Adaptive Morphological Responses of Cold Acclimated Wheat Cultivars to Freezing Stress

This thesis is composed of two chapters. Chapter one reviews what is known about adaptive plasticity in response to predators, describes the physiological systems involved in such plasticity, and outlines the evolutionary consequences of adaptive plasticity. Chapter two describes a scientific experiment that investigates how malathion may impact adaptive plasticity in the Sierran Treefrog, Pseudacris sierra. Anuran tadpoles suffer high mortality rates due to predation. In response to strong selective forces relating to these high predation rates, tadpoles evolved the ability to adaptively respond to predators through morphological and behavioral plasticity. The morphological and behavioral responses are varied and depend on the hunting strategy of the predator, and the adaptive responses may be influenced by other biotic and abiotic factors. Tadpoles detect alarm cues released from tadpoles being eaten and kairomones that are released by predators. Tadpoles respond to these signals by changing tail and body shape along with a reduction of activity level, which enables tadpoles to escape predators more effectively. These changes in morphology can occur within a week, and behavioral changes can occur within 15 minutes. The adaptive responses are critical for increasing survival rates of tadpoles to metamorphosis and may have important evolutionary consequences for anurans. Amphibians are in decline worldwide, and pollutants are considered to be a major contributor to these declines. Every year 5.2 billion pounds of active ingredients of pesticides are applied worldwide, and these application rates have led to ubiquitous low-level contamination of aquatic ecosystems. How low-level contamination of pesticides directly and indirectly affect how tadpoles respond to their predators is poorly understood. One potential indirect effect of pesticides is the inhibition of adaptive plasticity. Pesticides have been shown to modulate corticosterone levels in tadpoles. Corticosterone is the most likely mediator of the physiological response that results in adaptive morphological change. If the physiological system of tadpoles relies on corticosterone as the mediator of adaptive response, and pesticides can modulate corticosteone levels, then pesticides may inhibit or negatively impact adaptive responses to important biotic factors, like predators. Pesticides have been shown to weaken immune systems, affect developmental and physiological pathways that lead to malformations, and cause direct mortality in anurans. Little research has investigated the effect of pesticides on adaptive morphological and behavioral plasticity in response to predators. Adaptive phenotypic responses to predators increase survival rates to metamorphosis and are important in stabilizing amphibian populations through time. If pesticides influence the ecological

BackgroundFish encounter oxidative stress several times during their lifetime, and it has a pervasive influence on their health and welfare. One of the triggers of oxidative stress in fish farming is the use of oxidative disinfectants to improve rearing conditions, especially in production systems employing recirculation technology. Here we report the physiological and morphological adaptive responses of Atlantic salmon (Salmo salar L.) post-smolts to intermittent exposure to a potent oxidative agent peracetic acid (PAA). Fish reared in semi-commercial scale brackish water recirculating aquaculture system (RAS) were exposed to 1 ppm PAA every 3 days over 6 weeks. Mucosal and systemic responses were profiled before exposure, 22 and 45 days during the intermittent PAA administration.ResultsOxidative stress was likely triggered as plasma antioxidant capacity increased significantly during the exposure period. Adaptive stress response to the periodic oxidant challenge was likewise demonstrated in the changes in plasma glucose and lactate levels. PAA-induced alterations in the transcription of antioxidants, cytokines, heat shock proteins and mucin genes showed a tissue-specific pattern: downregulation was observed in the gills and olfactory rosette, upregulation occurred in the skin, and no substantial changes in the liver. Further, PAA exposure resulted in histological changes in key mucosal organs (i.e. olfactory rosette, skin and gills); pathological alterations were predominant in the gills where cases of epithelial lifting, hypertrophy and clubbing were prevalent. In addition, intermittent PAA administration resulted in an apparent overproduction of mucus in the nasal mucosa. Lastly, PAA did not dramatically alter the ability of salmon to mount a physiological stress response in the presence of a secondary stressor, though some subtle interference was documented in the kinetics and magnitude of plasma cortisol and glucose response post-stress.ConclusionsThe present study collectively demonstrated that intermittent oxidant exposure was a mild environmental stressor that salmon could mount strong adaptive responses at systemic and mucosal levels. The results will be valuable in optimising the rearing conditions of post-smolts in RAS, especially in adopting water treatment strategies that do not considerably interfere with fish health and welfare.

Phenotypic plasticity, a process by which individuals modify their morphology, physiology, or behaviour in response to environmental changes, can be seen as the first step in adaptive evolution. Phenotypic plasticity is adaptive if two conditions are met: (1) the phenotype is associated with an environment (plastic response) and (2) the phenotype–environment association increases individual fitness (adaptive response).Using a reciprocal transplant experiment, we tested the hypothesis that functional morphological responses are correlated with growth at two organizational levels (between and within ecotypes) in brook charr.Four‐month‐old individuals from four littoral and four pelagic families raised in the laboratory were transferred into eight littoral (3 m × 4 m × 1.5 m depth) and eight pelagic (3 m × 4 m × 6 m depth) lake enclosures for a period of 12 weeks.Fin length (the main discriminant trait of the littoral and pelagic ecotypes) was less plastic than body shape. Growth was higher in the pelagic than in the littoral habitat, but offspring from littoral and pelagic parental origins did not experience higher growth in their respective habitats (comparison between ecotypes). The body shape of most individuals transplanted to their reciprocal environment shifted toward the form expected in that environment. This plastic response in body shape was functionally correlated with growth within ecotypes, but only in the littoral habitat. Furthermore, the within‐ecotype variance of both morphological traits and growth were higher in the littoral than in the pelagic habitat.Small phenotypic differences could have direct consequences on fitness in the less favourable habitat, inducing higher inter‐individual variance in growth and stronger phenotype–growth associations. We suggest that phenotypic accommodation and cryptic genetic variation, two mechanisms previously proposed as mechanisms involved in distinct situations, could be simultaneously involved to hasten the process of adaptive evolution in an unfavourable environment.Aplain language summaryis available for this article.

The objective of the paper was to illustrate using and usefulness of a joint AMMI and cluster analyses to assess the grain yield adaptive response of Polish and foreign 31 winter wheat cultivars in a range of 20 environments (locations) and across 3 years (2005-2007) under integrated crop management, using data obtained in the post-registration variety testing trials (called PDO trials), to identify those entries with specific and wide adaptation. Two-stage combined analysis of variance for data in the three-way GLY classification was carried out according to a mixed model (cultivar and location as fixed factors and years as random factor). GL repeated (across years) interaction effects were modeled by (a) joint regression and (b) additive main effects and multiplicative interaction (AMMI). The thirty one cultivar adaptive responses, expressed by nominal yields based on significant AMMI-1 model, accounting for 27.8% of SS for GL interactions, were divided into six homogenous groups by Ward’s method of cluster analysis. Group-mean cultivar adaptive responses indicated clearly the wide adaptation of cultivars in groups 1 and 2 including mostly German and United Kingdom entries and also two Polish ones. Cultivars from group 6, including three Polish cultivars and three foreign ones, were among at most four top-ranking entries at all locations excluding one environment (Wyczechy at Pomerania region). Cultivars from group 3, including seven Polish cultivars and one from United Kingdom and France, showed extremely specific adaptation characterized by nominal yield responses being positively related to GL interaction PC 1 scores of the locations. However, cultivars from group 5, including five Polish ones and a French one were poor adapted to the growing area. Presented the joint AMMI and cluster analyses were effective to distinguish adaptive responses of studied cultivars on the basis of data from PDO trials and could be seen as a better alternative, based more on probability-approached methodology, to common pattern analysis.

Vibrio vulnificus and Vibrio parahaemolyticus are natural inhabitants of estuarine environments of the Gulf of Mexico. V. vulnificus is the leading cause of death, while V. parahaemolyticus is a leading cause of foodborne gastroenteritis from the consumption of seafood in the United States. Refrigeration is commonly used as a preservation method to control the growth of microorganisms in food. The ability of some microorganisms to adapt, as a survival response when exposed to a downshift in temperature, could compromised efforts to use low temperature storage to reduce the risk of foodborne illnesses. Limited research is available on the growth characteristics of different strains of V. vulnificus and V. parahaemolyticus, or on the adaptation response to cold shock on their survival. This study was conducted to determine if strain-to-strain differences exist in the growth and survival of V. vulnificus and V. parahaemolyticus at refrigeration temperatures, and to determine if these strains exhibit a cold temperature adaptation response. Results obtained from this study show that various V. vulnificus and V. parahaemolyticus strains grown in tryptic soy broth have significant differences in growth and survival when stored at 5, 8 or 10°C over 10 days. V. vulnificus strains were able to survive but not grow when shifted from 37°C to storage at 5 or 8°C, while most of these strains were able to grow at 10°C. V. parahaemolyticus strains survived but did not grow when shifted from 37°C to 5°C. During storage at 8 or 10°C however, V. parahaemolyticus strains were able to grow. When these strains were adapted at an intermediate temperature of 15°C for 4 hours, this resulted in an enhanced survival of V. vulnificus strains. This adaptation response however varied between strains. Not all of the V. parahaemolyticus strains had an enhanced survival when exposed to an intermediate temperature of 15°C. The cold adaptation response was more sustained for the V. vulnificus strains at some temperatures tested, while for the V. parahaemolyticus strains that had an adaptation response, this response was generally short lived.

1. Many biological textbooks present predator-induced morphological changes in prey species as an example of an adaptive response, because the morphological change is associated with lower predation risk. Here we show that the adaptive morphological response observed in many systems may actually be an indirect effect of decreased activity - which reduces the predation risk - rather than a direct adaptive response. 2. One of the classical examples comes from crucian carp, where the presence of pike leads to a deeper body. We manipulated pike cues (presence and absence) and water current (standing and running water) and found that both standing water and pike cues similarly and independently induced a deeper body. 3. Since the presence of pike cues as well as standing water might be associated with low swimming activity, we suggest that the presence of pike causes a reduction in activity (antipredator behaviour). Reduced activity subsequently induces a deeper body, possibly because the energy saved is allocated to a higher growth rate. 4. Our result suggests that even if morphological change is adaptive, it might be induced indirectly via activity. This important conceptual difference may be similar in many other systems.

Models of defence against multiple enemies predict that specialized responses to each enemy should evolve only under restrictive conditions. Nevertheless, tadpoles of Rana temporaria can differentiate among several predator species. Small tadpoles used a refuge when Notonecta backswimmers were in the pond, but showed a weaker hiding response to adult Triturus alpestris newts and no response to aeshnid dragonfly larvae (Aeshna and Anax). All predators caused a decline in feeding and swimming activity. Large tadpoles reserved the strongest behavioural response for dragonflies, while Triturus caused no response. The shift during development suggests that tadpoles distinguished among predators, rather than exhibiting a graded dosage response to a single cue associated with predation. Information on habitat distributions of predators suggests that they are regularly encountered, which would facilitate evolution of adaptive behavioural responses. Morphological responses to all predators were similar, perhaps because similar morphologies defend against all four predators. The evolutionary maintenance of specialized responses to multiple predators may be possible because adaptive responses do not conflict and the predators themselves do not interact strongly.

Most plants demonstrate wide interactive and complex adaptive morphological, biochemical, and physiological responses when subjected to salinity stress. Salt stress negatively impacts agricultural yields more especially cultivated crops throughout the world. Of interest to this study is maize a salt- sensitive crop that is widely grown worldwide, and receiving most attention due to its significant attributes and ability to serve as a great model for stress response studies. We exposed QN701 maize cultivar, to simulated salinity stress and investigated its morphological and physiological responses. Salinity negatively induced various morphological responses such as the reduction in plant height, number of leaves, shoot and root (length and biomass), and leaf width; however, it significantly increased the leaf area. On the physiological aspect, salt stress decreased the number of stomata, stomatal density, and photosynthesis, while it increased the respiration rate. This study expanded our knowledge of the morphological and physiological responses of maize to salinity stress. Additionally, these findings may serve as a recommendation for salinity breeding programs in maize and related cereal crops.

Adaptive, morphometric and productive responses of Brazilian hair lambs: Crossing between indigenous breeds - A machine learning approach

Phosphate (Pi) deficiency severely influences the growth and reproduction of plants. To cope with Pi deficiency, plants initiate morphological and biochemical adaptive responses upon sensing low Pi in the soil, and the plant hormone ethylene plays a crucial role during this process. However, how regulation of ethylene biosynthesis influences the Pi-induced adaptive responses remains unclear. Here, we determine the roles of rice 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), the rate-limiting enzymes in ethylene biosynthesis, in response to Pi deficiency. Through analysis of tissue-specific expression of OsACS in response to Pi deficiency and OsACS mutants generated by CRISPR/Cas9 [clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9] genome editing, we found that two members of the OsACS family, i.e. OsACS1 and OsACS2, are involved but differed in their importance in controlling the remodeling of root system architecture, transcriptional regulation of Pi starvation-induced genes, and cellular phosphorus homeostasis. Interestingly, in contrast to the known inhibitory role of ethylene on root elongation, both OsACS mutants, especially OsACS1, almost fail to promote lateral root growth in response to Pi deficiency, demonstrating a stimulatory role for ethylene in lateral root development under Pi-deficient conditions. Together, this study provides new insights into the roles of ethylene in Pi deficiency response in rice seedlings and the isoform-specific function of OsACS genes in this process.

Linkage between belowground and aboveground sections of ecological system is mainly depending on root system. But root system is the parts of plant that people less understand. The absorption function of root system is closely related to their morphology and activity. Moreover root system can interact with the environmental stress under the adverse situation, and adjust its system to take adaptation responses in morphology and physiology to strengthen its survival chance. This research is focused on three desert halophyte species of H. ammodendron (C.A.Mey.) Bge., S. physophora Pall., and S. nitraria Pall. under solution culture, to study the differences of their root system morphology and activity in the seedling stage under varying salt concentration conditions. The study results show that: A certain salt concentration can promote development of these three halophytes; but rather high salt concentration will restrain their growth, in particular inhibit the root system development. Under the same salt concentration condition, S. nitraria Pall. grows fast and accumulates the largest amount of biomass. Under relatively low salt concentration, the length of axial root and the total length of root system of these three halophyte species are all increased; and compared to the checking samples, S. physophora Pall. occupies the top place of root system growth, but the high salt concentration will restrain the increase of total root length; among them, the impact intensity on S. physophora Pall. is lighter than to H. ammodendron (C.A.Mey.) Bge. and S. nitraria Pall. is lighter; the salinity does not bring distinct influence on the average diameter of root system of these three plant species, but trends to reducing the size; under the solution culture conditions, the middle and lower parts of the axial root of H. ammodendron (C.A.Mey.) Bge. and S. physophora Pall. are rather equally distributed, but the central zone of S. nitraria Pall. root system is more significantly increased than the upper and lower zones; salt concentration does not bring significant impact on the root system spatial distribution of each species. The root activity of the three plants is increased along with the increase of the salt concentration. When the salt concentration is low, the root activity is not significantly increased; but when the salt concentration is high, the root activity is increased significantly. The experimental results show that the saline tolerance capacity of H. ammodendron (C.A.Mey.) Bge. is lower than the other two species, and the capacity of S. physophora Pall. ranks the top place.

An unusual transverse ridge was documented at the trochlear notch of the ulna in an adult sample from the Bronze Age tomb at Tell Abraq, United Arab Emirates (2200 BC), located on the Arabian gulf. The tomb housed over 300 individuals that were disarticulated and commingled.The ulna (n = 166), radius (n = 201) and scaphoid (n = 274) bones were assessed for morphological variations and pathology. Eighty‐five percent of assessed radii had a depressed facet for attachment of the volar carpal ligament and 34% of the scaphoid bones had an exaggerated dorsal ridge for attachment of the dorsal carpal ligament. While assessing the ulnae an elevation at the transverse midtrochlear region was identified on 58% of the sample. This ridge appears to be a newly documented anatomical phenomenon. There was a strong positive correlation between the presence of this transverse midtrochlear ridge (TTR), proximal elbow joint OA (rs = .330, p<.01) and assigned sex (rs = .263, p<.01) showing a strong correlation in males. We hypothesize that this transverse elevation at the trochlear notch increased stability at the medial elbow joint in this population. The presence of the TTR in conjunction with the findings on the radii and scaphoid bones suggest that the inhabitants of Tell Abraq lived physically arduous lives.

Linking antipredator behaviour, ingestion, gut evacuation and costs of predator-induced responses in tadpoles

SUMMARY: When a vein segment is grafted into arterial circulation, biomechanical forces stimulate modification of its structure. This morphological adaptive response is progressive during a medium or long term and occludes the vessel lumen, leading to a graft failure. The objective of this study was to characterize the early morphological response of the vascular wall in a terminal-terminal vascular vein graft model in Wistar rats. A segment of the femoral vein was placed in the femoral circulation. An end to end microsurgical graft anastomosis technique was implemented and standardized in twenty rats. The samples were processed with histological technique to analyze the overall structure with hematoxylin and eosin, the composition of the vessel wall with Masson trichrome technique, the proliferating and smooth muscle cells were detected with immunohistochemistry (anti-PCNA, anti-actin and anti CD68) and the induction of apoptosis with TUNEL technique. The times periods studied were 1, 3 and 5 days postoperative. There is progressive increase of cell proliferation and intensity of the density detected by PCNA with its peak at postoperative day 3. Apoptosis was not evident in any of the postoperative days. Smooth muscle had no significant change in any of the time periods studied. Macrophage and leukocyte migration was evident since the first postoperative day with infiltration into the media by the 5th day. This study characterizes the morphological aspects in the early arterialization of the vascular wall in a vein graft process. These results contribute to a better understanding of the morphopathological mechanism involved in vein graft failure. KEY WORDS: Hyperplasia; Morphology; Microsurgical model; Vascular adaptive changes; Venous graft.

Shade stress alters soybean growth through transcriptomic changes and adaptive responses that optimize light capture and utilization, regulated by a phytohormonal network. This study examined the physiological, morphological, and molecular responses of Guru (shade-tolerant) and Heinong 53 (shade-sensitive) soybean cultivars under 0% (control), 30%, and 70% shade. Results revealed morphological responses where Heinong 53 exhibited greater plant height (52.8 cm) compared to Guru (45.2 cm) under 30% shade. However, physiological responses favored Guru, with higher chlorophyll content under both 30% shade (2.8 mg/g vs 2.1 mg/g) and 70% shade (2.5 mg/g vs 1.6 mg/g). Guru also demonstrated superior photosynthetic performance, with higher net photosynthetic rates under control conditions (18.5 vs 15.2 µmol CO₂/m2/s) and under 70% shade (12.4 vs 8.7 µmol CO₂/m2/s). Transcriptome analysis identified 2,596 differentially expressed genes (DEGs) across nine comparison groups, with 279 up-regulated and 388 down-regulated genes common across shade treatments. Significant DEGs were associated with shade avoidance (GO:0009641), programmed cell death (GO:0012501), and shoot development (GO:0010223). Key molecular functions included histone deacetylase activity and calcium-dependent protein kinase (GO:0009931). Gene-trait correlations revealed 37 up-regulated DEGs positively correlated with photosynthesis-related metrics, while 28 were negatively correlated with transpiration rate. Additionally, 12 DEGs positively correlated with plant height, and 6 down-regulated DEGs negatively correlated with photosynthetic characteristics. Overall, the cultivar Guru exhibited effective resource allocation, maintained robust photosynthetic activity, and displayed consistent gene expression patterns under shade stress, revealing key mechanisms of soybean shade tolerance. These findings advance the development of shade-resilient soybean cultivars and offer strategies to enhance crop productivity in low-light environments.