Starvation Symptoms Research Articles

Effect of chlorate, nitrogen source, and light on chlorate toxicity and nitrate reductase activity in soybean leaves

Growth chamber studies were conducted to assess the relationship between nitrate reductase (NR) activity and development of chlorate (KClO3) toxicity symptoms in leaflets of soybeans [Glycine max (L.) Merr.]. Fourteen day‐old soybean seedlings, grown in NO3 ‐ or urea‐nutrient solutions, were exposed to various KClO3 concentrations (0 to 2.0 mM) and light levels (100, 67, 33 and 0% of full light which was 750 μE m−2s−1) for 24 h. Visual KClO3 toxicity symptoms were noted and NR activity was measured.Toxicity symptoms (interveinal chlorosis) were evident within 24 h following addition of 0.5 mM KClO3 to the nutrient solution, regardless of N nutrition, and symptom severity increased with increased KClO3 concentration (up to 2.0 mM). Leaflet NR activity was lower following 24 h KClO3 treatments at concentrations of 0.5 mM and higher, indicating that ClO3 ‐ or some reduction product of ClO3 ‐ likely ClO2 ‐ was detrimental to enzyme functionality. The light study supported involvement of NR activity in KClO3 toxicity in that comparison of control and KClO3 treated plants exposed to decreased light levels revealed a decrease in NR activity of control plants parallel to a decrease in severity of KClO3 toxicity symptoms of treated plants. Urea‐grown plants, which have an apparent constitutive NR enzyme, were used to verify that the KClO3 toxicity symptoms were not simply N starvation symptoms due to competition of ClO3 ‐ and NO3 ‐ for uptake and reduction. In vivo NR assays also ruled out that ClO3 ‐ was decreasing NR activity through competition with NO3 ‐ for reduction sites. The close relationship between KClO3 toxicity symptoms and NR activity, in response to light treatments, suggested that KClO3 toxicity symptoms were associated with reduction of ClO3 ‐ to ClO2 ‐ by the NR enzyme. However, the possibility that a more direct photochemical reaction occurred in the presence of KClO3 to produce the toxicity symptoms could not be ruled out.

A Non‐Nodulating Peanut1

Nodules that form on the roots of peanut (Arachis hypogaea L.) when infected with Rhizobium are the site of N‐fixation. F3 plants were identified in a breeding nursery at Marianna, Fla., which showed N starvation symptoms toward maturity and apparently had no nodules on their roots. These plants were derived from a cross between two normal nodulating parents, 487A‐4‐1‐2 ✕ PI 262090. Subsequent evaluations in the F4 to F6 generations confirmed that numerous selections from this cross failed to nodulate in the field at Marianna. Growth chamber inoculation studies with various strains of rhizobia confirmed the field evaluations. Seed of selected plants from field plots classified as non‐nodulated were utilized in these studies. Only five of 400 progeny from non‐nodulating plant selections bore nodules in these tests.

Effect of organic matter supplementation on nitrogen transformations in soils: II. Nitrogen balance and yield

Under controlled laboratory conditions, the effect of the application of uncomposted plant materials (sawdust and maize stalks) or horns and hooves (narrow C/N ratio) on soil nitrogen and plant growth was investigated. From nitrogen balance calculations it was found that the addition of the wide C/N ratio materials alone either increased soil nitrogen through N2-fixation or lessened nitrogen loss through denitrification. Although such materials resulted in the immobilisation of mineral nitrogen, no nitrogen starvation symptoms were noted on the growing plants. Negative nitrogen balances were usually obtained when soils received mineral nitrogen fertilizers either alone or together with maize stalks or supplemented with the narrow C/N ratio organic material.

Observations of boll weevil midgut when fed natural food or on bacterially contaminated artificial diet

Boll weevils fed natural food had normal midgut morphology, but weevils fed bacterially contaminated artificial diet had deteriorated midguts which became progressively less functional with continued feeding on the diet. Reversal of the conditions occurred when the weevils were returned to natural food. This recovery did not take place, however, if the deterioration was too advanced. All strains of boll weevils had similar midgut responses. Cellular destruction in the midgut and loss of tissue function led to typical symptoms of starvation and desiccation during the first 10 days of adult life. Continued feeding upon contaminated food resulted in premature death. These observations show the importance of sanitation in mass-rearing procedures. It also may provide an explanation for subnormal boll weevil quality as reported by other authors who measured longevity, pheromone, and fatty acid production.

On the course of anorexia nervosa

The authors trace three phases in the course of anorexia nervosa and compare its physical and psychological symptoms with those of starvation. Phase I, which may occur months or years before the illness, usually includes precipitating events that result in loss of self-esteem and increased self-consciousness about physical appearance. During phase II patients develop the "anorectic attitude," an unreasonable fear of eating, and show pride in their ability to lose weight. By phase III patients are forced by the severity of starvation symptoms to admit that they are ill. Although many of the physical symptoms of starvation and anorexia nervosa are similar, anorectic patients, in contrast to victims of starvation, show high initiative, the ability to suppress hunger, restless hyperactivity, and body image distortion.

Infant depression due to separation from siblings: syndrome of depression, retardation, starvation, and neurological symptoms. A re-evaluation of the concept of maternal deprivation.

Infant depression due to separation from siblings: syndrome of depression, retardation, starvation, and neurological symptoms. A re-evaluation of the concept of maternal deprivation.

A dietary choline requirement for egg production in Drosophila melanogaster.

Adult Drosophila melanogaster require dietary choline for oogenesis. Early symptoms of choline starvation are a decline in egg pro¬ duction and egg hatchability followed by oviposition of malformed eggs. Choline-starved females can store viable spermatozoa. Sterility due to choline starvation can be corrected by choline administration. Females fed DL-carnitine in place ofcholine are fertile but produce fewer eggs with

Effect of Withholding Feed and Water on Early Poult Mortality and Growth

The severe loss of poults between the fifth and twelfth days after hatching is partially attributed to lack of water (Hammond 1944). Retarded growth, slimy gizzard lining that frequently forms a ball which plugs the opening to the duodenum, and absence of specific infection are typical water starvation symptoms. Withholding of feed for a period of 96 hours resulted in 40 percent mortality during the first 2 weeks of age while a 24 hour withholding time produced a mortality of only 8 percent.Our laboratories have been investigating the factors responsible for high mortality and irregularity in poult growth during the early growing period of turkey poultsEXPERIMENTALThis experiment was outlined to determine the influence of withholding feed and water on rate of growth and mortality of turkey poults up to 12 weeks of age. Bronze turkey poults were used during these studies. They were divided into uniform groups .

THE RELATION OF ENDOCRINE FEEDING TO REGENERATION, GROWTH AND EGG CAPSULE PRODUCTION IN PLANARIA MACULATA

1. Individuals of Planaria maculata were fed on abundant, exclusive diets of beef liver, anterior lobe of the pituitary and thyroid glands. Others were given aqueous extracts of the glands or were completely starved.2. No significant differences were noted in the head regeneration time of the gland-fed animals following each of five amputations of the anterior region.3. Decapitated animals which were starved and those which were kept on the aqueous extract diet and which showed starvation symptoms regenerated more slowly than those which were fed the fresh glands. There appeared to be a correlation between the rate of regeneration and the initial size of the animals.4. Thyroid-fed individuals increased in size but to a lesser extent than the liver and pituitary-fed forms. All were in excellent condition following four decapitations. Individuals newly emerged from capsules also increased in size when fed thyroid gland exclusively.5. Liver-fed animals produced a greater number of egg capsules than any of the others. The starved and extract-treated forms, with the exception of a single capsule by the Liver L Aqueous Extract set, produced no capsules.

RESPIRATION AND METABOLISM IN ETIOLATED WHEAT SEEDLINGS AS INFLUENCED BY PHOSPHORUS NUTRITION

Phosphorus plays an important role in the process of respiration (12, 13, 29). It forms, in the presence of sugars, monoand di-hexosephosphoric acid esters (8, 27), which are then broken down in the respiratory process. Under certain conditions it may form with sucrose a sucrose phosphoric acid ester (19). It is also known that plants starved for phosphorus differ considerably in their chemical composition from those not thus starved. MacGillivray (15) has pointed out that tomato plants starved for phosphorus show a decrease in coagulable nitrogen, and an increase in total nitrogen. There is also a marked increase in percentage of sugar. Kraybill (10) also showed that when phosphate is limiting in tomato plants nitrates as well as carbohydrates accumulate. According to Eckerson (5) the lack of phosphorus causes a breakdown of the reducase activity of the plant, which is then followed by an accumulation of nitrates, sugars, and starch, and results in an essentially nitrogen-starved plant. It is desirable then to know the relation between respiration and the chemical composition of plants deficient in phosphorus as compared with plants not deficient in phosphorus. In view of these facts and because phosphorus very often becomes limiting in agricultural soils the present investigation was undertaken. All of the chemical data cited above were obtained with green plants and after phosphorus starvation had become rather severe. It was the desire of the writer to determine some of the early symptoms of phosphorus starvation as shown by internal composition, as well as to measure the respiration during this period, and to relate any differences in composition to respiration, if possible. For these purposes large green plants are not suited ; hence, etiolated seedlings with a considerable reserve of carbohydrates were used. Wheat was chosen as the most uniform plant at hand. Since Lyon had obtained an increase in respiration owing to increased phosphate supply, the respiration behavior of wheat was reinvestigated, and, at the same time, the chemical changes caused by differences in phosphorus nutrition during early development were determined. It will be noted that the differences obtained in this

On the Fixation of Atmospheric Nitrogen by Phoma Radicis Callunae, Including A New Method for Investigating Nitrogen-Fixation in Micro-Organisms

ABSTRACT (1) Evidence from chemical analyses of seeds of Calluna mdgaris and of seedlings grown on a nitrogen-free medium confirms the view that this plant can obtain nitrogenous supplies from the air, probably in the form of molecular nitrogen, in sufficient amount to prevent the advent of any symptoms of nitrogen starvation. (2) A new apparatus for the investigation of nitrogen-fixation by micro-organisms is described. (3) Using the above apparatus, experiments on the mycorrhizal fungus of Calluna vulgaris are described in which this organism was grown in pure culture on a nitrogen-free medium with and without a supply of molecular nitrogen. The evidence obtained indicates that the amount of glucose used by the fungus during growth, and the amount of nitrogen contained in the culture at the end of the growth period are greater under the former condition. It is concluded that the fungus in question can utilise the molecular nitrogen of the air in some degree under the conditions of the experiments, although these were not the most favourable possible for nitrogen-fixation. It is considered that the results obtained justify an extension of these experiments using a strain of the fungus freshly extracted from the Calluna plant.