Location of chromosomal control of GA-induced enzyme release by distal half-grains of wheat

The three enzymes, alpha-amylase, peroxidase, and acid phosphatase, are among those released by the aleurone of bread wheat, Triticum aestivum, as a direct response to gibberellins (GA) from the embryo during germination. Aneuploid genotypes are used to investigate the chromosomal location, nature, and extent of genetic control of the release of these enzymes in endosperms after induction by exogenous GA. Ditelosomics demonstrate the effect of removal of known chromosome arms, and tetrasomics show the effect of duplication of chromosome pairs. Quantitative analysis demonstrates complex control systems over and above those previously found using zymogram techniques. For alpha-amylase, chromosome arms with net promoter effects and chromosomes with net inhibitor effects were found. These effects were not chromosome-dosage responsive, unlike the promoter-inhibitor system found for acid phosphatase control. Peroxidase levels in the endosperms were generally high in both types of aneuploids. With one exception, all chromosomes showing involvement as ditelosomics showed a similar effect as tetrasomics, indicating that in the euploid a balanced state restricting, rather than promoting, peroxidase levels existed.

Histiocytoma presenting as swelling on the toe

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Studies on a Maize Mutant Sensitive to Low Temperature II. Chloroplast Structure, Development, and Physiology

In the Zea mays L. mutant M11 grown in the dark at 15 degrees , the ultrastructure of the etioplast is abnormal. The pigment content of the etioplasts is reduced but the in vivo absorption characteristics suggest that the normal protochlorophyll (ide)-holochrome is present. The lowered synthetic ability of the etioplasts is not primarily due to a reduced complement of plastid ribosomes. The plastids of mutant M11 grown in the light at 15 degrees contain little pigment, are markedly deficient in ribosomes and their ultrastructure is abnormal. In mutant M11 grown at 15 degrees , an extreme sensitivity of the plastid membranes to light was observed.

A model of blebbing in mitotic tissue culture cells

A preliminary study of blebbing in tissue cultures has been made. The tubal epithelium of fetal mouse oviduct was cultured at 37 degrees C in Rose chambers. A cinematographic record was obtained of phase microscope observations of mitotic cells. Measurements of the size of both cells and blebs were made on the film using a "traveling" microscope. The duration and the rise and decay times of blebs were determined simply by counting frames on the film. Detailed observations are reported on blebbing in four cells undergoing mitosis. The results indicate that the frequency of blebbing as well as the duration of individual blebs exhibits a maximum during telophase. A model is proposed to account for blebbing in mitotic cells. The model attributes to local regions of the cell membrane the property of constant tension independent of stretch over some restricted range of stretch. This property implies that the cell membrane is locally unstable. Further assumptions stated explicitly in the model are that (i) cell division occurs at constant volume, (ii) the cell membrane stretches during cleavage, (iii) there is a positive pressure drop across the cell membrane. Evidence is cited in support of these assumptions as well as independent evidence that the cell membrane may be locally unstable. A physical model is described which would be expected to exhibit blebbing given the above assumptions.

Phaeochromocytoma as a cause of gastro-intestinal distension

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Biochemical and Structural Correlations in Isolated Spinach Chloroplasts Under Isotonic and Hypotonic Conditions

Methods are described for obtaining preparations of isolated spinach chloro-plasts which are predominantly either "whole", i.e. retain the outer limiting membrane, or "naked", i.e. with the outer membrane removed. The whole chloro-plasts are shown to retain more of their soluble components as evidenced by higher endogenous capacities for CO.-fixation, photophosphorylation, and light-dependent reduction of triphosphopyridine nucleotide. The isolation is also described of whole chloroplasts whose peripheral jackets have retained the property of mobility seen in living cells.

Manganese as a Functional Component of Chloroplasts

A series of experiments has been carried out to determine whether manganese is directly or indirectly involved in the photochemical reactions (as measured by the Hill reaction) of chloroplasts of higher plants.

The Effect of Nutrient Deficiencies on the Hill Reaction of Isolated Chloroplasts From Tomato

Tomato plants were grown deficient in each known essential macro- and micronutrient (except chlorine) and the effect of each deficiency on the Hill reaction activity of chloroplasts isolated from these plants was studied.

The effect of calcium and soil pH on nodulation of T. subterraneum L. clover on a yellow podsol

The mechanism of the action of lime in stimulating nodulation of subterranean clover on some soils of the Southern Tablelands of New South Wales was studied in pot experiments. Increased soil pH or increased calcium supply alone did not markedly improve nodulation. With a combination of both these factors, excellent nodulation resulted. Nodulation was shown to be increased by increasing the amount of the inoculum of Rhizobium added with the seed. It was also increased if the moisture content of the soil was maintained continually at field capacity.

Sulphur in Nitrogen Metabolism of Legumes and Non-Legumes

A study was made of the influence of sulphur on the nitrogen metabolismof subterranean clover (Trifolium subterraneum L.) and the non-legUmes oats(Avena sativa L.), Hax and linseed (Linum usitatissimum L.), andPaspalumdilatatum Poir. All these species responded to fertilizers containing sulphur onthe three soils used. Sulphates of aJl1lIlonium, potassium, sodium, and manganesewere all effective.

Molybdenum in Nitrogen Metabolism of Legumes and Non-Legumes

A study was made of the growth and nitrogen metabolism of plants inrelation to molybdenum supply. Four soils low in available molybdenum wereused in pot cultures for this work.