Effect of (Changes in) Air Humidity on Transpiration and (Adaptation of) Stomatal Closure of Tradescantia Leaves during Water Stress

This paper summarises our recent research on the physiological effects of prolonged high RH during growth on stomatal function and we discuss possibilities that arise from this work for reducing postharvest quality problems in cut flowers. Chlorophyll fluorescence imaging was used to measure stomatal closure in response to desiccation of Tradescantia virginiana leaves grown under high (90%) and moderate (55%) relative humidities, or transferred between these humidities. Stomata of plants transferred from moderate RH conditions to high RH showed the same diminished closure in response to desiccation, as did stomata that developed at high RH. This response was found both when the leaves were either fully expanded or still actively expanding during the moderate RH pre-treatment. However, when leaves were grown in high RH prior to a moderate RH treatment, the reduced stomatal closure response to desiccation was only reversed in leaves (regions) which were still actively expanding during moderate RH treatment. This indicates that with respect to stomatal responses to desiccation, high RH leaf regions have only a limited capacity to adapt after transfer to moderate RH conditions. It is suggested that the diminished stomatal closure in high RH-grown plants is the result of changes in the signalling pathway for ABA-related closure induced by a prolonged period (several days) at a low ABA level. A short increase of VPD (by decreasing RH or increasing temperature) once every 2 or 3 days is probably sufficient to overcome vase life problems of cut flowers grown at high RH. Testing the acclimation ability of stomata to desiccation by transferring high RH grown plants to low VPD for just a few days would be a simply and effective screening procedure for genotypes with more adaptable stomat

Spatial Implications of Urban Functional Classification: A Study of Small Urban Places in the North-Central United States

The idea that cities have diverse economic structures and social characteristics is commonly understood. Many times these differences can be traced to historical regional growth or resource availability. Recognition and better understanding of these different types of cities requires their classification. Classification is way to organize complex and diverse information in order to create a better understanding of processes and relationships. One of the ways in which geographers have classified cities, in terms of describing the external relations, is called functional town classification. The simplest way of classifying cites is to identify the distinctive role they play in the city system. The purpose of this thesis is to examine the spatial distribution of economic functions for the small urban places in the study area using a standard classification method for urban geography, and by utilizing nearest neighbor analysis. This study should produce spatial patterns of distribution based on the site and situation of the place. There may also be a strong influence of function based upon proximity to a larger urban area. The creation of a contemporary taxonomy of the small urban places in the study area, and subsequent understanding of the spatial distribution of dominant economic features should provide the base for future investigation into small urban center relationships and classification

A systematic review on heart-rate recovery to monitor changes in training status in athletes

Heart-rate recovery (HRR) has been proposed as a marker of autonomic function and training status in athletes. The authors performed a systematic review of studies that examined HRR after training. Five cross-sectional studies and 8 studies investigating changes over time (longitudinal) met our criteria. Three out of 5 crosssectional studies observed a faster HRR in trained compared with untrained subjects, while 2 articles showed no change as a result of training. Most longitudinal studies observed a corresponding increase in HRR and power output (training status). Although confounding factors such as age, ambient temperature, and the intensity and duration of the exercise period preceding HRR make it difficult to compare these studies, the available studies indicated that HRR was related to training status. Therefore, the authors conclude that HRR has the potential to become a valuable tool to monitor changes in training status in athletes and less well-trained subjects, but more studies and better standardization are required to match this potential

DOCIS :a Model to Simulate Carbohydrate Balance and Development of Inflorescence during Vase Life

The concept of a dynamic and deterministic model (DOCIS) was developed to simulate post harvest development of an inflorescence during vase life based on carbohydrate content at harvest. The model was partly parameterized using lily ‘Enchantment’. The inflorescence as a system was defined by the state variables: the carbohydrate pool, structural biomass and development stage of each floret in the inflorescence and the carbohydrate pool in the stem. An additional auxiliary state variable was used to describe whether a floret is alive or dead due to shortage of carbohydrate supply. The model is temperature driven. It is assumed that the available carbohydrates are distributed among the floret(bud)s proportional to their total sink strengths. An osmotic pool of the petal cells is included which is treated as an independent sink. By priority, carbohydrates imported by a floret are used for maintenance respiration. Distribution of available carbohydrates among the osmotic and the non-osmotic (substrate available for structural biomass production) pool was assumed to be proportional to the sink strengths of both pools. Sink strength was defined as the capacity to accumulate carbohydrates under conditions of non-limiting carbohydrate supply. Available carbohydrates did not influence osmotic potential of petal juice (vacuolar solution) at a certain development stage. The resulting concept of constant osmotic potential makes it possible to predict floret fresh weight (size), an important aspect of decorative value

Effect of pharmacologically induced smooth muscle activation on permeability in murine colitis.

BACKGROUND: Both intestinal permeability and contractility are altered in inflammatory bowel disease. Little is known about their mutual relation. Therefore, an in vitro organ bath technique was developed to investigate the simultaneous effects of inflammation on permeability and smooth muscle contractility in different segments of the colon. METHODS AND MATERIALS: BALB/c mice were exposed to a 10% dextran sulphate sodium drinking water solution for 7 days to induce a mild colitis, while control mice received normal tap water. Intestinal segments were placed in an oxygenated organ bath containing Krebs buffer. Permeability was measured by the transport of the marker molecules 3H-mannitol and 14C-polyethyleneglycol 4000. Contractility was measured through a pressure sensor. Smooth muscle relaxation was obtained by salbutamol and l-phenylephrine, whereas contraction was achieved by carbachol and 1-(3-chlorophenyl)-biguanide. RESULTS: The intensity of mucosal inflammation increased throughout the colon. Also, regional differences were observed in intestinal permeability. In both normal and inflamed distal colon segments, permeability was diminished compared with proximal colon segments and the non-inflamed ileum. Permeability in inflamed distal colon segments was significantly decreased compared with normal distal segments. Pharmacologically induced relaxation of smooth muscles did not affect this diminished permeability, although an increased motility positively affected permeability in inflamed and non-inflamed distal colon. CONCLUSIONS: Inflammation and permeability is inversely related. The use of pro-kinetics could counteract this disturbed permeability and, in turn, could regulate the disturbed production of inflammatory mediators

NAA and STS effects on potted bougainvillea: early flower death allows delayed bract abscission

The effects of Silver Thiosulphate (STS) and Naphtalene Acetic Acid (NAA) (0,45%NAA+1,2% NAA-amide at 500 mg.l-1) on flowering bud development, anthesis duration, bract longevity and bract photosynthetic rate were studied in Bougainvillea spectabilis ‘Killie Campbell’ plants, under interior conditions. The relationships between bract longevity and the above parameters were also investigated. NAA induced longer bract longevities, shorter flower anthesis duration and lower percentage of flowers reaching anthesis. STS alone increased duration of flower anthesis but did not affect CD (completely developed) bract abscission, as compared to the water treatment. Depending on the experiment, adding STS to NAA delayed or had no effect on bract abscission. Longer bract longevities were related to shorter flower anthesis and lower percentage of flowers reaching anthesis. Manual removal of flowers from the bract+flower unit increased bract longevity. Despite the low level of irradiance, bracts photosynthesized and plants treated with NAA (alone or with STS) had lower bract photosynthetic rates. Bract photosynthetic activity, although with relevant rates (similar to leaves and most probably capable of covering respiration expenditure) did not seem important as an energy source for bract longevity since bracts that lasted longer had lower photosynthetic rates. In the water control, percentage of flowers reaching anthesis positively correlated with bract photosynthetic rates. In potted bougainvillea under low light conditions, flower senescence and bract abscission are under different types of control. In addition to the classical effect of auxin reducing ethylene production, and/or sensitivity of the abscission zone to ethylene, NAA delays bougainvillea bract abscission via early interruption of flower development.Praxis XXI/BD/15640/98, PBIC/C/2286/95, da Fundação para a Ciência e Tecnologica. CDCTPV/University of Algarve (incluindo Projecto de Unidade I&D: CDCTPV 2003- 2005. POCTI7POCI 2010) pelas instalações. Viveiros Monterosa, (Moncarapacho, Portugal) ofereceram algumas das plantas

Somatostatin does not attenuate intestinal injury in dextran sodium sulphate-induced subacute colitis.

FRom several in vitro and in vivo studies involvement of somatostatin (SMS) in intestinal inflammation emerge. Acute colitis induced in rats is attenuated by the long-acting SMS analogue octreotide. We studied the potential beneficial effect of SMS on non-acute experimental colitis. BALB/c mice received either saline, SMS-14 (36 or 120 microg daily) or octreotide (3 microg daily) subcutaneously delivered by implant osmotic pumps. A non-acute colitis was induced by administration of dextran sodium sulphate (DSS) 10% in drinking water during 7 days. DSS evoked a mild, superficial pancolitis, most characterized by mucosal ulceration and submucosal influx of neutrophils. Neither SMS-14 nor octreotide reduced mucosal inflammatory score or macroscopical disease activity, although reduction of intestinal levels of interleukin-1beta (IL-1beta), IL-6 and IL-10 during DSS was augmented both by SMS and octreotide. A slight increase of neutrophil influx was seen during SMS administration in animals not exposed to DSS. In conclusion, SMS or its long-acting analogue did not reduce intestinal inflammation in non-acute DSS-induced colitis. According to the cytokine profile observed, SMS-14 and octreotide further diminished the reduction of intestinal macrophage and Th2 lymphocyte activity

Genotypic differences in metabolomics changes during storage induced-degreening of chrysanthemum disk florets

Plant science