Endogenous Auxin Profile in the Christmas Rose (Helleborus niger L.) Flower and Fruit: Free and Amide Conjugated IAA

The reproductive development of the Christmas rose (Helleborus niger L.) is characterized by an uncommon feature in the world of flowering plants: after fertilization the white perianth becomes green, photosynthetically active and persists during fruit development. In the flowers in which fertilization was prevented by emasculation (unfertilized) or entire reproductive organs were removed (depistillated), the elongation of the peduncle was reduced by 20 to 30%, and vascular development, particularly lignin deposition in sclerenchyma was arrested. Chlorophyll accumulation in sepals and their photosynthetic efficacy was up to 80% lower in comparison to fertilized flowers. Endogenous auxins were investigated in floral and fruit tissues and their potential roles in these processes were discussed. Analytical data of free indole-3-acetic acid (IAA), indole-3-ethanol (IEt), and seven amino acid conjugates were afforded by LC-MS/MS in floral tissues of fertilized as well as unfertilized and depistillated flowers. Among amino acid conjugates novel ones with Val, Gly, and Phe, were identified and quantified in the anthers, and in the fruit during development. Reproductive organs before fertilization, followed by developing fruit at post-anthesis were the main source of auxin. Tissues of unfertilized and depistillated flowers accumulated significantly lower level of auxin. Upon depistillation, auxin content in the peduncle and sepal was decreased to 4% and 45%, respectively, in comparison to fruit-bearing flowers. This study suggests that auxin arising in developing fruit may participate, in part, in coordination of the Christmas rose peduncle elongation and its vascular development

Emerging carbon-based nanosensor devices: structures, functions and applications

Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Carbon-based materials are critical for sensing applications, as they have physical and electronic properties which facilitate the detection of substances in solutions, gaseous compounds and pollutants through their conductive properties and resonance-frequency transmission capacities. In this review, a series of recent studies of carbon nanotubes (CNTs) based nanosensors and optical systems are reported, with emphasis on biochemical, chemical and environmental detection. This study also encompasses a background and description of the various properties of the nanomaterials, and the operation mechanism of the manufactured nanosensors. The use of computational chemistry is applied in describing the electronic properties and molecular events of the included nanomaterials during operation. This review shows that resonance-based sensing technologies reach detection limits for gases, such as ammonia down to 10(-24) level. The study also shows that the properties of the carbon nanomaterials give them unique features that are critical for designing new sensors based on electrocatalysis and other reactive detection mechanisms. Several research fields can benefit from the described emerging technologies, such as areas of research in environmental monitoring, rapid-on site diagnostics, in situ analyses, and blood and urine sampling in medical and sport industry. Carbon nanomaterials are critical for the operational sensitivity of nanosensors. Considering the low cost of fabrication, carbon nanomaterials can represent an essential step in the manufacturing of tomorrow's commercial sensors