Photoperiod. Medical search. Frequent questions

Unstratified and stratified seeds of western hemlock (Tsugaheterophylla) germinated fastest under 4-h photoperiods and slowest under 24-h photoperiods at 20 °C. No differences were found between total darkness and an 8-h photoperiod. (gc.ca)
We have the Best Genetics and now carry photoperiod seeds. (autoflower.ca)
Autoflower's are great for indoor grows as well with much shorter seed to harvest time than traditional photoperiod seeds. (autoflower.ca)
Introducing Slusherz Feminized Photoperiod cannabis seeds - The extremely potent euphoric cannabis strain that stands out from the rest. (supernaturalseeds.uk)
Slusherz Feminized Photoperiod cannabis seeds - get them while you still can. (supernaturalseeds.uk)
There is a constant debate in the cannabis world about the difference between Autoflower vs Photoperiod seeds many experts discuss and tackle the possible harvest time, yields, effects, and ease of growth of both Autoflower vs Photoperiod seeds comparing them and having an understanding of which seeds are the best for every grower. (cropkingseeds.com)
Photoperiod seeds require specific light cycles to initiate flowering, making them ideal for indoor growers who can control light exposure. (organiccatalog.com)
Outdoor growers can also benefit from photoperiod seeds by planting during certain seasons to ensure optimal growth. (organiccatalog.com)

The result showed worms had 1.5 times faster oocyte growth rates when exposed to accelerated rate of change in photoperiod (2.5 times faster). (frontiersin.org)
Does panicle initiation in tropical sorghum depend on day-to-day change in photoperiod? (icrisat.org)
Given the change in photoperiod length (longer nights and shorter days) and that bright-light therapy has an antidepressant effect, circadian rhythms have been hypothesized to contribute to the onset of SAD. (medscape.com)

Autoflower vs Photoperiod: What is the difference? (cropkingseeds.com)

Plants are extremely sensitive to changes in their environment, particularly variations in photoperiod or day length. (who.int)

Siberian hamsters (Phodopus sungorus) are long-day breeders that adjust reproductive physiology and behavior, body mass, and immune function following exposure to short photoperiods. (duke.edu)
Sorghum is known as a short day plant requiring short photoperiods (PP) to flower. (icrisat.org)

This alters exposure to the regular photoperiod ical studies of night shift work and cancer since and may disrupt circadian rhythms in humans. (who.int)

The result showed females collected during summer showed the highest oocyte growth when exposed to constant temperatures combined with decreasing photoperiod and decreasing temperature combined with constant photoperiod. (frontiersin.org)
In summary, in this paper we describe, for the first time in the sea bass, the effect of constant photoperiod regimes on the 17β-oestradiol plasma profiles, the timing of spawning and the quality of the eggs. (eauetbiodiversite.fr)

Explore our diverse menu below, and find the perfect autoflower and photoperiod strains to elevate your winter growing endeavours. (autoflower.ca)
These strains are distinct from "photoperiod" strains, which require specific signals from the sun to start flowering and need special light schedules to produce buds. (cropkingseeds.com)
However, a breeder recognized that the autoflowering capability and short growing period of Ruderalis could benefit hobbyist cannabis growers, so they began breeding Ruderalis plants with photoperiod strains to increase bud potency while retaining autoflowering ability. (cropkingseeds.com)
Photoperiod strains need at least 12 hours of daily darkness to start budding, and outdoor growers must ensure that their plants are planted in the spring and will finish flowering before winter. (cropkingseeds.com)

This article reviews photoperiod manipulation for marijuana, the role of red light versus blue light, and explores autoflowering marijuana as an alternative. (potguide.com)
Autoflowering cannabis plants typically have a shorter growing period and are ready for harvest earlier than photoperiod plants. (cropkingseeds.com)
Unlike photoperiod plants, autoflowering plants continue to grow taller while buds are forming. (cropkingseeds.com)
Even when grown from seed, photoperiod plants take longer to reach maturity than autoflowering plants, and their yields are often lower. (cropkingseeds.com)

This article briefly reviews photoperiodism and photoperiod control systems for greenhouses. (umass.edu)
The terms photoperiod and photoperiodism are commonly used in extension bulletins and other literature, but what actually do these terms mean? (umass.edu)
Through a process known as photoperiodism, plants can detect and react to variations in the number of daylight hours, or photoperiod. (who.int)
The regulation of flowering in response to day length or photoperiod is called photoperiodism . (ufl.edu)

Thus, for photoperiodic responses, photoperiods are estimated by adding the periods of civil twilight to the duration of daylight. (umass.edu)
Scholars@Duke publication: Effects of photoperiod history on immune responses to intermediate day lengths in Siberian hamsters (Phodopus sungorus). (duke.edu)
Divergent reproductive responses to the same intermediate photoperiod depend on a photoperiod history, communicated during gestation. (duke.edu)
These experiments assessed whether photoperiod history during gestation likewise impacts immunological responses to intermediate photoperiods. (duke.edu)
Using long-term phenological records in Europe, we examined simultaneously the responses of both leaf-out and flowering of four common temperate tree species to climate warming and further examined the effects of winter chilling, spring forcing and photoperiod on the responses of the two events. (wiley.com)
The role of photoperiods in the development of antioxidants and their responses to microalgae, however, is poorly understood. (japsonline.com)
The goal of this study was to determine the effect of the photoperiod on growth and antioxidant responses of three species of marine microalgae, Chlorella vulgaris , Isochrysis galbana (CB) , and Tetraselmis chuii (CT), commonly found in tropical brackish and marine environments. (japsonline.com)
Genetic analysis and QTL detection of reproductive period and post-?owering photoperiod responses in soybean. (xjegi.com)

The effects of selected environmental factors [temperature, photosynthetic photon flux (PPF), and photoperiod] that contribute to optimal vegetative growth of Canary Island ivy (Hedera canariensis Willd. (illinois.edu)
Postflowering photoperiod regulates vegetative growth and reproductive development of soybean. (xjegi.com)

Winterhardiness has three primary components: photoperiod (day length) sensitivity, vernalization response, and low temperature tolerance. (oregonstate.edu)
In order to investigate these contradictory results, three tropical sorghum varieties of different photoperiod sensitivity were planted monthly in Mali and the dates of panicle initiation (PI) were recorded. (icrisat.org)
However, the photoperiod sensitivity is not observed in the cultivars of highlands such as Peru, Bolivia and coastal parts of Chile (Curti et al. (springer.com)
The sensitivity of the Nicotiana plumbaginifolia wild-type and phytochrome B (hlg) mutant to photoperiod was investigated. (illinois.edu)

Three different experiments were conducted to examine the oocyte development of the polychaete Hediste diversicolor in response to changing photoperiod and temperature at three different periods of oogenesis. (frontiersin.org)
In experiment I, worms collected during summer were reared under constant or decreasing photoperiod and temperatures to test the combined effects of the summer-autumn photoperiod and temperature transition on oogenesis. (frontiersin.org)
It was concluded temperature and photoperiod transition can increase the oocyte development. (frontiersin.org)
11 h light) coupled with an endogenous timer synchronizes spawning of the first cohort of oocytes in Harmothoe imbricate L. The authors also mentioned that in H. imbricate vitellogenesis was favored by low temperature and increasing photoperiod. (frontiersin.org)
Bud endodormancy is induced by a decreasing photoperiod and/or low temperature during autumn. (sdstate.edu)
In Vitis there is considerable variation in response to photoperiod, with some genotypes becoming endodormant in response to a decreasing photoperiod (SD) and others requiring low temperature to induce dormancy. (sdstate.edu)
Seyval' ('Seyve Villard 5-276'), which has a higher chilling requirement and a short critical photoperiod and/or low temperature requirement for dormancy induction, their F 1 , and F 2 and BC populations. (sdstate.edu)

Photoperiod and vernalization regulate the vegetative to reproductive phase transition, and photoperiod regulates expression of key vernalization genes. (oregonstate.edu)
The Photoperiod-Driven Cyclical Secretion of Pineal Melatonin Regulates Seasonal Reproduction in Geese ( Anser cygnoides ). (bvsalud.org)

Using two barley mapping populations, we mapped six individual photoperiod response QTL and determined their positional relationship to the phytochrome and cryptochrome photoreceptor gene families and the vernalization regulatory genes HvBM5A, ZCCT-H, and HvVRT-2. (oregonstate.edu)
It was concluded that the B-type phytochrome absent in the hlg mutant is required for the measurement of photoperiod duration in N. plumbaginifolia, but is not required for entrainment of the circadian clock. (illinois.edu)
Hudson, M & Smith, H 1998, ' The phytochrome B encoded by the HLG locus of Nicotiana plumbaginifolia is required for detection of photoperiod: hlg mutants show altered regulation of flowering and circadian movement ', Plant Journal , vol. 15, no. 2, pp. 281-287. (illinois.edu)

It should be noted that local conditions, i.e., shading from trees or adjacent buildings, persistant cloudiness, or fog, may make the actual photoperiod shorter than estimated photoperiod (Table 2). (umass.edu)

Both photoperiod extension and night interruption are common practices used by greenhouse growers to inhibit flowering of short-day plants. (ufl.edu)

Achieving photoperiod manipulation for marijuana indoors , like in a grow tent , is much easier. (potguide.com)
Samples were incubated indoors for the photoperiod-specific to the time of the year. (cdc.gov)

Genetic Segregation for Indicators of Photoperiod Control of Dormancy " by Anne Fennell, Kathy Mathiason et al. (sdstate.edu)
This system includes: a long critical photoperiod (dormancy induction), cold hardy, lower chilling requirement V. riparia parent, a less cold hardy parent, Vitis sp. (sdstate.edu)

Let's begin with a crash course in earth science because to fundamentally understand photoperiod manipulation, growers should understand the photoperiod we are manipulating. (potguide.com)

Welcome to the enchanting realm of Sunset Sherbet, our exclusive photoperiod strain with a captivating lineage. (autoflower.ca)

Auxin, photoperiod and putrescine are factors involved in the control of the reproductive phase of the flowering process in planta. (uniroma1.it)

For example, a 12-hour photoperiod consists of 12 hours of light and 12 hours of darkness, whereas an 8-hour photoperiod consists of 8 hours of light and 16 hours of darkness. (umass.edu)

The effect of photoperiod after photostimulation on male broiler breeder fertility. (ukzn.ac.za)

Stratification tended to reduce the degree of response to photoperiod. (gc.ca)
Here we propose a model of adaptive starch metabolism in response to various photoperiods. (frontiersin.org)
Positional relationships between photoperiod response QTL and photoreceptor and vernalization genes in barley. (oregonstate.edu)
Of the six photoreceptors mapped in the current study (HvPhyA and HvPhyB to 4HS, HvPhyC to 5HL, HvCry1a and HvCry2 to 6HS, and HvCry1b to 2HL), only HvPhyC coincided with a photoperiod response QTL. (oregonstate.edu)
Each of these three vernalization genes is located in chromosome regions determining small photoperiod response QTL effects. (oregonstate.edu)
In this essay, I will cover the current understanding of how plants respond to photoperiod and the molecular mechanisms underpinning this response. (who.int)
Analysis of this trait indicates that it is heritable and may be controlled largely by a single locus with the longer critical photoperiod response of the V. riparia parent being dominant. (sdstate.edu)

Photoperiods of intermediate-duration, encountered in nature by juvenile hamsters born in early-spring and by those born in mid-summer, trigger gonadal development in the former cohort and inhibit the onset of puberty in the latter. (duke.edu)
At 51 weeks of age, testes weights were affected by the degree of photostimulation with a trend of lower testes weights from birds on longer photoperiods which suggests the earlier onset of adult photorefractoriness in birds on longer photoperiods. (ukzn.ac.za)

However, in field experiments based on monthly plantings reported elsewhere, panicle initiation took place during long days as well as during short days even for highly photoperiod-sensitive varieties thought to be of the absolute type, or was particularly early for the sowings in September, well before days were shortest. (icrisat.org)
Typically, cannabis plant varieties begin their flowering stage growth based on photoperiod. (joecettina.com)

The coincidence of photoperiod-responsive vernalization genes with photoperiod QTL suggests vernalization genes should also be considered candidates for photoperiod effects. (oregonstate.edu)
The data suggest that photoperiodic mechanisms that enhance and suppress several aspects of immunity in young-adult hamsters are not responsive to prenatally communicated photoperiod history information. (duke.edu)

This type of photoperiod imitates early spring conditions for our cannabis plants with long days and short nights. (joecettina.com)
Photoperiod plants require a vegetative stage before flowering and are not well-suited for quick harvests. (cropkingseeds.com)

At 42o N. latitude, the photoperiod (=daylight plus civil twilight) varies from 10 hours and 11 minutes on December 21 (winter solstice) to 16 hours and 25 minutes on June 23 (summer solstice) (Table 2). (umass.edu)

In experiment II, worms collected in late autumn were under mimicked or shortened seasonal changes in photoperiod to evaluate the effect of accelerated change on oocyte growth. (frontiersin.org)

A photoperiod is the duration of light within a particular time span, usually a 24-hour period. (umass.edu)
other males were gestated in short days and transferred to an intermediate-duration photoperiod at birth. (duke.edu)

In the stored data screen, it shows the DLI measurement, photoperiod, and which day the data was collected (up to 99 days ago). (hoskin.ca)

We performed gradient descents for various photoperiod conditions to find the corresponding optimal sets of phase shifts that minimize starvation. (frontiersin.org)

Leaf number at bolting and rosette-leaf movement were measured under conditions of different light quality and photoperiod. (illinois.edu)

In a replicated field planting of the F 2 and BC populations, summer lateral emergence was used for determining photoperiod responsiveness. (sdstate.edu)

Careful control of carbon partitioning, starch degradation, and sucrose export rates is crucial to avoid carbon starvation, insuring optimal growth whatever the photoperiod. (frontiersin.org)

Both DLI and photoperiod influence plant growth and development, and they are often measured in greenhouses and growth chambers to aid in light management and decision making. (hoskin.ca)

Photoperiod is a word that describes the amount of light vs. dark time that a plant needs to grow. (joecettina.com)
This light cycle translates to a photoperiod of 18/6. (joecettina.com)
Light and photoperiod affect microalgae accumulation of antioxidants. (japsonline.com)
A "photoperiod," from the Greek root photo meaning light, is a period of time exposed to light, generally a cycle of light and dark. (potguide.com)
In addition to measuring ePAR, the DLI-600 meter calculates daily light integral (DLI) and photoperiod. (hoskin.ca)
Included here are proteins that transmit intracellular and intercellular signals in a chronological manner along with proteins that sense light and time-dependent changes in the environment such as the PHOTOPERIOD. (bvsalud.org)

Photoperiod is the total amount of time in which PAR or ePAR is incident on a plane during a 24-hour period and is expressed in units of hours (h). (hoskin.ca)
The numbers of sperm trapped in the perivitelline layer of a hen's egg, and the probability of the egg being fertile, were significantly affected by the photoperiod, age of the male and the time elapsed between artificial insemination and the laying of the egg. (ukzn.ac.za)

Behavioral tolerance to endotoxin is enhanced by adaptation to winter photoperiods. (uchicago.edu)

For example, cultivars grown close to equator, mainly in Colombia, are more photoperiod-sensitive. (springer.com)

Semen characteristics were generally not affected by the final photoperiod apart from the semen concentration measured at female ASM. (ukzn.ac.za)

HvBM5A and HvPhyC are closely linked on 5HL and therefore are currently both positional candidates for the same photoperiod effect. (oregonstate.edu)

By contrast, photoperiod during gestation did not affect most immune endpoints. (duke.edu)

We recently mapped the candidate genes for the 5HL VRN-H1 (HvBM5A) and 4HL VRN-H2 (ZCCT-H) loci, and in this study, we mapped HvVRT-2, the barley TaVRT-2 ortholog (a wheat flowering repressor regulated by vernalization and photoperiod) to 7HS. (oregonstate.edu)

Anatomy14

Organisms18

Diseases1

Chemicals and Drugs16

Analytical, Diagnostic and Therapeutic Techniques and Equipment5

Psychiatry and Psychology2

Phenomena and Processes28

Health Care5

Seeds8

Change in photoperiod3

AutoFlower-VS-Photoperiod1

Variations in photoperiod1

Short photoperiods2

Regular Photoperiod1

Constant photoperiod2

Strains4

Autoflowering4

Photoperiodism4

Responses8

Vegetative growth2

Sensitivity4

Temperature7

Regulates2

Phytochrome3

Shorter1

Greenhouse1

Indoors2

Dormancy2

Growers1

Sherbet1

Reproductive1

Darkness1

Breeder1

Response7

Onset2

Varieties2

Responsive2

Plants2

Daylight1

Seasonal1

Duration2

Measurement1

Phase shifts1

Conditions1

Populations1

Optimal1

Growth1

Light6

Time2

Tolerance1

Grown1

Characteristics1

Effect1

Affect1

Wheat1