Showing papers in "Australian Journal of Biological Sciences in 1972"
TL;DR: In the ungerminated seed, the cell walls of the aleurone layer of wheat are strongly autofluorescent and are stained by aniline blue, resorcinol blue, toluidine blue, and the periodic acid-Schiff's reaction, suggesting that the ferulic acid-carbohydrate complex in this wall is relatively resistant to the action of the hydro-lases which digest the endosperm.
Abstract: In the ungerminated seed, the cell walls of the aleurone layer of wheat (Triticum aestivum cv. Heron) are strongly autofluorescent and are stained by aniline blue, resorcinol blue, toluidine blue, and the periodic acid-Schiff's reaction. Thin-layer chromatography of acid or alkaline extracts and microspectrofluorimetry indicate that the fluorescent component of the wall is ferulic acid. During germina-tion, the ferulic acid disappears from the aleurone cell wall in a specific pattern and its loss is accompanied by loss of stainable substance except in the innermost layer of the wall. These facts suggest that the aleurone cell wall contains a ferulic acid-carbohydrate complex which renders it relatively resistant to the action of the hydro-lases which digest the endosperm.
139 citations
TL;DR: In this paper, it was shown that the rate of transport from root to shoot is correlated with relative growth rate, and that the concentration of potassium in the shoot was independent of the ratio of root-to-shoot, and little affected by relative growth rates.
Abstract: Determinations of potassium transport are described for plants growing at varied relative growth rates. These determinations were based on differences in total potassium content of the shoot over a 3.day period for plants growing on culture solution. It is shown that rate of transport from root to shoot is correlated with relative growth rate. The concentration of potassium in the shoot was independent of ratio of root to shoot, and little affected by relative growth rate (potassium was the only available univalent cation).
137 citations
TL;DR: Abscisic acid was shown to inhibit transport of potassium and chloride from the cut ends of excised barley and maize roots and transport to the shoot of intact barley seedlings was inhibited.
Abstract: Abscisic acid was shown to inhibit transport of potassium and chloride from the cut ends of excised barley and maize roots. Transport to the shoot of intact barley seedlings was also inhibited. Total uptake into the excised root of barley did not appear to be affected by abscisic acid. There was an increase in tracer accumulated in the root accompanying the reduction in transport from the cut end. Concentrations of abscisic acid above 10-6M produced the maximum effect.
132 citations
TL;DR: In this paper, a method was developed for examining the effect of locally applied ions on the initiation and early extension growth of first-order laterals of wheat roots, avoiding sealing, flexibility in the positioning of treatments, and freedom to examine the root systems during growth.
Abstract: A method has been developed for examining the effect of locally applied ions on the initiation and early extension growth of first-order laterals of wheat roots. Features of the method are the avoidance of sealing, flexibility in the positioning of treatments, and freedom to examine the root systems during growth.
116 citations
TL;DR: A radioimmunoassay for glucagon has been used to study the regulation of the plasma glucagon concentration in sheep and found that during a more prolonged fast plasma glucagons concentrations declined.
Abstract: A radioimmunoassay for glucagon has been used to study the regulation of the plasma glucagon concentration in sheep. The mean plasma glucagon concentra· tion after an overnight fast was 0·20 ng/ml in crossbred sheep and 0 ·12 ng/ml in Merinos. During a more prolonged fast plasma glucagon concentrations declined.
107 citations
TL;DR: An attempt has been made to determine the properties of root growth responsible for the phenomenon of roughly constant relations between the total number, length, surface area, and volume of graminaceous root members during vegetative growth.
Abstract: Previous papers have reported that relations between the total number, length, surface area, and volume of graminaceous root members tend to remain roughly constant during vegetative growth. Through the use of a model of the extension and branching of a seminal root of barley (Hordeum vulgare L.), which was developed for the purpose, an attempt has now been made to determine the properties of root growth responsible for the phenomenon.
91 citations
TL;DR: Haploid callus and plants were cultured from the anthers of diploid A. thaliana and attempts to produce embryoids directly from' anothers were unsuccessful.
Abstract: Haploid callus and plants were cultured from the anthers of diploid A. thaliana. This depends on removing anthers during late prophase of meiosis, selecting a genotype favouring callus formation from dividing sporocytes on a high auxin-low kinetin concentration, fully defined medium, then inducing differentiation by transfer to a low auxin-high kinetin concentration, fully defined medium, with a light-dark cycle. Attempts to produce embryoids directly from' anthers were unsuccessful. The view that our approach may have Ii. more general application is discussed in relation to the work of others and our culture of haploid callus and plantlets from tomato (LycoperBicon eBculentum) and haploid callus from barley (Hordeum vulgare).
87 citations
TL;DR: Comparisons have been made of [6_3H], [3-3H]-, and [2-3h]glucose with [U-14C]gl glucose for measuring parameters of glucose metabolism in sheep given their daily ration in 24 equal amounts at hourly intervals.
Abstract: Comparisons have been made of [6_3H]-, [3-3H]-, and [2-3H]glucose with [U-14C]glucose for measuring parameters of glucose metabolism in sheep given their daily ration in 24 equal amounts at hourly intervals. The specific radioactivity (R) of plasma glucose was measured at frequent intervals from 0 to 10 hr and 0 to 32 hr after the start of a constant infusion. or single injection, of mixtures of these isotopes respectively.
86 citations
TL;DR: Experiments involving sterilization, or emasculation and delayed pollination, of the basal florets of central spikelets of wheat ears were carried out in the field, in England and maxico, and in the Australian phytotron, to investigate how grain set in those floret influences that elsewhere in the ear.
Abstract: Experiments involving sterilization, or emasculation and delayed pollination, of the basal florets of central spikelets of wheat ears were carried out in the field, in England and maxico, and in the Australian phytotron, to investigate how grain set in those florets influences that elsewhere in the ear
84 citations
TL;DR: It is shown that it is also necessary to have a second, active transport prior to entry to the xylem, as the result of a single active transport at the outer surface of the cells of the root.
Abstract: For some purposes it is adequate to explain the exudation of salt from roots, and the transport from root to shoot, as the result of a single active transport at the outer surface of the cells of the root. This paper shows that it is also necessary to have a second, active transport prior to entry to the xylem. Support for this model is based on a variety of observations. Tracer uptake interpreted on a symplast model is investigated experimentally and tested by comparison with simulated properties of the system. The effects of CCCP on uptake and transport are related to this model and compared with effects of low salt content on transport and accumulation. The behaviour of excised roots is also compared with the behaviour of whole plants.
79 citations
TL;DR: Specific staining showed that phosphatase in control plants was located primarily in and around the vascular strands, and in P·deficient plants it was located in the epidermis of the root and undersurface of the frond.
Abstract: Phosphorus deficiency (P deficiency) caused a 10-20·fold increase in phos-phatase activity of S. oligorrhiza homogenates. Specific staining showed that phosphatase in control plants was located primarily in and around the vascular strands, and in P·deficient plants it was located in the epidermis of the root and undersurface of the frond. Dissection experiments showed that roots of P·deficient plants contained a disproportionately high phosphatase activity. When plant and root homogenates were fractionated, phosphatase activity was recovered in the supernatant rather than in any cell particle fraction. However, intact plants released very little phosphatase to the external medium.
TL;DR: Six factorial experiments were conducted to examine the effects of effects of tris(hydroxymethyl)aminomethane (Tris) and type and concentration of sugar in the freezing diluent and of composition of thawing solution on the survival of ram spermatozoa following the freeze-thaw procedure.
Abstract: Six factorial experiments were conducted to examine the effects of concentra tion of tris(hydroxymethyl)aminomethane (Tris) and type and concentration of sugar in the freezing diluent, and of composition of thawing solution on the survival of ram spermatozoa following the freeze-thaw procedure.
TL;DR: The total number of spermatozoa in the urogenital tract of all rams at slaughter divided by the predicted time taken for spermatozosa to traverse the tract was found to be approximately 6% below the mean value.
Abstract: Daily spermatozoan output from the urogenital tract (DSOU), scrotal circumference, testis weight, and the numbers of spermatozoa in the epididymis and other parts of the urogenital tract were measured in 10 rams. Testis weight and the numbers of spermatozoa in the head, body, and tail of the epididymis and in the vas deferens and ampulla were found to be bilaterally symmetrical in each ram. The daily spermatozoan output from the urogenital tract was linearly correlated with testis weight (r = o· 83), with epididymal spermatozoan reserves (r = 0'86), with extragonadal spermatozoan reserves (r = 0·90), and with the total number of spermatozoa in the urogenital tract (r = O· 84). The significance levels of the regression coefficients indicated that these parameters would give good estimates of each other. The total number of spermatozoa in the urogenital tract of all rams at slaughter divided by the predicted time taken for spermatozoa to traverse the tract was found to be approximately 6% below the mean value for the daily spermatozoan output of all rams.
TL;DR: It is suggested that competing co-dominant species in natural ecosystems may be maintained in equilibrium by an ecological, negative feedback system involving reciprocal, host-specific parasites.
Abstract: It is suggested that competing co-dominant species in natural ecosystems may be maintained in equilibrium by an ecological, negative feedback system involving reciprocal, host-specific parasites. A simple model is derived to describe this relationship and a hypothetical example computed to illustrate its use. The model has important implications for the management of natural forests and for the practice of monoculture. These are briefly discussed.
TL;DR: The order of priority for supply of assimilate and nitrogen between individual grains of the wheat ear was studied by determining their accumulation of dry matter and nitrogen when the supply was varied by shading and defoliation from 2 weeks after anthesis.
Abstract: The order of priority for supply of assimilate and nitrogen between individual grains of the wheat ear was studied by determining their accumulation of dry matter and nitrogen when the supply was varied by shading and defoliation, alone and combined, from 2 weeks after anthesis.
TL;DR: In this communication another variation found in the nodal region of the spikelet of the rice plant will be described.
Abstract: Recently Zee and O'Brien (1971a, 1971b) have described the distribution of the vascular tissue and transfer cell in the nodes of the spikelet axis of wheat and millet. From those reports it was clear that the distribution of the vascular system and its associated transfer cells could be quite variable. In this communication another variation found in the nodal region of the spikelet of the rice plant will be described.
TL;DR: The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy.
Abstract: The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.
TL;DR: It is shown that native and cultivated grasses can play an effective part in the evolution of new strains of this pathogen and the principles governing hybridization between these two formae speciales of P. gramini8 may also be applicable to corresponding events between other rusrs.
Abstract: Although Berberi8 vulgari8, the alternate host of Puccinia gramini8, occurs rarely on the Australian mainland, the present studies show that native and cultivated grasses can play an effective part in the evolution of new strains of this pathogen. Agropyron 8cabrum and Hordeum leporinum appear to be important as sources of somatic hybrids involving P. graminiB f. sp. tritici and P. graminiB f. sp. 8ecali8. On the Darling Downs of Queensland the former grass species was found to be infected by more than 25 different hybrid strains. The principles governing hybridization between these two formae speciales of P. gramini8 may also be applicable to corresponding events between other rusrs.
TL;DR: Whole cuticle is separated from wool by treatment in formic acid and Digestion of cuticle with pronase is complete after 36% by weight of cuticles is dissolved and the residue is shown by electron microscopy to be exocuticle, with no evidence of adhering endocuticles.
Abstract: Whole cuticle is separated from wool by treatment in formic acid. Digestion of cuticle with pronase is complete after 36% by weight of cuticle is dissolved and the residue is shown by electron microscopy to be exocuticle, with no evidence of adhering endocuticle. The digested protein corresponds to endocuticle and the residue to exocuticle. The endocuticle contains only 3 residues per 100 of !cystine and is generally similar in amino acid analysis to the non-keratinous material from the cortex (Peters and Bradbury 1972).
TL;DR: A sporophytic self· incompatibility system, such as occurs in Carthamus jlavescens Spreng.
Abstract: A sporophytic self· incompatibility system, such as occurs in Carthamus jlavescens Spreng., was studied by computer simulation. Equilibrium gene fre-quencies in an infinite population were estimated for three-allele and six-allele systems and found to be independent of initial frequencies. In a species existing as a series of more or less isolated small populations genetic drift caused rapid loss of alleles. Maintenance of the S allele system was enhanced by increased population size, and particularly by migration, by which alleles lost from one local population could be re-introduced from adjacent populations. Hard seed carryover had a lesser effect.
TL;DR: Sodium chloride was found to improve the water balance of A. halimus plants under conditions of high evaporative demand as discussed by the authors, which was expressed by higher values of turgor pressure and percentage saturation value in plants grown in salinized culture solutions.
Abstract: Sodium chloride was found to improve the water balance of A. halimus plants under conditions of high evaporative demand. This improvement was expressed by higher values of turgor pressure and percentage saturation value in plants grown in salinized culture solutions (Knop solution to which sodium chloride was added to give final osmotic potentials of from -3 to -10 bars) as compared with plants grown in the control (Knop) solutions.
TL;DR: A formaldehyde-treated casein-safflower oil supplement was included in the diet of nine Friesian steers and the incorporation of linoleic acid in their tissues, their liveweight gain, and their intake of dry matter and energy, were compared with those of nine' steers given a conventional diet.
Abstract: A formaldehyde. treated' casein-safflower oil supplement was included in the diet of nine Friesian steers and the incorporation of linoleic acid in their tissues, their liveweight gain, and their intake of dry matter and energy, were compared with those of nine' steers given a conventional diet. Three steers from each group were slaughtered after 2, 4, and 8 weeks of feeding and the proportion of linoleic acid in samples of muscle and adipose tissue was measured. In addition, two steers were slaughtered prior to the start of the experiment to provide initial values for ,tissue composition. The steers were 9 months old when the experiment began.
TL;DR: The photosynthetic advantage of individual grass leaves compared with legumes was reflected in higher productivity of whole plants and, to a lesser extent, of grass swards, and it is an important determinant of the lower transpiration ratios of grasses at leaf, plant, and sward levels.
Abstract: Differences in leaf net photosynthetic rate were associated with differences in intracellular resistance. The larger intracellular resistance of legume leaves appeared to result from larger resistances to the movement of CO from the mesophyll cell wall to the photosynthetic sites rather than from high resistances associated with its fixation at the sites. Photorespiration could not be detected in grasses but their dark respiration rates at normal ambient CO concentrations were higher than the values for legumes. Although legumes had an appreciable photo respiration rate, this alone could not account for their lower photosynthetic rates. The higher intracellular resistance appeared to be an equally important factor. The photosynthetic advantage of individual grass leaves compared with legumes was reflected in higher productivity of whole plants and, to a lesser extent, of grass swards. Furthermore, it is an important determinant of the lower transpiration ratios of grasses at leaf, plant, and sward levels.
TL;DR: Potassium accumulation by guard cells during the light opening of V. jaba stomata in epidermal strips was determined quantitatively with 42K and 86Rb tracers and the sodium cobaltinitrite stain for potassium was used.
Abstract: Potassium accumulation by guard cells during the light opening of V. Jaba stomata in epidermal strips was determined quantitatively with 42K and 86Rb tracers. The sodium cobaltinitrite stain for potassium was also used. Particular attention was paid to errors arising from the presence of intact epidermal cells.
TL;DR: In this article, green bananas were held in humidified gas streams comprising air (control), high carbon dioxide (A) (5% CO2, 20% O2,75% N2); low oxygen (B) (0% CO 2, 3,02,97% N 2); "high carbon dioxide-low oxygen" (C) ( 5% CO dioxide, 3% O 2, 92% N
Abstract: Green bananas were held in humidified gas streams comprising air (control); "high carbon dioxide" (A) (5% CO2, 20% O2,75% N2); "low oxygen" (B) (0% CO2, 3%,02,97% N2); "high carbon dioxide-low oxygen" (C) (5% CO2, 3% O2, 92% N2). Ripening in A, B, and C was delayed at least 2, 8, and 12 times respectively compared with air. These three gas streams also reduced the rates of oxygen uptake by the fruit but increased the total oxygen uptake over the period before the beginning of the respiratory climacteric.
TL;DR: Evidence recently obtained suggests that the soil-borne fungus Phytophthora cinnamomi Rands may be indigenous to eastern Australia and may have been partly instrumental in determining the distribution of certain susceptible species, particularly Eucalyptu8 spp.
Abstract: The soil-borne fungus Phytophthora cinnamomi Rands is a particularly impor-tant pathogen in Australia because of its consistent association with root-rot disease of a wide variety of exotic and native plant species. It was thought originally to have been introduced from south-east Asia (Crandall and Gravatt 1967), but evidence recently obtained (Pratt, Heather, and Shepherd, unpublished data), suggests that it may be indigenous to eastern Australia and may have been partly instrumental in determining the distribution of certain susceptible species, particularly Eucalyptu8 spp.
TL;DR: Evidence was found of a greater resistance to export from a leaf in the upward than in the downward direction and this is consistent with the observed arrangement of the sieve elements linking the bundles at the nodes.
Abstract: During the phase of stem extension in plants of Triticum aestivum L. cv. Stewart, the distribution of assimilated 14C appeared to be related to sink size, proximity to the source, and a canalizing effect imposed by the vascular system on the movement between leaves. Evidence was found of a greater resistance to export from a leaf in the upward than in the downward direction and this is consistent with the observed arrangement of the sieve elements linking the bundles at the nodes. The cross· sectional area of the phloem did not appear to impose a limitation on the amount of material transported to the apex. The bulk of carbon imported by a growing leaf was consistently transported from the second lamina below. Import from other leaves continued after the emergence of a lamina and accounted for some 80% of its final dry weight and 50% of that in the attached sheath. The elongating inter-nodes 81ther side of the leaf formed large sinks for its photosynthate. Ear growth, prior to its emergence, was supported by the upper three leaves. After emergence the flag leaf was the main supplier.
TL;DR: The fungus did not sporulate in oulture but oonditions neoessary for fruit body formation and sporulation were studied in the field and fluotuations in fruit body numbers were oorrelated with fluotuated in disease inoidenoe.
Abstract: Vasoular·streak diebaok of ooooa in Papua New Guinea has different symptoms from the diseases oommonly referred to as ooooa diebaok in other ooooa·growing oountries. The symptoms of this destruotive disease of ooooa have not previously been reported outside Papua New Guinea. A speoies of tulasnelloid fungus, Oncobasidium theobromae (Talbot & Keane), was oonsistently assooiated with the disease. It grew speoifically within xylem vessels of diseased stems and leaves, preoeding symptom development. It was the only fungus whioh was oonsistently isolated from, and sporulated on, living diseased ooooa stems: it grew from xylem vessels exposed on leaf soars formed by the absoission of diseased leaves and formed white, effused, adherent fruit bodies exolusively on these leaf soars and their adjaoent bark. When spores were shed from these fruit bodies on to expanding leaves of young seedlings, the disease symptoms developed after 3 months and the fungus was re-isolated. o. theobromae therefore appears to be the oause of vasoular-streak diebaok. The fungus did not sporulate in oulture but oonditions neoessary for fruit body formation and sporulation were studied in the field and fluotuations in fruit body numbers were oorrelated with fluotuations in disease inoidenoe.
TL;DR: The histology and fine structure of the transverse veins that connect the longitudinal veins in the leaf of wheat are illustrated and discussed and it is revealed that the vessel wall may severely restrict passage of solutes from the transpiration stream to the free space of the mesophyll.
Abstract: The histology and fine structure of the transverse veins that connect the longitudinal veins in the leaf of wheat (Triticum aestivum L. cv. Heron) are illustrated and discussed. The transverse veins consist of a single sieve tube and vessel, and two files of vascular parenchyma cells. They lack the mestome sheath and parenchyma sheath that is present around longitudinal veins except where they make connection with longitudinal veins. The vascular elements of the transverse veins are connected to metaxylem and metaphloem of the longitudinal veins and these connections are illustrated in sections. The tracheary elements have an unusual pattern of wall thickening. Experiments with ferric chloride solutions reveal that the vessel wall may severely restrict passage of solutes from the transpiration stream to the free space of the mesophyll.
TL;DR: The action spectrum for pinnule opening was not influenced by leaf age, the presence or absence of CO2, or by simultaneous red light, and there is a subsidiary peak in the far red.
Abstract: The opening movements of both V. faha stomata and A. julibris8in pinnules have been shown previously to depend on a redistribution of potassium ions under the influence of light. Action spectra for both systems show peak effectiveness in blue light, at 440 nm, but for pinnule opening in A. julibri88in there is a subsidiary peak in the far red (720 nm). However, opening in far red shows an initial lag period, whereas opening in blue light is rapid. The action spectrum for pinnule opening was not influenced by leaf age, the presence or absence of CO2, or by simultaneous red light.