scholarly journals The Early Stages of Grain Development in Wheat: Response to Light and Temperature in a Single Variety

1970 ◽  
Vol 23 (4) ◽  
pp. 765 ◽  
Author(s):  
IF Wardlaw
Keyword(s):  
Cell Division ◽  
Growth Period ◽  
Dry Weight ◽  
Stem Growth ◽  
Grain Development ◽  
Endosperm Tissue ◽  
Final Number ◽  
Early Stages ◽  
Number Of Cells ◽  
Single Variety

For wheat plants (cv. Gabo) grown under natural daylight at a temperature of 21/16�C, increase in dry weight of the stem exceeded that of the ear for the first 10 days following anthesis. Higher temperatures (27/22�C) resulted in a greater rate of grain development, with a corresponding increase in the rate of cell division in the endosperm tissue, and a shortening of the stem growth period. Despite initial differences in the rates of cell division with variation in temperature, the final number of cells formed in an endosperm did not vary significantly between temperature treatments. Dry weight accumulation in the stem was, in contrast to the grain, highest at lower temperatures (15/10�C).

Nitrogen, Phosphorus and Water Contents During Grain Development and Maturation in Wheat

1977 ◽  
Vol 4 (5) ◽  
pp. 799 ◽  
Author(s):  
I Sofield ◽  
IF Wardlaw ◽  
LT Evans ◽  
SY Zee
Keyword(s):  
Grain Growth ◽  
Dry Matter ◽  
Nitrogen Concentration ◽  
Growth Period ◽  
Calcium Content ◽  
Dry Weight ◽  
Water Entry ◽  
Grain Development ◽  
Nitrogen And Phosphorus ◽  
Steady Rate

Plants of five cultivars of wheat were grown under controlled-environmental conditions in order to analyse the effect of cultivar and of temperature and illuminance after anthesis on the accumulation of nitrogen and phosphorus by grains in relation to dry matter. The water relations of the grain during maturation were also examined, using calcium content as an index of water entry. The nitrogen and phosphorus contents of grains increased linearly throughout the grain growth period. The percentage of nitrogen and phosphorus in grains fell sharply during the first few days after anthesis but rose progressively thereafter. The higher the temperature, and the lower the illuminance, the higher was the percentage of nitrogen in the grain of all cultivars. Such conditions also reduce final grain size, but their effects on nitrogen concentration in the grain were apparent early in grain development. No evidence was found of a flush of nitrogen or phosphorus into the grain late in its development. Water entry into the grain continued at a steady rate until maximum grain dry weight was reached, then ceased suddenly. No evidence was found of an increased rate of water loss by the grain at that stage, and the rapid fall in water content at the cessation of grain growth may have been due to blockage of the chalazal zone of entry into the grain by the deposition of lipids. Accumulation of dry matter, nitrogen and phosphorus and entry of water into the grain all ceased at the time of lipid deposition in the chalazal zone.

scholarly journals Increasing the Growth and Quality of Red Chili with Growth Hormone from Endophytic Bacteria

2019 ◽  
Vol 15 (2) ◽  
pp. 75
Author(s):  
Rafika Yuniawati ◽  
Siti Fatimah ◽  
Reni Indrayanti ◽  
Ifa Manzila ◽  
Tri Puji Priyatno ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Foliar Spray ◽  
Growth Period ◽  
Dry Weight ◽  
Positive Control ◽  
Fruit Weight ◽  
Growth Hormones ◽  
Synthetic Hormones ◽  
Potential Test

<p>Red chili is a very important horticultural commodity in Indonesia having low productivity and quality. Cultivation method needs to be improved including the use of exogenous growth hormones. The purpose of this study was to determine (1) the optimum concentration of IAA and GA growing hormones from isolate B6.2 in stimulating plant growth and improving the quality of large red chili fruit; (2) molecular identity of the B6.2 bacterial isolate. The growth hormone content of B6.2 isolates using HPLC obtained 0.49 ppm IAA and 64.53 ppm GA. The growth hormone potential test on the growth and quality of chili was carried out with a concentration of 1, 3, 5 ml/l, while water and synthetic hormones was used as negative and positive control, respectively. The experimental design used was a Complete Random Design with the foliar spray application to the plant canopy three times during the growth period. The results showed the best concentration in increasing plant height, fruit weight, shooth wet, and dry weight compared to controls at the age of 76 days after planting (dap) was a concentration of 5 ml/l, with the values of 71.7±0.9 cm , 94.7±0.3 g, 11.5±0.43 g, and 1.4±0.09 g, respectively. The molecular identification showed that B6.2 isolate was classified as Bacillus vallismortis with 100% homology. The growth hormone from isolate B6.2 has the potential to increase growth and production of red chili plants.</p>

scholarly journals Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest in decadal scale

2009 ◽  
Vol 6 (5) ◽  
pp. 8633-8660
Author(s):  
B. Koehler ◽  
M. D. Corre ◽  
E. Veldkamp ◽  
J. P. Sueta
Keyword(s):  
Growth Period ◽  
Montane Forest ◽  
Stem Growth ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
N Addition ◽  
Soil Co2 ◽  
Lowland Forest ◽  
Soil Carbon Dioxide ◽  
Decadal Scale

Abstract. Atmospheric nitrogen (N) deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide CO2 efflux to long-term experimental N-addition (125 kg N ha−1 yr-1) in mature lowland and montane forests in Panamá. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In the montane forest, on soils with low nutrient supplying capacity and an organic layer, fine litterfall and stem-growth were N-limited. Our objectives were to 1) explore the influence of soil temperature and moisture on the dynamics of soil CO2 efflux and 2) determine the responses of soil CO2 efflux from an N-rich and N-limited forest to elevated N input. Annual soil CO2-C efflux was larger from the lowland (15.20±1.25 Mg C ha−1) than the montane forest (9.36±0.29 Mg C ha−1). In the lowland forest, soil moisture explained the largest fraction of the variance in soil CO2 efflux while soil temperature was the main explanatory variable in the montane forest. Soil CO2 efflux in the lowland forest did not differ between the control and 9–11 yr N-addition plots, suggesting that chronic N input to nutrient-rich tropical lowland forests on well-buffered soils may not change their C balance in decadal scale. In the montane forest, first year N addition did not affect soil CO2 efflux but annual CO2 efflux was reduced by 14% and 8% in the 2- and 3 yr N-addition plots, respectively, compared to the control. This reduction was caused by a decrease in soil CO2 efflux during the high stem-growth period of the year, suggesting a shift in carbon partitioning from below- to aboveground in the N-addition plots where stem diameter growth was promoted.

scholarly journals Balancing dynamic tradeoffs drives cellular reprogramming

2018 ◽  
Author(s):  
Kimberley N. Babos ◽  
Kate E. Galloway ◽  
Kassandra Kisler ◽  
Madison Zitting ◽  
Yichen Li ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Division ◽  
Motor Neuron ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cellular Reprogramming ◽  
Cellular Event ◽  
Chemical Factors ◽  
Number Of Cells ◽  
Transcription And Replication

AbstractAlthough cellular reprogramming continues to generate new cell types, reprogramming remains a rare cellular event. The molecular mechanisms that limit reprogramming, particularly to somatic lineages, remain unclear. By examining fibroblast-to-motor neuron conversion, we identify a previously unappreciated dynamic between transcription and replication that determines reprogramming competency. Transcription factor overexpression forces most cells into states that are refractory to reprogramming and are characterized by either hypertranscription with little cell division, or hyperproliferation with low transcription. We identify genetic and chemical factors that dramatically increase the number of cells capable of both hypertranscription and hyperproliferation. Hypertranscribing, hyperproliferating cells reprogram at 100-fold higher, near-deterministic rates. We demonstrate that elevated topoisomerase expression endows cells with privileged reprogramming capacity, suggesting that biophysical constraints limit cellular reprogramming to rare events.

Action of nuclear and cytoplasmic fractions of liver homogenate on liver growth in the chick embryo

Development ◽  
1968 ◽  
Vol 20 (1) ◽  
pp. 53-71
Author(s):  
G. D. Tumanishvili ◽  
Naira V. Salamatina
Keyword(s):  
Cell Division ◽  
Chick Embryo ◽  
Mitotic Activity ◽  
Liver Homogenate ◽  
Liver Growth ◽  
Organ Growth ◽  
Tissue Volume ◽  
Number Of Cells

A number of observations have been made during a study of the regulation of organ growth which lead to the conclusion that there is a certain correlation between the density of cell packing and mitotic activity in the tissue (Tumanishvili, 1964, 1965a, b; Tumanishvili & Tabidze, 1962, 1963). The density of cell packing is expressed as the concentration of nuclei (CN), reflecting not only the number of cells in a given tissue volume, but an aspect of interrelation of nuclei and cytoplasm as well. Observations have shown that an increase in mitotic activity always leads to an increase in the concentration of nuclei, and a decrease to a decrease. At the same time an increase in the concentration of nuclei appears to cause suppression of mitotic activity, while a decrease of the nuclear concentration to cause vigorous cell division.

scholarly journals New Insights into Methyl Bromide Cooxidation byNitrosomonas europaea Obtained by Experimenting with Moderately Low Density Cell Suspensions

2000 ◽  
Vol 66 (7) ◽  
pp. 2726-2731 ◽  
Author(s):  
Khrystyne N. Duddleston ◽  
Peter J. Bottomley ◽  
Angela J. Porter ◽  
Daniel J. Arp
Keyword(s):  
Cell Division ◽  
Methyl Bromide ◽  
Cell Activity ◽  
Dry Weight ◽  
Cell Suspensions ◽  
Low Density ◽  
Level Of Activity ◽  
End Products ◽  
Uptake Activity ◽  
Fresh Growth Medium

ABSTRACT We examined the rates and sustainability of methyl bromide (MeBr) oxidation in moderately low density cell suspensions (∼6 � 107 cells ml−1) of the NH3-oxidizing bacterium Nitrosomonas europaea. In the presence of 10 mM NH4 + and 0.44, 0.22, and 0.11 mM MeBr, the initial rates of MeBr oxidation were sustained for 12, 12, and 24 h, respectively, despite the fact that only 10% of the NH4 +, 18% of the NH4 +, and 35% of the NH4 +, respectively, were consumed. Although the duration of active MeBr oxidation generally decreased as the MeBr concentration increased, similar amounts of MeBr were oxidized with a large number of the NH4 +-MeBr combinations examined (10 to 20 μmol mg [dry weight] of cells−1). Approximately 90% of the NH3-dependent O2uptake activity and the NO2 −-producing activity were lost after N. europaea was exposed to 0.44 mM MeBr for 24 h. After MeBr was removed and the cells were resuspended in fresh growth medium, NO2 −production increased exponentially, and 48 to 60 h was required to reach the level of activity observed initially in control cells that were not exposed to MeBr. It is not clear what percentage of the cells were capable of cell division after MeBr oxidation because NO2 − accumulated more slowly in the exposed cells than in the unexposed cells despite the fact that the latter were diluted 10-fold to create inocula which exhibited equal initial activities. The decreases in NO2 −-producing and MeBr-oxidizing activities could not be attributed directly to NH4 + or NH3 limitation, to a decrease in the pH, to the composition of the incubation medium, or to toxic effects caused by accumulation of the end products of oxidation (NO2 − and formaldehyde) in the medium. Additional cooxidation-related studies of N. europaea are needed to identify the mechanism(s) responsible for the MeBr-induced loss of cell activity and/or viability, to determine what percentages of cells damaged by cooxidative activities are culturable, and to determine if cooxidative activity interferes with the regulation of NH3-oxidizing activity.

The effect of age on the response of wheat to nutrient stress

1971 ◽  
Vol 11 (49) ◽  
pp. 223 ◽  
Author(s):  
MA Chapman ◽  
J Keay
Keyword(s):  
Growth Rate ◽  
Stem Elongation ◽  
Dry Weight ◽  
Nutrient Stress ◽  
Stages Of Development ◽  
Early Stages ◽  
Potassium Starvation ◽  
Effect Of Age ◽  
Nitrogen Phosphorus

Wheat plants (CV. Gamenya) were deprived of nitrogen, phosphorus, or potassium at several stages of development. Starvation for only two weeks affected the growth rate at early stages, but not at later stages, and had no effect on dry-weight of the ear. Continuous starvation for any of the nutrients at any stage up to ear emergence reduced the weight of inflorescence, the reduction being greater the earlier starvation occurred. Starvation of any of the three nutrients after ear emergence had no effect on dry-weight. Potassium starvation before joitning prevented stem elongation more than starvations for nitrogen or phosphorus.

726. Histological changes in the mammary gland of guinea-pigs during lactation

1958 ◽  
Vol 25 (3) ◽  
pp. 392-396 ◽  
Author(s):  
M. Naito
Keyword(s):  
Mammary Gland ◽  
Dna Content ◽  
Guinea Pigs ◽  
Dry Weight ◽  
Histological Changes ◽  
Opposite Trend ◽  
Histological Factors ◽  
Porosity Index ◽  
Number Of Cells

Certain histological factors of the mammary gland and the DNA content unit per dry weight were studied at four stages of lactation in guinea-pigs.The porosity index, the number of alveoli per field, the number of cells per field and the DNA content, showed maximal values at parturition and minimal values at the peak of lactation, whereas the opposite trend was shown by the value for modal alveolar diameter and the number of cells per modal alveolus.The relationships between these results are discussed.

Relationship Between Grain Nitrogen, Non-Protein Nitrogen and Nucleic Acids During Wheat Grain Development

1979 ◽  
Vol 6 (4) ◽  
pp. 449 ◽  
Author(s):  
GR Donovan
Keyword(s):  
Total Nitrogen ◽  
Culture Medium ◽  
Nitrogen Concentration ◽  
Dry Weight ◽  
Grain Development ◽  
Fresh Weight ◽  
Wheat Varieties ◽  
Protein Nitrogen ◽  
Apparent Relationship ◽  
Grain Nitrogen

Eight wheat varieties which normally produce grain of different final percentage nitrogen content were grown under field and glasshouse conditions. The final percentage grain nitrogen of the field grown varieties ranked in the expected order; however, total nitrogen/grain, DNAIgrain, RNA/grain and non-protein nitrogen/grain during grain development differed between varieties. DNA/grain reached a maximum value in all varieties between 21 and 28 days post- anthesis, suggesting a longer period of cell division than previously reported. There was no apparent relationship between final percentage grain nitrogen and either DNA, total grain RNA or the concentration of grain amino acids during development. Heads from glasshouse grown wheat were detached at 8 days postanthesis and grown in liquid culture under conditions where the nitrogen concentration of the culture medium was varied. Fresh weight/grain, DNA/grain, RNA/grain and total grain nitrogen all increased with increasing nitrogen concentration in the culture medium, but grain dry weight remained constant at the different nitrogen concentrations. The changes in fresh weight/grain, DNA/grain and RNA/grain were not the same for all varieties. A possible relationship between total grain nitrogen and DNA/grain and RNA/grain during seed development exists for heads grown in culture for individual varieties. This apparent relationship for individual varieties cannot be used to explain intervarietal differences in total grain nitrogen because in some cases different varieties grown under identical culture conditions, although producing grain of equivalent total nitrogen, had widely differing levels of both DNA and RNA per grain.

Modelling nutrient uptake: a possible indicator of phosphorus deficiency

Soil Research ◽  
1997 ◽  
Vol 35 (2) ◽  
pp. 313 ◽  
Author(s):  
D. S. Mendham ◽  
P. J. Smethurst ◽  
P. W. Moody ◽  
R. L. Aitken
Keyword(s):  
Nutrient Uptake ◽  
Phosphorus Deficiency ◽  
Soil Phosphorus ◽  
Soil Nutrient ◽  
Growth Period ◽  
Dry Weight ◽  
Root Surface ◽  
P Uptake ◽  
P Deficiency ◽  
Highly Correlated

An understanding of the processes controlling soil nutrient supply and plant uptake has led to process-based models that can predict nutrient uptake and the concentration gradient that develops at the root surface. By using this information, it may be possible to develop an indicator of soil phosphorus status based on the predicted uptake and/or concentration of phosphorus (P) at the root surface. To identify the potential for such a test, the relationships between model output and observed plant growth were examined using data from a published experiment. The experiment was initially designed to investigate the relationship between common indices of soil-available P and the growth of maize (Zea mays) in 26 surface soils from Queensland. There was a high correlation between observed and predicted P uptake, and between relative dry matter yield and predicted P uptake. The predicted concentration of P at the root surface was also highly correlated with P uptake and dry weight increase. It is hypothesised that the short growth period (25 days) was responsible for the high correlation between P uptake and measured soil solution P. The hypothesis that a predicted concentration of P at the root surface or predicted P uptake may be valuable indicators of P deficiency in the longer term still remains to be tested.

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