DIAPAUSE IN CHRYSOPA CARNEA (NEUROPTERA: CHRYSOPIDAE): II. MAINTENANCE BY PHOTOPERIOD

1970 ◽  
Vol 102 (4) ◽  
pp. 474-478 ◽  
Author(s):  
Maurice J. Tauber ◽  
Catherine A. Tauber ◽  
Charlène J. Denys
Keyword(s):  
Primary Role ◽  
Similar Time ◽  
Late Autumn ◽  
Short Day ◽  
Long Day ◽  
Chrysopa Carnea ◽  
Time Periods ◽  
The Times ◽  
Active Adults ◽  
Short Days

AbstractAfter diapause was initiated in reproductively active adults, short-day (LD 12:12) maintained diapause and prevented oviposition for 66 ± 22 days. Subsequently all females remaining in the conditions that produced diapause (LD 12:12), began to lose the red-brown diapause coloration and began to oviposit. When animals were transferred to long-day at various intervals during diapause, oviposition resumed within similar time periods, thereby indicating that the intensity of diapause did not differ at the times tested.We suggest that in nature the short days of early autumn induce diapause, that the short days of late autumn maintain this diapause, that subsequently diapause ends under short-day conditions and that factors other than photoperiod, such as temperature accumulations, play a primary role in timing the initiation of reproduction in late spring.

DIAPAUSE IN CHRYSOPA CARNEA (NEUROPTERA: CHRYSOPIDAE): I. EFFECT OF PHOTOPERIOD ON REPRODUCTIVELY ACTIVE ADULTS

1969 ◽  
Vol 101 (4) ◽  
pp. 364-370 ◽  
Author(s):  
Maurice J. Tauber ◽  
Catherine A. Tauber
Keyword(s):  
Fat Body ◽  
Colour Change ◽  
Rapid Decline ◽  
Reproductive Diapause ◽  
Short Day ◽  
Long Day ◽  
Chrysopa Carnea ◽  
Males And Females ◽  
Active Adults ◽  
Lighting Regimen

AbstractUpon transfer to a photoperiod of LD 12:12 all young, reproductively active Chrysopa carnea Stephens, reared and maintained under LD 16:8, showed a rapid decline in fecundity. One group entered diapause, as shown by the cessation of oviposition within 22 to 34 days, fat body accumulation, and an associated colour change. The females in this group resumed oviposition within 3 to 7 days after being returned to LD 16:8. Females in the other group under short-day conditions continued to oviposit, but at a lower rate than those kept under constant LD 16:8. Our data indicate that the imago is sensitive to both long-day and short-day photoperiods and that some males and females enter a facultative reproductive diapause which is induced and terminated in this stage solely by manipulating the adult lighting regimen.

Flowering of Stylosanthes guianensis in controlled temperatures under natural photoperiod

1984 ◽  
Vol 35 (2) ◽  
pp. 219 ◽  
Author(s):  
RL Ison ◽  
LR Humphreys
Keyword(s):  
Floral Initiation ◽  
Minimum Duration ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Long Day ◽  
Natural Photoperiod ◽  
Low Levels ◽  
Short Days

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and cv. Endeavour were grown in naturally lit glasshouses at Brisbane (lat. 27� 30' S.) at 35/30, 30/25 and 25/20�C (day/night), and were sown so as to emerge at 18-day intervals from 18 January to 11 June. Cook behaved as a long day-short day plant, with seedlings emerging after 5 February flowering incompletely or remaining vegetative until the experiment was terminated in mid-October. In the 25/20�C regimen flowering was incomplete in Cook; in Endeavour flowering was delayed but a conventional short-day response was observed. At 35/30�C Endeavour flowering was inhibited in the shortest days of mid-winter, suggesting a stenophotoperiodic response, but short days were confounded with low levels of irradiance. Minimum duration of the phase from emergence to floral initiation was c. 66-70 days in Cook and c. 40-45 days in Endeavour; the duration of the phase floral initiation to flower appearance was linearly and negatively related to temperature.

Photoperiod modulates the effects of norepinephrine on lymphocyte proliferation in Siberian hamsters

2003 ◽  
Vol 285 (4) ◽  
pp. R873-R879 ◽  
Author(s):  
Gregory E. Demas ◽  
Timothy J. Bartness ◽  
Randy J. Nelson ◽  
Deborah L. Drazen
Keyword(s):  
Lymphocyte Proliferation ◽  
Splenic Tissue ◽  
Splenocyte Proliferation ◽  
Short Day ◽  
Siberian Hamsters ◽  
Long Day ◽  
Β Adrenergic Receptors ◽  
Short Days

Siberian hamsters ( Phodopus sungorus) rely on photoperiod to coordinate seasonally appropriate changes in physiology, including immune function. Immunity is regulated, in part, by the sympathetic nervous system (SNS), although the precise role of the SNS in regulating photoperiodic changes in immunity remains unspecified. The goal of the present study was to examine the contributions of norepinephrine (NE), the predominant neurotransmitter of the SNS, to photoperiodic changes in lymphocyte proliferation. In experiment 1, animals were maintained in long [16:8-h light-dark cycle (16:8 LD)] or short days (8:16 LD) for 10 wk, and splenic NE content was determined. In experiment 2, in vitro splenocyte proliferation in response to mitogenic stimulation (concanavalin A) was assessed in spleen cell suspensions taken from long- or short-day hamsters in which varying concentrations of NE were added to the cultures. In experiment 3, splenocyte proliferation was examined in the presence of NE and selective α- and β-noradrenergic receptor antagonists (phenoxybenzamine and propranolol, respectively) in vitro. Short-day animals had increased splenic NE content compared with long-day animals. Long-day animals had higher proliferation compared with short-day animals independent of NE. NE (1 μM) further suppressed splenocyte proliferation in short but not long days. Last, NE-induced suppression of proliferation in short-day hamsters was blocked by propranolol but not phenoxybenzamine. The present results suggest that NE plays a role in photoperiodic changes in lymphocyte proliferation. Additionally, the data suggest that the effects of NE on proliferation are specific to activation of β-adrenergic receptors located on splenic tissue. Collectively, these results provide further support that photoperiodic changes in immunity are influenced by changes in SNS activity.

scholarly journals Photoperiodic Response of Peanut Species1

1983 ◽  
Vol 10 (2) ◽  
pp. 59-62 ◽  
Author(s):  
H. T. Stalker ◽  
J. C. Wynne
Keyword(s):  
North Carolina ◽  
Day Treatment ◽  
Photoperiodic Response ◽  
Reproductive Capacity ◽  
Arachis Species ◽  
Short Day ◽  
The North ◽  
Long Day ◽  
Wild Peanut ◽  
Short Days

Abstract Many Arachis species collections do not produce pegs in North Carolina even though they flower profusely. To investigate reasons for the failure of fruiting, nine wild peanut species of section Arachis and three A. hypogaea cultivars representing spanish, valencia and virginia types were evaluated for response to short and long-day treatments in the North Carolina State Phytotron Unit of the Southeastern Environmental Laboratories. The objective of this investigation was to determine the flowering and fruiting responses of Arachis species to short and long-day photoperiods. Plant collections grown under a 9-hour short-day treatment were generally less vigorous, but produced more pegs than corresponding plants grown in long-day treatments which were produced by 9 hours of light plus a 3-hour interruption of the dark period. Annual species produced significantly more flowers and pegs than perennial species during both long and short days. The total number of flowers produced ranged from 0 during short days for A. correntina to more than 300 for A. cardenasii in long-day treatments. Only one plant of each species A. chacoense and A. villosa, and no plants of A. correntina, flowered in short days. Total numbers of pegs produced in short-day treatments were generally greater than in long-day treatments and the ratio of total number of pegs/total number of flowers was consistently greater during short-day treatments. A general trend was observed for more flowers produced in long-day treatments, but more pegs produced in short days. This study indicated that photoperiod can be manipulated to increase the seed set of some species and the success rate of obtaining certain interspecific hybrids. Furthermore, introgression from wild to cultivated species may possibly alter the reproductive capacity of A. hypogaea to photoperiod.

Short Day Induction of Inflorescence Initiation in Some Winter Wheat Varieties

1987 ◽  
Vol 14 (3) ◽  
pp. 277 ◽  
Author(s):  
LT Evans
Keyword(s):  
Winter Wheat ◽  
High Irradiance ◽  
Inflorescence Development ◽  
Wheat Varieties ◽  
Short Day ◽  
Long Day ◽  
European Winter Wheat ◽  
Lower Irradiance ◽  
Short Days ◽  
Winter Wheat Varieties

Experiments in the Canberra phytotron with several European winter wheat varieties, especially cv. Templar, have shown that their need for vernalisation at low temperature can be replaced entirely by growth in short days at 21/16°C for the same period. In fact, although wheat is usually classified as a long day plant, inflorescence initiation at 21/16°C in unvernalised plants was twice as rapid in 8 h photoperiods as in 16 h ones. Short day induction was fastest in photoperiods of less than 12 h and was relatively insensitive to irradiance. Inflorescence development following initiation was faster the longer the photoperiod. At high irradiance, anthesis eventually occurred in 8 h days, but not at lower irradiance. These wheats are therefore short-long day plants, and may appear to be indifferent to daylength if only their time to anthesis is observed. Although short days can replace low temperatures, there are several important differences in their modes of action, and short day induction is better not referred to as short day vernalisation. Vernalisation of developing grains in the ear was more effective in long days.

scholarly journals Inflorescence Initiation in Lolium Temulentum l. II. Evidence for Inhibitory and Promotive Photoperiodic Processes Involving Transmissible Products

1960 ◽  
Vol 13 (4) ◽  
pp. 429 ◽  
Author(s):  
LT Evans
Keyword(s):  
Leaf Blade ◽  
Light Period ◽  
Continuous Illumination ◽  
Rate Of Development ◽  
Lolium Temulentum ◽  
Short Day ◽  
Long Day ◽  
Inductive Treatment ◽  
Short Days

Plants of Lolium temulentum, raised in short days, were given an inductive treatment by exposure of one leaf blade to a 32-hr period of continuous illumination. Then either the leaf exposed to this one long light period or varying areas of lower leaves which were simultaneously in short-day conditions were removed at intervals after the long-day exposure. The longer the long-day leaves remained on the plants, the greater was the proportion of plants which initiated inflorescences and the greater the rate of development of their inflorescences. This was so even when short-day leaves were present above the long-day ones. The longer the short-day leaves remained, and the greater their area, the lower was the proportion of plants which initiated inflorescences.

Leaf development in two-row spring barley under long-day and short-day field conditions

2004 ◽  
Vol 84 (2) ◽  
pp. 477-486 ◽  
Author(s):  
B. H. Paynter ◽  
P. E. Juskiw ◽  
J. H. Helm
Keyword(s):  
Hordeum Vulgare ◽  
Western Australia ◽  
Spring Barley ◽  
Linear Regression Analysis ◽  
Leaf Number ◽  
Hordeum Vulgare L ◽  
Short Day ◽  
Leaf Emergence ◽  
Long Day ◽  
Short Days

To gain an understanding of the adaptation of Australian and Canadian barley (Hordeum vulgare L.) cultivars to the environments of western Canada and Western Australia, phyllochron and number of leaves on the mainstem in eight cultivars of two-row, spring barley were examined when sown at two dates in two locations. The locations were a short-day environment at Northam, Western Australia, Australia in 1997 and a long-day environment at Lacombe, Alberta, Canada in 1998. At each location highly significant relationships between leaf number on the mainstem and thermal time were found (r2 > 0.94). Using linear estimates, the phyllochron of barley under short days was longer than under long days and was correlated to time to awn emergence. Later sowing shortened phyllochron under short days, but generally not under long days. Error messages from the linear regression analysis suggested that residuals were not random for all cultivars. Bilinear models were fitted to those datasets. Bilineal responses were observed under both short and long days, being independent of cultivar, date of seeding, final leaf number, phenological development pattern and time to awn emergence. The occurrence of a bilinear response was also independent of any ontogenetic events. The change in phyllochron occurred between leaves 4–7 at Northam and between leaves 6–9 at Lacombe. The leaf number at which the phyllochron change occurred was positively related to final leaf number and time to awn emergence. The phyllochron of early forming leaves was positively related to time to awn emergence and shorter than later forming leaves. Leaf emergence patterns in spring barley under both long-day and short-day conditions may therefore be linear or bilinear. Key words: barley (spring), Hordeum vulgare L., phyllochron, leaf emergence, daylength

The effect of photoperiod on flowering, growth habit, and dry matter production in four species of the genus Stylosanthes SW

1965 ◽  
Vol 16 (5) ◽  
pp. 767
Author(s):  
Mannetje L t
Keyword(s):  
Dry Matter ◽  
Growth Habit ◽  
Dry Matter Production ◽  
Short Day ◽  
Long Day ◽  
Matter Production ◽  
Short Days

S. humilis H.B.K., S. guyanensis (Aubl.) Sw. subsp, guyanensis, S. mucronata Willd., and S. montevidensis Vog. were subjected to photoperiods of 8,10,12, and 14 hr in the CSIRO Phytotron in Canberra. S. guyanensis and S. humilis appeared to be short-day plants and S,.montevidensis a long-day plant for flowering. S. mucronata showed a rather indefinite response, but appeared to flower more rapidly under short days than under long days. Under photoperiods of 8 and 10 hr, S. humilis had a prostrate habit and S. montevidensis plants were stunted, while under photoperiods of 12 and 14 hr both species grew erect. S. guyanensis and S. mucronata showed no differences in growth habit with photoperiod. Dry matter yields for the 12 and 14 hr photoperiods were significantly larger than those for the 8 and 10 hr photoperiods for all species except S. mucronata, which gave a significantly higher yield only under the 14 hr photoperiod.

scholarly journals Chrysanthemum Cultivars Differ in Response to Photoperiod when Grown under Far-red Absorbing Filters

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 437A-437
Author(s):  
M.J. McMahon
Keyword(s):  
Acetic Acid ◽  
Ethyl Alcohol ◽  
The Other ◽  
Short Day ◽  
Long Day ◽  
Floral Primordia ◽  
Lateral Branches ◽  
And Control ◽  
Short Days

Two chrysanthemum [Dendranthema × grandiflorum (Ramat) Kitamura] cultivars, Bright Golden Anne and Spears, were grown in unfiltered sunlight (control) or under filters that removed far-red (FR) light under long- or short-day photoperiods for a total of four treatments. Eight plants from each cultivar were exposed to each treatment. Tips of lateral branches were harvested every 3 days and preserved in formalin, acetic acid, 70% ethyl alcohol (5:5:90 by volume), then observed and photographed under a dissecting microscope. In `Spears', all short-day treatments developed floral primoridia at the same time and rate and the development was normal. Under long days and under FR-absorbing filters, floral primordia initiated and developed normally, but was delayed several days compared to short days. Plants under long days and control filters also developed normal primoridia, but at a slower rate than any of the other treatments. In `Bright Golden Anne', only short-day treatments developed normal floral primordia. Development was the same regardless of filter. Under long days, plants under FR-absorbing filters eventually initiated floral primordia, but development was abnormal. No floral primordia developed under long-day and control filter conditions. In all cases, `Spears' primoridia development was much more rapid than `Bright Golden Anne'.

scholarly journals Echinacea purpurea `Magnus': Is It an Intermediate-day or a Short-day/Long-day Plant?

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1100D-1100
Author(s):  
Ki Sun Kim ◽  
Art Cameron ◽  
Erik S. Runkle
Keyword(s):  
Developmental Stage ◽  
Continuous Light ◽  
Echinacea Purpurea ◽  
Flower Induction ◽  
Research Groups ◽  
Short Day ◽  
Purple Coneflower ◽  
Long Day ◽  
Primary Induction ◽  
Short Days

Echinacea purpurea Moench., or purple coneflower, has been classified both as an intermediate-day plant and a short-day/long-day plant by different research groups. We performed experiments to determine at what developmental stage Echinacea`Magnus' became sensitive to inductive photoperiods, and identified photoperiods that induced the most rapid flowering. Seedlings were raised under continuous light in 128-cell plug trays, then were transplanted into 11.4-cm plastic pots. Plants were transferred to 10-hour short days (sd) once seedlings developed 3, 4, 5, 6, 7, or 8 true leaves. After 4 or 6 weeks of sd treatment (primary induction), plants were moved to 16- or 24-hour photoperiods until flowering (secondary induction). Plants were also grown under continuous 10-, 14-, and 24-hour photoperiods to serve as controls. At least 4 leaves were required for flower induction; flowering was delayed and the percentage was low when plants had 3 leaves at the beginning of primary induction. Plants under continuous 14-hour photoperiods had the highest flower percentage (100%) and flowered earliest (87 days). Plants under continuous 10- and 24-hour photoperiods did not flower. Four weeks of sd followed by 16-hour photoperiods induced complete flowering and in an average of 95 days. However, 6 weeks sd was required for 100% flowering when the final photoperiod was 24 hours.

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