No description available.

No description available.

Soil texture, organic matter content, and hydrogen-ion concentration of soil samples were determined to find the correlation between soil characteristics, seed germination and seedling establishment of Pinus contorta. Scarification and stratification were treatments used for determining germination requirements of dormant seeds. Seeds were planted in different soils and experiments were conducted to determine the effects of different light intensities, temperatures, and depths of the water table on apparent photosynthesis rate and seedling establishment. Soil samples, pine cones, and young trees needed for the experiments were collected near Lily Lake, in the Uintah Mountains. The greatest and the fastest germination was found in soil with high organic matter and low PH. Seedling establishment succeeded only in mineral soil. Lodgepole seedlings grown in three fourths of full light had the best growth in both shoot and root systems. Low temperature favored photosynthesis rate more than respiration rate. Lodgepole seedlings preferred a moderately deep water table, since this species has a shallow absorbing system and not very extensive lateral roots.

<p> Barley coleoptiles were observed to be remarkably variable in height at 72 hr of germination. The objective or the study presented here was to analyze this variation in growth among coleoptiles and to attempt to determine its cause. The first step in this analysis of the variation was to determine the growth patterns of 900 individual coleoptiles by measuring their heights periodically during their growth period. In determining the cause for the variation, genetic, environmental, hormonal, metabolic and cytoplasmic factors were considered. For example, since gibberellin and kinetin have been implicated in the control of cell division and cell elongation these growth factors were supplied exogenously to germinating seedlings in an attempt to stimulate uniform growth of all coleoptiles. In similar studies, the effect or physical conditions and co2 on coleoptile growth was determined variation in growth is shown by any one of a number of parameters. Proteins, however, because they are closer to gene activity than the others are a better indicator of whether the variation in growth is caused at a fundamental level. Variations similar to those in coleoptile height were found in the amino acid analysis of different types of coleoptiles. Experiments were also done to determine if a genetic component was responsible for the variation in coleoptile growth. There was no correlation between germination pattern of a seedling and that of its progeny; therefore, the variation in growth was attributed to differences in cytoplasmic constituents of individual coleoptiles. </p> / Thesis / Doctor of Philosophy (PhD)

<p> The experiments described in this thesis were performed to investigate the: 1. Role of nitrate in the growth of maize seedling and 2. Role of amino acids in the assimilation of nitrate by the growing embryo.</p> <p> Nitrate stimulated the germination of Zea mays L. seeds by 10 to 15 percent. Further growth of the embryo axis, up to 6 days, however, was not affected by nitrate. During the early growth of the seedling, endosperm nitrogen was able to support the requirements of the embryo for 6 to 8 days. After a lag of 2 days, the protein content of the embryo increased linearly up to 6 days at a rate of 597 μ g a day. Some increase was observed between 6 and 8 days also. After 8 days, the protein level of embryo plateaued. Addition of 10 mM nitrate caused an increase in the protein and total nitrogen of the embryo only after 6 days. The endosperm mutant of maize, opaque-2, also responded to the nitrate in the same way.</p> <p> The protein content of the primary leaves increased linearly between 5 and 7 days. After 7 days, there is no increase in the leaf protein. Nitrate increased the protein level of primary leaves by 25 percent after 7 days. It protected against the further loss of protein in mature leaf. These results suggest that the primary role of nitrate in the growth of maize seedlings is to prevent protein loss.</p> <p> Out of 8 amino acids tested individually, only lysine and to a lesser extent arginine, inhibited the induction of nitrate reductase in the maize root tips. Different ammonium salts had no effect on the induction of nitrate reductase. The initial rate of induction in opaque-2 mutant (high lysine) was lower than the wild type, W64A (low lysine). From a comparison of the rate of induction of nitrate reductase between young and mature leaf, it was suggested that the amino acid supply from the endosperm may inhibit the induction of nitrate reductase. In the young maize seedling, this effect of amino acids may be more effective in vivo and in this way the assimilation of exogenous nitrate could be restricted, when the endosperm amino acids are supporting the growth of the embryo.</p> / Thesis / Master of Science (MSc)

Temperature is a major abiotic stress limiting plant growth. Thermotolerance evaluation during germination and early growth may help identify adaptable genotypes of new crops. Two studies were conducted to evaluate temperature effects on 12 Brassica carinata genotypes during germination and early growth. During germination, genotype AX17004 was both the most cold- and heat-tolerant. During early-season growth (35 d after seeding), there were temperature and genotype effects on shoot, root, and physiological components. Cumulative low- and high-temperature response indices, and cumulative root and shoot response indices were related, indicating the importance of these traits. Genotype AX17006 was identified as heat tolerant, and AX17009 as cold tolerant during early-season growth. When genotypes were grouped according to breed types, hybrids generally had better responses than the inbred lines, and double haploids and the check responses were intermediate. These studies provided rapid results that will reduce the number of genotypes assessed in field studies.

No description available.

No description available.

<p>The content and utilization of carbohydrate during the yeast life cycle were studied with special reference to spore germination. The experiments were designed to investigate the nutritional requirements, the changes in the carbohydrate content and dry weight, the respiratory activities, the possible substitution of exogenous glucose by other carbon sources, the effect of temperature treatments, the uptake and distribution of exogenous glucose and the effect of inhibitors of carbohydrate metabolism on germination.</p> <p>The experiments showed the relative importance of endogenous and exogenous carbohydrates, the kind of respiratory activity and the fate of exogenous glucose carbon during germination. The pathway of carbon metabolism essential for germination was also indicated.</p> <p>The present work is the first attempt to compare qualitatively and quantitatively the carbohydrate content of yeast during the three major· phases of life cycle, viz., growth, sporulation and germination. Quantitative data on uptake and distribution of exogenous glucose during germination of yeast ascospores are provided. From an analysis of the results an attempt is made to assess the role, of carbohydrate in the germination of yeast ascospores.</p> / Doctor of Philosophy (PhD)

Studies on the activity of femlic, gallic, and vanillic acids on germination and growth of corn (Zea mays L.), radish (Raphanus sativus L.), and peanut (Arachis hypogaea L.) showed that the inhibitory effects of these acids were concentration and growth variable dependent. Ten days after treatment, significant reduction in percent germination of the three species occurred with higher phenolic acid treatments, except that gallic acid did not significantly inhibit peanut germination. Among the growth parameters investigated, root elongation and dry weight were more affected than either germination or shoot length and dry weight. Radish and corn were more sensitive than peanut. In two-combination experiments, the interactive effects of phenolic acids on corn germination and shoot growth were generally not significant, indicating an additive effect. Femlic acid, generally, antagonized higher concentrations of vanillic or gallic acids on corn root length and dry weight, suggesting a differential uptake of phenolic acids by corn roots or a limited uptake of gallic and vanillic acids in the presence of ferulic acid. In a soil system, higher and repeated phenolic acid treatments were required to bring about inhibition of corn growth than those which were effective in petri dishes. All levels of the synthetic auxin, 2,4-D (2,4-dichlorophenoxyacetic acid) were effective in reversing the inhibitory effects of 1 mM ferulic acid on corn root length when these two acids were applied in combination. No 2,4-D treatment counteracted 10 mM of ferulic acid. All levels of 2,4-D combined with 1 mM ferulic acid and the mixture of 0.1 nM 2,4-D with 10 mM ferulic acid were antagonistic for corn shoot length. No significant interactions were obtained on corn germination or seedling growth when 2,4-D was combined with gallic acid. Using manometric techniques, no inhibitory effects of ferulic or gallic acids observed on 02 consumption of germinating corn seeds. Ferulic acid did not interfere with water uptake of corn seeds during imbibition and germination. These findings indicate that the phytotoxicity of these acids observed on corn germination and seedling growth are not due to their interference with water uptake and respiratory activity of germinating seeds. / Ph. D.