Showing papers in "Australian Journal of Biological Sciences in 1962"
TL;DR: The relative turgidity technique as discussed by the authors compares the initial and turgid water contents, on a percentage basis, of disks punched from leaves, the turgity water content being obtained by floating the disks on water.
Abstract: The relative turgidity technique consists in comparing the initial and turgid water contents, on a percentage basis, of disks punched from leaves, the turgid water content being obtained by floating the disks on water.
2,701 citations
TL;DR: A comparative study has been made of the response by varieties of Hordeum to high sodium chloride treatment and to sodium chloride removal from the substrate.
Abstract: A comparative study has been made of the response by varieties of Hordeum to high sodium chloride treatment and to sodium chloride removal from the substrate
155 citations
TL;DR: In experimental studies of the competition between plant species, plants of two species are grown together in the same pot or plot to compare a number of species.
Abstract: In experimental studies of the competition between plant species, plants of two species are grown together in the same pot or plot. To compare a number of species, a suitable balanced arrangement is to grow each species in association with each other and on its own (i.e. associated with itself) once in each replication. The interpretation of the results of such experiments is discussed in this paper.
140 citations
TL;DR: Plants of wheat, ryegrass, red clover, whiteClover, and Neptunia amplexicaul'is (a selenium accumulator) were grown in nutrient solutions containing 75Se-selenite ion and the root and shoot tissues fractionated to examine the products of selenite assimilation.
Abstract: Plants of wheat, ryegrass, red clover, white clover, and Neptunia amplexicaul'is (a selenium accumulator) were grown in nutrient solutions containing 75Se-selenite ion. The uptake of 75Se was measured and the root and shoot tissues fractionated to examine the products of selenite assimilation.
129 citations
TL;DR: The distribution of He·labelled assimilate in the soybean has been studied, emphasis being placed on the expanding leaf as the major apical sink.
Abstract: The distribution of He·labelled assimilate in the soybean has been studied, emphasis being placed on the expanding leaf as the major apical sink. The expanding leaf imports assimilate from leaves below, this import rising to a maximum and then falling to almost zero when the leaf is half-expanded. At this stage in the growth of the leaf, it has begun exporting assimilate to the younger leaves. Export, both to younger leaves and down the stem to the root, increases until the leaf is fully expanded
117 citations
TL;DR: growth studies were carried out on a small number of filamentous fungi of special interest to the problem of disease resistance in plants and the following points were demonstrated.
Abstract: Representative groups of microorganisms were assayed for sensitivity to pisatin in agar media. Detailed growth studies were carried out on a small number of filamentous fungi of special interest to the problem of disease resistance in plants. The following points were demonstrated.
82 citations
TL;DR: In this article, young barley plants, Hordeum vulgare cv. Chevron, were subjected to a sodium chloride concentration of 100 m-equiv/l. In a "removed" treatment, sodium chloride was removed from the substrate after 5 days, and the subsequent response was studied over a period of 10 days.
Abstract: Young barley plants, Hordeum vulgare cv. Chevron, were subjected to a sodium chloride concentration of 100 m-equiv/l. In a "continued" treatment, the salinity stress was maintained for 15 days. In a "removed" treatment, sodium chloride was removed from the substrate after 5 days, and the subsequent response was studied over a period of 10 days.
77 citations
TL;DR: Observations have been made by phase contrast and fluorescence microscopy on chloroplasts both in living cells of higher plants and in an isolated state.
Abstract: Observations have been made by phase contrast and fluorescence microscopy on chloroplasts both in living cells of higher plants and in an isolated state.
69 citations
TL;DR: "Colloidal" chitin, prepared by precipitation of chit in from solution in cold 21N sulphuric acid, has a very much shorter chain length than the chitIn from which it was prepared, and is more stable in dilute (2N) hydrochloric acid.
Abstract: Chitin undergoes rapid and extensive degradation at 20°C when dissolved in ION hydrochloric acid, 21N sulphuric acid, or 85% phosphoric acid. Most of the degradation occurs in the first few minutes after the chitin is dissolved and the products formed are oligosaccharides (which are to some extent deacetylated) and N·acetyl-D.glucosamine. Glucosamine was not found except possibly in the smallest traces. "Colloidal" chitin, prepared by precipitation of chitin from solution in cold 21N sulphuric acid, has a very much shorter chain length than the chitin from which it was prepared. Chitin is more stable in dilute (2N) hydrochloric acid.
63 citations
TL;DR: Radioisotope techniques were used to study kinetics of sucrose, glucose, and fructose accumulation in slices of immature sugar·cane tissue, suggesting intermediate compound formation between the sugars and some receptor or "carrier" in the cell.
Abstract: Radioisotope techniques were used to study kinetics of sucrose, glucose, and fructose accumulation in slices of immature sugar·cane tissue. For all three sugars, accumulation rate was P. hyperbolic function of sugar concentration, suggesting intermediate compound formation between the sugars and some receptor or "carrier" in the cell. Sucrose and glucose interacted competitively, implying that, these two sugars (and probably also fructose, fructose 6-phosphate, and glucose I-phosphate) shared the same carrier.
39 citations
TL;DR: It is shown that the main factor in the phenomena of potential change and current flow, during the initial stages of the action potential in Nitella, is a tran-sient increase in the permeability of the cell membrane to calcium ions, and a consequent flow of these ions into the cell from the external medium.
Abstract: Experiments are described in which a "voltage· clamping" technique has been applied to large ecorticate internodal cells of the freshwater alga Nitella. In this technique, a feedback circuit is used to change the potential difference between the vacuole of the cell and the external medium to some predetermined level and maintain it as close as possible to this level during the electrical activity of the cell. It is shown that the main factor in the phenomena of potential change and current flow, during the initial stages of the action potential in Nitella, is a tran-sient increase in the permeability of the cell membrane to calcium ions, and a consequent flow of these ions into the cell from the external medium.
TL;DR: In this paper, the bioelectric field of a bean root growing in a weakly conducting solution is examined and it is estimated by a method which is described, that a total current of about 3 X 10-7 A flows through the external medium due to the bio-electric source, resulting in power dissipation outside the plant of about 10-9 W.
Abstract: The bioelectric field of a bean root growing in a weakly conducting solution is examined. It is estimated by a method which is described, that a total current of about 3 X 10-7 A flows through the external medium due to the bioelectric source, resulting in power dissipation outside the plant of about 10-9 W. This is considered in relation to respiratory energy production in the root.
TL;DR: The quantitative changes in starch content during the growth and senescence of tobacco leaves have been followed and the maximum was reached when more than half of the original chlorophyll content had gone.
Abstract: The quantitative changes in starch content during the growth and senescence of tobacco leaves have been followed. The starch content was low while the leaves were expanding but rapidly increased after expansion stopped. The maximum was reached when more than half of the original chlorophyll content had gone. The starch content was then reduced rapidly and when the leaf was all yellow there was only a small quantity of starch and this remained when the leaf turned brown.
TL;DR: A series of experiments have been carried out to determine whether manganese is directly or indirectly involved in the photochemical reactions (as measured by the Hill reaction) of chloroplasts of higher plants.
Abstract: A series of experiments has been carried out to determine whether manganese is directly or indirectly involved in the photochemical reactions (as measured by the Hill reaction) of chloroplasts of higher plants.
TL;DR: The effects of environmental conditions on pea seeds developing in pods were investigated by growing the plants under controlled conditions in the Earhart Plant Research Laboratory and the most striking results were the effects of night and day tem-peratures on the growth and composition of the seeds, particularly on the sugar content.
Abstract: The effects of environmental conditions on pea seeds developing in pods were investigated by 'growing the plants under controlled conditions in the Earhart Plant Research Laboratory. In one experiment plants were kept under a variety of conditions throughout their period of growth and of seed-pod development. In two experiments plants were grown under standard conditions until they flowered and were then transferred to a series of different environments. The environmental conditions investigated included photoperiod, light intensity, and day and night temperatures. Samples of seeds were taken at different times after flowering and seed growth was recorded by fresh weight and dry weight measurements. 'The samples were analysed for total sugar, reducing sugar, starch, total nitrogen, and protein nitrogen. The most striking results were the effects of night and day tem-peratures on the growth and composition of the seeds, particularly on the sugar content. At low temperatures, the conversion of sugar to starch was much delayed and sugar continued to increase in concentration during growth; at higher tem-peratures the sugar entering the seeds was rapidly converted to starch; thus the carbohydrate composition of seeds grown at different temperatures was markedly different. Protein synthesis was also delayed at lower temperatures. Water uptake and rate of drying out of the seeds were also affected. The possible implications and interrelations of these observations are discussed.
TL;DR: The effect of cold shock on bull and ram spermatozoa was studied by rapidly cooling semen suspensions to ooe over 3 min.
Abstract: The effect of cold shock on bull and ram spermatozoa was studied by rapidly cooling semen suspensions to ooe over 3 min. Bull spermatozoa that survived this treatment were less susceptible to subsequent rapid cooling.
TL;DR: The percentage germination of conidia of Peronospora tabacina Adam on leaves and leaf disks of Nicotiana tabacurn L. cv.
Abstract: The percentage germination of conidia of Peronospora tabacina Adam on leaves and leaf disks of Nicotiana tabacurn L. cv. Virginia Gold ranged from less than 1 to 22% with a mean value of 1-7%. Addition of riboflavin-increased germination to a mean value of 44%. Prior washing of the leaf disks allowed 64% germination, which was increased to 95% on the addition of riboflavin, reaching a similar value to that recorded for conidia on agar. It is suggested that the degree of germination attained on N. labacum leaves is controlled by the amount of available riboflavin and by the presence of water-soluble compounds inhibitory to germination.
TL;DR: The particular purpose of this study is to set out the prediction formulae for all possible general combining ability selection methods which can be generated by one or two base populations.
Abstract: This study is the first of a series in which theoretical comparisons are made among various general combining ability and specific combining ability selection methods. The particular purpose of this study is to set out the prediction formulae for all possible general combining ability selection methods which can be generated by one or two base populations.
TL;DR: The present observations cast doubt on the individuality of these reported components in the iochemical sense and they may best be interpreted as a series of physically stable complexes.
Abstract: Chromatographic methods for preparing a carbohydrate-protein complex containing an apparently homogeneous single ,a-glucosidase species are described. This complex may be disrupted to give an enzymically active, but very unstable protein. There seems to be a single ,a-glucosidase present in S. atra culture filtrates, fractionations on the column being due to complexing with polysaccharide. Many of the cases reported in the literature of "multiple enzyme components" in simi· lar systems have never been shown to have components of distinctly different enzyme properties. In the absence of such demonstrations, the present observations cast doubt on the individuality of these reported components in the iochemical sense and they may best be interpreted as a series of physically stable. complexes.
TL;DR: A small Australian marsupials, the mulgara or crest-tailed marsupial-mouse (Dasycercu8 cristicauda Krefft), lives on a predominantly or exclusively carnivorous diet and can maintain or gain weight without drinking water on a diet of whole mice or fresh lean meat.
Abstract: A small Australian marsupial, the mulgara or crest-tailed marsupial-mouse (Dasycercu8 cristicauda Krefft), lives on a predominantly or exclusively carnivorous diet. It, inhabits the most arid part of central Australia where the average rainfall is 5-10 in. per year. In the laboratory and in the absence of heat stress, the animal can maintain or gain weight without drinking water on a diet of whole mice or fresh lean meat. Its kidney can produce a urine highly concentrated with respect to urea, and the large amounts of urea formed on a carnivorous diet can therefore be excreted in a relatively small volume of urine. This desert animal can therefore subsist on the water contained in its food without drinking free water or eating succulent plant material.
TL;DR: One of the inversions in Chironomus (Kiefferulus) intertinctus Skuse, the Corio inversion in chromosone III, is closely linked to the sex-determining region.
Abstract: One of the inversions in Chironomus (Kiefferulus) intertinctus Skuse, the Corio inversion in chromosone III, is closely linked to the sex-determining region. Different selective values in males and females result in the Standard sequence being more common in the Y -chromosomes while the Corio sequence is more common in the X-chromosomes. In a population from Echuca, Vic., only the Standard sequence occurs in the Y-chromosomes.
TL;DR: Observations of acquisition feeding behaviour yielded results which are interpreted to indicate that most transmission occurs with virus acquired intracellularly in bean yellow mosaic virus.
Abstract: Efficiency of bean yellow mosaic virus (BYMV) transmission from broad bean source plants varied with age of leaf on which aphids, MYZU8 persicae (Sulz.), fed. Duration of infection in the source plants did not affect transmission. Observations of acquisition feeding behaviour yielded results which are interpreted to indicate that most transmission occurs with virus acquired intracellularly.
TL;DR: The influence of haemoglobin type and erythrocyte potassium concentration on oxygen dissociation curves and rate of denaturation of haenoglobin by alkali have been studied in Southdown sheep.
Abstract: The influence of haemoglobin type and erythrocyte potassium concentration on oxygen dissociation curves and rate of denaturation of haemoglobin by alkali have been studied in Southdown sheep.
TL;DR: In this article, a study was made of the preferential extraction of high sulphur protein components from wool by alkaline solutions of potassium thioglycollate, and it was found that in general the high. sulphur proteins were extracted in quantity at lower values of pH, temperature, and time than the low sulfur proteins.
Abstract: A study has been made of the preferential extraction of high· sulphur protein components from wool by alkaline solutions of potassium thioglycollate. It was found that in general the high. sulphur proteins were extracted in quantity at lower values of pH, temperature, and time than the low· sulphur proteins. The extraction of low· sulphur proteins was repressed by small increases in salt concentration and by the addition of divalent cations such as zinc and calcium, whereas the solubility of the high. sulphur proteins was much less affected by these additions.
TL;DR: In this paper, Steiner, Neukom, and Deuel reported the chromatography of a variety of wheat and sugar-beet polysaccharides on DEAEcellulose.
Abstract: The chromatography of polysaccharides on resinous ion-exchangers has been reported by Steiner, Neukom, and Deuel (1958). Neukom et al. (1960) later reported the chromatography of a variety of wheat and sugar-beet polysaccharides on DEAEcellulose. Only "neutral" polysaccharides could be eluted at pH 6-8 by increasing buffer and salt concentrations; acid polysaccharides, e.g. pectic acid, were eluted by various strengths of alkali. Neutral polysaccharides could also be hromatographed at a somewhat alkaline pH by working with borate systems, which give charged complexes with many carbohydrates.
TL;DR: Mercaptoethanol and thioglycollate are very similar in their extent of reduction of wool at low concentrations of thiol but the neutral thiol is more effective as a reducing agent at high concentrations.
Abstract: The reduction of wool with mercaptoethanol and thioglycollate at pH 5 has been compared by measuring the disulphide contents of the reduced wool after alkylation of the thiol groups with iodoacetate at pH 8·5--9. Mercaptoethanol and thioglycollate are very similar in their extent of reduction of wool at low concentrations of thiol but the neutral thiol is more effective as a reducing agent at high concentrations. In contrast with the earlier findings of Patterson et al.
TL;DR: R. exaltata is a strict short·day plant with a critical photoperiod of about 13 hr, and the expanding leaf is the one most sensitive to short.day induction and removal of the leaves below it accelerates inflorescence development.
Abstract: R. exaltata is a strict short·day plant with a critical photoperiod of about 13 hr. The number of short days required for inflorescence initiation varies with age, being 6 with plants 5 weeks old. Exposure to additional short days increases the rate of inflorescence development. The expanding leaf is the one most sensitive to short.day induction and removal of the leaves below it accelerates inflorescence development.
TL;DR: The ratio of E to k in sheep of different productive efficiency was found to be constant and the relation is expressed by the equation W = Ei-kG.
Abstract: The wool growth responses to changes in feed intake are related to the changes produced in body weight. The relation is expressed by the equation W = Ei-kG, where W = wool growth rate, i = feed intake rate, G = rate of body weight change, and E and k are constants. The ratio of E to k in sheep of different productive efficiency was found to be constant.
TL;DR: The contribution of ear photosynthesis to grain growth has now been measured for wheat over intervals between anthesis and maturity, by a technique involving stem shading and grain removal.
Abstract: Cereal ears are important as photosynthetic organs in contributing to grain yield and, since ear tissues are the last to yellow, their relative activity may increase during grain development. Glume surface exposed to light has been observed to increase as grains swell, and thus actual photosynthetic capacity of ears may also increase. The contribution of ear photosynthesis to grain growth has now been measured for wheat (Triticum vulgare cv. Gabo) over intervals between anthesis and maturity, by a technique involving stem shading and grain removal.
TL;DR: Body temperature measurements on the short-nosed bandicoot have shown a nocturnal cycle with a range of 1· 2°C and a short active phase at 2200-0400 hr, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40°C.
Abstract: Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1· 2°C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3°C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36· 4 to 34· 2°C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O°C). Both species could regulate effectively at an ambient temperature of 5°C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40°C.