ofSuaeda fruticosa Forsk in the reclamation of saline and alkaline soils in West Pakistan plains

Summary Investigations onSuaeda fruticosa show that it can bring about reclamation of saline and alkaline soils in certain parts of West Pakistan Plains by collecting non-saline blown soil of sandy loam type and by absorbing large quantities of salts from the top soil. An estimate shows that more than 2,400 lbs of salts can be removed from one acre by a single harvest of the aerial parts in the fall each year. The dunes help in reclamation by diluting the salt concentration and decreasing the salt-holding capacity of the topsoil by changing the texture. It is estimated that by this method saline soils can be reclaimed within three years in southern and central parts of West Pakistan Plains which are frequented by dust storms.     

The dependence of isotopically exchangeable phosphate (L-value) on phosphate uptake

Summary L-values were determined using clover and ryegrass, grown either separately or together, in soil or soil/sand media. Where the two species were grown in the same pot, there was no interspecific effect on L-value. However, as the experiment progressed L-values increased and clover and ryegrass grown separately gave different values. The increases can be explained by P uptake, single regressions of L-value on phosphate uptake accounting for 86 and 88 per cent of the variations in L-value on the two soils used, with little improvement for treating the two crops separately. The most likely explanation for the observation is that the phosphate stress placed on the soil system caused mobilization of previously non-labile P by the dissolution of sparingly soluble phosphate compounds.     

Use of partially acidulated rock phosphate as a possible means of minimising phosphate fixation in acid soils

Summary To examine the possibility of minimising phosphate fixation the lateritic soil at various levels of liming was incubated with phosphate rock from U.A.R. acidulated to different degree viz. 0, 10, 20, 50, and 100 per cent both with phosphoric and nitric acid. The soil was incubated for 90 days on addition of different phosphate carriers at the rate of 100 ppm total P₂O₅ containing different proportion of water-soluble, citrate-soluble and insoluble phosphorus. Samples were drawn at an interval of 30 days. Bray's p₁ and pH of the soil samples were measured. The dry-matter yield and uptake of phosphorus by two successive crops of maize grown in pots, the treatments being same as in incubation study, were well correlated with the Bray's p₁. Ground rock phosphate and 10 per cent acidulated material were effective in minimising the fixation in soil of pH 4.0 whereas 50 per cent acidulation was suitable for soils of higher pHi.e. 5.6 and 6.5. H₃PO₄ acidulated material was proved superior to HNO₃ acidulated product. The use of partially acidulated rock phosphate for acid soils may be recommended to receive economic return. Associate Professor Senior Research Assistant.     

Photosynthetic Properties of Chloroplasts from Chlamydomonas reinhardii

Chloroplasts isolated from synchronous cultures of the unicellular green alga Chlamydomonas reinhardii, SAG 11-32/b (−), fix CO₂ at rates between 25 and 50 micromoles per milligram chlorophyll per hour. The upper value is approximately half of the rate of the intact cell.

During storage in the dark on ice, the chloroplast preparation loses 30 to 50% of its CO₂ fixing capability per hour. Under reducing conditions (+ 1 millimolar dithiothreitol), this loss of activity is about twice as fast. The same reducing conditions stimulate CO₂ fixation in the light.

High concentrations of inorganic phosphate (>2 millimolar) inhibit CO₂ fixation. This inhibition is overcome by the addition of glycerate 3-phosphate. It is concluded that chloroplasts from C. reinhardii possess a higher plant type phosphate translocator. With respect to dependency upon light intensity, pH and Mg²⁺ concentration, the results were similar to that reported for chloroplasts from higher plants. However, in contrast to higher plant chloroplasts, maximum CO₂ fixation is observed at the relatively low osmotic concentration of 0.12 molar mannitol in the reaction buffer.

     

SOIL SAMPLING FOR WHEAT-BLOSSOM MIDGES

A method of assessing the population of wheat-blossom midges by the recovery of the cocoons from soil is described.
In the dry summer of 1947, considerable numbers of larvae of Sitodiplosis mosellana Géhin were still in the ears at the time of harvesting. Burning the straw immediately after combining may considerably reduce the numbers of midges.
The majority of the larvae are found in the top 3 in. of the soil although a considerable number may be found from 3 to 6 in. Headland infestations may be lighter than the rest of the field.
Cocoons of S. mosellana remain viable in the soil for several years, and 150,000 per acre were recovered in February 1951 from a field which had not had a wheat crop since 1944. At the same time 50,000 Contarinia tritici Kirby cocoons per acre were found in a field which was last under wheat in 1947.
Viable pupae were successfully obtained by soil sampling, and the pupation in the soil and subsequent emergence of the midges can be followed. Thus it is possible also to estimate the numbers of midges that will emerge.
Progress has been made towards predicting outbreaks of these two midges.     

A metachromatic dye-ATPase method for the simultaneous identification of skeletal muscle fiber types I, IIA, IIB and IIC.

The histochemical demonstration of quantitative differences in myofibrillar ATPase activity at the selective pH optima of the various types of human skeletal muscle fibers is the most widely used technique for their differentiation. The basis of the reaction is the deposition of insoluble salts of inorganic phosphate cleaved from ATP by myofibrillar ATPase(s) followed by substitution of the phosphates with less soluble chromogenic salts. Doriguzzi and associates reported using metachromatic dyes to demonstrate quantitative differences in phosphate deposition among different fiber types. Following routine ATPase histochemistry and staining with either azure A or toluidine blue, fibers with low ATPase activity (and low phosphate content) were stained metachromatically while fibers with high ATPase activity (and high phosphate content) were orthochromatic with the intensity of color proportional to the content of insoluble phosphate. The metachromasia was readily lost after immoderate washing in aqueous solutions or routine dehydration in ethanol, with consequent diminished fiber type distinction. A critical modification of this technique is reported in which incubation of frozen sections of human skeletal muscle in ATP-containing medium is carried out at room temperature (22-24 C), rather than the usual 37 C, followed by a revised washing and dehydration protocol. With these modifications, the four human skeletal muscle fiber types (types I, IIA, IIB, and IIC) can be identified rapidly and reliably in single sections, obviating the need for examination of serial sections. The tinctorial differentiation allows fiber type identification even in black and white photographs.     

A Metachromatic Dye-Atpase Method for The Simultaneous Identification of Skeletal Muscle Fiber Types I, IIA, IIB and IIC

The histochemical demonstration of quantitative differences in myofibrillar ATPase activity at the selective pH optima of the various types of human skeletal muscle fibers is the most widely used technique for their differentiation. The basis of the reaction is the deposition of insoluble salts of inorganic phosphate cleaved from ATP by myofibrillar ATPase(s) followed by substitution of the phosphates with less soluble chromogenic salts. Doriguzzi and associates reported using metachromatic dyes to demonstrate quantitative differences in phosphate deposition among different fiber types. Following routine ATPase histochemistry and staining with either azure A or toluidine blue, fibers with low ATPase activity (and low phosphate content) were stained metachromatically while fibers with high ATPase activity (and high phosphate content) were orthochromatic with the intensity of color proportional to the content of insoluble phosphate. The metachromasia was readily lost after immoderate washing in aqueous solutions or routine dehydration in ethanol, with consequent diminished fiber type distinction. A critical modification of this technique is reported in which incubation of frozen sections of human skeletal muscle in ATP-containing medium is carried out at room temperature (22-24 C), rather than the usual 37 C., followed by a revised washing and dehydration protocol. With these modifications, the four human skeletal muscle fiber types (types I, HA, IIB, and IIC) can be identified rapidly and reliably in single sections, obviating the need for examination of serial sections. The tinctorial differentiation allows fiber type identification even in black and white photographs.     

The effect of phosphate withdrawal by plant and by an anion-exchange resin on the phosphate potential of a soil

Summary Varying degrees of phosphate depletion by plants and AER were brought about in two acid soils. After depletion, the monocalcium phosphate potential was determined in soil suspended in dilute CaCl₂ solution.The results showed that phosphate depletion either by plants or AER did not change the phosphate potential of a soil. It seemed that some of the labile phosphate removed by plants was replaced by a mobilization of non-labile soil phosphate fraction in the soil.The constancy of the phosphate potential indicated that the concentration of phosphate in the soil solution was controlled by the solubility of sparingly soluble soil phosphates. The data implied that it was the solubility of hydroxyapatite which determined the phosphate potential of both soils.     

磷酸盐修复重金属污染土壤的研究进展

从研究方法、反应机理以及风险评价等方面综述了磷酸盐修复重金属污染土壤的研究进展,分析和讨论了其中存在的问题和不足,提出了今后加强研究的重点。目前磷酸盐修复重金属污染土壤时,使用的主要研究方法有化学形态提取法、化学平衡形态模型法和光谱及显微镜技术,各个方法都有其优缺点,应该结合使用并探索新方法。磷酸盐稳定重金属的作用机理主要有3个:磷酸盐诱导重金属吸附、磷酸盐和重金属生成沉淀或矿物和磷酸盐表面吸附重金属,但磷酸盐与重金属反应的机理十分复杂,人们尚不完全清楚,因此难以有效区分和评价诱导吸附机理和沉淀机理或其它固定机理,相应地对磷酸盐修复重金属的长期稳定性难以预测。磷酸盐修复重金属污染土壤时由于其较高的施用量可能会造成磷的积聚从而引发一些环境风险,如磷淋失造成水体富营养化,营养失衡造成作物必需的中量和微量元素缺乏以及土壤酸化等。所以应该谨慎选择磷肥种类和用量,最好是水溶性磷肥和难溶性磷肥配合、磷肥与石灰物质等配合施用。今后应着重研究磷酸盐与重金属相互作用的机理区分和评价;关注磷酸盐修复重金属污染土壤时存在的潜在风险,特别是加强植物长期不断吸收磷或其它环境条件变化致使土壤磷素持续减少过程中稳定的重金属溶解性和移动性的研究,磷酸盐修复重金属污染土壤的长期田间实践等。     

The Uptake of Phosphate by Plants from Flowing Nutrient Solution: IV. EFFECT OF PHOSPHATE CONCENTRATION ON THE GROWTH OF TRIFOLIUM REPENS L. SUPPLIED WITH NITRATE, OR DEPENDENT UPON SYMBIOTICALLY FIXED NITROGEN

Breeze, V. G. and Hopper, M. J. 1987. The uptake of phosphateby plants from flowing nutrient solution. IV. Effect of phosphateconcentration on the growth of Trifolium repens L. suppliedwith nitrate, or dependent upon symbiotically fixed nitrogen.—J.exp. Bot. 38: 618–630. Nodulated white clover plants were subjected to a range of phosphateconcentrations in flowing solution culture (0.32 to 8.0 mmolm^–3 P) at 41 d from sowing, either supplied with nitrateor dependent on symbiotically-fixed nitrogen. No effect of phosphateconcentration in solution on dry matter production, relativegrowth rate, root/shoot ratio, or water soluble carbohydrateconcentration of the plant tissue was observed after 24 d fromthe start of the experiment, although the plants supplied withnitrate yielded more than the others. Phosphate uptake throughoutthe experimental period was related to the solution concentration,but the source of nitrogen did not affect the phosphorus concentrationsof the shoots. However, the roots of the plants dependent onsymbiotically-fixed nitrogen had higher concentrations of phosphorusthan those supplied with nitrate, but this did not appear tobe due to an increased phosphorus requirement for nitrogen fixation,because the amount fixed was unaffected by the phosphate concentrationin solution. The cation-anion balance showed that plants dependenton nitrogen fixation had no larger requirement for calcium thanplants supplied with nitrate, but a requirement for hydroxylions equivalent to over 130 kg lime per tonne of dry shoot.It is suggested that the enhanced phosphate uptake by plantsdependent on nitrogen fixation is due to this need for a cation-chargebalancing anion. Key words: Phosphate uptake, nitrogen fixation, Trifolium repens L., repens L., cation-anion balance, flowing solution culture     

植物体内铁的萃取预富集分离条件的研究

植物体和土壤中的铁与其它营养盐一样都是限制植物生产力的重要因素,目前,植物体和土壤中的铁通常都采用原子吸收和电化学法进行分析,本研究用萃取法从盐酸溶液中分离Fe(Ⅲ）,采用萃取剂磷酸三丁酯（TBP）,研究酸度,温度以及盐析剂等条件对萃取分配系数的影响并对铁的反萃取进行讨论,从而确定最优萃取条件,为植物体内铁的萃取富集分离提供实验依据。