Vegetative growth, morphogenesis and carbohydrate content of the onion plant as a function of light and temperature under field- and controlled conditions

Growth, morphogenesis and carbohydrate content of the onion plant (Allium cepa L., cv. 'Wijbo' as influenced by light and temperature, during the entire growth cycle, were studied under field conditions and controlled conditions (phytotron).A. LIGHT INTENSITY EFFECTSPlants were grown at various light intensities in the field and in the phytotron.1. Fresh and dry weight of the entire plant and its various organs, i.e., root, blade, neck, and bulb increased with increasing light intensity. The time trend shows a rise in entire plant fresh and dry weight up to a maximum at the end of the growing season. Bulb weight progressively increased with time to a maximum at the end of the growth period, whereas root, neck, and leaf weight usually increased with time up to a certain moment and then decreased or flattened off; however, in some cases, leaf and neck continued to increase up to the end of experiment.2. The average daily growth rate over the entire season (dry weight gain per plant per day) increased with increasing light intensity; the increase was exponential in 1964, linear in 1965 and curvilinear in the phytotron experiment. The average NAR over 126 and 135 days after sowing in the 1964 and 1965 field experiments respectively was linearly related to relative light intensity, while in the phytotron a curvilinear relationship was found. Although NAR at the highest light intensity in the phytotron only was about one-half of that in the field experiments, the daily growth rate in the phytotron was about two times that in the field experiments, owing to more vigorous growth in leaf area under controlled conditions.3. Leaf number per plant was positively correlated with light intensity; at all light intensities, leaf number increased with time to a maximum, and thereafter decreased. Leaf thickness and diameter decreased with reduction of light intensity; this also holds true for leaf length in the early stages of growth, while later on leaf length at 37 % in the 1965 field experiment and at 35 % in the phytotron experiments, surpassed that at all other light intensities. Leaf length/diameter ratio increased with reduction of light intensity.4. In the early stages of growth, total green leaf area per plant in all experiments increased with increasing light intensity; later on total green leaf area at 35 % light intensity the phytotron experiment exceeded that in all other treatments. In all cases, total green leaf area increased with time to a maximum, and then decreased.5. There was a positive effect of light intensity on neck diameter; it increased with time to a maximum, and then fell off in most cases. In the 1965 field experiment and in the phytotron experiment, neck length in the 37 and 35 % treatments at a certain moment surpassed that at all light intensities.6. Leaf area ratio, top/bulb ratio and top/root ratio were negatively correlated with light intensity. With the exceptional rise between the first and the second harvest, leaf area ratio decreased with time to a minimum at the end of the experiment.7. The reduction of light intensity to as low as 12 % in the field experiments and to 11 % = 10 000 ergs/cm 2/sec in the phytotron experiment delayed bulb development, but did not prevent it.8. With reduction in light intensity, the total soluble sugar content in various plant organs decreased. The sugar level in different plant parts increased with time to a maximum and then, in some cases, tended to decline especially in leaf and neck.In general, growth of the onion plant was reduced by the reduction of light intensity and, moreover, distribution of dry weight over the various organs changed with change in light intensity in such a way that with reduction of light intensity, leaves accumulated relatively more weight, roots and bulbs relatively less. Along with energetic effects, light intensity also induced some morphogenetic changes, e.g., relative increase in length and decrease in diameter of leaves with the reduction in light intensity. As long as the light intensity is sufficient for the survival of the plants, bulb development will ultimately occur.B. DAYLENGTH, INTENSITY AND QUALITY OF SUPPLEMENTARY LIGHT EFFECTS1. Under short day conditions (8hrs. in the field, or 12 hrs. of a mixture of fluorescent and incandescent light in the phytotron), the plants failed to develop bulbs. This also holds true when fluorescent light of 120 W/33 or 40 W/55 Philips tubes was used to extend a short photoperiod or even under continuous fluorescent light alone (24 hrs.).2. In the early stages of growth (up to 120 days after sowing), total plant fresh and dry weight was little affected by the quality of the supplementary light (fluorescent or incandescent); being somewhat higher under supplementary incandescent light than under short day (8 hrs.) or short day with supplementary fluorescent light. Later on, the position was reversed. Similarly, root, neck and swollen neck base early in the season tended to have slightly higher weights under incandescent light supplementation than under short day or short day with fluorescent light extension. At later stages the reverse was true, however, bulb weight under incandescent supplementary light exceeded that of swollen neck base under short day or short day extended by fluorescent supplementary light. Leaf fresh and dry weight and total green leaf area per plant were more or less the same in all treatments from the date of sowing up to 120 days old; at more advanced age, leaf fresh and dry weight and total green leaf area were lower in plants grown under long day with incandescent light supplementation.3. In general, longer leaves were produced under long day conditions, and particularly with incandescent light supplementation. Leaf diameter under short day and long day with supplementary incandescent light, while close together, exceeded that under long day with supplementary fluorescent light. Specific leaf weight (weight per unit area) under long day with supplementary incandescent light was lower than under short day and under long day with supplementary fluorescent light.4. Neck length was greater under long day conditions, especially with in candescent light extension. Up to 120 days after sowing, neck length, while equal under short day and long day with supplementary incandescent light, surpassed that under long day with supplementary fluorescent light. At more advanced age, neck diameter under long day with supplementary incandescent light lagged behind those at the other treatments.5. Whether admixed to fluorescent light in a long photoperiod or used to extend a short photoperiod, incandescent light proved essential to bring about the photoperiodic reactions. The superiority of incandescent light over other light sources is due to the ratio of red: far-red it contains; neither red nor far red alone induced bulbing.6. The daily duration of light appears more important than the intensity of supplementary light. Eight hours of incandescent supplementary light, used to extend a main photoperiod of 12 hrs. supplied by fluorescent light tubes induced bulbing, whereas 4 hrs. failed to do so within the range of intensities of the supplementary light used. However, under 720 ergs/cm 2/sec supplementary incandescent light for 8 hrs., bulb development was not homogeneous; increasing the intensity of supplementary light supplied for 8 hrs. tended to speed up bulb development.7. Young (up to 45 days old) as well as very old plants (189 days) are less sensitive to photoperiodic treatments than those of intermediate ages. In 45 days old plants, total green leaf area per plant continued to increase during 8 weeks in long day; in plants ranging from 74 to 130 days old it increased during the first 4 weeks in long day only; in still older plants total green leaf area did not show any increase following transfer to inductive cycles.8. A positive correlation was observed between the size of the plant at the time of exposure to long day, and the final bulb weight.Generally speaking, bulb development begins only under long day conditions provided the light is of the proper light quality. Incandescent light which contains a reasonable ratio of red: far-red energy proved essential in this respect. Increase of the intensity of supplementary light speeds up bulb development, the daily duration of light, however, is more important than the intensity of supplementary light. The quality of supplementary light induces some formative changes aside of induction of bulbing, e.g., in leaf shape. The plants do not respond to the photoperiodic treatment until after they had attained a certain physiological age.C. TEMPERATURE EFFECTS (EXPERIMENTS UNDER CONTROLLED CONDITIONS)1. In the early stages of growth (up to 73 days after sowing), differences in entire plant fresh and dry weight were not marked at a temperature range of 15 to 25°C, though there was a tendency to be slightly higher at 15 and 20°C than at 25°C, with temperatures beyond this range, total plant fresh and dry weight markedly decreased. The decrease, however, was more pronounced at 10 than at 30°C. At all temperatures, the entire plant fresh and dry weight increased with time till a maximum was obtained at the end of the experiment; the highest values recorded by then (186 days after sowing) were those at 20 and 25°C, Growth in weight of various plant organs was differently affected by temperature; leaf and bulb weight in contrast to root weight was favoured by relatively high temperature. The time trend shows an increase in root, leaf and neck weight up to a certain moment which varied with temperature, thereafter, usually decreased or levelled off. The higher the temperature, the earlier this tended to be. By contrast, bulb fresh and dry weight progressively increased with time, up to the end of the growth period; the highest bulb weight was found at 25°C,2. Early in the growth cycle, leaf number per plant increased with rise in temperature up to 30°C. however, in the range from 20 to 30°C. differences in leaf number were not appreciable. Later on, leaf number at 25°C, exceeded those at all other temperatures. At all temperatures, leaf number increased with time to a maximum, and then decreased. The predominance of bulbing on new leaf emergence was clearer at 25 than at 30°C.3. Temperature influences leaf shape. Increase in temperature up to 25°C, resulted in longer leaves; higher temperature (30°C) reduced leaf length. Leaf diameter was less influenced by temperature. Up to 127 days old, growth in leaf diameter tended to be favoured by relatively low temperature (15 -20 °C); leaf diameter at 10 and 30°C. while close together, lagged behind those at the other temperatures.4. The largest total green leaf area per plant was found at 20 or 25°C higher or lower temperatures reduced green leaf area per plant. At all temperatures, green leaf area increased with time up to a certain moment, different according to treatment, and then declined.5. Leaf area ratio and top/root ratio increased with temperature up to 25°C, and then slightly decreased with further increase in temperature; these ratio's, however, at 30 °C were still higher than in the temperature range from 10 to 20°C In general, leaf area ratio at all temperatures decreased with time.6. Under long day conditions (15.5 hrs.) high temperatures speeded up bulb development; low temperatures (10 and 15°C) markedly delayed it and all plants bolted. Under the experimental conditions applied, 25°C, appeared optimal for bulb growth.7. Throughout the growth cycle, the total soluble sugar content in various plant organs was highest at 15°C, except in the latest stage where the concentration at 10°C, generally, exceeded those at other temperatures. The time trend shows an increase in sugar level till a maximum was reached at a certain moment which differed according to treatment.On the whole, temperature influences growth and development of the onion plant, induces some morphogenetic changes, alters the duration of the growth cycle, affects dry weight distribution over the various plant parts and leads to changes in the total soluble sugar content of the different plant organs.Carbohydrate by itself does not appear to be a causal factor for bulb development.It should be observed that the reported temperature effects are found under the values for the other experimental conditions as applied. It is likely that the effect of temperature on various growth and developmentphenomenadifrers, e.g., in different light intensity, as far as magnitude or optimal temperatures for the various effects are concerned.It might be remarked that the same may hold for, e.g., light intensity effects with respect to temperature, but this is not the same, as light intensity as the main source of energy strongly predominates other effects under not specifically extreme conditions

Immunoablation of cells expressing the NG2 chondroitin sulphate proteoglycan

YesExpression of the transmembrane NG2 chondroitin sulphate proteoglycan (CSPG) defines a distinct population of NG2-glia. NG2-glia serve as a regenerative pool of oligodendrocyte progenitor cells in the adult central nervous system (CNS), which is important for demyelinating diseases such as multiple sclerosis, and are a major component of the glial scar that inhibits axon regeneration after CNS injury. In addition, NG2-glia form unique neuron–glial synapses with unresolved functions. However, to date it has proven difficult to study the importance of NG2-glia in any of these functions using conventional transgenic NG2 ‘knockout’ mice. To overcome this, we aimed to determine whether NG2-glia can be targeted using an immunotoxin approach. We demonstrate that incubation in primary anti-NG2 antibody in combination with secondary saporin-conjugated antibody selectively kills NG2-expressing cells in vitro. In addition, we provide evidence that the same protocol induces the loss of NG2-glia without affecting astrocyte or neuronal numbers in cerebellar brain slices from postnatal mice. This study shows that targeting the NG2 CSPG with immunotoxins is an effective and selective means for killing NG2-glia, which has important implications for studying the functions of these enigmatic cells both in the normal CNS, and in demyelination and degeneration

Evaluating the quality of sampling frames used in European cross-national surveys

This report addresses the quality of the population registers which are currently being used as sampling frames in countries participating in the four cross-European surveys cooperating in SERISS: the European Social Survey (ESS), the European Values Study (EVS), the Gender and Generations Program (GGP), and the Survey of Health, Ageing, and Retirement in Europe (SHARE). It summarizes what efforts have been undertaken by register authorities to improve and update the registers and presents an inventory of the main problems encountered in the field by survey sampling experts. In addition, it discusses the quality of alternative methods of sampling and possible improvements. Finally, the report reflects on how the major problems in sampling frames affect survey research and how they could be tackled to jointly improve sampling practice

Neuroimmunomodulatory and neuroprotective effects of the flavonoid apigenin in in vitro models of neuroinflammation associated with Alzheimer's disease

Neurodegenerative disorders (ND) are characterized by the progressive and irreversible loss of neurons. Alzheimer’s Disease (AD) is the most incident age-related ND, in which the presence of a chronic inflammatory compound seems to be related to its pathogenesis. Different stimuli in the central nervous system (CNS) can induce activation, proliferation, and changes in phenotype and glial function, which can be modulated by anti-inflammatory agents. Apigenin (4,5,7–trihydroxyflavone) is a flavonoid found in abundance in many fruits and vegetables, that has shown important effects upon controlling the inflammatory response. This study evaluated the neuroprotective and neuroimmunomodulatory potential of apigenin using in vitro models of neuroinflammation associated with AD. Co-cultures of neurons and glial cells were obtained from the cortex of newborn and embryonic Wistar rats. After 26 days in vitro, cultures were exposed to lipopolysaccharide (LPS; 1 μg/ml), or IL-1β (10 ng/ml) for 24 h, or to Aβ oligomers (500 nM) for 4 h, and then treated with apigenin (1 μM) for further 24 h. It was observed that the treatment with apigenin preserved neurons and astrocytes integrity, determined by Rosenfeld’s staining and immunocytochemistry for β-tubulin III and GFAP, respectively. Moreover, it was observed by Fluoro-Jade-B and caspase-3 immunostaining that apigenin was not neurotoxic and has a neuroprotective effect against inflammatory damage. Additionally, apigenin reduced microglial activation, characterized by inhibition of proliferation (BrdU+ cells) and modulation of microglia morphology (Iba-1 + cells), and decreased the expression of the M1 inflammatory marker CD68. Moreover, as determined by RT-qPCR, inflammatory stimuli induced by IL-1β increased the mRNA expression of IL-6, IL-1β, and CCL5, and decreased the mRNA expression of IL-10. Contrary, after treatment with apigenin in inflammatory stimuli (IL-1β or LPS) there was a modulation of the mRNA expression of inflammatory cytokines, and reduced expression of OX42, IL-6 and gp130. Moreover, apigenin alone and after an inflammatory stimulus with IL-1β also induced the increase in the expression of brain-derived neurotrophic factor (BDNF), an effect that may be associated with anti-inflammatory and neuroprotective effects. Together these data demonstrate that apigenin presents neuroprotective and anti-inflammatory effects in vitro and might represent an important neuroimmunomodulatory agent for the treatment of neurodegenerative conditions

Earthworm records and habitat associations in the British Isles

The National Earthworm Recording Scheme (NERS) is the most comprehensive national database of earthworm species occurrence records for the British Isles, and possibly for any individual country in the world. Utilising the NERS database, we sought to update the current knowledge of earthworm species occurrences in the UK, Ireland and Channel Islands; identify species-specific habitat and microhabitat associations; reveal any biases and complementarities between amateur naturalist and research-related earthworm record collection; and inform how future earthworm sampling can be better focussed to improve our knowledge of earthworm ecology. We found that the most commonly occurring earthworm species were present in farmland and woodland, and recovered via soil pit sampling, the most common habitat-sampling protocol combinations. However, several earthworm species showed specificity to alternative habitats (such as trees, wetlands, and compost), and association with microhabitat (non-soil) sampling. There were clear disparities between scientific researchers and amateur naturalist recorders in terms of habitat types visited and sampling protocols/microhabitats used in the collection of earthworm records. Most importantly, we found that earthworm species currently considered to be nationally ‘rare’ in the British Isles are significantly associated with the most under-represented habitat-protocol/microhabitat combinations (forest deadwood and other microhabitats, in addition to scrubland, wetland and heathland habitats), and thus may not be rare, only under-sampled. We therefore encourage earthworm researchers and recorders to give greater attention to these situations, to gain new insights into these earthworm species' ecologies and distributions. Finally, we would like to promote the establishment of earthworm recording schemes in other countries, to enable national and global collaborative monitoring of earthworm responses to environmental change

Magnetic fields in cosmic particle acceleration sources

We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review

Phytoestrogen agathisflavone ameliorates neuroinflammation-induced by LPS and IL-1β and protects neurons in cocultures of glia/neurons

Inflammation and oxidative stress are common aspects of most neurodegenerative diseases in the central nervous system. In this context, microglia and astrocytes are central to mediating the balance between neuroprotective and neurodestructive mechanisms. Flavonoids have potent anti-inflammatory and antioxidant properties. Here, we have examined the anti-inflammatory and neuroprotective potential of the flavonoid agathisflavone (FAB), which is derived from the Brazilian plant Poincianella pyramidalis, in in vitro models of neuroinflammation. Cocultures of neurons/glial cells were exposed to lipopolysaccharide (LPS, 1 µg/mL) or interleukin (IL)-1β (10 ng/mL) for 24 h and treated with FAB (0.1 and 1 µM, 24 h). FAB displayed a significant neuroprotective effect, as measured by nitric oxide (NO) production, Fluoro-Jade B (FJ-B) staining, and immunocytochemistry (ICC) for the neuronal marker β-tubulin and the cell death marker caspase-3, preserving neuronal soma and increasing neurite outgrowth. FAB significantly decreased the LPS-induced microglial proliferation, identified by ICC for Iba-1/bromodeoxyuridine (BrdU) and CD68 (microglia M1 profile marker). In contrast, FAB had no apparent effect on astrocytes, as determined by ICC for glial fibrillary acidic protein (GFAP). Furthermore, FAB protected against the cytodestructive and proinflammatory effects of IL-1β, a key cytokine that is released by activated microglia and astrocytes, and ICC showed that combined treatment of FAB with α and β estrogen receptor antagonists did not affect NF-κB expression. In addition, qPCR analysis demonstrated that FAB decreased the expression of proinflammatory molecules TNF-α, IL-1β, and connexins CCL5 and CCL2, as well as increased the expression of the regulatory molecule IL-10. Together, these findings indicate that FAB has a significant neuroprotective and anti-inflammatory effect in vitro, which may be considered as an adjuvant for the treatment of neurodegenerative diseases

The flavonoid agathisflavone modulates the microglial neuroinflammatory response and enhances remyelination

Myelin loss is the hallmark of the demyelinating disease multiple sclerosis (MS) and plays a significant role in multiple neurodegenerative diseases. A common factor in all neuropathologies is the central role of microglia, the intrinsic immune cells of the central nervous system (CNS). Microglia are activated in pathology and can have both pro- and anti-inflammatory functions. Here, we examined the effects of the flavonoid agathisflavone on microglia and remyelination in the cerebellar slice model following lysolecithin induced demyelination. Notably, agathisflavone enhances remyelination and alters microglial activation state, as determined by their morphology and cytokine profile. Furthermore, these effects of agathisflavone on remyelination and microglial activation were inhibited by blockade of estrogen receptor α. Thus, our results identify agathisflavone as a novel compound that may act via ER to regulate microglial activation and enhance remyelination and repair

Precision X-ray spectroscopy of kaonic atoms as a probe of low-energy kaon-nucleus interaction

In the exotic atoms where one atomic $1s$ electron is replaced by a $K^{-}$, the strong interaction between the $K^{-}$ and the nucleus introduces an energy shift and broadening of the low-lying kaonic atomic levels which are determined by only the electromagnetic interaction. By performing X-ray spectroscopy for Z=1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the shift and width for the $1s$ state of $K^{-}p$ and the $2p$ state of kaonic helium-3 and kaonic helium-4. These results provided unique information of the kaon-nucleus interaction in the low energy limit.Comment: 4 pages, 1 figure, proceedings for oral presentation at the ICNFP2015 conference, Kolymbari, Cret

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe