Effects of photoperiod on development, survival, feeding, and oviposition of boll weevils, Anthonomus grandis grandis Boheman, were assessed under Þve different photophases (24, 14, 12, 10, and0h) at a constant 27 Ctemperature and65%RHin the laboratory.Analyses of our results detected positive relationships between photoperiod and puncturing (mean numbers of oviposition and feeding punctures pe...

Effects of photoperiod on development, survival, feeding, and oviposition of boll weevils, Anthonomus grandis grandis Boheman, were assessed under five different photophases (24, 14, 12, 10, and 0 h) at a constant 27 degrees C temperature and 65% RH in the laboratory. Analyses of our results detected positive relationships between photoperiod and puncturing (mean numbers of oviposition and feed...

Petiole growth in Thlaspi arvense L. was stimulated when a basic 8 hour photoperiod (4.20 milliwatts per square centimeter) was extended with low intensity light (0.16 milliwatt per square centimeter) from incandescent lamps. The day length extension was effective only when the light contained high proportions of far red light. Exogenous gibberellin A(3) (GA(3)) could partially substitute for t...

Cognitive dysfunction in depression has recently been given more attention and legitimacy as a core symptom of the disorder. However, animal investigations of depression-related cognitive deficits have generally focused on emotional or spatial memory processing. Additionally, the relationship between the cognitive and affective disturbances that are present in depression remains obscure. Intere...

Chirostoma jordani is a native annual species inhabiting lacustrine waters of the Central Mexico Plateau. It is widely distributed and is currently facing high environmental pressures. Five experiments were performed to study the reproductive performance of this species. Four of the experiments were conducted in 270-L indoor recirculation tanks. Two males and one female at the first stage of re...

In order to investigate how photoperiod affects the expression of KiSS-1/G-protein-coupled receptor 54 (GPR54), the hypothalamus, the ovaries and testicles of the striped hamster were studied following photoperiod treatment and melatonin injection. We found that the melatonin concentration in the blood of the striped hamster was consistent with the treated photoperiods and that the photoperiod ...

Changes in photoperiod modulate the circadian system, affecting the function of the central clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The aim of the present study was to elucidate the dynamics of adjustment to a change of a long photoperiod with 18 h of light to a short photoperiod with 6 h of light of clock gene expression rhythms in the mouse SCN and in the perip...

The main factors triggering and releasing bud dormancy are photoperiod and temperature. Their individual and combined effects are complex and change along a transition from a dormant to a non-dormant state. Despite the number of studies reporting the effects of temperature and photoperiod on dormancy release and budburst, information on the parameters defining these relationships is scarce. The...

Variation in reproductive status in response to photoperiods has been observed in laboratory rats. We investigated the effects of photoperiod on testicular activity in Sprague-Dawley rats (Rattus norvigicus) maintained in experimental photoperiodic condition. Twenty-four adult male rats weighing 170+/-10g were conditioned to different lighting conditions of Light/Dark (LD) Cycle for 6 weeks. Gr...

Circadian and seasonal variations were observed in the karyometric index of pinealocytes in the cortical and medullary regions of the distal pineal body. The study involved 70 Wistar rats over a 24-hour interval (0:6, 10:00, 14:00, 18:00, 22:00, 02:00, 06:00 h) during two natural photoluminous periods, i.e. late summer (Long photoperiod) and Winter (Short photoperiod). The results show a differ...