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To adapt to climate change and water scarcity during dry, hot summers, more sustainable, or even deficit, irrigation is required in the ornamental sector, as it uses large amounts of water to sustain high-value crop production. Biostimulants, especially seaweed extracts, could offer a sustainable solution against drought stress as they are known to increase plant tolerance to abiotic stress. The effect of four seaweed extracts based on Ascophyllum nodosum, Soliera chordalis, Ecklonia maxima, and Saccharina latissima and one microbial biostimulant were tested on container-grown Hydrangea paniculata under drought stress conditions for two years. During the first trial year, in 2019, overall irrigation was reduced by 20%. In 2021, plants were subjected to repeated drying and wetting cycles. In general, less irrigation, and thus a lower substrate moisture content, reduced stomatal conductance, biomass production, and root development, but increased plant compactness. The biostimulants showed minor effects, but these were not observed in both experiments. Treatment with the A. nodosum extract resulted in longer branches and more biomass under deficit irrigation but tended to accelerate flowering when repeated drying and wetting cycles were applied. The E. maxima extract negatively affected the branching of Hydrangea under repeated drying and wetting cycles.

Phytochrome photoreceptors are known to regulate plastic growth responses to vegetation shade. However, recent reports also suggest an important role for phytochromes in carbon resource management, metabolism, and growth. Here, we use 13CO2 labelling patterns in multiallele phy mutants to investigate the role of phytochrome in the control of metabolic fluxes. We also combine quantitative data of 13C incorporation into protein and cell wall polymers, gas exchange measurements, and system modelling to investigate why biomass is decreased in adult multiallele phy mutants. Phytochrome influences the synthesis of stress metabolites such as raffinose and proline, and the accumulation of sugars, possibly through regulating vacuolar sugar transport. Remarkably, despite their modified metabolism and vastly altered architecture, growth rates in adult phy mutants resemble those of wild-type plants. Our results point to delayed seedling growth and smaller cotyledon size as the cause of the adult-stage phy mutant biomass defect. Our data signify a role for phytochrome in metabolic stress physiology and carbon partitioning, and illustrate that phytochrome action at the seedling stage sets the trajectory for adult biomass production.

Studies on pH stress in marine animals typically focus on direct or species-specific aspects. We here test the hypothesis that a drop to pH = 7.6 indirectly affects the intra- and interspecific interactions of benthic invertebrates by means of chemical communication. We recorded fitness-relevant behaviours of small hermit crabs Diogenes pugilator, green shore crabs Carcinus maenas, and harbour ragworms Hediste diversicolor in response to short-term pH drop, and to putative stress metabolites released by conspecifics or gilt-head sea bream Sparus aurata during 30 min of acute pH drop. Not only did acute pH drop itself impair time to find a food cue in small hermit crabs and burrowing in harbour ragworms, but similar effects were observed under exposure to pH drop-induced stress metabolites. Stress metabolites from S. aurata, but not its regular control metabolites, also induced avoidance responses in all recipient species. Here, we confirm that a short-term abrupt pH drop, an abiotic stressor, has the capacity to trigger the release of metabolites which induce behavioural responses in conspecific and heterospecific individuals, which can be interpreted as a behavioural cost. Our findings that stress responses can be indirectly propagated through means of chemical communication warrant further research to confirm the effect size of the behavioural impairments caused by stress metabolites and to characterise their chemical nature.

Lay Summary: We studied moose calves to investigate the links between stress and nutrition, a detrimental parasite during challenging winter conditions and winter survival. We identified several covariates related to fecal glucocorticoid metabolite concentrations and urea nitrogen:creatinine ratios and linked these physiological metrics to a survival rate., Moose populations in the northeastern United States have declined over the past 15 years, primarily due to the impacts of winter ticks. Research efforts have focused on the effects of winter tick infestation on moose survival and reproduction, but stress and nutritional responses to ticks and other stressors remain understudied. We examined the influence of several environmental factors on moose calf stress hormone metabolite concentrations and nutritional restriction in Vermont, USA. We collected 407 fecal and 461 snow urine samples from 84 radio-collared moose calves in the winters of 2017–2019 (January–April) to measure fecal glucocorticoid metabolites (fGCM) concentrations and urea nitrogen:creatinine (UN:C) ratios. We used generalized mixed-effects models to evaluate the influence of individual condition, winter ticks, habitat, climate and human development on stress and nutrition in calf moose. We then used these physiological data to build generalized linear models to predict calf winter survival. Calf fGCM concentrations increased with nutritional restriction and snow depth during adult winter tick engorgement. Calf UN:C ratios increased in calves with lighter weights and higher tick loads in early winter. Calf UN:C ratios also increased in individuals with home ranges composed of little deciduous forests during adult winter tick engorgement. Our predictive models estimated that winter survival was negatively related to UN:C ratios and positively related to fGCM concentrations, particularly in early winter. By late March, as winter ticks are having their greatest toll and endogenous resources become depleted, we estimated a curvilinear relationship between fGCM concentrations and survival. Our results provide novel evidence linking moose calf stress and nutrition, a problematic parasite and challenging environment and winter survival. Our findings provide a baseline to support the development of non-invasive physiological monitoring for assessing environmental impacts on moose populations.

Endophytes contribute to plant performance, especially under harsh conditions. We therefore hypothesized that wild plants have retained beneficial endophytes that are less abundant or not present in related crop plants. To test this hypothesis, we selected two endophytes that were found in Sharon goatgrass, an ancestor of wheat, and tested their effect on bread wheat. Both endophytes infected wheat and improved sustainability and performance under water-limited conditions. To determine how the endophytes modify plant development, we measured parameters of plant growth and physiological status and performed a comparative metabolomics analysis. Endophyte-treated wheat plants had reduced levels of stress damage markers and reduced accumulation of stress-adaptation metabolites. Metabolomics profiling revealed significant differences in the response to water stress of endophyte-treated plants compared with untreated plants. Our results demonstrate the potential of endophytes from wild plants for improvement of related crops and show that the beneficial effects of two endophytes are associated with alteration of physiological responses to water-limited conditions.

The addition of an aqueous extract from fruitbodies of Tylopilus felleus to tissue cultures of Holarrhena antidysenterica (Apocynaceae) caused the accumulation of an unknown compound in the culture medium. The compound was isolated and identified as 5-hydroxymethyl-2-furancarboxaldehyde (1). Moreover, biosynthesis of phenolic compounds was stimulated in response to the stress agents of the fungal preparation. Methyl ferulate (2) was the major phenolic constituent.

A study on the heterocystous, nitrogen fixing cyanobacterium, Anabaena fertilissima was carried out to investigate the effect of an organochlorine insecticide (hexachloro-hexahydro-methano-benzodioxathiepineoxide, called as endosulfan) at different concentrations of 3, 6 and 12 μgml-1 on the photosynthetic pigments-Chl-a, Carotenoids and Phycobiliproteins-phycocyanin, allophycocyanin and phycoerythrin, stress metabolites such as carbohydrates, proteins, amino acids, phenols and enzyme activities-nitrate reductase and glutamine synthetase. The insecticide- Endosulfan showed to be deleteriously affecting the activities in the cyanobacterium. As early as the 4th day, chl-a and carotenoids reduced by 38% and 20% respectively. The phycobiliproteins declined by 60%, 64% and 28% with respect to Phycocyanin, Allophycocyanin and Phycoerythrin. Moreover, Endosulfan adversely depleted the cellular activities, leading to a marked decrease in the carbohydrates, proteins, phenols and amino acids and enzymes-nitrate reductase and glutamine synthetase. Despite of deleterious effects of Endosulfan on the cyanobacterium Anabaena fertilissima, a unique regenerating ability in presence of the insecticide was observed by the end of 12 days in the lower doses of insecticide.

This investigation was made to study and compare the effects of different diets on sensory meat quality and ultimate pH values in reindeer muscles and to relate stress-induced blood metabolites and carcass parameters to the meat quality traits measured. Altogether 23 female reindeer calves were included in the study. During an adaptation period, all reindeer were allowed free access to a mimicked natural diet containing 80% lichens (lichen diet). On January 28, 8 reindeer (group Cjan) were slaughtered. Five reindeer (group C.Mar) were allowed continuous free access to the lichen diet throughout the experiment. During 8 days, the other reindeer (groups PL and PS) were given the lichen diet, half of the amount offered to the control group, and were then starved for one day. Thereafter, these reindeer were fed 80% commercial reindeer feed (pellets) and either 20% lichens (group PL), or 20% silage (group PS) for 5 weeks. After this, all animals were slaughtered. The average carcass weight and dressing percentage in the group fed commercial reindeer feed and lichens (PL) were higher than in group CMar- Fat registrations were generally higher in groups PL and PS than in the groups Cj2n and CMar- Ultimate pH values in M. triceps brachii and M. longissimus were significantly lower in the group CMST than in PL. The levels of all blood metabolites (urea, ASAT and Cortisol) were generally higher in groups PL and PS than in groups Cja„ and CMEF- NO significant differences were found in any of sensory attributes of the meat (monitored according to ISO standards). The present study shows that muscle and fat depots in reindeer can be improved by feeding a diet based on reindeer pellets but suggests that a feeding period of 35 days might be too short to affect the sensory properties of reindeer meat.