Ethylene is essential for many developmental processes and a key mediator of biotic and abiotic stress responses in plants. The ethylene signaling and response pathway includes Ethylene Response ...Factors (ERFs), which belong to the transcription factor family APETALA2/ERF. It is well known that ERFs regulate molecular response to pathogen attack by binding to sequences containing AGCCGCC motifs (the GCC box), a cis-acting element. However, recent studies suggest that several ERFs also bind to dehydration-responsive elements and act as a key regulatory hub in plant responses to abiotic stresses. Here, we review some of the recent advances in our understanding of the ethylene signaling and response pathway, with emphasis on ERFs and their role in hormone cross talk and redox signaling under abiotic stresses. We conclude that ERFs act as a key regulatory hub, integrating ethylene, abscisic acid, jasmonate, and redox signaling in the plant response to a number of abiotic stresses.
Vitamin E, which includes both tocopherols and tocotrienols, comprises lipid-soluble antioxidants that modulate lipid peroxidation. Recently, significant advances have been made in our understanding ...of vitamin E biosynthesis, transport, and function. The phytyl moiety from chlorophyll degradation is used for tocopherol biosynthesis. An α-tocopherol-binding protein (TBP) has been identified in tomato (SlTBP) serving in intraorganellar vitamin E transport in plants. Moreover, α-tocopherol not only scavenges free radicals through flip-flop movements in the lipid bilayer, but may also contribute to fine-tuning the transmission of specific signals outside chloroplasts. Vitamin E, and α-tocopherol in particular, appear to be essential for plant development and help to provide the most suitable response to a number of environmental stresses.
α-Tocopherol is a lipophilic antioxidant synthesized from the methylerythritol and shikimate pathways in chloroplasts that modulate the extent of lipid peroxidation in plants.Increased α-tocopherol content, which is both biochemically and functionally related to chlorophyll loss, improves photoprotection.The recent discovery of an α-tocopherol-binding protein sheds light on intraorganellar prenyllipid transport in plants.High α-tocopherol content in some nonphotosynthetic tissues poses intriguing questions about the biosynthesis, transport, and function of vitamin E in plants.
Plant species distribution across ecosystems is influenced by multiple environmental factors, and recurrent seasonal stress events can act as natural selection agents for specific plant traits and ...limit species distribution. For that, studies aiming at understanding how environmental constraints affect adaptive mechanisms of taxonomically closely related species are of great interest. We chose two Scabiosa species inhabiting contrasting environments: the coastal scabious S. atropurpurea, typically coping with hot‐dry summers in a Mediterranean climate, and the mountain scabious S. columbaria facing cold winters in an oceanic climate. A set of functional traits was examined to assess plant performance in these congeneric species from contrasting natural habitats. Both S. atropurpurea and S. columbaria appeared to be perfectly adapted to their environment in terms of adjustments in stomatal closure, CO2 assimilation rate and water use efficiency over the seasons. However, an unexpected dry period during winter followed by the typical Mediterranean hot‐dry summer forced S. atropurpurea plants to deploy a set of photoprotective responses during summer. Aside from reductions in leaf water content and Fv/Fm, photoprotective molecules (carotenoids, α‐tocopherol and anthocyanins) per unit of chlorophyll increased, mostly as a consequence of a severe chlorophyll loss. The profiling of stress‐related hormones (ABA, salicylic acid and jasmonates) revealed associations between ABA and the bioactive jasmonoyl‐isoleucine with the underlying photoprotective response to recurrent seasonal stress in S. atropurpurea. We conclude that jasmonates may be used together with ABA as a functional trait that may, at least in part, help understand plant responses to recurrent seasonal stress in the current frame of global climate change.
Reactive oxygen species (ROS) play a key role in the regulation of many developmental processes, including senescence, and in plant responses to biotic and abiotic stresses. Several mechanisms of ROS ...generation and scavenging are similar, but others differ between senescing leaves and petals, despite these organs sharing a common evolutionary origin. Photosynthesis-derived ROS, nutrient remobilization, and reversibility of senescence are necessarily distinct features of the progression of senescence in the two organs. Furthermore, recent studies have revealed specific redox signaling processes that act in concert with phytohormones and transcription factors to regulate senescence-associated genes in leaves and petals. Here, we review some of the recent advances in our understanding of the mechanisms underpinning the production and elimination of ROS in these two organs. We focus on unveiling common and differential aspects of redox signaling in leaf and petal senescence, with the aim of linking physiological, biochemical, and molecular processes. We conclude that the spatiotemporal impact of ROS in senescing tissues differs between leaves and flowers, mainly due to the specific functionalities of these organs.
The way we currently capture biological processes in space and time often limits our understanding of plant development and stress responses, leading to an incomplete picture of plant life. Choosing ...the correct time frame for the study of every biological process, from seed germination to senescence or in plant stress responses, is essential, despite methodological limitations. A greater effort is needed in current plant biology studies to incorporate spatiotemporal approaches so that scientific knowledge meets the possibilities technological advances currently provide. From molecular, biochemical, and cellular approaches to (eco)physiological and population studies scaled up to the ecosystem level, there is an urgent need to link space and time using integrative and scalable data.
Choosing the correct time frame in every biological process, from seed germination to senescence, or in plant stress responses, is essential, despite methodological limitations.There is an urgent need to link space and time using integrative and scalable data to better understand plant physiological processes.Spatiotemporal approaches in plant development and stress responses provide more accurate and useful data for both basic and applied research.It is essential to adopt new frames of reference to better characterize plant physiological processes.
Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of ...hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M) and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS) to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor), jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis.
A combination of ecophysiological features makes some invasive plants difficult to eradicate in Mediterranean-type ecosystems.The human footprint in these ecosystems increases propagule pressure, ...helps habitat fragmentation, and facilitates adaptation of these invasive plants.Citizen science is as important as fundamental science and environmental management by public authorities to prevent new invasions.
An in-depth analysis of the mechanistic processes underlying the evolution and ecophysiology of typical invasive plants such as Carpobrotus spp., Acacia spp., Agave spp., and Opuntia spp. in Mediterranean-type ecosystems shows very sophisticated, complex, and efficient strategies for invasion success, particularly in fragmented habitats. Propagule pressure at both geographical and temporal scales and the establishment of long-term seed banks are determinant for invasion success. A two-sword strategy based on long-term prevention and eradication is proposed for the management of Mediterranean-type ecosystems. Eradication of invasive plants in Mediterranean-type ecosystems appears to be extremely difficult nowadays and, at least for some invaders like Carpobrotus spp., long-term approaches that ultimately culminate in the elimination of seed banks is the only path for success.
An in-depth analysis of the mechanistic processes underlying the evolution and ecophysiology of typical invasive plants such as Carpobrotus spp., Acacia spp., Agave spp., and Opuntia spp. in Mediterranean-type ecosystems shows very sophisticated, complex, and efficient strategies for invasion success, particularly in fragmented habitats. Propagule pressure at both geographical and temporal scales and the establishment of long-term seed banks are determinant for invasion success. A two-sword strategy based on long-term prevention and eradication is proposed for the management of Mediterranean-type ecosystems. Eradication of invasive plants in Mediterranean-type ecosystems appears to be extremely difficult nowadays and, at least for some invaders like Carpobrotus spp., long-term approaches that ultimately culminate in the elimination of seed banks is the only path for success.
Limits to Tree Growth and Longevity Munné-Bosch, Sergi
Trends in plant science,
November 2018, 2018-11-00, 20181101, Letnik:
23, Številka:
11
Journal Article
Recenzirano
Tree growth and longevity are key features to understand fundamental issues of plant biology, environmental sciences, and current forest management plans. Here I discuss current evidence on the ...limits of tree growth and longevity and present a new conceptual framework to understand how and why they are closely interconnected. Despite the tremendous plasticity of trees, growth and longevity are limited not only by biotic and abiotic stresses, but also by age-related structural constraints such as height-related hydraulic limitations and vascular discontinuities, which are strongly species specific. Continuous growth and plastic branching may serve as a means to reach extreme longevities in some nonclonal trees, but even in these millennial organisms immortality can be attained only through the germ line.
Long-lived trees with extreme longevity maintain some growth capacity and defy aging.
Mosaic-like organization of meristematic (growing) points is one of the most important mechanisms behind their extreme longevity.
Senescence cannot be gauged in long-lived trees growing in their natural habitat because of limited sample size at advances ages.
Despite cases of extreme longevity in nonclonal trees, immortality can be achieved only through clonal reproduction or the germ line.
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