Endophytic Chaetomium globosum enhances maize seedling copper stress tolerance

This study aims at characterisation of the impact of Chaetomium globosum on copper stress resistance of maize seedlings. Higher levels of copper treatment decreased maize dry weight and induced a marked increase in osmotic solutes, antioxidant enzyme activity and the level of lipid peroxidation. On the other hand, addition of the endophytic C. globosum alleviated the toxic effect of copper on maize growth. The combination of copper sulphate and Chaetomium increased seedling dry weight, osmotic solute content and antioxidant enzyme activity compared to copper sulphate alone, while lipid peroxidation levels were also decreased. The fungal scavenger system might be important for supporting the ability of maize seedlings to resist copper toxicity.     

The reconstitution of microsomal redox chains. A comparative analysis of the effectiveness of membrane self-assembly and template binding of electron carriers

The osmotic pressure of solutions of sulphated proteoglycans isolated from the intervertebral discs of animals of various ages was determined. The behaviour of the solutions in salt-added systems was investigated in terms of the Donnan distribution of the mobile ions. It is evident that this effect is the dominating factor in explaining the observed nonidealities. Although marked variations in the compositions of the proteoglycan, with regard to their chondroitin sulphate and keratan sulphate content and hence charge content, occur with increasing age of parent tissue, the osmotic activities of the various preparations are very similar. This is explained by the ;fixation' of the counterions in such a way as to counteract any change in the charge content of the polyion; an ;osmotic buffering' effect. The swelling behaviour of gelatin gels containing the proteoglycan preparations has been measured. In all cases pressures in excess of the sum of the osmotic pressures of the individual components are observed. However, the magnitude of the excess decreases with increasing age of the parent tissue. It is suggested that the age changes, as reflected by a decrease in water content of the gel system, are not the result of changes in the osmotic properties of the individual components but rather reflect changes in the entropic interaction of the proteoglycan with the gelatin matrix. The relevance of this observation to the situation in vivo is discussed.     

Fermentation of molasses using a thermotolerant yeast,Kluyveromyces marxianus IMB3: simplex optimisation of media supplements

 The use of molasses as a substrate for ethanol production by the thermotolerant yeast Kluyveromyces marxianus var. marxianus was investigated at 45°C. A maximum ethanol concentration of 7.4% (v/v) was produced from unsupplemented molasses at a concentration of 23% (v/v). The effect on ethanol production of increasing the sucrose concentration in 23% (v/v) molasses was determined. Increased sucrose concentration had a similar detrimental effect on the final ethanol produced as the increase in molasses concentration. This indicated that the effect may be due to increased osmotic activity as opposed to other components in the molasses. The optimum concentration of the supplements nitrogen, magnesium, potassium and fatty acid for maximum ethanol production rate was determined using the Nelder and Mead (Computer J 7:308–313, 1965) simplex optimisation method. The optimum concentrations of the supplements were 0.576 g l^-1 magnesium sulphate, 0.288 g l^-1 potassium dihydrogen phosphate and 0.36% (v/v) linseed oil. Added nitrogen in the form of ammonium sulphate did not affect the ethanol production rate. Received: 29 January 1996/Received revision: 23 April 1996/Accepted: 29 April 1996     

Sulphur and phosphorus requirements of Curvularia pallescens Boed

The effect of different sulphur and phosphorus compounds on the growth and sporulation ofCurvularia pallescens Boed. has been studied. Nine different sulphur sources were tried but among them only magnesium sulphate yielded the best dry weight of the fungus. Zinc sulphate, sodium sulphate, sodium thiosulphate, potassium sulphate and calcium sulphate supported good growth. Poor growth was recorded on sodium bisulphite, ammonium sulphate, sodium sulphide and control. Sporulation was excellent on magnesium sulphate. It was good on zinc sulphate, sodium sulphate and potassium sulphate. On sodium thiosulphate, calcium sulphate, sodium bisulphite and control it was fair. Sodium sulphide and ammonium sulphate had inhibitory effect as sporulation was poor and nil on these two compounds respectively.Six phosphorus compounds were studied. Tripotassium phosphate gave best growth and excellent sporulation. Good growth and excellent sporulation was recorded on monobasic potassium phosphate and magnesium phosphate. Growth and sporulation were good on dibasic potassium phosphate and sodium dihydrogen phosphate. Ammonium phosphate was poorly utilized.     

Some causes of chlorosis and necrosis of sugar-beet foliage

The symptoms and characteristics of two virus and one fungus disease and four nutritional disorders of sugar beet which cause chlorosis and necrosis of the foliage are described. The causes of the diseases and methods of distinguishing between them have been investigated by analytical, pathological and field experimental methods.
Experiments in which diagnosis was confirmed by serological and spectrochemical methods show that the two often easily confused diseases, sugar-beet yellows virus and magnesium deficiency, can be visually distinguished.
Sugar-beet yellows virus reduces the potassium, but slightly increases the magnesium content of the leaves.
Magnesium deficiency symptoms are associated with a low magnesium content of the foliage, but may be induced by salt applications without greatly affecting the magnesium analysis.
'Potash' deficiency symptoms are often, but not necessarily, associated with a low potassium analysis and may actually be caused solely by a deficiency of sodium. In the field, symptoms are induced by sulphate of ammonia and phosphate applications and may be prevented in some cases by the application of either salt or muriate of potash, in others by salt only. Some interchangeability of the functions of potassium and sodium in the plant is suggested.
Manganese deficiency symptoms are associated with a low manganese content of the leaves, which can be readily increased by spraying or injection with manganese sulphate solution, but a high concentration of manganese in the foliage, such as sometimes occurs naturally on acid soils, has a toxic effect.     

On the effect of ferrous sulphate on the available manganese in the soil and the uptake of manganese by the plant II

Summary Pot experiments with oats on manganese deficient sandy and moor soils, which are not deficient in iron, showed a steady increase in yield and manganese uptake by the plants with increasing additions of ferrous sulphate at four levels of manganese. Residual effects from ferrous sulphate application were not found either in the case of yields or manganese uptake by oats on a sandy soil.The effect observed following application of ferrous sulphate was due to a manganese effect. This is corroborated by the coincidence of the yield curves, showing the relationship between absorbed manganese and yield of dry matter, following the application of manganese sulphate and ferrous sulphate.Soils treated withM magnesium nitrate in the presence of equivalent quantities of either ferrous sulphate or hydroquinone yielded the same amounts of manganese. This result suggests that the manganese effect of ferrous sulphate is due to reduction of higher manganese oxides by ferrous sulphate.     

Effect of magnesium deficiency on the metabolism of glycosamino-glycans in rats

Magnesium deficiency in rats has significant effect on the concentration of different glycosaminoglycans in the tissues, the nature of the change being different in different tissues. Total glycosaminoglycans, chondroitin-4-sulphate + chondroitin-6-sulphate and dermatan sulphate increased in the aorta while hyaluronic acid, heparan sulphate and heparin decreased. In the liver, total glycosaminoglycans, hyaluronic acid, chondroitin-4-sulphate + 6-sulphate and heparin decreased while total glycosamino-glycans and all the glycosaminoglycan fractions increased in the heart. In the kidney, total glycosaminoglycans showed no significant alteration, hyaluronic acid and heparin decreased while chondroitin-4-sulphate + 6-sulphate increased. Activity of biosynthetic enzymesviz. glucosamine-o-phosphate isomerase and UDPG-dehydrogenase showed decrease in the liver. The concentration of 3’-phosphoadenosine 5’-phosphosulphate, activity of sulphate activating system and sulphotransferase were also similarly altered in the liver in magnesium deficiency.     

Sulphur requirements of certain isolates ofAlternaria tenuis Auct

The sulphur nutrition of three isolates ofAlternaria tenuis Auct., isolated from the diseased leaves ofMangifera indica L.,Musa paradisiaca L. andPsidium guajava L., was studied. They were grown on the medium devoid of sulphur as well as on media containing various sources of sulphur viz., ammonium sulphate, sodium hyposulphite, sodium thiosulphate, magnesium sulphate, potassium sulphate, potassium metabisulphite, zinc sulphate and thiourea. Sodium hyposulphite, sodium thiosulphate, magnesium sulphate, potassium sulphate and zinc sulphate were generally found to be satisfactory sources for the growth of all the isolates under study. Poor growth of the different isolates was observed on the medium devoid of sulphur.     

Effect of salinity stress on organic and mineral constituents in the leaves of pigeonpea (Cajanus cajan L. Var. C-11)

Summary Effects of sodium chloride and sodium sulphate on the content of some organic and inorganic constituents in the leaves of pigeonpea (Cajanus cajan L. Var. C-11) were studied. Increased water content under saline conditions made the leaves succulent. The concentration of reducing sugars appeared to be higher while that of total sugars and starch was lower. The plants also failed to accumulate proline at higher salinity levels. Phosphorus and potassium content were lowered while those of calcium, magnesium, sodium, chloride and sulphate were increase under both salinities. This indicates that there is no regulation on the uptake of latter elements under saline conditions.     

Osmotic Adaptation in Panicum repens. Differences Between Organ, Cellular and Subcellular Levels

The process of osmotic adaptation was studied in leaves of Panicum repens. Two phases were observed: the first phase, which continued for 2–4 days, was mainly characterized by dehydration of leaves, a fast synthesis of organic acids and penetration of sodium into leaf cells. Chloride becomes dominant in the leaves only from the third day of exposure and onwards. The second phase of adaptation lasted for 4–6 days. During this phase, a decrease in organic acid content and an increase in leaf-chloride content was observed. In spite of the fact that the osmotic potential of the leaves reached lower values than that of the external medium already after 2 days, the rate of growth of the plants was hampered. Such inhibition of growth disappeared 6–8 days after exposure to salinity. Ion content of the cell walls, chloroplasts and vacuoles of Panicum leaf cells was investigated during the various stages of osmotic adaptation. An increase in sodium and chloride content of the cell walls during the early period of adaptation probably prevented the full osmotic adaptation of the protoplasts. It is suggested that a locally unbalanced distribution of ions may be one of the reasons for the decrease in growth rate during the process of osmotic adaptation and frequently after that.     

The dynamics of the sodium, potassium, calcium, magnesium contents in the fresh water mollusc zebra musselDreissenia polymorpha during stress

The sodium and magnesium concentration in the hemolymph of the zebra musselDreissenia polymorpha decreased by 25.1 and 25.6%, respectively, in 7.5 h after catching and transportation. One day later, the content of all four cations studied in the molluscan body was significantly reduced. After 7 days, the decrease in the tissue concentration, as compared to initial levels, was 2.7, 2.5, 4, and 4.4 times for sodium, potassium, calcium, and magnesium, respectively. After 18 days of acclimation, the concentrations of cations in the hemolymph and molluscan body did not differ from the initial values. Comparative analysis shows that bivalve molluscs and fish have a common negative mechanism connected with a loss of salt from the organism during the initial period of stress. Possible causes are discussed of the decrease in the salt content in the body of the marine bivalve molluscs to minimal values during their migration to the fresh water in the course of evolution.     

The dynamics of the sodium, potassium, calcium, magnesium contents in the fresh water mollusc zebra musselDreissenia polymorpha during stress

The sodium and magnesium concentration in the hemolymph of the zebra musselDreissenia polymorpha decreased by 25.1 and 25.6%, respectively, in 7.5 h after catching and transportation. One day later, the content of all four cations studied in the molluscan body was significantly reduced. After 7 days, the decrease in the tissue concentration, as compared to initial levels, was 2.7, 2.5, 4, and 4.4 times for sodium, potassium, calcium, and magnesium, respectively. After 18 days of acclimation, the concentrations of cations in the hemolymph and molluscan body did not differ from the initial values. Comparative analysis shows that bivalve molluscs and fish have a common negative mechanism connected with a loss of salt from the organism during the initial period of stress. Possible causes are discussed of the decrease in the salt content in the body of the marine bivalve molluscs to minimal values during their migration to the fresh water in the course of evolution.     

Sulphur and phosphorus requirements of three fungi causing diseases in storage

Summary The effect of different sulphur and phosphorus compounds on the growth and reproduction of three fungi causing storage rot, viz.,Fusarium solani, Botryodiplodia ananassae andMacrophomina phaseoli has been studied. Sixteen different sources of sulphur were used and out of them magnesium sulphate was found to be most favourable for the growth and reproduction of all the three fungi. Sodium sulphite and sodium bisulphite were toxic. Potassium metabisulphite prevented growth ofF. solani and M. phaseoli while it supported moderate growth ofB. ananassae. Only magnesium sulphate could induce the sporulation ofB. ananassae while sporulation and sclerotial development ofF. solani andM. phaseoli respectively varied with the type of sulphur sources used. Optimum concentration of magnesium sulphate was also determined and it was found that the growth and sporulation ofF. solani andB. ananassae were best at 0.375 g/l and 0.75 g/l.M. phaseoli tolerated higher doses of this substance as the best growth and excellent sclerotial development were recorded at 3.0 g/l (the maximum concentration used). Phosphorus was found to be essential for the present fungi as none of them could grow in complete absence of this substance. Onthophosphates and nucleic acid, were found to be favourable sources for growth and reproduction of the 3 organisms.     

The Components of the CO2-Indluced Stomatal Movements

Leaf discs of Vicia Faba were allowed to float on water in glass dishes placed in vessels containing KOH. The vessels were kept in darkness at constant temperature. The stomatal width and osmotic values of the guard cells and epidermal cells were measured, generally at one-hour intervals. When the CO₂ content of the air surrounding the leaf specimen falls, it causes a disturbance in the osmotic equilibrium between guard cells and epidermal cells. Sometimes the changes start in the form of falling osmotic values in both kinds of cell. In other cases the values rise, and in still others the changes may be confined chiefly to one of these kinds of cell. Since the changes are not the same in guard cells and epidermal cells, the osmotic difference between them rises or falls. The difference rises during the time immediately after removal of CO₂ from the surrounding air. This causes an osmotic surplus to arise or increase in the guard cells. Later, this change may take place in the opposite direction. The stomatal movements occurring simultaneously follow, on broad lines, the osmotic surplus of the guard cells. Consequently, the CO₂-induced stomatal movement is the result of an interaction between an active component—i.e., the intrinsic osmotic changes in the guard cells—and an osmopassive component, by which is meant here the osmotic changes in the epidermal cells.     

The effects of La(III) on the peroxidation of membrane lipids in wheat seedling leaves under osmotic stress

The physiological effects of the rare earth ion La³⁺ on the peroxidation of membrane lipids in wheat (Triticum aestivum L.) seedling leaves under osmotic stress were determined. With the passage of time under osmotic stress, the inhibition ability of lanthanum ions to the relative membrane permeability and concentration of malondialdehyde, Superoxide radicals, and hydrogen peroxide caused by osmotic stress increased substantially, but no changes were noted in ferrous and relative water content. It indicated that lanthanum ions could not retain the water content because of osmotic stress. However, La³⁺ appears to decrease the production of OH by reducing the content of O₂ and H₂O₂ of Haber-Weiss and Fenton reactions, which efficiently alleviated peroxidation of membrane lipids under osmotic stress and, to some degree, protected the membrane from injury of free radicals. Thus, La³⁺ increased the tolerance ability of plant to osmotic stress, which could assure the function of membrane normal temporally after stressed.     

Osmotic pressure effects and intracellular accumulation of ethanol in yeast during fermentation

Summary The intracellular accumulation of ethanol in yeast and its potential effects on growth and fermentation have been topics of controversy for the past several years. The determination of intracellular ethanol based on the exclusion of [¹⁴C]sorbitol to estimate aqueous cell volume was used to examine the question of intracellular ethanol accumulation. An intracellular accumulation of ethanol inSaccharomyces cerevisiae was observed during the early stages of fermentation. However, as fermentation continued, the intracellular and extracellular concentrations of ethanol became similar. Increasing the osmotic pressure of the medium with glucose or sorbitol was observed to cause an increase in the intracellular ethanol concentration. Associated with this was a decrease in yeast growth and fermentation rates. In addition, increasing the osmotic pressure of the medium was observed to cause an increase in glycerol production. Supplementation of the media with excess peptone, yeast extract, magnesium sulfate and potassium phosphate was found to relieve the detrimental effects of high osmotic pressure. Under these conditions, though, no effect on the intracellular and extracellular ethanol distribution was observed. These results indicate that nutrient limitation, and not necessarily intracellular ethanol accumulation, plays a key role during yeast fermentations in media of high osmolarity.     

A preliminary study of the applicability of sweet potatoes for mycological fat production

Summary For mycological fat production,Aspergillus nidulans andPenicillium lilacinum were grown on media made up of crushed and boiled sweet potatoes. Mycelial mats containing a fair amount of fat were obtained, namely, 15 % in case ofAspergillus and 24 % in case ofPenicillium. Media containing an external supply of glucose gave rise to increase in percentage fat in mycelium, but the amount of mycelium and consequently the total fat content decreased.Addition of sodium nitrate gave heavier mycelial mats but the total fat content could not be raised.Addition of potassium phosphate or magnesium sulphate or both to the sweet potato medium gave rise to heavier mycelial mats but with lower fat content.     

Nitrogen and sulphur requirements of Colletotrichum inamdarii Lal

Summary Nitrogen and sulphur requirements ofColletotrichum inamdarii Lal isolated from the leaves ofCarissa carandas L. have been studied. DL-serine, L-asparagine and L-phenylalanine have been found to be of good nitrogen source followed by potassium nitrate, calcium nitrate, magnesium nitrate, DL-alanine, ammonium nitrate, glutamic acid, ammonium sulphate, DL-valine, aspartic acid, ammonium chloride, ammonium hydrogencarbonate, L-histidine and potassium nitrite. There was no growth in the absence of nitrogen.Sporulation was excellent on calcium nitrate and sodium nitrate, Very good on DL-serine, potassium nitrate, and magnesium nitrate. Good on L-asparagine, L-phenylalanine and ammonium oxalate. Fair on DL-alanine, DL-leucine, ammonium sulphate, DL-valine, ammonium chloride and L-histidine whereas poor on glutamic acid, aspartic acid, ammonium tartarate and ammonium nitrate. Few spores were observed on ammonium hydrogencarbonate but potassium nitrite did not show any sporulation.Amongst the sulphur compounds sodium bisulphate gave the best growth and good sporulation, followed by sodium thiosulphate, magnesium sulphate, ammonium sulphate and potassium sulphate. Thiourea gave negligible growth whereas it failed to grow on zinc sulphate and potassium persulphate.