Thesis (Ph. D.)--University of Chicago, 1916. / "A Private Edition Distributed by the University of Chicago Libraries." "Reprinted from the Botanical gazette, Vol. LXII, No. 6." "Literature cited": p. 505-506. Also available on the Internet. Also issued online.

There are several limitations to the use of the 'direct' method for studying root systems in their natural habitats. Newer techniques are needed in understanding many characteristics of roots, which are still obscure. The growing of orchardgrass, colonial bentgrass and red clover in special containers, demonstrated a technique for optical study of root systems, and illustrated an apparent localization of individual plant roots in dense stands. Field tests on square foot plots of orchardgrass and Kentucky bluegrass with placements of a dye, acid fuchsin, at various depths, failed to replicate the preliminary laboratory findings, that the absorption by roots of this material not only stained the roots red, but was soon evident in the aerial portions. Plant injections and soil placement of the fluorescent compounds, eosin, fluorescein and esculin failed to produce fluorescence in plants growing in special containers. The strategic placements of small quantities of radioactive phosphorus (P³²) at various depths in plots of orchard grass, red fescue, Kentucky bluegrass and colonial bentgrass on Alderwood loamy sand, enabled the depth of root penetration to be assessed by measuring radioactivity in the leaves with a Geiger-Muller counter. The movement of P³² in the soil was studied on the profiles of similar plots kept bare of vegetation, and on which similar placements were made. A modified technique resulted in the localization of the radioactive phosphorus in the soil. Plants in established plots of orchardgrass, red fescue, Kentucky bluegrass and colonial bentgrass were injected with P³² near the crown. The movement to the roots was found to be very slow when radioactivity was checked in the roots from the profiles. In a four week old alfalfa clone, injected three weeks earlier, P³² was recorded to have reached the maximum depth attained by visible roots. This was not the case with the grasses. The absorption of lithium from lithium chloride placed at various depths in rows of orchardgrass and alfalfa was determined by photometric analysis of samples from aerial portions. The extent of the root penetration was determined by the relatively higher concentrations of lithium in plants located above these placements. / Land and Food Systems, Faculty of / Graduate

Roots smaller than 5 mm in diameter were studied in three typical high elevation forested plant associations of coastal Southwestern British Columbia. The objectives were to quantify their distribution with depth, examining changes with plant association and time; to examine their relationships with foliage; and to seek correlations with soil properties. Coring randomly in three replicates of each plant association was followed by washing of soil and organic matter from roots with water in combination with manual sorting. Length and surface area were estimated for all samples. Standard analytical methods were used for determining soil physical and chemical properties. Soil temperature and moisture were measured during the growing season. The peak in mass of both overstory and understory < 2 mm roots was within the upper 10 cm of the soil. Overstory 2-5 mm roots peaked between 5 and 30 cm. Understory 2-5 mm roots peaked within 10 cm of the surface of the forest floor. The large variation between replicates of the plant associations made it impossible to determine if changes in root mass with time of sampling were real or due to random variation. Unsuberized roots of the overstory vegetation contributed very little to biomass of ≤ 5 mm roots. Biomass of ≤ 5 mm roots of the overstory vegetation varied from 740 to 1320 g m⁻², length from 3.8 to 6.5 km m⁻², and surface area from 7.3 to 11.9 m² m⁻². The ridgetop association had the most overstory and understory roots and its soil (including organic horizons) was lowest in total nitrogen concentration and CEC. The midslope association had intermediate amounts of overstory roots, the lowest amount of understory roots, and its soil was intermediate in nitrogen concentration and CEC. The receiving association had the lowest amounts of overstory roots, intermediate amounts of understory roots, and its soil had the highest nitrogen concentration and CEC. The ridgetop ecosystems had the highest ratio of root-to-shoot and ratio of root-to-foliage plus twig, being approximately double the ratio for the receiving association. The midslope association was intermediate. Correlations of root mass with soil properties were generally poor. / Forestry, Faculty of / Graduate

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 137-153).

Call number: LD2668 .T4 1946 H33 / Master of Science

No description available.

Thesis (MSc)--Stellenbosch University. / VOORWOORD: Die skrywer wens daarop te wys dat in sover dit die wynstok aangaan, hierdie werk wat Suid-Afrika betref, van 'n aanvoor-geaardheid is. Ook in verband met die wortelverspreidings van bladwisselende vrugtebome is daar, sover bekend, in hierdie land nog geen wetenskaplike werk gepubliseer nie. Direkte leiding in verband met hierdie studie was dus tot 'n groot mate onverkrygbaar. Daar dien ten slotte daarop gewys te word, dat hierdie studie op 'n beperkte hoeveelheid geskikte onderstokke uitgevoer is, en dat wingerde nie vooraf vir die doel aangelê kon word nie. By 'n studie van hierdie aard sou die voltydse samewerking van 'n grondskeikundige ook 'n aanbeveling gewees het.

Adventitious root formation can be inhibited in stem cuttings of Pisum sativum L. (pea), an easy-to-root species, if the apical and lateral buds are removed. Application of exogenous auxin to the apical stump can replace the rooting stimulus produced by the buds. Root number was reduced by 50 to 100% in the decapitated and disbudded cuttings supplied with an apical source of auxin if photosynthesis was inhibited by 50 to 100% by any of several treatments. The extent to which rooting was reduced was roughly proportional to the extent to which photosynthesis was reduced. Basipetal transport of radioactivity from apically applied ¹⁴C-IAA, as well as basal carbohydrate content, was also consistently reduced under conditions where photosynthesis was inhibited. It appears the reduction in rooting due to a reduction in photosynthesis must take at least two factors into consideration, the transport of auxin from the apex to the base of the cutting and the basal carbohydrate content. The environmental conditions during the stock plant growth are important to the rooting of cuttings. In the present investigation, when pea and Rhododendron stock plants were subjected to low light or to a period of darkness, the rooting of cuttings taken from these plants was significantly promoted. For pea, the promotive effect of darkness was significantly greater when the entire plant was placed in the dark compared to a localized darkening of the stem segment from which roots emerge after excision. The timing of the light and dark periods during stock plant growth also greatly influenced rooting, the greatest promotion was observed when the dark period was given immediately after emergence of the stock plant. This suggests that the root promoting effect of darkness can be destroyed by a brief period of light early in the development of the stock plant. The basal carbohydrate concentration during the first week of rooting was similar in cuttings taken from stock plants receiving light throughout the growth period and those receiving a dark period of 4 days, regardless of whether the dark period was given immediately after emergence or after an exposure to light. This suggests carbohydrates do not play a major role in the promotion of rooting due to a dark treatment on the stock plant. / Graduation date: 1985

Dissertation submitted for the qualification Master of Science in Chemistry (full time) University of Witwatersrand November 2015 / Irones are the pleasantly smelling terpenoids of orris oil used in the fragrance industry that are extracted from the rhizomes of Iris species through a lengthy process. Unfortunately syntheses of irones using chemical methods or Iris rhizome-derived sources have been reported to be long, unsafe and low yielding. These inefficient methods have therefore resulted in a high cost of the orris absolute (an alcohol extract of orris butter) which costs between 40 000 and 70 000 Euros/kg. A promising enzymatic process for irones production with good conversion of the precursors has been reported. However, the processing of the irone source into iridals (irone precursors) requires high temperatures and as a result the safety as well as energy input of the method is affected. Moreover, the prior solvent extraction was reported to affect the quality of the product. The present research aimed to develop a rapid and effective enzymatic process for the production of α- and γ-irones at 2L scale-up, as well as obtaining the final product in the form of orris butter. During the current studies a method for analysis of the irones samples was developed, and subsequently different solvents were investigated to identify the best sampling method. Thereafter different oxidoreductases were screened to identify the best enzyme source for maximum production of irones. Optimization of temperature, loading of lipoxidase, orris root, oleic acid, and dioxane, the ratio of minerals to irone concentration, incubation period and use of anti-fungal agents were investigated for maximum irones production. Furthermore, different methods to concentrate the irones and to produce the final orris butter product were evaluated. Lastly, testing the effect of purifying the enzyme on the production of irones was investigated. At laboratory scale the optimum reaction conditions were found to consist of incubating 5 g of fresh homogenised orris root with 20 mL crude soybean lipoxidase (prepared as 1 g soybean flour in 25 mL of 0.01 M borate buffer pH 9.2), with 50 mg manganese chloride and 25 mg ferrous sulphate, 1 mL dioxane and 0.25 mL oleic acid, for 5 days at 37°C in a rotatory shaker incubator. The laboratory scale product could be recovered by using a mixture of equal proportions of acetone and-DMSO for sampling under stringent sterile conditions. At the 700 mL and 2L scale it was determined that with improved agitation and oxygenation of the reaction mixture and subjecting the maturated suspension to Likens-Nickerson distillation resulted in the required orris butter profile. It was further found that purification of the enzyme reduced its ability to efficiently convert the precursors in fresh orris root into irones. Alpha (α-) and gamma (γ-) irones) of the same retention times (3.79 and 3.82) and mass (207 Da) as the α-irone commercial sample were produced at yields around 696 mg irone/kg dry orris root compared with 530 mg irone/kg dry orris root seen with traditionally processed rhizome. The current research is the first to use crude soybean lipoxidase to oxidize macerated fresh orris root into irones, and the first to identify the importance of minerals in the bioconversion.

Typescript (photocopy) / xii, 160 leaves, 11 leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.) Dept. of Soil Science, University of Adelaide, 1982