Although temperature is an important driver of seasonal changes in photosynthetic physiology, photoperiod also regulates leaf activity. Climate change will extend growing seasons if temperature cues predominate, but photoperiod-controlled species will show limited responsiveness to warming. We show that photoperiod explains more seasonal variation in photosynthetic activity across 23 tree speci...

Seasonal changes in temperature and photoperiod are important environmental cues used by small birds to adjust their body mass (Mb) and thermogenesis. However, the relative importance of these cues with respect to seasonal adjustments in Mb and thermogenesis is difficult to distinguish. In particular, the effects of temperature and photoperiod on energy metabolism and thermoregulation are not w...

Many small mammals respond to seasonal changes in photoperiod via alterations in morphology, physiology and behaviour. In the present study, we tested the hypothesis that the preweaning (from embryo to weaning) photoperiod experience can affect subsequent development in terms of body mass and thermogenesis. Brandt's voles (Lasiopodomys brandtii) were gestated and reared to weaning under either ...

This study investigated possible involvement of photoperiodic regulation in reproductive endocrine system of female olive flounder. To investigate the influence on brain-pituitary axis in endocrine system by regulating photoperiod, compared expression level of Kisspeptin and sbGnRH mRNA in brain and FSH-β, LH-β and GH mRNA in pituitary before and after spawning. Photoperiod was treated natural ...

Perinatal photoperiod is an important regulator of physiological phenotype in adulthood. In this study, we demonstrated that postnatal (0-4 weeks old) exposure of C57BL/6J mice to long photoperiod induced persistent increase in body weight until adulthood, compared with the mice maintained under short photoperiod. The expression of peroxisome proliferator-activated receptor δ, a gene involved i...

Photoperiod disruption, which occurs during shift work, is associated with changes in metabolism or physiology (e.g. hypertension and hyperglycaemia) that have the potential to adversely affect stroke outcome. We sought to investigate if photoperiod disruption affects vulnerability to stroke by determining the impact of photoperiod disruption on infarct size following permanent middle cerebral ...

In Channa punctatus testicular regression commonly observed during spawning and postspawing phases of reproductive cycle. In the present study testicular regression was frequently noticed in fish maintained under both long photoperiod-warm temperature (LD 16 : 8-30 degrees C) and short photoperiod-warm temperature (LD 8 : 16-30 degrees C) regimes. Testicular regression was characterized by dist...

this research was carried at the university of reading in 1999. the aim was to estimate the effects of 18 hd-1 (long-day, ld) and 12 hd-1 (short-day, sd) light exposure duration of plants before bolting or flowering on time to bolt and flower in two bolting susceptible (bsg, ic1) and bolting resistant (brg, saxon) genotypes of sugar beet. so, two experiments were conducted. the experiments were...

The circadian clock controls 24-h rhythms in many biological processes, allowing appropriate timing of biological rhythms relative to dawn and dusk. Known clock circuits include multiple, interlocked feedback loops. Theory suggested that multiple loops contribute the flexibility for molecular rhythms to track multiple phases of the external cycle. Clear dawn- and dusk-tracking rhythms illustrat...

In wild-type (WT) Columbia and Landsberg erecta ecotypes of Arabidopsis thaliana (L.) Heynh., trichomes are present on the adaxial surfaces of all rosette leaves but are absent from the abaxial surfaces of the first-formed leaves. We have determined that both long-day (LD) photoperiod and gibberellin (GA) stimulate trichome formation. WT plants grown in LD conditions produce the first abaxial t...