Miracle-dz/UniFAR-FTUs huggingface dataset:
Chromosomal location of a gene conditioning insensitivity in wheat to a necrosis-inducing culture filtrate from Pyrenophora tritici-repentis

Previous research indicates that infection by the tan spot fungus (Pyrenophora tritici-repentis) produces two genetically distinct symptoms in wheat (Triticum aestivum) : tan necrosis and extensive chlorosis. Necrosis-inducing isolates of P. tritici-repentis release a host-selective toxin in culture that produces a reaction highly associated with the induction of tan necrosis in susceptible wheat genotypes. The objectives of this research were to determine the number of genes conditioning insensitivity to a necrosis-inducing culture filtrate in a population of wheat F 3 families, and to map the insensitivity gene(s) using restriction fragment length polymorphisms (RFLPs). The population consisted of 58 F 3 families derived from the cross of a resistant synthetic hexaploid, W-7976, with the susceptible cultivar 'Kulm. ' At least 16 individuals from each F 3 family were infiltrated with culture filtrate from the P. tritici-repentis isolate 86-124 and were scored as insensitive or sensitive. Low-copy DNA clones that hybridized to group 5 wheat chromosomes were used to detect RFLPs associated with insensitivity. The families segregated in a ratio of 15 :29 :14 homozygous insensitive/segregating/homozygous sensitive, suggesting that a single nuclear gene was responsible for conditioning insensitivity to the pathogenic factor(s) in the culture filtrate. RFLPs were detected that flanked the locus conferring insensitivity at distances of 5.7 and 16.5 cM. Aneuploid analysis indicated that this gene resided on the long arm of chromosome 5B. We proposed the symbol tsnl to designate this gene.
Alfalfa Root Carbohydrates and Regrowth Potential in Response to Fall Harvests

The adverse effect of harvesting alfalfa (Medicago saliva L.) during a critical fall rest period on the persistence and the following spring regrowth has been historically attributed to a reduction in the levels of root organic reserves, especially total nonstructural carbohydrates (TNC). Recent reports also pointed out the role of specific carbon (C) reserve components in winter survival. This study assessed the effect of the timing of a fall harvest on the regrowth potential in relation to quantitative changes in C reserves in alfalfa roots during fall and winter. The experiment was conducted under simulated winter conditions in an unheated greenhouse with two alfalfa cultivars (AC Caribou and WL 225) subjected to four fall harvest treatments: two summer harvests (control) and a third harvest taken in the fall at 400, 500, or 600 growing degree days (GDD) after the second harvest. Shoot regrowth was reduced by a fall harvest, especially when plants were harvested at 400 or 500 GDD. Root soluble sugar concentrations (sucrose, raffinose, and stachyose) measured during the overwintering period were higher in plants harvested in the fall than in those harvested only twice; these concentrations were also higher in the more hardy cultivar AC Caribou compared with WL 225. A fall harvest did not consistently affect root TNC concentrations, but decreased markedly the total amount of TNC in roots, especially in plants harvested at 400 GDD. In both cultivars, shoot regrowth in spring was correlated positively to the total amounts of root starch (r = 0.54 and 0.61) and TNC (r = 0.55 and 0.56), but not correlated to their concentrations. Our results suggest that the total amount of C organic reserves in alfalfa roots rather than their concentrations can be determinant factors of shoot regrowth.
How New Guinea rainforest flower resources vary in time and space: implications for nectarivorous birds

Variability in spatial and temporal patterning of flowering by populations of rainforest trees fed upon by honeyeaters and flower-visiting parrots was studied for 2 years in lowland tropical hill forest in Papua New Guinea. All 2200 trees in a 3 ha plot were tagged, identified, mapped and monitored monthly. Of 274 tree species present, 86 flowered during the course of the study; during any given month, approximately 20% of the species flowering that month were visited by nectarivorous birds. Results showed that overall flower resources (total number of species, and number of bird-pollinated species, individuals and flowers) fluctuated during the year, decreased during the dry season and increased during the wet season. In addition, there was a wide range of temporal variation within and among tree species in length and timing of flowering period, percentage of each conspecific population flowering from year to year, and degree of synchrony among flowering conspecifics. Spatial dispersion of tree populations also varied, from clumps to scattered single individuals. Resident bird species were correlated with synchronously flowering trees, whereas nomadic bird species were correlated with asynchronously flowering trees. Resident birds were also associated with smaller blooming displays per tree, whereas nomadic birds were associated with trees that bloomed massively. There was no correlation between avian nomadism and spatial dispersion of tree populations. Thus nomadic birds seem to range in search of rich but unpredictable resources; resident birds may rely more on predictable, but smaller resources.
Variation in Food-Web Structure: The Determinants of Connectance

Although there is considerable evidence for a number of patterns in the structure of food webs, there is a conspicuous lack of agreement among explanations for such patterns (Pimm 1982; DeAngelis et al. 1983; May 1986; Paine 1988; Strong 1988; Lawton 1989). One pattern that has received considerable attention is the observation that connectance of a food web generally decreases with increasing species richness (Pimm 1982; Strong 1988; Lawton 1989). Connectance is a parameter of central importance in both static and dynamic theories of community structure (May 1986; Lawton 1989), and, hence, understanding the determinants of connectance in food webs is a significant problem. Connectance (C) is defined, in general terms, as the number of actual direct interactions in a web divided by the total number of possible interactions. It can be calculated (excluding intraspecific feeding) either in terms of trophic links in the food-web matrix (where each link is represented by a single element of the matrix) as C = L/[S(S 1)] or in terms of the community matrix (where each link is represented by two elements, aij and aji) as C = 2L/[S(S 1)], where S is the number of species in the web and L is the number of trophic links. Calculations in this study are all based on the former measure. In various collections of food-web data, C declines approximately hyperbolically with increasing species richness (Rejm'anek and Star' 1979; Yodzis 1980; Pimm 1982; Auerbach 1984); in other words, the product SC is approximately constant. More or less equivalently, the relationship between L and S in these data is roughly linear (Cohen and Briand 1984). Throughout this note I treat these two ways of looking at the density of links in a food web as equivalent, but for clarity I concentrate discussion on the links-to-species (L-S) relationship. Three explanations have been proposed to account for the observed patterns in this relationship, and a brief review of these is worthwhile. The first hypothesis suggests that C is determined by stability. Studies of certain general models of communities indicate that increased complexity reduces the probability of such systems' being stable; the transition from predominantly stable to predominantly unstable models is marked by the switch from i(SC)? 05 < 1 to i(SC)05 > 1 (where i is the average interaction strength) (May 1972, 1973; McMurtie 1975). That is, for a given interaction strength, C must decline with increasing S for a system to remain stable. Although the models make many
Analysis of the Use of Local Resources in Extension Education Programme in Nkonkobe Local Municipality of Eastern Cape

The paper identified the available local resources for extension education and the constraints in the use of these local resources in Nkonkobe local Municipality. The survey was conducted in the peri-urban areas of Fort Beaufort, Alice, Seymour, Balfour, Hogsback and Middledrift from 7th to 29th September 2010 by interviewing 58 farmers on the identification of local resources and their perception of constraints in the use of local resources. The study revealed that there are local resources embedded in the area for use in Extension teaching and learning. The perception of constraint (inadequate access to local resources) increased significantly with age (P = 0.04) and farm experience (P = 0.045). The fundamental strategies for a successful Extension work should be to develop a process which not only creates co-operative platforms for the use of local resources for rural improvement, but also reinforces farmer’s ingenuity and inspires them to learn and accept innovation.The available local resources in Nkonkobe Local Municipality are well distributed in the community and are important for the achievement of educational goals in Extension teaching and learning.
Isolation and differential expression of β-1,3-glucanase messenger RNAs, SrGLU3 and SrGLU4, following inoculation of Sesbania rostrata.

We report here the isolation and characterisation of two new β-1,3-glucanase cDNAs, SrGLU3 and SrGLU4, from a tropical legume Sesbania rostrata Bremek. & Oberm. , which form N2-fixing nodules on the stem after infection by Azorhizobium caulinodans. SrGLU3 was characterised as being grouped in a branch with tobacco class I β-1,3-glucanases, where the isoforms were reported to be induced by either pathogen infection or ethylene treatment. SrGLU4 was characterised as separate from other classes, and we propose this new branch as a new class (Class VI). The SrGLU3 gene was constitutively expressed in normal stem nodules induced by the wild type strain of A. caulinodans (ORS571), and also even in immature stem nodules induced by a mutant (ORS571-C1), which could not form mature stem-nodules. In contrast, the transcript accumulation of SrGLU4 was hardly detectable in immature nodules inoculated by the ORS571-C1 mutant. We suggest that S. rostrata makes use of SrGLU4 to discriminate between symbionts and non-symbionts (mutants) in developing nodules. We propose the SrGLU4 gene as a new nodulin during nodulation.
Effect of oxygen concentration on intracellular pH, glucose-6-phosphate and NTP content in rice (Oryza sativa) and wheat (Triticum aestivum) root tips: in vivo 31P-NMR study

Hypoxic pretreatment is known to induce anoxia tolerance in plant species sensitive to oxygen deprivation. However, we still do not have detailed information on changes in cytoplasmic and vacuolar pH (PH cyt and pH vac ) in plants under low-oxygen availability (hypoxia) and under anoxia. To investigate this, we have studied the influence of hypoxia and anoxia on pH cyt and pH vac , glucose-6-phosphate (Glc-6-P) and nucleotide triphosphate (NTP) contents in rice (Oryza sativa L.) root tips in comparison with those of wheat (Triticum aestivum L.) with in vivo 31 P-nuclear magnetic resonance. Both cereals responded to hypoxia similarly, by rapid cytoplasmic acidification (from pH 7.6-7.7 to 7.1), which was followed by slow partial recovery (0.3 units after 6 h). Anoxia led to a dramatic pH cyt drop in tissues of both species (from pH 7.6-7.7 to less than 7.0) and partial recovery took place in rice only. In wheat, the acidification continued to pH 6.8 after 6 h of exposure. In both plants, NTP content followed the dynamics of pH cyt . There was a strong correlation between NTP content and cytoplasmic H + activity ([H + ] cyt = 10 -pH ) for both hypoxic and anoxic conditions. Glc-6-P content increased in rice under anoxia and hypoxia. In wheat, Glc-6-P was not detectable under anoxia but increased under hypoxia. In this study, rice root tips were shown to behave as anoxia tolerant tissues. Our results suggest that the initial cytoplasmic acidification and subsequent pH cyt are differently regulated in anoxia tolerant and intolerant plants and depend on the external oxygen concentration.
Morphological and ecological differentiation of Eupelops and Propelops (Acari, Oribatida, Phenopelopidae)

In this study, the morphological and ecological differentiation of Eupelops Ewing, 1917 and Propelops Jacot, 1937 were investigated in the light of Eupelops strenzkei and Propelops canadensis. The juveniles of these species have plicate integument and a dorsoventrally flattened hysterosoma, with short and thin setae c1, c3 and of d-series on the gastronotum, whereas the shape of marginal gastronotal setae differs in these species. The juveniles of P. canadensis have all these setae short and thin, except for setae lp and of h-series in the tritonymph, which are usually longer and thicker than other setae, whereas those of E. strenzkei have most marginal setae on the gastronotum longer and thicker than other setae, especially lp and h1 in the larva and h3 in the nymphs. Moreover, P. canadensis has short seta h3 in the larva, whereas in E. strenzkei only a vestige of this seta remains, as in other Eupelops species, and this morphological character has generic value. The deutonymph, tritonymph and adult of P. canadensis have solenidion φ on tibia IV, but lack seta d, whereas those of E. strenzkei have thick seta d on this segment, but lack solenidion φ, as in other Eupelops species, which have also generic value. The adults of both species have 10 pairs of notogastral setae, including c2, but in P. canadensis setae lp and h3 are inserted close to each other, with porose area A1 between them, as in some species of Eupelops, whereas in E. strenzkei these setae are separated, with porose area A1 adjacent to seta lp, as in other species of Eupelops. The adults of both species have ventrodistal apophysis on genu I, as in other species of Eupelops and Propelops. All instars of E. strenzkei have secondarily anarthric subcapitulum, as other Eupelops species, which are used to remove dead parenchymous tissue, whereas those of P. canadensis have diarthric subcapitulum and normal chelicerae, which crumble the litter.
Study on Rehydration Characteristics of Dried Lablab Bean ( Lablab purpureus ) Seeds

The present study was carried out to evaluate the rehydration characteristics of solar and mechanically dried lablab bean ( Lablab purpureus (L.) sweet; hitherto Dolichos lablab ) seeds. Bean seeds with and without coat were used to study the rehydration properties. The rehydration ratios were higher for both mechanically and solar dried bean seeds without seed coat than those with coat. Mechanically dried without coat bean seeds had rehydration ratio of 2.34 while with coat was 2.06. For mechanically dried samples, the co-efficient of reconstitution were 0.58 and 0.56 for bean seeds without and with coat, respectively, and were higher than those of solar dried samples having co-efficient of reconstitution of 0.54 and 0.52 for bean seeds without and with coat, respectively. For both mechanical and solar drying the rehydration rate constant was higher for bean seeds without coat than those with coat. Both rehydration ratio and rehydration rate indicated that mechanically and solar dried bean seeds samples without coat showed better reconstitution properties than those with coat. Both fresh and dried bean seeds without seed coat gave higher nutrient content than their counterpart with coat. Solar and mechanical dried seeds were good source of nutrients. DOI: http://dx.doi. org/10.3329/jard.v6i1. 1673 J Agric Rural Dev 6 (1&2), 157-163, June 2008
Repeatability Precision of the Falling Number Procedure Under Standard and Modified Methodologies

The falling number (FN) procedure is used worldwide to assess the integrity of the starch stored within wheat seed. As an indirect measurement of the activity level of α-amylase, FN relies on a dedicated viscometer that measures the amount of time needed for a metal stirring rod of precise geometry to descend a fixed distance through a column of water–flour or water–meal slurry that undergoes enzyme-activated starch hydrolysis under controlled mixing and heating conditions. For U.S. wheat, FN values of 300 s and above generally indicate soundness in the condition of the seed starches, whereas values less than 300 s often indicate that some seeds have broken dormancy, which deleteriously affects bread-, cake-, and noodle-making quality of products derived from their flour. Domestic and especially overseas sales contracts will often specify a minimum FN value for consignments, thus making it critical to ensure that the FN procedure be highly precise. The study described herein examined the level of repeatab.
Grazer-epilithon interactions in an Australian upland stream

Effects of macroinvertebrate grazers on the distribution of their food resource, epilithon, were examined in a south-eastern Australian stream. The hypothesis that grazers would significantly alter the development of epilithon was tested experimentally: macroinvertebrates were excluded from some experimental substrata and allowed to colonize others. Epilithic chlorophyll a concentration, organic matter content and total diatom density were used to monitor the effects of the grazer assemblage over 35 days. As predicted, epilithon density was higher on bricks with exclusion barriers than on bricks open to colonization by grazers. Similarly, diatom densities were significantly higher on bricks from the grazer-exclusion treatment. Patterns in the development of epilithon over time point to the importance of prevailing abiotic conditions in determining the outcome of macroinvertebrate grazing. Differences in total epilithon biomass, algal biomass and diatom density between treatments clearly indicate the independent importance of macroinvertebrate grazing to the microdistribution of epilithon in upland streams.
Multiple Perforation Plates in Gmelina Arborea Roxb. (Verbenaceae)

Vessel members of Gmelina arborea Roxb. (Verbenaceae) have been reported so far to have exclusively simple perforations. In the present study based on SEM observations, however, various forms of multiple perforation plates have been found. These perforation plates always occurred as simple to multiple combination plates and the vessel members having them occurred only rarely, irregularly and solitarily in the wood. The morphology of the multiple perforation plates is illustrated by SEM micrographs.
Ecological Performance in the Actively Foraging Lizard Ameiva ameiva (Teiidae)

Abstract We examined maximal and ecological performance in Ameiva ameiva on Union Island, St. Vincent and the Grenadines. Maximal sprint speed was correlated positively with lizard body size but not with hind-limb or relative hind-limb length. Lizards in the field used over 85% of maximal capacity when escaping a putative predator, and the proportion of maximal speed used was highly dependent on behavioral context. Mean and median speeds used by adults when moving undisturbed through the habitat were 15.37 ± 2.01 (SE) and 11.41% of maximal speed; and approximately 65% of undisturbed movement is at speeds <15% of maximal capacity. No individual movement exceeded 40% of maximal capacity. Mean and median values for distances moved were 7.88 ± 0.72 (SE) and 8.14 cm, with 91% of distances moved <12 cm and 69.5% <10 cm, demonstrating that undisturbed lizards move through their habitat using short individual movements at low speeds. Similar to other studies on primarily sedentary lizards, actively foraging lizards may experience stronger natural selection on locomotor speed when evading a predator rather than while foraging because these lizards use nearly 90% of their maximal capacity during the former activity.
‘Andean‐centred’ genera in the short‐branch clade of Annonaceae: testing biogeographical hypotheses using phylogeny reconstruction and molecular dating

Aim We test biogeographical hypotheses regarding the origin of Andean‐centred plant groups by reconstructing phylogeny in the short‐branch clade (SBC) of Annonaceae, and estimating the timing of diversifications in four apparently Andean‐centred genera: Cremastosperma R.E. Fr. , Klarobelia Chatrou, Malmea R.E. Fr. and Mosannona Chatrou. The SBC includes species distributed in both the Old and New World tropics. A number of the Neotropical genera display ‘Andean‐centred’ distribution patterns, with high species richness on both sides of the Andes mountain range. In particular, we test whether these groups could have originated on the South American continent during the time frame of the Andean orogeny [from c. 23 Ma (Miocene) to the present].
Predicting fine root production and turnover by monitoring root starch and soil temperature

To determine how the longevity of fine roots (those without secondary thickening) is controlled, shoots of Douglas-fir (Pseudotsugamenziesii Mirb. (Franco)) seedlings were exposed to light or maintained in darkness while roots were maintained at 10, 20, or 30 °C. Fine root maintenance respiration rates, estimated from rates of starch and sugar depletion in the seedlings maintained in darkness, ranged from 0.83 to 3.25 mg starch g dry weight−1 day−1. At 20 and 30 °C, starch deposition was curtailed and previously deposited starch was used to maintain the older roots, whether current photosynthate was entering the root system or not. On the other hand, at 10 °C starch was deposited in the roots whenever the root systems grew. Based on these results, we suggest that starch deposition in a fine root occurs only when the root is being formed and the root carbon balance is positive. Starch is subsequently respired to meet maintenance requirements exclusively. A simple means of estimating root biomass production.
A biophysical process model of tree mortality in surface fires

The mechanisms governing tree mortality in surface fires are poorly understood, owing in large part to the ab- sence of a process-based framework for defining and evaluating these mechanisms. This paper begins the development of such a framework by deriving a first-order process model of tree mortality in surface fires (intensities less than approxi- mately 2500 kWm -1 ). A buoyant line-source plume model is used to drive heat transfer models of vascular cambium and vegetative bud necroses, which are linked to tree mortality using an allometrically-based sapwood area budget. Model pre- dictions are illustrated for white spruce (Picea glauca), lodgepole pine (Pinus contorta), and trembling aspen (Populus tremuloides) and are compared with independent mortality data for Engelmann spruce (Picea engelmannii Parry ex En- gelm.) and Pinus contorta Dougl. Results help define first-order mortality mechanisms and suggest second-order mortality mechanisms that should be incorporated into future modeling efforts. Resume´ : Les mecanismes qui regissent la mortalitedes arbres ala suite d'un feu de surface sont peu connus, surtout a cause de l'absence de cadre theorique basesur les processus permettant de definir et d'evaluer ces mecanismes. Cet article jette les bases d'un tel cadre theorique en derivant un modele de premier ordre de mortalitedes arbres basesur les proces- sus ala suite d'un feu de surface (intensiteinferieure aenviron 2500 kWm -1 ). Un modele de panache flottant dont la source est lineaire est utilisepour faire fonctionner des modeles de transfert de chaleur du cambium vasculaire et de ne ´- crose des bourgeons foliaires, laquelle est relieeala mortalitedes arbres grace a un bilan de surface d'aubier basesur des relations allometriques. Les predictions du modele sont illustrees pour l'epinette blanche (Picea glauca), le pin tordu (Pinus contorta), et le peuplier faux-tremble (Populus tremuloides) et sont comparees ades donnees independantes de mortalitepour le l'epinette d'Engelmann (Picea engelmannii Parry ex Engelm.) et Pinus contorta Dougl. Les resultats ai- dent a definir les mecanismes de premier ordre et a suggerer des mecanismes de second ordre al'origine de la mortalite ´. Ces mecanismes devraient etre retenus lors de tentatives futures de modelisation. (Traduit par la Redaction)