The present study was carried out to determine effect of different photoperiod regimes on sperm quality parameters, ovulation/spermiation time and hatchery performance of rainbow trout (Oncorhynchus mykiss) broodstock. The designation was done as combination of different long and short photoperiod regimes such as: 18L:6D and 18D:6L (group I); 14L:10D and 14D:10L (group II) and natural lighting ...

(Reproductive development of Hyptis suaveolens (L.) Poit.: relationship among photoperiod, meristem cell density and expression pattern of a putative arabidopsis gene LEAFY ortholog). Hyptis suaveolens (L.) Poit. (Lamiaceae) is a typical invasive plant that produces an essential oil with several biological properties. The largest essential oil content is found at the flowers. So, advances in th...

Effect of photoperiod and food duration on body weight gain, energy intake, energy expenditure, and sexual development were investigated in two strains of Japanese quail ( Coturnix c. japonica ), bred for meat (broilers) or egg production (layers), from 7 to 71 days of age. In a first experiment chicks were subjected to 18L:6D, 15L:9D, 12L:12D, 9L:15D, or 6L:18D, with ad lib food during the lig...

Individuals of many nontropical rodent species display reproductive, immunological, and somatic responses to day length. In general, short day (SD) lengths inhibit reproduction and enhance immune function in the laboratory when all other conditions are held constant. Most studies to date have focused on seasonal variation in immune function in adulthood. However, perinatal photoperiods also com...

Siberian hamsters (Phodopus sungorus) have the ability to express daily torpor and decrease their body temperature to approximately 15 degrees C, providing a significant savings in energy expenditure. Daily torpor in hamsters is cued by winterlike photoperiods and occurs coincident with the annual nadirs in body fat reserves and chronic leptin concentrations. To better understand the neural mec...

Abstract Alpine plants complete their seasonal phenological cycle during two to three snow-free months. Under climate change, snowmelt advances and the risk of summer droughts increases. Yet, photoperiodism may prevent alpine from benefiting an earlier start growing season. To identify drivers flowering phenology in seven main species grassland, we experimentally shifted date through snow manip...

Autumn phenology, determined mainly by temperature and photoperiod, is essential for ecosystem carbon sequestration. Usually, the variations in maximum rate of Rubisco (Vcmax) ribulose-bisphosphate regeneration (Jmax) are taken as mechanism regulating seasonal pattern photosynthetic rates autumn phenology. In this study, we used Quercus mongolicus seedlings an example to examine photosynthetica...

The life histories of succineids have received relatively little attention. To evaluate life history characteristics of Omalonyx matheroni, we studied a Brazilian population (Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala, in Caratinga, Minas Gerais, Brazil) under laboratory conditions. The aims of the present study were (1) to describe in detail an appropriate rearing method;...

What is the flowering transition? It marks the end of vegetative growth and the beginning of reproductive development in flowering plants. The physiological changes that cause it are referred to as floral induction. What is SAM? The shoot apical meristem — a group of undifferentiated progenitor cells that occupies the tip of the stem. It gives rise to both vegetative organs (leaves) and reprodu...

Photoperiod times the transition to sexual maturity in many seasonal breeders. In male and female sheep, photoperiod influences the timing of puberty differentially. Whereas in females, age at sexual maturity is highly dependent on photoperiod, puberty in males begins at the same age regardless of day length. We have determined that this sex difference is due to the organizing action of androge...