Effects Of Photoperiod Research Articles

Effect of parturition time and photoperiod on milk production, quality, and somatic cell count traits of pure and crossbred goats in a different production system.

This is the first study to compare the effects of parturition time and photoperiod on milk yield, quality, and somatic cell count (SCC) traits in pure and crossbred doe genotypes reared with supplementary feeding at various physiological stages in a mountain-pasture grazing system. Data were collected from Hair, Alpine × Hair F1 (AHF1), and Saanen × Hair F1 (SHF1) crossbred doe genotypes with an average live weight of 49.60±0.40 kg. Hair doe had significantly lower (P < 0.001) milk yields and lactation length, but higher (P < 0.001) fat, protein, and lactose contents and electrical conductivity (EC) than AHF1 and SHF1 crossbred doe genotypes. Does giving parturition in the hours of darkness had higher (P < 0.05) milk volume and lower (P < 0.05) SCC compared to does giving parturition in the hours of daylight. Daily milk yield was positively correlated with daylight (P < 0.05; r = 0.50 to 0.53), while milk fat, protein, and lactose contents were negatively correlated with daylight (P < 0.05 to P < 0.001; r = -0.51 to -0.82, respectively) in Hair, AHF1, and SHF1 crossbred doe genotypes. Lactation stages and daily milk yield levels significantly affected (P < 0.05) the SCC, pH, total solids, and freezing point of milk. It was concluded that the milk yield traits of goats can be rapidly improved by better modelling of physiological and environmental variations such as photoperiod, reproduction, and hormonal effects in sustainable production systems.

Performance of parasitoid Bracon hebetor (Say.) (Hymenoptera

Harbobracon hebetor say (Hymenoptera: Braconidae) is a gregarious larval ectoparasitoid of several species of Lepidoptera that are associated with stored products. The present study addresses the effect of photoperiod of H.Hebetor reared on the host C. cephalonica. The results revealed that the effect of photoperiod of H. hebetor reared host in C. cepholonica was not significantly varied. The highest percentage of parasitism (98.553%) was recorded in 08L:16D followed by 91.110% in 24L:00D photoperiod. 86.667% in 00L:24D respectively. However the photoperiod 12L:12D showed the lowest percentage 82.223% of parasitism. The highest percent of pupae formed and adult emergence of parasitoid H. hebetor was achieved (98.045%) for 00L: 24D and (98.923%) for 08L:16D photoperiod when reared on C.cephalonica. The highest number of larval production (86.33) was recorded for 00L:24 photoperiod and lowest was 20.67 for 12L:12D photoperiod. The result showed the highest adult male and female body, head width and wing span length in 08L:16D photoperiod when reared on the host C. cepholonica.

Effects of Photoperiod and Drought on Flowering and Growth Development of Protein-Rich Legumes under Atlantic Environments

Legumes have an important role in European agriculture. They assimilate N2 to sustainably support maximum crop growth, in turn providing high-protein food for human consumption and livestock feed. However, the extent of the area for legume cultivation in Europe has declined due to the lower economic competitiveness of legumes in relation to other crops, particularly of cereals and oilseed. To increase yields, there is a need to increase the genetic diversity of legumes in terms of adaptation to environmental stresses. We attempted to address this by conducting field and controlled experiments under drought vs. nondrought and different photoperiod conditions. The current study identified the physiological and agronomic traits correlated with productivity and quality performance in five economically important grain legume species (Pisum sativum, Phaseolus vulgaris, Cicer arietinum, Lupinus spp., and Vicia faba). In all species, the days to flowering and seed yield were affected by temperature and photoperiod. For cool-season legume species, long-day photoperiods were favorable and days to flowering was negatively correlated with the average air temperature. For the warm-season legumes, short-day photoperiods and warm temperatures were favorable. Under drought stress, the C/N balance, leaf nutrient (Ca, Fe, and K) concentrations, and yield were significantly reduced, contrary to Zn accumulation, and this information may contribute to improving our understanding and ability to develop sustainable growth. Based on our results, we conclude that the drought-tolerant and photoperiod-insensitive legume genotypes identified in this study constitute valuable starting materials for future programs aimed at improvement of legume productivity at a global/regional scale, which helps to strengthen the competitiveness and economic growth of legumes for European farmers.

A straightforward strategy for reducing variability in flowering time at warm ambient temperatures

ABSTRACT Ambient temperature is one of the major environmental factors affecting flowering. As the temperature rises, most plants, including Arabidopsis, flower more rapidly. In addition, phenotypic variability in flowering time tends to increase at warm ambient temperatures. The increased variability of flowering time at warm temperatures prevents accurate flowering time measurements, particularly when evaluating the flowering time of Arabidopsis plants under short-day conditions in order to restrict the photoperiodic effect. Here, we propose a simple method for reducing the variability of flowering time at warm temperatures. Instead of growing plants at different temperatures from germination, the strategy of first vegetative growth at cool temperatures and then shifting to warm temperatures allows plants to respond more stably and robustly to warm temperatures. Consistent with flowering time measurements, plants grown under the modified growth condition exhibited higher levels of FLOWERING LOCUS T (FT) gene expression than plants grown exclusively at warm temperatures. This approach enables more precise thermo-response studies of flowering time control in Arabidopsis.

Gut Microbiota Influences the Photoperiod Effects on Proanthocyanidins Bioavailability in Diet-Induced Obese Rats.

Polyphenols health effects on obesity are mainly attributed to their metabolites generated after their gastrointestinal digestion, in which gut microbiota plays an important role. Moreover, gut microbiota composition and polyphenols bioavailability are influenced by differences in day light length (photoperiod). Thus, this study evaluates if a grape seed proanthocyanidins (GSPEs) extract bioavailability is influenced by different photoperiod exposure via gut microbiota modulation in an obesogenic context. Cafeteria diet-induced obese Fischer 344 rats are housed under different photoperiod conditions (6, 12, or 18h of light per day) during 9weeks and administered with GSPE (25mgkg-1 ) or GSPE and an antibiotic cocktail (ABX) for the last 4weeks. Serum GSPE-derived metabolites are quantified by HPLC-MS/MS. A higher bioavailability is observed under 6h light/18h darkness (L6) compared to 18h light/6h darkness (L18). Individual metabolites, especially those from the gut microbiota, are affected by photoperiods. ABX treatment alters these photoperiod-mediated changes. Therefore, these results suggest that gut microbiota plays a key role in the photoperiod effects on GSPE bioavailability in obese rats.

Population-specific effects of temperature and photoperiod on development and body mass in Cassida vibex (Coleoptera: Chrysomelidae).

An interplay of genetic divergence and phenotypic plasticity in shaping geographic variation is increasingly receiving attention in the entomological literature. Two major environmental variables that govern life histories are temperature and photoperiod. Studies of thermal and photoperiodic reaction norms help us understand how insect diversity evolved and how insects respond to environmental change. We studied survival, development, and body mass in three geographic populations of the beetle Cassida vibex reared in the laboratory under several combinations of constant temperature (16, 19, 22, 25, and 28°C) and photoperiod (short-day and long-day). The three collection sites are situated along a climatic gradient and separated by hundreds of kilometers. Each population subtly but significantly differs in the absolute values of survival rate, developmental rate, and body mass as well as in the thermal and photoperiodic plasticity of these traits, but the geographic differences do not form a latitudinal cline. The southernmost population from a relatively warm climate survives worse at low temperatures than the other two, but the overall survival is lowest in the latitudinally intermediate population. Short-day conditions tend to accelerate postembryonic development and increase the slope of the developmental rate-temperature relationship, especially so in the intermediate population, followed by the southernmost population and then by the northernmost population. The latter, which inhabits a harsh climate, has the fastest and most temperature-sensitive development, regardless of photoperiod, and attains the largest body mass among the three populations. The intermediately located and photoperiodically plastic population, which lives in a cool but mild climate, in contrast, has the smallest body size. Hence, although the importance of short-day conditions as a seasonal cue increases poleward, the photoperiodic responses do not always become more pronounced in colder, high-latitude environments. Our results emphasize that insect life-history traits can exhibit quite sophisticated patterns of variation along climatic gradients.

Effect of photoperiod during incubation on embryonic temperature, hatch traits, and performance of 2 commercial broiler strains

Provision of light during incubation has shown the potential to enhance hatching traits and affect posthatch productivity, physiology, and behavior. In this study, 2 repeated trials were conducted to investigate the effect of photoperiod and strain on the embryo temperature, hatching traits and posthatch growth performance of 2 commercial strains of broilers (Ross 308 and Cobb 500). In each trial, hatching eggs were randomly distributed into 6 incubators with 3 photoperiod treatments: blue LED light for 12 h d-1 (12L:12D) or 18 h d-1 (18L:6D) during entire incubation were compared with no illumination condition (DARK). Data were analyzed as a 3×2 factorial arrangement with the trial as the blocking factor. Embryos incubated under 12L:12D and 18L:6D had lower air cell temperature (P < 0.05) than the DARK embryos from d 13 of incubation onward except on the day of candling. The response of air cell temperature to periodic illumination differed between 2 strains. Cobb embryos had lower air cell temperature in 12L:12D than those incubated with 18L:6D from d 16 of incubation onward, whereas lower air cell temperature was found in Ross embryos when illuminated with 18L:6D photoperiod compared to those under 12L:12D. The 12L:12D treatment was associated with improved (P < 0.05) navel closure condition of hatchlings. There were no differences in hatchability, embryo mortality, body weight, or length at hatch among photoperiod groups or its combination with strain. No differences in production parameters were found between DARK and illuminated groups. However, 12L:12D had heavier (P < 0.05) body weight on d 14 of age and higher (P < 0.05) body weight gain than 18L:6D from d 7 to 14 of age. The results of this study indicate that providing blue LED light up to 18 h d-1 has no detrimental effect on production of broilers, however, 12L:12D light regime improved chick quality at hatch compared to DARK and resulted in heavier birds by d 14 compared to 18L:6D.

Moving Away from 12:12; the Effect of Different Photoperiods on Biomass Yield and Cannabinoids in Medicinal Cannabis

The standard practice to initiate flowering in medicinal cannabis involves reducing the photoperiod from a long-day period to an equal duration cycle of 12 h light (12L)/12 h dark (12D). This method reflects the short-day flowering dependence of many cannabis varieties but may not be optimal for all. We sought to identify the effect of nine different flowering photoperiod treatments on the biomass yield and cannabinoid concentration of three medicinal cannabis varieties. The first, "Cannatonic", was a high cannabidiol (CBD)-accumulating line, whereas the other two, "Northern Lights" and "Hindu Kush", were high Δ9-tetrahydrocannabinol (THC) accumulators. The nine treatments tested, following 18 days under 18 h light/6 h dark following cloning and propagation included a standard 12L:12D period, a shortened period of 10L:14D, and a lengthened period of 14L:10D. The other six treatments started in one of the aforementioned and then 28 days later (mid-way through flowering) were switched to one of the other treatments, thus causing either an increase of 2 or 4 h, or a decrease of 2 or 4 h. Measured parameters included the timing of reproductive development; the dry weight flower yield; and the % dry weight of the main target cannabinoids, CBD and THC, from which the total g cannabinoid per plant was calculated. Flower biomass yields were highest for all lines when treatments started with 14L:10D; however, in the two THC lines, a static 14L:10D photoperiod caused a significant decline in THC concentration. Conversely, in Cannatonic, all treatments starting with 14L:10D led to a significant increase in the CBD concentration, which led to a 50-100% increase in total CBD yield. The results show that the assumption that a 12L:12D photoperiod is optimal for all lines is incorrect as, in some lines, yields can be greatly increased by a lengthened light period during flowering.

A mis-splicing early flowering 3 (elf3) allele of lentil is associated with yield enhancement under terminal heat stress.

There is a vast scope of area expansion of lentils after harvesting wet rice in South Asia. However, due to the photoperiod effect and terminal heat, the existing short-duration varieties failed to minimize yield loss under late-sown conditions. A mis-splicing causing A/G SNP present in the last nucleotide of exon 3 of early flowering 3 (ELF3) gene (elf3 allele) in a lentil line, L4710, is associated with the photoperiod insensitive flowering and the fast absolute growth rate (AGR). None of the Indian cultivars tested in this study, either early or late, possesses the non-functional elf3 allele. However, the A to G transition in ELF3-exon2 replaces glycine with aspartic acid at the 403rd amino acid in all the Indian varieties tested, compared to the reference sequence of Mediterranean accession, ILL5588. Therefore, targeting A/G SNP of exon 3, a PCR-based codominant marker is developed. The elf3 allele is correlated with the fast AGR and early flowering, but low yield and biomass, in an L4710 × LL56-derived RIL-population, compared to ELF3 carrying alleles when sown on 15th November. However, in a month of delayed sowing (20th December), the same elf3-RILs revealed a higher yield and biomass with slower AGR Moreover, three elf3-carrying lines, grown in delayed condition (20 December) for two consecutive years in three locations, outyielded three popular high-yielding cultivars that carry functional ELF3. Thus, elf3-carrying high-yielding lines could be the breeder's choice to expand and enhance lentil yield in short-season environments and in vast rice fallows of south Asia, where delayed rice harvest occurs frequently.

Short-active gestational photoperiod reduces effortful choice behavior in mice, partial normalization by d-amphetamine.

Seasonal birth patterns consistently implicate winter gestation as a risk factor for several psychiatric conditions. We recently demonstrated that short-active (SA; 19:5 light:dark)-i.e., "winter-like"-photoperiod exposure across gestation and early life (E0-P28) induces psychiatrically relevant behavioral abnormalities in adult mice, including reduced immobility in the forced swim test (FST) and effortful amotivation. It is unknown, however, whether these effects were driven primarily by prenatal or postnatal mechanisms, and whether perinatal SA photoperiod would similarly reduce effort expenditure in a task relevant to everyday decision-making. We first tested male and female mice exposed to either gestational (E0-P0) or postnatal (E0-P28) SA photoperiod in the FST to determine whether the previously observed alteration was driven primarily by prenatal versus postnatal photoperiod. We then assessed whether SA gestational photoperiod reduces effortful choice behavior in the cross-species effort-based decision-making task (EBDMT) and whether any such deficit could be remediated by d-amphetamine (0.1 and 0.3 mg/kg, i.p.). Mice exposed to prenatal, but not postnatal, SA photoperiod exhibited reduced FST immobility relative to controls and also demonstrated condition-dependently reduced preference for high-effort/high-reward versus low-effort/low-reward contingencies in the EBDMT. This effortful choice deficit was normalized by 0.1 mg/kg amphetamine. These data: (1) suggest a greater contribution of gestational versus postnatal light conditions to the behavioral effects of perinatal SA photoperiod; and (2) implicate altered dopamine signaling in the behavioral phenotype of the SA-born mouse and possibly in the etiology of winter gestation-associated cases of psychiatric disease.

Identification of the global diurnal rhythmic transcripts, transcription factors and time-of-day specific cis elements in Chenopodium quinoa

BackgroundPhotoperiod is an important environmental cue interacting with circadian clock pathway to optimize the local adaption and yield of crops. Quinoa (Chenopodium quinoa) in family Amaranthaceae has been known as superfood due to the nutritious elements. As quinoa was originated from the low-latitude Andes, most of the quinoa accessions are short-day type. Short-day type quinoa usually displays altered growth and yield status when introduced into higher latitude regions. Thus, deciphering the photoperiodic regulation on circadian clock pathway will help breed adaptable and high yielding quinoa cultivars.ResultsIn this study, we conducted RNA-seq analysis of the diurnally collected leaves of quinoa plants treated by short-day (SD) and long-day conditions (LD), respectively. We identified 19,818 (44% of global genes) rhythmic genes in quinoa using HAYSTACK analysis. We identified the putative circadian clock architecture and investigated the photoperiodic regulatory effects on the expression phase and amplitude of global rhythmic genes, core clock components and transcription factors. The global rhythmic transcripts were involved in time-of-day specific biological processes. A higher percentage of rhythmic genes had advanced phases and strengthened amplitudes when switched from LD to SD. The transcription factors of CO-like, DBB, EIL, ERF, NAC, TALE and WRKY families were sensitive to the day length changes. We speculated that those transcription factors may function as key mediators for the circadian clock output in quinoa. Besides, we identified 15 novel time-of-day specific motifs that may be key cis elements for rhythm-keeping in quinoa.ConclusionsCollectively, this study lays a foundation for understanding the circadian clock pathway and provides useful molecular resources for adaptable elites breeding in quinoa.

The effects of photoperiod and temperature-related factors on maize leaf number and leaf positional distribution in the field.

Quantifying the effects of various environmental conditions on maize leaf number is essential to understanding the environmental adaptations and population structure of maize plants and for enhancing maize productivity. In this study, seeds of three temperate-adapted maize cultivars, each belonging to different maturity classes, were sown on eight different dates. Sowing dates ranged from the middle of April to early July, which allowed us to cover a wide range of environmental conditions. Random forest regression and multiple regression models with variance partitioning analyses were used to assess the effects of environmental factors on the number of leaves and their distributions on maize primary stems. We demonstrated that the total leaf number (TLN) increased in the three cultivars in the following order: FK139 < JNK728 < ZD958, and variations in TLN for each cultivar were 1.5, 1.76, and 2.75 leaves, respectively. The variation in TLN was ascribed to changes in LB (leaf number below the primary ear), which were higher than variations in LA (leaf number above the primary ear). Variations in TLN and LB were mainly affected by the photoperiod during growth stages V7 to V11, and differences in TLN and LB in response to different photoperiods ranged from 1.34 to 2.95 leaves h-l. Variations in LA was mainly affected by temperature-related factors. Therefore, the results of this study enhanced our current understanding of key environmental conditions that affect maize leaf numbers, and provides scientific support for the benefits of adjusting sowing dates and selecting suitable cultivars to mitigate the effects of climate change on maize production.

Effect of Extended Photoperiod on Performance, Health, and Behavioural Parameters in Nursery Pigs

Lighting influences the circadian rhythm and physiology of animals. Yet, the influence of light on nursery pigs is not fully understood and results remain controversial. The present study investigated the effects of a prolonged photoperiod on the performance, health, and behaviour of nursery pigs. This study was conducted in one farm and included 288 hybrid nursery pigs. Long (LONG) and short (SHORT) photoperiod animals were exposed to either 16 or 8 h of light per day, respectively. Performance, health, welfare, and behavioural parameters were monitored during a nursery period of five weeks. Short photoperiod piglets tended to have higher weights at the end of the nursery (LONG: 21.59 vs. SHORT: 22.19 kg; p = 0.064) and higher average daily gain (LONG: 385 vs. SHORT: 403 g/day; p = 0.063) compared to the long photoperiod piglets. The LONG piglets had significantly higher fecal consistency scores (0-100) than the SHORT piglets on days 7 (LONG: 21 vs. SHORT: 10; p = 0.039), 11 (LONG: 40 vs. SHORT: 14; p = 0.002), 21 (LONG: 21 vs. SHORT: 8; p = 0.008), and 25 (LONG: 26 vs. SHORT: 11; p = 0.015). The LONG piglets tended to have a slightly higher incidence of aggressive behaviour (LONG: 2.49% vs. SHORT: 2.36%; p = 0.071). No significant differences were found for the remaining parameters (p > 0.1). Under the present conditions, lengthening the photoperiod during the nursery period did not significantly improve the performance, health, and welfare of the pigs.

Interaction of temperature and photoperiod on male postsmolt maturation of Atlantic salmon (Salmo salar L.)

Maturation of Atlantic salmon male postsmolts is a concern in aquaculture due to its increasing occurrence under intensive rearing conditions and its negative impact on growth, welfare and seawater readiness. The effect of temperature and photoperiod on maturation was assessed in male postsmolts kept in freshwater. We used a 2 × 2 factorial design with two temperatures (12.5 and 15 °C) and two photoperiods (a group in continuous light LD24:0 or LL, and another receiving a 5-week LD12:12 winter signal or WS). Salmon in the four resulting treatments (1000 parr, initial mean weight 52.1 ± 5.2 g) were reared in a flow-through system from 28 October 2019 to 30 May 2020. Morphology (body weight, condition factor), maturation indicators including gonadosomatic index (GSI), plasma 11-Ketotestosterone (11-KT), pituitary follicle-stimulating hormone β-subunit (fshb) and luteinizing hormone β-subunit (lhb) transcript levels, as well as smoltification markers (Na+, K+- ATPase activity) were assessed. Results revealed that rearing salmon at 15 °C was the most important factor promoting early maturation, leading to 100% of males maturing in late May in 15-WS, and 75% in 15-LL. However, the groups receiving a winter signal (WS) displayed a highly synchronized onset and progression of maturation specially at 15 °C, revealed by the low variability observed among individuals in GSI and fshb transcription after the WS. This evidences the role of the photoperiod switch from short to long day as zeitgeber for sexual maturation. On the contrary, under constant light (LL), entry into maturation was not synchronized among individuals, and onset of maturation occurred spontaneously in a proportion of males highly dependent upon temperature (75% in 15-LL, 25% in 12.5-LL). Signs of smoltification were poor at both temperatures, and the WS did not induce development of hypo-osmoregulatory abilities in any case. This suggests that a winter signal may not induce smoltification if introduced at high temperature or when fish have reached large size, and instead may increase the risk of a sexual maturation response. These findings are relevant for the aquaculture industry, since similar rearing conditions are currently used in the industry, including constant high water temperature and winter signal regimes. The use of such conditions can increase the risk of early maturation, as well as of poor hypo-osmoregulatory performance.

Genetic variation in four maturity genes and photoperiod insensitivity effects on the yield components and on the growth duration periods of soybean

Soybean (Glycine max (L.) Merr.) is a typical short-day and thermophilic crop. Absence of or low sensitivity to photoperiod is necessary for short-day crops to adapt to high latitudes. Photoperiod insensitivity in soybeans is controlled by two genetic systems and involves three important maturity genes: E1, a repressor for two soybean orthologs of Arabidopsis FLOWERING LOCUS T, and E3 and E4, which are phytochrome A genes. The aim of this work was to investigate the role of four maturity genes (E1 through E4) on the yield components, seed quality and on phasic development of near isogenic by E genes lines of soybean: short-day (SD) lines with genotype e1E2E3E4e5E7, e1E2E3e4e5E7, E1e2e3E4e5E7 and photoperiodic insensitive (PPI) lines with genotype e1e2E3E4e5E7, e1e2e3E4e5E7 under a long photoperiod (the natural day length of 50 latitude) conditions and short day conditions. The results of the study showed that soybean development processes under conditions of different day lengths depend on the dominant/recessive state of the main maturity genes. In addition, the response to the photoperiod depends on certain combinations of genes. SD lines began flowering on average 16.9% later under the conditions of a natural long photoperiod. Dominant alleles of genes E1 and E3 extended the pre- and post-flowering phases under conditions of exposure to long and short photoperiods. The dominant allele of the E1 gene delayed the onset of flowering by an average of 26.9%, and the period of full maturity by 39.8% compared to the recessive e1. The dominant allele of the E3 gene, compared to the recessive e3, lengthened the transition to flowering by an average of 16.1%, and the period of full ripeness by 27.1%. The dominant allele of the E2 gene lengthened the duration of the vegetative phase by 20% under the conditions of a long photoperiod. No significant influence of the dominant E4 allele on the duration of the vegetative and generative phases of soybean development was found in our study. PPI lines begin flowering under the conditions of a long and short photoperiod at the same time, but the phases of flowering and full seed maturity in the line with genotype e1e2e3E4e5E7 occurred earlier, due to the loss of the photoperiod sensitivity of the E3 gene. PPI line with genotype e1e2e3E4e5E7 proved to be the most insensitive line to the effect of different photoperiod durations among the studied lines. It was shown that the dominant alleles of E1–E4 maturity genes reduced the parameters of seed weight per plant and the weight of 1000 seeds under the conditions of a natural long photoperiod in comparison with recessive alleles of these genes. The maximum weight of seeds per plant and the weight of 1000 seeds were recorded in the PPI line with genotype e1e2e3E4e5E7. It should be noted that the dominant alleles E1 and E3 increased yield under conditions of a short photoperiod. Maturity genes had different effects on the biochemical composition of seeds. It was shown that soybean lines with dominant E1, E2 and E4 genes showed a higher content of starch and a lower content of total nitrogen and oil in seeds under natural photoperiod conditions compared to lines with recessive alleles of these genes. The dominant E3 allele reduced the oil content and did not affect the starch and total nitrogen content of seeds under long day conditions compared to the recessive e3 allele. The analysis of the effect of photoperiod on the timing of phenophases, yield structure indicators and biochemical composition of seeds in soybean plants with different sensitivity to photoperiod showed that the PPI line with the genotype e1e2e3E4e5E7 was the most adapted to the natural conditions of 50 degrees latitude. The PPI line with the genotype e1e2e3E4e5E7 was characterized by the shortest phases of days from sowing to flowering and full maturity. As a result, this line had the shortest growing season without reducing the yield and seed quality. Clearly, photoperiod had strong effects on all stages of plant reproduction and often acted indirectly, as shown by delayed responses expressed in later phases of development. The obtained results can be useful for the selection of soybean cultivars adapted to the climatic conditions of cultivation of Kharkiv region.

Evaluation of the impact of photoperiod and light intensity on decreasing days to maturity in winter wheat

AbstractThe development and improvement of crop cultivars are necessary to meet the demands of the growing global population. The ability to decrease the generation time is imperative for breeders to achieve higher rates of genetic gain annually. Understanding the way in which photoperiod affects the maturation rate of these crops, including winter wheat (Triticum aestivum L.), is required for decreasing generation time in breeding programs. The effects of prolonged photoperiod and light intensity on winter wheat generation time were studied to determine if photoperiod may contribute to a shortened cycle time. Three winter wheat cultivars (Branson, CFBA1401, and Norstar) and one spring wheat cultivar (AC Carberry) were exposed to four treatments based on the daily light integral (DLI): high light (HL) or low light and photoperiod as follows: 22 h of light and 2 h of dark (22:2) or 16 h of light and 8 h of dark (16:8). Generation time, as measured by days to maturity in the HL22:2 treatment, resulted in a decrease of 8 days or 7% of the total generation time, compared to the control, HL16:8 treatment. Photoperiod itself had a minimal effect on generation time when both DLI and temperature were controlled. An improved understanding of the effects of photoperiod, thermal time, and DLI and their interactions is required prior to implementation in a winter cereal breeding program.

Photoperiod Impacts Nucleus Accumbens Dopamine Dynamics.

Circadian photoperiod, or day length, changes with the seasons and influences behavior to allow animals to adapt to their environment. Photoperiod is also associated with seasonal rhythms of affective state, as evidenced by seasonality of several neuropsychiatric disorders. Interestingly, seasonality tends to be more prevalent in women for affective disorders such as major depressive disorder and bipolar disorder (BD). However, the underlying neurobiological processes contributing to sex-linked seasonality of affective behaviors are largely unknown. Mesolimbic dopamine input to the nucleus accumbens (NAc) contributes to the regulation of affective state and behaviors. Additionally, sex differences in the mesolimbic dopamine pathway are well established. Therefore, we hypothesize that photoperiod may drive differential modulation of NAc dopamine in males and females. Here, we used fast-scan cyclic voltammetry (FSCV) to explore whether photoperiod can modulate subsecond dopamine signaling dynamics in the NAc core of male and female mice raised in seasonally relevant photoperiods. We found that photoperiod modulates dopamine signaling in the NAc core, and that this effect is sex-specific to females. Both release and uptake of dopamine were enhanced in the NAc core of female mice raised in long, summer-like photoperiods, whereas we did not find photoperiodic effects on NAc core dopamine in males. These findings uncover a potential neural circuit basis for sex-linked seasonality in affective behaviors.

Photoperiod Conditions Modulate Serum Oxylipins Levels in Healthy and Obese Rats: Impact of Proanthocyanidins and Gut Microbiota.

Seasonal rhythms are emerging as a key factor influencing gut microbiota and bioactive compounds functionality as well as several physiological processes such as inflammation. In this regard, their impact on the modulation of oxylipins (OXLs), which are important lipid mediators of inflammatory processes, has not been investigated yet. Hence, we aimed to investigate the effects of photoperiods on OXLs metabolites in healthy and obesogenic conditions. Moreover, we evaluated if the impact of proanthocyanidins and gut microbiota on OXLs metabolism is influenced by photoperiod in obesity. To this purpose, Fischer 344 rats were housed under different photoperiod conditions (L6: 6 h light, L12: 12 h light or L18:18 h light) and fed either a standard chow diet (STD) or a cafeteria diet (CAF) for 9 weeks. During the last 4 weeks, obese rats were daily administered with an antibiotic cocktail (ABX), an oral dose of a grape seed proanthocyanidin extract (GSPE), or with their combination. CAF feeding and ABX treatment affected OXLs in a photoperiod dependent-manner. GSPE significantly altered prostaglandin E2 (PGE2) levels, only under L6 and mitigated ABX-mediated effects only under L18. In conclusion, photoperiods affect OXLs levels influenced by gut microbiota. This is the first time that the effects of photoperiod on OXLs metabolites have been demonstrated.

Effects of temperature and photoperiod on growth, physiological, and behavioral performance in steelhead trout (Oncorhynchus mykiss) under indoor aquaculture condition

Light and temperature are necessary conditions for migratory fish. The assessment of fish physiology and behavior is important for identifying fish welfare, but also for the assessment of the optimal setting of recirculating aquaculture systems (RASs). This study aimed to explore the interactive effect of photoperiod and temperature on steelhead trout culture. Four treatments were set up with specific settings were as follows: a LP-LT group treated with 16L:8D and 12°C, a LP-HT group treated with 16L:8D and 16°C, a SP-LT group treated with 12L:12D and 12°C, and a SP-HT group treated with 12L:12D and 16°C. Growth performance, behavioral and physiological parameters were measured. Two indexes, locomotor activity and social interaction were used for behavioral analysis, and the results were applied to interpret the behavioral responses to the photoperiod and temperature stimulation in juveniles. The growth performances were significantly lower in treatments LP-LT and SP-LT. The treatment LP-HT had significantly higher growth performance than the other treatments, but no significant differences were noted in survival rate and coefficient of variation. The results of fish behavior indicated that the movement of juveniles should be primarily monitored at high temperatures or long photoperiods, and the state parameters should be primarily monitored at low temperatures or short photoperiods. The results of the physiological parameters showed that the recovery time from stress varied among different treatments. After 60 days of the experiment, superoxide dismutase and alanine aminotransferase dropped back to their initial level. The results of Na+-K+-ATPase showed that although the combined effect of photoperiod and temperature could advance the time of smoltification, it may result in poorer salt tolerance. Our findings underscore the importance of the interaction of photoperiod and temperature on steelhead trout culture. The outcome could provide guidance for the development of effective aquaculture systems.

Effect of photoperiod on growth, survival, and lipid metabolism of mud crab Scylla paramamosain juveniles

Photoperiod is one of the most important environmental cues for the organism, and it plays a critical role in regulating organisms' survival, growth, and metabolism. In the present study, the effects of photoperiod (0 L∶24 D, 6 L∶18 D, 12 L∶12 D, 18 L∶6 D, and 24 L∶0 D) on mortality, growth performance, and lipid metabolism of juvenile mud crab (Scylla paramamosain) were studied with an 8-week experiment. The results showed that the highest final weight of crabs was observed in the 18 L∶6 D (0.48 ± 0.08 g), which was significantly higher than 0 L∶24 D (0.22 ± 0.03 g) and 6 L∶18 D (0.28 ± 0.04 g) (P < 0.05). In addition, the specific growth rate (SGR) of crabs reared at 12 L∶12 D (natural photoperiod) (5.83 ± 0.26% day−1) and 18 L∶6 D (6.28 ± 0.27% day−1) were significantly higher than 0 L∶24 D (4.70 ± 0.42% day−1), 6 L∶18 D (5.16 ± 0.22% day−1) and 24 L∶0 D (5.60 ± 0.23% day−1) (P < 0.05). The survival rate of the natural photoperiod group was significantly higher than 18 L∶6 D group (69.23 ± 6.28% vs 35.90 ± 3.63%) (P < 0.05), but no significant difference between 0 L∶24 D (58.97 ± 3.63%), 6 L∶18D (66.67 ± 7.25%) and 24 L∶0 D (58.97 ± 7.25%) groups was observed (P > 0.05). Crabs exposed to 18 L∶6 D photoperiod also had higher melatonin (311.12 ± 79.53 pg mL−1 vs 168.79 ± 31.24 pg mL−1) and cortisol levels (451.37 ± 237.64 ng mL−1 vs 112.91 ± 39.32 ng mL−1) than those reared in constant light (24 L∶0 D) (P < 0.05). In addition, compared with natural photoperiod, crabs reared under constant darkness showed significantly higher TG and TC content (P < 0.05). Moreover, in constant darkness, lipogenesis-related genes such as fatty acid synthase (fas), sterol regulatory element binding protein-1 (srebp-1), and acetyl-CoA carboxylase (acc) of the crab were up-regulated, and lipolysis-related genes as carnitine palmitoyltransferase-1 (cpt-1), Acyl-CoA oxidase-3 (aco-3) were significantly down-regulated (P < 0.05). Besides, fatty acid binding protein (fabp) was also up-regulated in crabs reared under constant darkness. Thus, these results suggest that the crabs in constant darkness did not effectively utilise the lipid as an energy source. Overall, the present research confirmed that light cues are indispensable for the indoor mud crab culture system, and the natural photoperiod was recommended for mud crab during the juvenile grow-out phase in commercial operations.