The Effect of Soil Nutrients on the Production of Proteoid Roots by Hakea Species

1972 ◽  
Vol 20 (1) ◽  
pp. 27 ◽  
Author(s):  
B Lamont
Keyword(s):  
Root Growth ◽  
Response Curve ◽  
Nitrogen Availability ◽  
Root Production ◽  
Proteoid Roots ◽  
Relative Contribution ◽  
Root Response ◽  
Proteoid Root ◽  
Two Phases ◽  
The Relationship

The mode of the proteoid root response curve occurs at a considerably lower level of nitrogen or phosphorus than that of the response curve for non-proteoid roots. As a consequence, the relationship between proteoid and non-proteoid roots can be regarded as passing through four phases as nutrient availability increases: (a) an increase in proteoid root production as non-proteoid root growth increases; (b) a decrease in proteoid root production as non-proteoid root growth increases; (c) a decrease in proteoid root production as non-proteoid root growth decreases; (d) an absence of proteoid roots as non-proteoid root growth decreases. Only the first two phases are considered relevant to plants growing under field conditions. It is concluded that nutrient concentration in a number of soils, especially nitrogen availability, largely determines the relative contribution of proteoid roots to the root systems of two species of Hakea.

The morphology and anatomy of proteoid roots in the genus Hakea

1972 ◽  
Vol 20 (2) ◽  
pp. 155 ◽  
Author(s):  
B Lamont
Keyword(s):  
Special Reference ◽  
Root System ◽  
Plant Age ◽  
Proteoid Roots ◽  
Relative Contribution ◽  
Endophytic Microorganisms ◽  
As Species ◽  
The Family ◽  
Proteoid Root

This paper extends the introductory work of Purnell(1960) on proteoid roots in the family Proteaceae by a detailed study of the genus Hakea, with special reference to H. prostrata. The presence of proteoid roots is reported in 63 Hakea species. Their relative contribution to the root system is related to such plant factors as species, age, and cotyledon size. The dimensions of proteoid roots are dependent on plant age and species. The morphology and anatomy of these structures are described. Endophytic microorganisms are not normally associated with proteoid roots. Proteoid rootlets survive 2-3 months, though their parent roots last indefinitely. Proteoid roots are produced by the youngest roots in the root system. While proteoid rootlets arise laterally, the parent root may arise either laterally or adventitiously. Both proteoid and non-proteoid roots may be initiated within a proteoid root.

Introduction

2018 ◽  
Author(s):  
Chris Jones
Keyword(s):  
Nineteenth Century ◽  
Old English ◽  
English Studies ◽  
Anglo Saxon ◽  
Political Events ◽  
Two Phases ◽  
Scholarly Contribution ◽  
Anglophone World ◽  
The Relationship

This introductory chapter contextualizes the philological study of language during the nineteenth century as a branch of the evolutionary sciences. It sketches in outline the two phases of poetic Anglo-Saxonism for which the rest of the book will subsequently argue in more detail. Moreover, the relationship between Anglo-Saxonism and nineteenth-century medievalism more generally is articulated, and historical analogies are drawn between nineteenth-century Anglo-Saxonism and more recent political events in the Anglophone world. Finally, the scholarly contribution of Fossil Poetry itself is contextualized within English Studies; it is argued that ‘reception’ is one of the primary objects of Anglo-Saxon or Old English studies, and not merely a secondary object of that field’s study.

scholarly journals Strategic resources and smallholder performance at the bottom of the pyramid

2019 ◽  
Vol 22 (3) ◽  
pp. 365-380 ◽  
Author(s):  
Matthias Olthaar ◽  
Wilfred Dolfsma ◽  
Clemens Lutz ◽  
Florian Noseleit
Keyword(s):  
Large Scale ◽  
Business Environment ◽  
Agricultural Economics ◽  
Local Market ◽  
Bottom Of The Pyramid ◽  
Fine Grained ◽  
Strategic Resources ◽  
Relative Contribution ◽  
The Relationship ◽  
Resource Based Theory

In a competitive business environment at the Bottom of the Pyramid smallholders supplying global value chains may be thought to be at the whims of downstream large-scale players and local market forces, leaving no room for strategic entrepreneurial behavior. In such a context we test the relationship between the use of strategic resources and firm performance. We adopt the Resource Based Theory and show that seemingly homogenous smallholders deploy resources differently and, consequently, some do outperform others. We argue that the ‘resource-based theory’ results in a more fine-grained understanding of smallholder performance than approaches generally applied in agricultural economics. We develop a mixed-method approach that allows one to pinpoint relevant, industry-specific resources, and allows for empirical identification of the relative contribution of each resource to competitive advantage. The results show that proper use of quality labor, storage facilities, time of selling, and availability of animals are key capabilities.

scholarly journals Adaptation Mechanism of Roots to Low and High Nitrogen Revealed by Proteomic Analysis

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wei Xin ◽  
Lina Zhang ◽  
Jiping Gao ◽  
Wenzhong Zhang ◽  
Jun Yi ◽  
...  
Keyword(s):  
Root Growth ◽  
Nitrogen Use Efficiency ◽  
Root Morphology ◽  
Nitrogen Availability ◽  
Rice Root ◽  
Global Changes ◽  
High Nitrogen ◽  
Nitrogen Use ◽  
Rice Roots ◽  
Use Efficiency

Abstract Background Nitrogen-based nutrients are the main factors affecting rice growth and development. Root systems play an important role in helping plants to obtain nutrients from the soil. Root morphology and physiology are often closely related to above-ground plant organs performance. Therefore, it is important to understand the regulatory effects of nitrogen (N) on rice root growth to improve nitrogen use efficiency. Results In this study, changes in the rice root traits under low N (13.33 ppm), normal N (40 ppm) and high N (120 ppm) conditions were performed through root morphology analysis. These results show that, compared with normal N conditions, root growth is promoted under low N conditions, and inhibited under high N conditions. To understand the molecular mechanism underlying the rice root response to low and high N conditions, comparative proteomics analysis was performed using a tandem mass tag (TMT)-based approach, and differentially abundant proteins (DAPs) were further characterized. Compared with normal N conditions, a total of 291 and 211 DAPs were identified under low and high N conditions, respectively. The abundance of proteins involved in cell differentiation, cell wall modification, phenylpropanoid biosynthesis, and protein synthesis was differentially altered, which was an important reason for changes in root morphology. Furthermore, although both low and high N can cause nitrogen stress, rice roots revealed obvious differences in adaptation to low and high N. Conclusions These results provide insights into global changes in the response of rice roots to nitrogen availability and may facilitate the development of rice cultivars with high nitrogen use efficiency through root-based genetic improvements.

Annealing effect on the optical and photoelectrochemical properties of lead oxide

2018 ◽  
Vol 84 (3) ◽  
pp. 30301 ◽  
Author(s):  
Wided Zerguine ◽  
Djamila Abdi ◽  
Farid Habelhames ◽  
Meriem Lakhdari ◽  
Hassina Derbal-Habak ◽  
...  
Keyword(s):  
Lead Oxide ◽  
Orthorhombic Phase ◽  
Heat Treatments ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Size And Morphology ◽  
Two Phases ◽  
P Type ◽  
The Relationship

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

scholarly journals Soil Nutrient and Vegetation Diversity Patterns of Alpine Wetlands on the Qinghai-Tibetan Plateau

2021 ◽  
Vol 13 (11) ◽  
pp. 6221
Author(s):  
Muyuan Ma ◽  
Yaojun Zhu ◽  
Yuanyun Wei ◽  
Nana Zhao
Keyword(s):  
Species Diversity ◽  
Tibetan Plateau ◽  
Soil Properties ◽  
Soil Ph ◽  
Plant Biomass ◽  
Principal Component ◽  
Vegetation Diversity ◽  
Vegetation Biomass ◽  
Relative Contribution ◽  
The Relationship

To predict the consequences of environmental change on the biodiversity of alpine wetlands, it is necessary to understand the relationship between soil properties and vegetation biodiversity. In this study, we investigated spatial patterns of aboveground vegetation biomass, cover, species diversity, and their relationships with soil properties in the alpine wetlands of the Gannan Tibetan Autonomous Prefecture of on the Qinghai-Tibetan Plateau, China. Furthermore, the relative contribution of soil properties to vegetation biomass, cover, and species diversity were compared using principal component analysis and multiple regression analysis. Generally, the relationship between plant biomass, coverage, diversity, and soil nutrients was linear or unimodal. Soil pH, bulk density and organic carbon were also significantly correlated to plant diversity. The soil attributes differed in their relative contribution to changes in plant productivity and diversity. pH had the highest contribution to vegetation biomass and species richness, while total nitrogen was the highest contributor to vegetation cover and nitrogen–phosphorus ratio (N:P) was the highest contributor to diversity. Both vegetation productivity and diversity were closely related to soil properties, and soil pH and the N:P ratio play particularly important roles in wetland vegetation biomass, cover, and diversity.

Incidental specialised vocabulary acquisition: a case of incidental medical terms acquisition from students’ perspective

2021 ◽  
Author(s):  
Elham Abdullah Ghobain ◽  
Keyword(s):  
Negative Relationship ◽  
Extended Period ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Medical Terms ◽  
Significant Negative Relationship ◽  
Post Test ◽  
Two Phases ◽  
The Relationship ◽  
Technical Terms

This study observes a particular group of students learning medical terms (MT) implicitly through studying medical subjects. That is, based on the policy followed in the context of the study, students shall not receive any deliberate terms instruction. This paper investigates their experiences and attitudes towards acquiring MT in such a situation. Students’ acquisition and proficiency, hypothesizing a positive relationship between the two constructs, are self-assessed through pre- and post-test surveys. The surveys included 114 and 95 students in each phase, respectively. Prior to the surveys, focus group discussions were conducted, according to which the questionnaire was developed. A statistical correlational Pearson test was done to examine the relationship between students’ proficiency and incidental terms acquisition. The results indicated a significant negative relationship between the two constructs tested. The study also tested the effect of time on increasing acquisition through conducting a paired independent t-test between the two sets of data. The results found that a more extended period was significant to incidental acquisition. Overall, through comparing the means, modes, and medians in the two phases (pre- and post-test), the findings reveal an increase in the students’ terms acquisition volume. However, students seem not to favour the approach and still advocate explicit instruction for technical terms.

Statistical characterization of the random errors in the radioimmunoassay dose--response variable.

1976 ◽  
Vol 22 (3) ◽  
pp. 350-358 ◽  
Author(s):  
D Rodbard ◽  
R H Lenox ◽  
H L Wray ◽  
D Ramseth
Keyword(s):  
Least Squares ◽  
Dose Response ◽  
Curve Fitting ◽  
Response Curve ◽  
Dose Response Curve ◽  
Random Errors ◽  
Statistical Characterization ◽  
Response Variable ◽  
Least Squares Curve Fitting ◽  
The Relationship

Abstract We have developed practical methods for evaluating the magnitude of the random errors in radioimmunoassay dose--response variables, and the relationship between this error and position on the dose--response curve. This is important: to obtain appropriate weights for each point on the dose--response curve when utilizing least-squares curve-fitting methods; to evaluate whether the standards and the unknowns are subject to error of the same magnitude; for quality-control purposes; and to study the sources of errors in radioimmunoassay. Both standards and unknowns in radioimmunoassays for cAMP and cGMP were analyzed in triplicate. The same mean (Y), sample standard deviation, sy, and variance (2-y) of the response variable were calculated for each dose level. The relationship between s 2-y and y was calculated utilizing several models. Results for standards and unknowns from several assays were pooled, and a curve smoothing procedure was used to minimize random sampling errors. This pooling increased the reliability of the analysis, and confirmed the presence of the theoretically predicted nonuniformity of variance. Thus, the calculation of results from these radioimmunoassays should utilize a weighted least-squares curve-fitting program. These analyses have been computerized, and can be used as a "pre-processor" for programs for routine analysis of results of radioimmunoassay.

Responses of two hybrid Populus clones to flooding, drought, and nitrogen availability. I. Morphology and growth

1992 ◽  
Vol 70 (11) ◽  
pp. 2265-2270 ◽  
Author(s):  
Zhijun Liu ◽  
Donald I. Dickmann
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Nitrogen Availability ◽  
Carbon Allocation ◽  
Hybrid Poplar ◽  
Leaf Expansion ◽  
Root Production ◽  
Leaf Initiation ◽  
Stem Biomass ◽  
Nitrogen Levels

Repeated progressive drought and flooding stress were imposed on hybrid poplar clones Populus × euramericana 'Eugenei', and Populus tristis × Populus balsamifera ‘Tristis’ grown in pots in a greenhouse under two nitrogen levels. In both clones the rate of leaf initiation was promoted only in high-N plants subjected to minimum water stress. Water stress alone did not retard the rate of leaf initiation, but it significantly reduced leaf expansion of 'Eugenei', whereas only flooding led to smaller leaves in 'Tristis'. The addition of N stimulated leaf expansion, leaf chlorophyll and N concentrations, and leaf and stem biomass production across soil moisture levels, but the greatest effect of N was associated with minimum water stress. High N altered carbon allocation towards the aboveground portions, leading to lower root to shoot ratios. High N also appeared to stimulate initiation of fine roots. Soil moisture determined the amount of biomass that accumulated in roots, with highest root production in well-watered pots and lowest in flooded pots, with the droughted treatment in between. Leaves became thinner as soil moisture decreased from flooding. Stem biomass of 'Tristis' declined more under flooding than under drought, whereas 'Eugenei' displayed a greater reduction of stem biomass in droughty than in flooded soil. Key words: water stress, nitrogen, leaf and root morphology, root to shoot ratio, biomass, Populus, flooding.

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