Continuous light after a long-day treatment is equivalent to melatonin implants to stimulate testosterone secretion in Alpine male goats

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.

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The role of photoperiod and temperature in the induction and termination of an arrested development in two species of freshwater cyclopia copepods

Canadian Journal of Zoology ◽

10.1139/z71-128 ◽

1971 ◽

Vol 49 (6) ◽

pp. 855-862 ◽

Cited By ~ 51

Author(s):

Nelson H. F. Watson ◽

B. N. Smallman

Keyword(s):

Continuous Light ◽

Temporary Pond ◽

Environmental Cues ◽

Complete Darkness ◽

Arrested Development ◽

Short Day ◽

Long Day ◽

Critical Daylength ◽

Ecological Implications

Daylength and temperature were shown to be environmental cues which interact to cause an arrest in development at the fourth copepodite instar of two cohabiting, temporary pond species of the genus Diacyclops; D. navus Herrick, and a second species of uncertain specific designation. The first species entered arrest under short-day conditions, the latter under long days. Arrest did not occur in rearings conducted in either continuous light or complete darkness. Cyclopids were sensitive to the photoperiodic stimulus only during the first copepodite instar. Temperature was shown to affect the critical daylength values associated with a transition from a long-day to a short-day response for each species.Similarities with insect diapause and the ecological implications of the response are discussed.

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Causal Relationships among Metabolic Circadian Rhythms in Lemna

Zeitschrift für Naturforschung C ◽

10.1515/znc-1984-1-213 ◽

1984 ◽

Vol 39 (1-2) ◽

pp. 73-84 ◽

Cited By ~ 19

Author(s):

Ken Goto

Keyword(s):

Circadian Rhythms ◽

Kinase Activity ◽

Continuous Light ◽

Mirror Image ◽

Nad Kinase ◽

Long Day ◽

Level Of Activity ◽

Night Period

Abstract Biochemical aspects of circadian rhythms were studied using a long-day duckweed, Lemna gibba G3 cultured in short day condition (9 h light at 3800 lux followed by 15 h darkness), which was transferred in continuous light (LL) at the end (LL 0) of the last night period. With such a system I have previously reported a rhythm of affinity for NAD+ of cytoplasmic NAD - dependent glyceraldehyde 3-phosphate dehydrogenase (Cyt-NAD -GPD ) 180° out of phase with that of affinity for NADP+ of chloroplastic NADP-dependent GPD (Chl-NADP-GPD ) and that NADP+ could increase in vitro the affinity for NADP+ of Chl-NADP-GPD . I report here that NADP+ can decrease in vitro the affinity for NAD+ of Cyt-NAD -GPD as well, and furthermore, that the in vivo level of NADP+ oscillates in phase with the rhythm of the affinity for NADP+ of Chl-NADP-GPD. Moreover, I found the existence of mirror-image circadian rhythms, of comparable am plitudes, of in vivo levels of NAD+ + NADH (total NAD) (with peaks, as the ones of Cyt-NAD - GPD. at LL 0 and 24) and of NADP+ + NADPH (total NADP) (with peaks, as the ones of Chl-NADP-GPD, at LL 12 and 36). Consequently, a circadian rhythm in the rate of net in vivo production of total NADP (or NAD) might be expected 90° in advance of that in the level of total NADP (or NAD). Indeed. I found oscillations in the activities of NAD kinase and of NADP phosphatase with peaks occurring, respectively, at LL 6 and at LL 18. Moreover, in vitro treatments with EGTA (a Ca2+-chelator), chlorpromazine and W7 (both inhibitors of calmodulin) were able to both inhibit NAD kinase from its highest level of activity to its minimal one and activate NADP phosphatase from its lowest level of activity to its maximal one. I conclude, therefore, that the in vivo level of Ca2+-calmodulin could oscillate in phase with the rhythm of NAD kinase activity and induce the mirror-image circadian rhythms of activities of NAD kinase and of NADP phosphatase. I propose that the control sequence among the several circadian rhythms I studied could start with changes in Ca2+-calmodulin, then proceed through oscillations in NAD kinase and NADP phosphatase activities, leading to changes in NAD+, NADP+, and NADPH levels, which would themselves induce the Chl-NADP-GPD and Cyt-NAD -GPD rhythms.

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Photoperiodic Response of Peanut Species1

Peanut Science ◽

10.3146/i0095-3679-10-2-4 ◽

1983 ◽

Vol 10 (2) ◽

pp. 59-62 ◽

Cited By ~ 16

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.

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Magnesium localization in shoot apices during flower induction in Pharbitis nil

Canadian Journal of Botany ◽

10.1139/b06-145 ◽

2006 ◽

Vol 84 (12) ◽

pp. 1908-1916

Author(s):

Natsuko I. Kobayashi ◽

Keitaro Tanoi ◽

Tomoko M. Nakanishi

Keyword(s):

Day Treatment ◽

Continuous Light ◽

Flower Induction ◽

Pharbitis Nil ◽

Elemental Distribution ◽

Short Day ◽

Induction Process ◽

Staining Methods ◽

First Time ◽

Flowering Process

We present the potential involvement of Mg2+ in the flowering mechanism in the shoot apex of the short-day plant Pharbitis nil (L.). To analyze elemental distribution in shoot apical meristems, fluorescence staining methods with Mag-fluo-4 AM and Fluo-3 AM were used. The former is sensitive to both Mg2+ and Ca2+, and the latter is a specific Ca2+ indicator. When plants were grown under continuous light conditions, some cells with intensive fluorescence of Mg2+ appeared in the top layers of the shoot apical meristem. During growth in the vegetative phase, cells in the center of the top layers accumulated large amounts of Mg2+. Exposure to a single 16 h short-day treatment induced the flowering process and dramatically reduced the fluorescence associated with Mg2+ accumulation in the top layers, suggesting that Mg2+ contributes to the flower induction process. The fluorescence associated with Ca2+ did not show this distribution difference between growth phases. A night-break treatment also influenced the fluorescence pattern. It was suggested for the first time that Mg2+ plays an important role in flower induction.

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Effects of Long-Day Treatment Using Fluorescent Lamps and Supplemental Lighting Using White LEDs on the Yield of Cut Rose Flowers

Japan Agricultural Research Quarterly JARQ ◽

10.6090/jarq.48.443 ◽

2014 ◽

Vol 48 (4) ◽

pp. 443-448 ◽

Cited By ~ 1

Author(s):

Taro HARADA ◽

Tomoyuki KOMAGATA

Keyword(s):

Day Treatment ◽

White Leds ◽

Fluorescent Lamps ◽

Long Day ◽

Supplemental Lighting ◽

Cut Rose

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Methods of Long-day Treatment to Promote Flowering for Winter and Spring Shipping of Eustoma grandiflorum (Raf.) Shinn.

Horticultural Research (Japan) ◽

10.2503/hrj.7.407 ◽

2008 ◽

Vol 7 (3) ◽

pp. 407-412 ◽

Cited By ~ 3

Author(s):

Asuka Yamada ◽

Takahiro Tanigawa ◽

Takuro Suyama ◽

Takatoshi Matsuno ◽

Toshihiro Kunitake

Keyword(s):

Day Treatment ◽

Eustoma Grandiflorum ◽

Long Day

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763 PB 307 ENVIRONMENTAL CONTROL ON FLOWERING AND GROWTH OF LYSIMACHIA CONGESTIFLORA

HortScience ◽

10.21273/hortsci.29.5.542c ◽

1994 ◽

Vol 29 (5) ◽

pp. 542c-542

Author(s):

Donglin Zhang ◽

Allan M. Armitage ◽

James M. Affolter ◽

Michael A. Dirr

Keyword(s):

Environmental Control ◽

Day Treatment ◽

Dry Weight ◽

High Irradiance ◽

Flower Initiation ◽

Low Light ◽

The North ◽

Long Day ◽

Total Plant ◽

Lower Temperature

Lysimachia congestiflora Wils. (Primulaceae) is a new crop for American nurseries and may be used as an annual in the north and a half-hardy perennial in the south. The purpose of this study was to investigate the influence of photoperiod, temperature, and irradiance on its flowering and growth. Three experiments were conducted with photoperiod of 8, 12, 16 hrs day-1, temperature of 10, 18, 26C, and irradiance of 100, 200, 300 μmol m-2s-1, respectively. Plant.9 given long day photoperiod (16 hours) flowered 21 and 34 days earlier, respectively, than plants at 12 sad 8 hour photoperiods. Plants under long day treatment produced more flowers than those at 8 and 12 hours. Plant dry weight did not differ between treatments, but plants grown in the long day treatment produced fewer but larger leaves. Total plant growth increased as temperature increased, but lower temperature (10C) decreased flower initiation and prevented flower development, while high temperature (26C) reduced the longevity of the open flowers. Flowering was accelerated and dry weight increased as plants were subjected to high irradiance levels. The results suggest that Lysimachia congestiflora is a quantitative long day plant. It should be grown under a photoperiod of at least 12 hours at a temperature of approximately 20C. Low light areas should be avoided and supplemental lighting to provide the long days may improve the plant quality.

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

HortScience ◽

10.21273/hortsci.40.4.1100d ◽

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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