Distribution of zinc in subterranean clover (Trifolium subterraneum L.) grown to maturity in a culture solution containing zinc labelled with the radioactive isotope 65Zn

1958 ◽  
Vol 9 (6) ◽  
pp. 730 ◽  
Author(s):  
DS Riceman ◽  
GB Jones
Keyword(s):  
Radioactive Isotope ◽  
Vascular Tissue ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Culture Solution ◽  
Root Tips ◽  
High Concentration ◽  
Vegetative Organs ◽  
Mature Seeds ◽  
Very High

Subterranean clover (T. subterraneum L. var. Bacchus Marsh) was grown to maturity in a culture solution containing zinc labelled with the radioactive isotope 65Zn. The distribution of zinc in the plants at different stages of growth was determined by means of radioautographs. These show that zinc is always present in very high concentration in the terminal portions of the main axis, runners, and laterals, in young, expanding leaves and petioles, in root tips and at points along the roots, in parts of the inflorescences, and in developing and mature seeds. The concentrations decrease in the vegetative organs as they expand and mature. In mature vegetative organs there is usually a higher concentration of zinc in the vascular tissue than in the tissue surrounding it. A higher concentration of zinc is found in the nodes of the runners and laterals than in the internodes. In the nodes themselves the concentration is highest where the amount of vascular tissue is increased by the presence of the vascular traces of petioles and of runners, laterals, or branches.

Distribution of zinc in subterranean clover (Trifolium subterraneum L.) during the onset of zinc deficicency, as determined by the use of the radioactive isotope 65Zn

1960 ◽  
Vol 11 (2) ◽  
pp. 162 ◽  
Author(s):  
DS Riceman ◽  
GB Jones
Keyword(s):  
Zinc Deficiency ◽  
Radioactive Isotope ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Main Axis ◽  
Culture Solution ◽  
Leaf Stage ◽  
Plant Parts ◽  
Subsequent Onset

Young plants of subterranean clover (T. subterraneum L. var. Bacchus Marsh) were grown between day 20 and day 43 in culture solutions containing zinc labelled with the radioactive isotope 65Zn and were then transferred to zinc-free culture solution. The distribution of labelled zinc in the plant parts during the subsequent onset of zinc deficiency was determined by means of radioautographs. By similar means the distribution of labelled zinc was determined in plants transferred to culture solutions containing inactive zinc. The zinc present in fully expanded living leaves was largely retained there while they remained alive, even during the onset of zinc deficiency which progressed to the "little leaf" stage. Some zinc was transported out of these leaves when they became prematurely senescent as a result of the deficiency. During the onset of the deficiency some zinc was transported out of the roots and the main axis. After zinc deficiency had become acute and growth had practically ceased, the concentration of zinc in the youngest leaves at the growing points of the main axis and runners remained higher than that in the slightly older, fully expanded leaves.

Effects of pH and aluminium on the growth of temperate pasture species. II. Growth and nodulation of legumes

1991 ◽  
Vol 42 (5) ◽  
pp. 893 ◽  
Author(s):  
DC Edmeades ◽  
FPC Blamey ◽  
CJ Asher ◽  
DG Edwards
Keyword(s):  
White Clover ◽  
Trifolium Pratense ◽  
Inorganic Nitrogen ◽  
Red Clover ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Lotus Corniculatus ◽  
Culture Solution ◽  
Solution Ph ◽  
Lotus Pedunculatus

Ten temperate pasture legumes inoculated with appropriate rhizobia were grown for 31 days in flowing solution culture. Solution ionic strength was approximately 2700 8M and contained inorganic nitrogen (150 , 8M NO3-) only at the commencement of the experiment. Solution pH was maintained at 4.5, 5.0, 5.5 and 6.0. Also, five aluminium (Al) treatments were imposed, with nominal Al concentrations of 0, 3, 6, 12 and 24 8M (2.5, 7.1, 8.3, 11.2 and 24.7 8M Al measured) at pH 4.5. Solution pH <6 . 0 markedly reduced total dry mass (TDM) in all cultivars of white clover (Trifolium repens) cvv. 'Grasslands Pitau, Huia, G18 and Tahora' and red clover (Trifolium pratense) cvv. 'Grassland Turoa and Pawera', and to a lesser extent in the two subterranean clover (Trifolium subterraneum) cvv. 'Tallarook and Woogenellup'. In contrast, solution pH had no effect on the growth of Lotus corniculatus cv. Maitland, while Lotus pedunculatus cv. Maku grew best at pH 4.5. Lotus pedunculatus cv. Maku grew best in solution where the sum of the activities of the monomeric Al species {Alm} was maintained at 5.9 8M. The growth of all other species was decreased with Al in solution, a 50% reduction in TDM being associated with c. 6 8M {Alm] for white clover and subterranean clover, and c. 3 8M in red clover and Lotus corniculatus cv. Maitland.

Seed-setting in subterranean clover (Trifolium subterraneum L.) 1. The importance of the microevironment

1957 ◽  
Vol 8 (5) ◽  
pp. 433 ◽  
Author(s):  
JJ Yates
Keyword(s):  
Seed Development ◽  
Surface Soil ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Protective Effects ◽  
Percentage Germination ◽  
Seed Setting ◽  
Before And After ◽  
Mature Seeds

An investigation was made of the relative efficiency of above- and belowground seeding, under unfavourable environmental conditions, in the subterranean clover variety Red Leaf, which normally sets some seed above and some below the ground. The experiment included artificial shielding of burrs in sponge rubber to simulate the protective effects of natural burial. Seed-setting, expressed in terms of mature seeds as percentage of reflexed florets, was considerably better when development occurred at or below the soil surface, or when burrs were enclosed in rubber, than when untreated burrs did not come in contact with the soil.The presence of moisture in the surface soil improved seed-setting above the ground. Breakdown of seed-forming processes occurred both before and after the stage at which seed development could be detected. Seeds formed above the surface were of light weight and gave very poor germination; seeds which had been buried or enclosed in rubber were much heavier and percentage germination was high; and those formed on the surface were intermediate.The results emphasize the importance of the microenvironment of individual inflorescences and burrs, and the value of protective or modifying influences, during the whole period of seed development in this species.

Nutrient potential and capacity. III. Minimum value of potassium potential for availability to Trifolium subterraneum in soil and in solution culture

1967 ◽  
Vol 18 (1) ◽  
pp. 55 ◽  
Author(s):  
NJ Barrow ◽  
CJ Asher ◽  
PG Ozanne
Keyword(s):  
Fine Root ◽  
Plant Root ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Solution Culture ◽  
Buffering Capacity ◽  
Free Energy Of Exchange ◽  
Solution Cultures ◽  
Very High ◽  
Nutrient Solutions

Plants of subterranean clover (Trifolium subterraneum L.) were grown in a range of soils until the supplies of potassium were exhausted. The potassium potential of each soil was then measured by determining the free energy of exchange of potassium for calcium plus magnesium. In soils of very high buffering capacity the potassium potential of the exhausted soil was about –6000 cal/equiv. In soils of lower buffering capacity the potential of the exhausted soil was higher but this may have been an artefact due to release of potassium from fine root material left in the soil at harvest. Subterranean clover plants were also grown in large volumes of well-stirred nutrient solutions which were held at a range of potassium concentrations. Again it was found that the plants were unable to take up potassium when the potassium potential was about –6000 cal/equiv. It is suggested that the potentials were similar because diffusion gradients were negligible in the exhausted soil and also in the swiftly flowing solutions. At potentials above –6000 cal/equiv. availability of potassium appeared to be greater in the solution cultures than in soils. It is suggested that this occurred because, in soils, the uptake of potassium causes the potential at the plant root to be lower than in the bulk of the soil.

Seed-Setting in subterranean clover (Trifolium Subterraneum L.). II. Strain-environment interactions in single plants

1958 ◽  
Vol 9 (6) ◽  
pp. 745 ◽  
Author(s):  
JJ Yates
Keyword(s):  
Negative Relationship ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Atmospheric Environment ◽  
Protective Mechanism ◽  
Seed Setting ◽  
Early Maturing ◽  
The Relationship ◽  
Mature Seeds ◽  
Number Of Seeds

The relationship between seed-setting (expressed as mature seeds per inflorescence), strain, and environment was investigated in subterranean clover, with special reference to burr burial. Single plants of a range of maturity types were grown in two environments, one cool and moist, the other hot and dry but with frequent watering of the plant roots. In the mild environment, early-maturing strains buried a high proportion of burrs, and late-maturing strains relatively few. Under the more severe conditions, late-maturing types buried the majority of their burrs. Seed-setting in buried burrs was generally good, and relatively constant in all the strains and the two environments tested. The capacity to set seed above the ground varied widely amongst strains, and within each strain was greater in the mild environment. The results indicate that seed-setting is influenced strongly by the microenvironment of inflorescences and developing burrs, and that strains differ in sensitivity to such microenvironment. Burr burial is apparently a protective mechanism against unfavourable factors (probably low relative humidity and high temperature) of the atmospheric environment. Under the more severe environmental conditions, there was a positive correlation between seed-setting above the ground and percentage leaf in the plant tops. It is presumed that this was due partly to amelioration of the microenvironrnent by the foliage. The negative relationship between efficiency of seed-setting above the ground and proportion of burrs buried is discussed in terms of natural selection. The microenvironmeilt, and the differential response of strains, affected not only the number of seeds per inflorescence, but also the weight and viability of the seeds produced. The concept of a threshold embryo weight for viability is discussed.

Elemental Analysis of Phloem Tissue in Lemna Minor Root Tips

1980 ◽  
Vol 38 ◽  
pp. 798-799
Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook
Keyword(s):  
Vascular Tissue ◽  
Lemna Minor ◽  
Atomic Weight ◽  
Companion Cell ◽  
Root Tips ◽  
Phloem Tissue ◽  
Cell Stage ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Xylem Element

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.

Ground water quality of selected areas of Punjab and Sind Provinces, Pakistan: Chemical and microbiological aspects

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Ionic Concentration ◽  
Chloride Ions ◽  
Potassium Ions ◽  
Ammonium Ions ◽  
High Concentration ◽  
Phosphate Ions ◽  
Sodium Magnesium ◽  
Very High ◽  
Microbiological Aspects

The assessment of groundwater is essential for the estimation of suitability of water for safe use. An attempt has been made to study the groundwater of selected areas of Punjab (Sheikhupura &amp; Sahiwal) and Sindh (Sindh, Jawar Dharki and Dharki), Pakistan. The results indicate that pH, color and odor were all within limits of WHO that is pH ranges 6.5–8.5, colorless and odorless, respectively. The high values of suspended solids were observed in the Sindh-1 and Dharki samples. Microbiologically only Sahiwal and Jawar Dharki were found fit for drinking purpose. Trace metals analysis of Sheikhupura-1 and Sindh-1 showed that values do not fall within limits of WHO for Iron. The ionic concentration analysis showed that high bicarbonate (HCO3-), ions are present in the samples of Sahiwal and Dharki; Sindh-1 and Jawar Dharki samples showed very high concentration for chloride ions, all samples were satisfactory level for sulphate (SO42-), sodium, magnesium and phosphate ions except samples of Sindh-1 and Jawar Dharki. High concentration of calcium and potassium ions was observed in samples of Sindh-1, while all other samples were found fit for drinking purposes in respect of nitrate, nitrite and ammonium ions. The high concentration of Fluoride was found only in Sheikhupura-2 samples.

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Small-volume vitrification and rapid warming yield high survivals of one-cell rat embryos in cryotubes

2021 ◽  
Author(s):  
Yasuyoshi Fukuda ◽  
Misako Higashiya ◽  
Takahiro Obata ◽  
Keita Basaki ◽  
Megumi Yano ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Small Volume ◽  
Sucrose Solution ◽  
High Concentration ◽  
Rat Embryos ◽  
Low Concentrations ◽  
Intracellular Ice Formation ◽  
Intracellular Ice ◽  
Warming Rate ◽  
Very High

Abstract To cryopreserve cells, it is essential to avoid intracellular ice formation during cooling and warming. One way to achieve this is to convert the water inside the cells into a non-crystalline glass. It is currently believed that to accomplish this vitrification, the cells must be suspended in a very high concentration (20–40%) of a glass-inducing solute, and subsequently cooled very rapidly. Herein, we report that this belief is erroneous with respect to the vitrification of one-cell rat embryos. In the present study, one-cell rat embryos were vitrified with 5 μL of EFS10 (a mixture of 10% ethylene glycol, 27% Ficoll, and 0.45 M sucrose) in cryotubes at a moderate cooling rate, and warmed at various rates. Survival was assessed according to the ability of the cells to develop into blastocysts and to develop to term. When embryos were vitrified at a 2,613 °C/min cooling rate and thawed by adding 1 mL of sucrose solution (0.3 M, 50 °C) at a warming rate of 18,467 °C/min, 58.1 ± 3.5% of the EFS10-vitrified embryos developed into blastocysts, and 50.0 ± 4.7% developed to term. These rates were similar to those of non-treated intact embryos. Using a conventional cryotube, we achieved developmental capabilities in one-cell rat embryos by rapid warming that were comparable to those of intact embryos, even using low concentrations (10%) of cell-permeating cryoprotectant and at low cooling rates.

Competition among seedlings of perennial grasses, subterranean clover, white clover, and annual ryegrass in replacement series mixtures

2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
White Clover ◽  
Plant Competition ◽  
Perennial Grass ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Maximum Likelihood Estimates ◽  
Annual Ryegrass ◽  
Replacement Series ◽  
Successful Establishment

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.

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