1,721,149 research outputs found
Leaf senescence-associated genes and transcriptional changes under dark conditions
No full textBackground Leaf senescence is a highly regulated and complex process that can be triggered by dark conditions, as demonstrated in various studies. Dark-induced leaf senescence resembles natural senescence by triggering typical symptoms such as protein degradation and chlorophyll loss. Transcription factors have been recognized as key modulators of dark-induced senescence and are associated with plant hormones such as cytokinins, ethylene, gibberellins and jasmonic acid. Treatments with cytokinins and gibberellins can delay leaf senescence caused by darkness.Scope This review aimed to collect information regarding the biochemical, physiological and molecular mechanisms underlying senescence induced by dark incubation. The main variations that occur during leaf senescence are highlighted and discussed. Specific genes associated with dark-induced senescence and related metabolic pathways are described.Conclusions This study highlights the intricate nature of the senescence process and explores how genetic and environmental factors can be manipulated to slow down or prevent senescence. These insights have significant implications for improving crop productivity, extending product shelf life and enhancing vase life of cut flowers
Decoding the intricate metabolic and biochemical changes in plant senescence: a focus on chloroplasts and mitochondria
No full textBackground Plant senescence is a genetically controlled process that results in the programmed death of plant cells, organs or the entire plant. This process is essential for nutrient recycling and supports the production of plant offspring. Environmental stresses, such as drought and heat, can hasten senescence, reducing photosynthetic efficiency and significantly affecting crop quality and yield.Scope This invited review seeks to clarify the complex metabolic and biochemical transformations involved in plant senescence by explaining the mechanisms in a straightforward and connected manner. It focuses on key cellular processes, such as genetically programmed or stress-induced senescence, chlorophyll metabolism and nutrient recycling, while also exploring the roles of signalling molecules and pathways.Conclusions Understanding the complexities of plant senescence might help to manage crop ageing, address climate change and cut post-harvest losses. Enhancing crop resilience to stress and decelerating ageing can reduce the need for overproduction, thereby decreasing pollution and conserving resources. Tackling food waste, which constitutes about one-third of global supplies, is crucial for ensuring food security and fostering environmental sustainability
Plant extract improves quality traits of green and red lettuce cultivars
Full text linkThe use of biostimulants in agriculture has been rapidly increasing in recent years, because of their positive effects on crop yield, product quality, and tolerance to abiotic stresses. In the present study the efficacy of multiple applications of a plant-derived biostimulant, obtained from the aqueous maceration of borage (Borago officinalis, L.) flowers on two lettuce cultivars, namely a green (Lactuca sativa L. cv. Expertise RZ) and red (Lactuca sativa L. cv. Codex RZ) Salanova® was evaluated. The treatment was applied at 10 mL L−1 as foliar spray three times, once a week starting from two weeks after transplant. Control plants were treated with water. Non-destructive measurements (pigments, leaf nitrogen index, chlorophyll a fluorescence) were taken during plant growth after at each treatment application. At the end of the experiment, destructive analyses were performed to assess qualitative traits. The research work was focused on the evaluation of physiological parameter changes during plant growth, and on primary and secondary metabolism. Foliar applications did not affect the accumulation of total sugars (4.56 mg g−1 in Expertise, 3.5 mg g−1 in Codex) in either cultivar. However, the lettuce head weight was negatively affected by the extract application in red cultivar (-10 g/plant), while no changes were observed in the green lettuce. The nitrogen-flavonol index (NFI) increased after the third application of borage extract in green cultivar (+67 %), suggesting an improvement of nitrogen nutrition status or a reduced stress condition. A different response resulted in term of maximum quantum efficiency of PSII (FV/FM), performance index (PI), nitrate, and anthocyanin accumulation in leaves. The FV/FM ratio significantly increased in green cultivar after the first application (from 0.80 to 0.84) and at harvest (from 0.79 to 0.84). The PI showed a slight but not significant increase at the same time points. On the contrary, the PI was significantly higher in red cultivar after the third application (+9.4 %). Interestingly, the borage extract induced a significant decrease of nitrate accumulation in lettuce leaves of the red cultivar (from 4149.7 to 2711.6 mg/kg, −34 %). At the same time a positive variation of anthocyanin content was observed in red lettuce (+24.7 %). The application of biostimulant products might improve the quality of some lettuce varieties as regards the accumulation of metabolites useful for the plant to overcome stress conditions and fundamental in human healthy diet, increasing the leaf concentration of Ca, Na, and Mg
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Melatonin induces proline, secondary metabolites, sugars and antioxidants activity to regulate oxidative stress and ROS scavenging in salt stressed sword lily
Full text linkSword lily is regarded as a useful and commercially demanding cut flower crop; hence, assessing its responses to abiotic stress, particularly salt stress, is vital. Melatonin (MT) exhibits stress tolerance in crop plants and is an emerging stress relieving alternative to chemicals. Nevertheless, the possible process underlying the effects of MT under salt stress has yet to be fully elucidated in plants. Herein, the salt stress (SS) mitigation potential of MT was assessed in a commercially important cut flower, sword lily. Melatonin, expressed as MT1, MT2, MT3, and MT4, was administered at concentrations of 0.2, 0.4, 0.6, and 0.8 mM. The results revealed that SS (5 dS m−1) restricted the growth and physiological aspects of sword lily. Furthermore, malondialdehyde (MDA), hydrogen peroxide (H2O2), membrane permeability, endogenous proline, and soluble protein contents were enhanced in SS. MT application improved morphological traits, photosynthetic pigments, and corm traits. The application of MT mitigated the effects of SS stress in Gladiolus grandiflorus plants by improving growth and photosynthetic pigments. MT application under SS improved the reducing and non-reducing sugar and NPK contents of the sword lily. Furthermore, MT improved the levels of secondary metabolites, such as anthocyanins, flavonoids, and ascorbic acid, in sword lily. Moreover, MT supplementation ameliorated salt-induced oxidative stress in the gladiolus, as depicted by a decrease in stress markers (EL, MDA, and H2O2) and an increase in defense-related enzymes (POD, CAT, and SOD) with highest increase in the MT3 treatment under salinity stress. The SOD and CAT enzyme activities were 3–3.6-fold higher in the MT3 under stress than the control. In conclusion, MT applications on cut flowers can be an effective strategy to reduce salt stress and can be used to regulate salinity stress in cut flower production. MT can be used as a safe alternative to other agrochemicals to maintain the growth and flower quality of sword lilies, with beneficial effects during vase life
Multiscale and multidisciplinary method for plant selection to design green urban and peri-urban areas
Full text linkThe planning and design of urban and peri-urban green spaces necessitate careful consideration of various factors, encompassing climatic and agronomic parameters, botanical and eco-physiological characteristics of ornamental plants, and interactions between buildings and green elements. These green areas, along with their composition, play a crucial role in providing essential ecosystem services within urban environments. The process of designing and planning green spaces is a complex, multidisciplinary endeavor, involving professionals such as architects, agronomists, botanists, hydrologists, and civil engineers. The initial steps involve evaluating the area and its location and prioritizing environmental and municipal constraints in the analysis. The selection of plants is heavily influenced by soil and climate parameters. In cases where the area is already green, a meticulous assessment of each plant is essential to determine whether preservation or substitution is more appropriate. Upon completion of the site analysis, the design of the future green area must consider its environmental and social functions, potential ecosystem services, its role within the broader context, compositional aspects, and the judicious use of plant species and materials. This paper proposes a working method that is both multidisciplinary and multiscale, aiming to create sustainable, effective green areas that thrive even in challenging conditions linked to human impact and climate change
Agronomic Management for Enhancing Plant Tolerance to Abiotic Stresses : High and Low Values of Temperature, Light Intensity, and Relative Humidity
Full text linkAbiotic stresses have direct effects on plant growth and development. In agriculture, sub-optimal values of temperature, light intensity, and relative humidity can limit crop yield and reduce product quality. Temperature has a direct effect on whole plant metabolism, and low or high temperatures can reduce growth or induce crop damage. Solar radiation is the primary driver of crop production, but light intensity can also have negative effects, especially if concurrent with water stress and high temperature. Relative humidity also plays an important role by regulating transpiration and water balance of crops. In this review, the main effects of these abiotic stresses on crop performance are reported, and agronomic strategies used to avoid or mitigate the effects of these stresses are discussed
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