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Root-boring insects in Gutierrezia sarothraeFalkenhagen, Thomas Jay, 1952- January 1978 (has links)
No description available.
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Root responses of crested wheatgrass to nitrogen and phosphorus fertilizationKoltz, Bruce George, 1943- January 1967 (has links)
No description available.
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Root decline of sodded, seeded and mature bentgrass turf as affected by nitrogen and temperatureEckhardt, James Henderson, 1944- January 1975 (has links)
No description available.
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Aspects of the role of cytokinins in adventitious root formation.Taylor, Joslyn Leanda Susan. 14 January 2014 (has links)
The initiation and development of adventitious roots in cuttings are highly
complex processes, influenced by both endogenous and exogenous factors.
These vary from the environmental factors prior to the striking of the cutting,
to the anatomical and physiological factors, within the stem. Encompassed are
the nutrient status, physiological age and degree of differentiation of the
tissues, and the balance of endogenous rooting inhibitors and/or promoters
(including hormones).
The role of cytokinins in root initiation and development has been perceived
as that of an inhibitor. This investigation considered several aspects of the
role played by cytokinins in the process of root development.
A qualitative/quantitative analysis of the cytokinin-like activity in stem
cuttings of several plants, including both easy- and difficult-to-root species
was conducted on a comparative basis. There was no clear correlation
between the type / level of cytokinins detected in the cuttings and the relative
ease of root formation. Both qualitative and quantitative changes in the
compounds exhibiting activity in the soybean callus bioassay were observed
over the period of root formation in Impatiens stem cuttings.
The effects on root formation in cuttings of exogenously applied auxins and
cytokinins were investigated. Auxins generally promoted root number and
elongation at relatively high concentrations (10[-4] M), but showed less effect
on lateral root initiation and development. At high concentrations, cytokinins
strongly inhibited root development, but did promote lateral root growth. In
suspension culture, the effect of these hormones differed slightly, with IAA
and IBA having no significant effect on root development, but NAA strongly
stimulating lateral root initiation. Zeatin (10¯¹¹ M) significantly increased root
length and the number of lateral roots produced. The effect of treatment of the stem cuttings with potassium permanganate
and centrifugation was examined. While both these treatments have been
perceived to increase root production in cuttings, no significant improvement
in rooting ability following centrifugation (relative to the control) was
observed. Impatiens cuttings centrifuged in the presence of distilled water
showed a significantly reduced rooting ability relative to those centrifuged in
the dry state. Treatment with an 8-hour pulse in 0.05 % potassium
permanganate significantly increased the average root length.
These treatments had an effect on the cytokinin levels and distribution in the
stem cuttings. Slightly higher levels of cytokinins were associated with the
increase in root number and length in both experiments. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.
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Tryptophan synthetase in pea seedlings and some effects of tryptophan on excised root culturesChen, James Chang-Yau. January 1967 (has links)
No description available.
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The regulation of root development by aluminium in Zea mays L.Bennett, Robin John. January 1986 (has links)
This investigation confirmed that plant reaction to Al was
directed through the disruption of intercellular co-ordination existing
between the cell populations comprising the root meristem.
The first detectable response to A1 in the root involved
disruption of Golgi apparatus function in the cap periphery.
Ultrastructural changes in the cap periphery coincided with the presence
of A1 in these cells. Conspicuous physiological changes involving cell
enlargement, cell metabolism and root elongation were identified in cells
initially remote from the site(s) of A1 uptake. Communication between
A1-damaged peripheral root cap cells and the cell populations of the cap
and proximal meristems, quiescent centre and region of cell growth
was therefore indicated. A decrease in amyloplast numbers in response
to increasing AI concentration coincided with diminished Golgi apparatus
activity in the peripheral cap. These changes preceded detectable
reductions in mitotic activity, indicated by decreases in cap volume and
root length, and it was consequently suggested that control of intercellular
activities in the root meristem may be directed through
polysaccharide metabolism.
Low concentrations of A1 (≤ 1,25 mg dm ¯³) produced a positive
growth response in the primary root. This coincided with an increase in
mean cap volume and these events were interpreted as an A1-induced
release of the proximal meristem from growth inhibition originating in
the cap. Experiments which followed the effect of decapping on the
morphology of quiescent centre cells in the presence and absence of A1
supported the existence of a Golgi apparatus-derived morphogen involved
in the control of Golgi apparatus secretory activity and plastid
differentiation. In contrast to the controls (0 ABA). treatment of
decapped roots with 2 X 10[-4] and 5 X 10[-5] M abscisic acid inhibited the
development of Golgi apparatus secretory activity and plastid
differentiation. It is postulated therefore, that an early response to
AI may involve inhibition of the basipetal movement of an endogenous
growth inhibitor originating in the cap, which may be ABA. The presence of A1 in the nutrient solution caused an efflux of
H[+] from the root. Some of the more adverse plant responses to AI were
initiated at A1 concentrations where the molar ratio of charge between
Ca[2+] and A1[3+] favoured A1. An hypothesis for an electrophysiological
plant response to A1 involving membrane hyperpolarisation by Al ions is
developed.
Chemical analysis of plant fractions did not connect
A1-induced nutrient disorders with the primary expression of A1 toxicity. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.
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Towards an operational root disease mapping methodology through lidar integrated imaging spectroscopyQuinn, Geoffrey 17 October 2011 (has links)
Root disease is a serious concern for the softwood timber industry. This thesis reports
on the development of a root disease detection procedure that applies lidar data integrated
with imaging spectrometer data. Photosynthetic pigments are frequently cited as one of
the most responsive indicators of vegetation stress. This study estimated pigment content
from needle and canopy reflectance and characterized the sensitivity of these pigments to
a fungal-mediated stress. Samples were collected from the Greater Victoria Watershed
District on Vancouver Island, BC, Canada. Lab reflectance measurements were made and
pigments were extracted. Reflectance spectra were transformed into derivative spectra
and a continuum removal band depth analysis was conducted. Reflectance metrics were
generated and used in modeling pigment content. Chlorophyll-a was found to be
significantly affected by the disease in the needle level portion of this study. The
predictive power of reflectance attributes were assessed and yielded strong coefficients of
determination (R2>0.80). Samples exhibiting stress responses affected by root disease
were discriminated. It was determined that younger trees were more severely affected by
the root pathogen than mature colonized trees. In the canopy level component of the
study, chlorophyll-a was estimated through the application of partial least squares
regression and achieved an R2 value of 0.82. Continuum removal metrics, which proved
to be good estimators at the needle level, were found to be insufficient at the canopy
level. Through the use of hyperspectral forest chemistry products, potential root disease
sites can be identified. / Graduate
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Effects of compression of some subtropical soils on the soil properties and upon root developmentTrouse, Albert Charles January 1964 (has links)
Photocopy (positive) of typescript. / Thesis (Ph. D.)--University of Hawaii, 1964. / Bibliography: leaves 158-161. / xi, 171 l illus., tables
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Root growth and phosphorus uptake in relation to soil structure and strength /Misra, Rabindra Kumar. January 1986 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept of Soil Science, 1987. / Includes bibliographical references (leaves 207-222).
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Soil mechanical properties and the behaviour of roots in structured soil : published works /Dexter, Anthony Roger. January 1988 (has links) (PDF)
Thesis (D. Sc.)--University of Adelaide, 1988. / Comprised of the author's previously published works. Includes bibliographical references.
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