The agricultural sector must produce resilient and climate-smart crops to meet the increasing needs of global food production. Recent advancements in elucidating the mechanistic basis of plant stress ...memory have provided new opportunities for crop improvement. Stress memory-coordinated changes at the organismal, cellular, and various omics levels prepare plants to be more responsive to reoccurring stress within or across generation(s). The exposure to a primary stress, or stress priming, can also elicit a beneficial impact when encountering a secondary abiotic or biotic stress through the convergence of synergistic signalling pathways, referred to as cross-stress tolerance. ‘Rewired plants’ with stress memory provide a new means to stimulate adaptable stress responses, safeguard crop reproduction, and engineer climate-smart crops for the future.
Plants have stress memories that lead to epigenetic, transcriptomic, proteomic, and metabolomic changes, enabling enhanced responses to additional stress exposure.Multi-omic studies have identified previously unrecognised regulators, metabolites, and pathways as key components of priming-induced thermotolerance.Successful acclimation for drought and flooding-induced stress memory is linked to changes in antioxidative capacity, biochemical modifications, and hormone pathways.Cross-stress tolerance can be elicited by pre-exposure of a primary stress to improve crop performance under subsequent stress. Application of priming agents is another effective cross-priming approach, particularly for seed priming or commercial seed production.Cross-stress priming success relies on synergistic stress signalling pathways being shared across stresses varying in nature and intensity.
Decades of research in attention have shown that salient distractors (e.g., a color singleton) tend to capture attention. However, in most studies, singleton distractors are just as likely to be ...present as absent. We therefore have little knowledge of how probabilistic expectations of the salient distractor's occurrence and features affect suppression. In three experiments, we explored this question by manipulating the frequency of a singleton distractor and the variability of its color within a search display. We found that increased expectations regarding the occurrence of the singleton distractor eliminated the singleton response time cost and reduced the number of first saccades to the singleton. In contrast, expectations regarding variability in the singleton color did not affect singleton capture. This was surprising and suggests the ability to suppress second-order salience over and above that of first-order features. We next inserted the probe display that included a to-be-reported letter inside each shape between search trials to measure if attention went to multiple objects. The letter in the singleton location was reported less often in the high-frequency condition, suggesting proactive suppression of expected singleton. Additionally, we found that trial-to-trial repetitions of a singleton (irrespective of its color and location) facilitated performance (i.e., singleton repetition priming), but repetitions of its specific color or location did not. Together our findings demonstrate that attentional capture by a color singleton distractor is attenuated by probabilistic expectations of its occurrence, but not of its color and location.
Public Significance Statement
The mechanisms of target selection have been well-studied whereas those of distractor suppression are less well understood. One of reasons may be that there is still disagreement about whether salient distractors necessarily capture attention, which has led to a rich debate regarding the automaticity of attentional capture by stimulus saliency. However, these previous studies have primarily pitted attentional goals based on the target search strategy against perceptual saliency that cannot be predicted. We therefore have little knowledge of how probabilistic expectations affect attentional capture by a singleton distractor, yet performance in real-world environments rely heavily on expectations. We address this question in a series of three studies. Our results demonstrate that increased expectations regarding the occurrence of the singleton distractor eliminated attentional capture (indexed by search response time and first saccades). In contrast, expectations regarding singleton feature (i.e., color) did not affect singleton capture, even when there were 192 different singleton colors used. These results suggest that attentional capture by a singleton distractor is attenuated by probabilistic expectations of its occurrence, but not its specific color and location. This indicates that distractor suppression, like target selection, can operate at different levels of stimulus processing and be flexibly attuned to the type of information expected within the current environment.
► We hypothesize that syntactic priming serves to reduce the expected future prediction error. ► We find that syntactic priming is sensitive to prediction error experienced while processing prime. ► ...Prediction error is based on both prior and recent experience, suggesting continuous adaptation. ► Production primarily affected by prediction error experienced during comprehension.
Speakers show a remarkable tendency to align their productions with their interlocutors’. Focusing on sentence production, we investigate the cognitive systems underlying such alignment (syntactic priming). Our guiding hypothesis is that syntactic priming is a consequence of a language processing system that is organized to achieve efficient communication in an ever-changing (subjectively non-stationary) environment. We build on recent work suggesting that comprehenders adapt to the statistics of the current environment. If such adaptation is rational or near-rational, the extent to which speakers adapt their expectations for a syntactic structure after processing a prime sentence should be sensitive to the prediction error experienced while processing the prime. This prediction is shared by certain error-based implicit learning accounts, but not by most other accounts of syntactic priming. In three studies, we test this prediction against data from conversational speech, speech during picture description, and written production during sentence completion. All three studies find stronger syntactic priming for primes associated with a larger prediction error (primes with higher syntactic surprisal). We find that the relevant prediction error is sensitive to both prior and recent experience within the experiment. Together with other findings, this supports accounts that attribute syntactic priming to expectation adaptation.
L’amorçage (priming) est une technique de traitement pré-germinatif qui consiste à imbiber la semence puis à la re-déshydrater avant la percée de la radicule. Notre travail consiste à étudier ...l’effet de deux agents de prétraitement des graines, notamment le PEG (20%) et l’AG3 (50 ppm) sur les performances germinatives, la croissance et l’hydratation des plantules de mil cultivées en présence de 100 mM NaCl. Notre objectif principal consiste à améliorer le phénotype et le comportement du mil cultivé sous contrainte saline via l’optimisation de l’amorçage des semences. Les résultats obtenus montrent que tous les types d’amorçage ont un effet bénéfique. Toutefois, le prétraitement des graines avec l’AG3 semble fortement associé à des processus mettant en jeu la croissance. Ce composé stimule de 100% la germination dès le 6ème jour de mise en germination en milieu salin. Cet effet est accompagné d’une amélioration de la croissance (193%) et d’une meilleure hydratation (330%), relativement aux plantes témoins. Cette réponse est primordialement liée à une capacité de détecter rapidement le stress salin et de le rendre facilement interprétable et même bénéfique pour sa croissance en milieux extrêmes.
Affective Processing Requires Awareness Lähteenmäki, Mikko; Hyönä, Jukka; Koivisto, Mika ...
Journal of experimental psychology. General,
04/2015, Letnik:
144, Številka:
2
Journal Article
Recenzirano
Studies using backward masked emotional stimuli suggest that affective processing may occur outside visual awareness and imply primacy of affective over semantic processing, yet these experiments ...have not strictly controlled for the participants' awareness of the stimuli. Here we directly compared the primacy of affective versus semantic categorization of biologically relevant stimuli in 5 experiments (n = 178) using explicit (semantic and affective discrimination; Experiments 1-3) and implicit (semantic and affective priming; Experiments 4-5) measures. The same stimuli were used in semantic and affective tasks. Visual awareness was manipulated by varying exposure duration of the masked stimuli, and subjective level of stimulus awareness was measured after each trial using a 4-point perceptual awareness scale. When participants reported no awareness of the stimuli, semantic and affective categorization were at chance level and priming scores did not differ from zero. When participants were even partially aware of the stimuli, (a) both semantic and affective categorization could be performed above chance level with equal accuracy, (b) semantic categorization was faster than affective categorization, and (c) both semantic and affective priming were observed. Affective categorization speed was linearly dependent on semantic categorization speed, suggesting dependence of affective processing on semantic recognition. Manipulations of affective and semantic categorization tasks revealed a hierarchy of categorization operations beginning with basic-level semantic categorization and ending with superordinate level affective categorization. We conclude that both implicit and explicit affective and semantic categorization is dependent on visual awareness, and that affective recognition follows semantic categorization.
NaCl and PEG stresses have negative impacts on seed germination and early seedling establishment in
Oryza sativa
. The present study was designed to ascertain the influence of different priming ...techniques (Hydro priming-HyP, Halo priming-HP, UV-B priming-UP) in enhancing oxidative and anti-oxidative mechanisms during seed germination phase in response to NaCl and PEG stresses tolerance of three rice varieties (Neeraja, Vaisakh and Vyttila 6). NaCl and PEG stresses caused delayed germination rate, enhanced reactive oxygen species content and thereby increased lipid peroxidation rate. Different priming techniques significantly hastened the metabolites/non enzymatic antioxidant contents (total sugars, total phenolics, free amino acids, proline, ascorbate and glutathione) as well as activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase), and thus reduced oxidative stress damages caused by NaCl and PEG stresses in rice seedlings. Seed priming techniques imparted abiotic stress tolerance not only to sensitive varieties but also additional tolerance potential to tolerant varieties. All three priming techniques protects the plants from toxicity caused by NaCl and PEG stresses but halo priming had proved to be more successful.
Plants can acquire an improved resistance against pathogen attacks by exogenous application of natural or artificial compounds. In a process called chemical priming, application of these compounds ...causes earlier, faster and/or stronger responses to pathogen attacks. The primed defense may persist over a stress-free time (lag phase) and may be expressed also in plant organs that have not been directly treated with the compound. This review summarizes the current knowledge on the signaling pathways involved in chemical priming of plant defense responses to pathogen attacks. Chemical priming in induced systemic resistance (ISR) and systemic acquired resistance (SAR) is highlighted. The roles of the transcriptional coactivator NONEXPRESSOR OF PR1 (NPR1), a key regulator of plant immunity, induced resistance (IR) and salicylic acid signaling during chemical priming are underlined. Finally, we consider the potential usage of chemical priming to enhance plant resistance to pathogens in agriculture.
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