Dependence of Dioscorea Tuber Growth Rate on Water Content of an Andept Soil

1980 ◽  
Vol 44 (6) ◽  
pp. 1298-1302 ◽  
Author(s):  
Ray F. Dawson ◽  
Jeffrey E. Shrum ◽  
Robert A. Mohammed
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Tuber Growth

Water Stressed Nodal Roots of Wheat: Effects on Leaf Growth

1997 ◽  
Vol 24 (1) ◽  
pp. 49 ◽  
Author(s):  
K. M. Volkmar
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Growth ◽  
Seminal Root ◽  
Nodal Roots ◽  
Nodal Root ◽  
Relative Water ◽  
Seminal Roots ◽  
Leaf Relative Water Content

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.

Growth and Productivity of Tapioca (Manihot utilissima) IV. Devlopment and Yield of Tubers

1974 ◽  
Vol 10 (1) ◽  
pp. 9-16 ◽  
Author(s):  
C. N. Williams
Keyword(s):  
Growth Rate ◽  
Root Length ◽  
Stem Growth ◽  
Tuber Number ◽  
High Yield ◽  
Tuber Growth ◽  
Tuber Weight ◽  
Storage Tissue ◽  
Slowing Down ◽  
Tissue Cells

SUMMARYRoot measurements on three Malayan varieties of tapioca (high, medium and low-yielding clones) showed that the onset of tuberization brings about a slowing-down or cessation of growth in root length, but no changes in stem growth rate were associated with the onset of tuber growth. High yield was associated with high tuber weight rather than with tuber number, which could be related to the size of storage tissue cells formed by the root cambium. The process of tuberization in tapioca is discussed generally.

Experimental time constraints on the kinetic and chemistry of amphibole at deep crustal levels

2020 ◽  
Author(s):  
Barbara Bonechi ◽  
Cristina Perinelli ◽  
Mario Gaeta ◽  
Vanni Tecchiato ◽  
Alessandro Fabbrizio
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Growth Rates ◽  
Dwell Time ◽  
Current Knowledge ◽  
Campi Flegrei ◽  
Crystallization Time ◽  
Alkaline Basalt ◽  
Experimental Time ◽  
Lower Crustal

<p>Aiming to improve the current knowledge about amphibole growth kinetics at deep crustal levels, new amphibole growth rate data are provided. Our findings, indeed, may be useful to correctly interpret the textural features of amphibole-bearing mafic cumulates and rocks, and for a better constraining of the timescales of magmatic processes at upper mantle-lower crustal depths. Experiments were performed to determine the amphibole growth rates in a primitive alkaline basalt from Procida island (Campi Flegrei Volcanic District, southern Italy) at the following conditions: temperature of 1030 and 1080 °C, pressure of 0.8 GPa, water content in the range 3.3-4.2 wt%, and variable dwell time from 0.25 to 9 h. Amphibole growth rates range from 1.5·10<sup>-7</sup> to 2.9·10<sup>-8</sup> cm·s<sup>-1 </sup>with increasing the duration of the experiments. It is observed that, keeping a constant dwell time, an increase of the experimental temperature or of the water content results in comparable growth rate increase. Coexisting synthetic amphibole and clinopyroxene show a faster growth rates in favour of amphibole regardless of the dwell time, since the chemical and structural similarities of these minerals cause kinetic competition. Moreover, the chemical composition of amphibole is influenced mainly by the experimental time; in detail, in the shortest (≤3 h) and low temperature runs edenite is the prevailing composition whereas the magnesiohastingsitic term becomes dominant at higher temperature and longer run duration. Based on the interpretation of the Fe-Mg exchange coefficient values between amphibole and coexisting liquid, the magnesiohastingsitic amphibole is considered to be the stable term at the investigated run conditions. Finally, the resulting growth rates have been applied to constrain the crystallization time of natural amphiboles and clinopyroxenes from the Oligo-Miocene cumulates of north-western Sardinia (i.e., Capo Marargiu  Volcanic District, Italy), yielding crystallization times in the range 1.46-3.12 yr.</p>

Studies on Schistocephalus solidus

Parasitology ◽  
1965 ◽  
Vol 55 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Morag L. O. McCaig ◽  
C. Adrian Hopkins
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Gasterosteus Aculeatus ◽  
Technical Assistance ◽  
Horse Serum ◽  
Electron Microscopic Examination ◽  
Dry Weight ◽  
Electron Microscopic ◽  
Schistocephalus Solidus

Schistocephalus plerocercoids in the weight range 2–200mg F.W. recovered from the perivisceral cavity of Gasterosteus aculeatus were cultured in various media. In a medium composed of 25% horse serum, 0·5% yeast extract, 0·65% glucose and Hanks's saline at pH 7·1, 21°C, 95% air +5% CO2, dry weight increases of up to 500% were recorded in 8 days. The specific growth rate of large plerocercoids was only one-tenth of the rate observed in small plerocercoids. A plerocercoid of double the weight of another had approximately half the specific growth rate.Worms after 8 days cultivation were found to have only slightly higher than normal glycogen and water content, and to be able to mature when heated to 40°C. However, the rate of growth slowed to zero by the 24th day in culture at 21°C. Electron microscopic examination showed a ‘deposit’ formed over the microvilli, thin at 8 days but dense after 21 days.The in vivo glycogen and water content of plerocercoids from 3–300 mg F.W. was determined. Glycogen rose from 24% in plerocercoids of 10mg F. W. to 50–55% in plerocercoids over 80mg F. W. The water content was found to mimic precisely this change, falling from 82% to a plateau of 67–69%.We wish to thank Professor Gareth Owen for permission to use the photograph shown in the Plate and for his help while using the electron microscope. It is also a pleasure to thank Miss Patricia Grant for her technical assistance.

scholarly journals Effect of Transplanting Dates and Plant Population on Growth Parameters of Potato (Solanum Tuberosum L.) Raised from True Potato Seed (Tps)

2014 ◽  
Vol 47 (1) ◽  
pp. 97-106
Author(s):  
D. Sen ◽  
A. Rakshit ◽  
D.C. Ghosh
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Solanum Tuberosum L ◽  
Plant Population ◽  
Potato Seed ◽  
True Potato Seed ◽  
Dry Matter Accumulation ◽  
Tuber Growth ◽  
Area Index ◽  
Tuber Bulking

ABSTRACT A field experiment was conducted during the rabi season of 2007- 2008 and 2008-2009 at Paschim Medinipore, West Bengal to study the effect of transplanting dates and plant population on growth parameters of potato raised from TPS. Dry matter accumulation per plant was more in early transplanted (December 3) and sparsely populated (60 cm x 15 cm) crop. The highest leaf area index was observed in early transplanted crop with closer spacing (40 cm x 10 cm) at 60 days after transplanting. The highest crop growth rate, tuber bulking rate and tuber growth rate values were also recorded in early and closely transplanted TPS crop between 45- 60 days after transplanting during both the years under investigation

Small Scale Sour Fatigue Testing With Dense Phase Gases

2012 ◽  
Author(s):  
Weiwei Yu ◽  
Pedro M. Vargas ◽  
Ben Crowder ◽  
Sam Mishael ◽  
Ramgopal Thodla
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
Water Content ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Performance ◽  
Small Scale ◽  
Dense Phase ◽  
High Crack ◽  
Crack Growth Rates

One way generally accepted by industry to evaluate the effect of sour environment on fatigue performance of girth welds is by small scale testing in sour brines. These tests are commonly done at room temperature and pressure and therefore can only contain a maximum of 14.7psia of H2S in a gaseous phase. In comparison, very little has been published about fatigue performance in sour environments where negligible amounts or no water is present. Such condition can be found for pipelines serving in a “dry” sour environment (H2S and other gases in dense phase) with high H2S concentration. This paper documents both small scale fatigue crack growth rate (FCGR) tests and S-N fatigue tests in a dense phase sour environment with ultra-low water content and high H2S concentration under high pressure. Fatigue life reduction factors were calculated from FCGR approach (with the name crack growth acceleration factor, CGAF) and S-N approach (with the name knockdown factor), respectively. Industry understanding today is that water is necessary for accelerating fatigue crack growth. Quite opposite to the expected effect of water content on crack growth, even ultra-low water content (<450ppm) resulted in high crack growth rates. Crack growth rates were comparable among tests with various water contents, all ultra low. Through limited testing, no temperature dependency on crack growth rate was identified. It is postulated that hydrogen dissociation due to high pressure and high concentration may be the cause for high crack growth rates on the absence of water. Small scale S-N tests on smooth specimens reveal that fatigue performance in ultra-low-water sour environments is the same as in air. We find that the dry gas environment dose not attack the metal surface preserving the fatigue performance.

scholarly journals COMPARISON OF GROWTH AND TUBER DEVELOPMENT IN THREE POTATO CULTIVARS WITH DIVERSE CANOPY SIZE

1977 ◽  
Vol 57 (3) ◽  
pp. 797-801 ◽  
Author(s):  
W. B. COLLINS
Keyword(s):  
Growth Rate ◽  
Potato Breeding ◽  
Dry Weight ◽  
Net Assimilation Rate ◽  
Tuber Growth ◽  
Assimilation Rate ◽  
Tuber Development ◽  
Final Yield ◽  
Net Assimilation ◽  
Canopy Size

The basis of differences in tuber and plant development in potato, due to differences in canopy size, was studied by measuring changes in plant dry weight and leaf area throughout the growing season. Differing canopy sizes were obtained by selecting three cultivars from the Canada Potato Breeding Program. These were F57048, Grand Falls, and F62008, which normally produce small, medium and large sized canopies respectively, with similar tuber yields. Differences in total and tuber dry weight through the season were slight compared to differences observed in leaf and stem growth. The branching capacity of the cultivars appeared to be the major determinant of canopy size. In these three cultivars, as canopy size increased, the initial tuber growth rate immediately following tuberization decreased. Thus, in the two smaller cultivars, the early tuber growth rate was more critical in determining final yield than was the case in the large-canopied cultivar, F62008. As expected, the net assimilation rate increased as canopy size decreased. The evidence indicated that the demands of the developing tubers exerted the greatest influence on the net assimilation rate.

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