IMPACT OF A VARIABLE LIGHT INTENSITY AT A CONSTANT LIGHT INTEGRAL: EFFECTS ON BIOMASS AND PRODUCTION OF SECONDARY METABOLITES BY HYPERICUM PERFORATUM

Abstract Radušienė J., Karpavičienė B., Stanius Ž., 2012: Effect of external and internal factors on secondary metabolites accumulation in St. John’s worth [Vidinių ir išorinių faktorių įtaka antrinių metabolitų kaupimuisi paprastojoje jonažolėje]. - Bot. Lith., 18(2): 101-108. The effect of modified external factors such as temperature and light intensity, and plant internal factors - phenological phase and their possible interaction was investigated on accumulation of bioactive secondary metabolites in Hypericum perforatum L. The plants were grown under different temperature and light intensity conditions in a greenhouse. The results suggested that accumulation of secondary metabolites highly depends on temperature and light intensity conditions and phenological cycle, though the influence of both variables differed for the particular compounds. Phenolic compound quantities changed greatly during plant development, and the highest levels were reached at flowering phase under both experiment conditions. Changes in naphthodianthrones content at higher temperature and light intensity followed the same increasing tendency as that for phenolic compounds. The significant decrease of temperature and light intensity were found to be crucial negative factors for accumulation of naphthodianthrones. The highest level of hyperforin was accumulated at vegetative phase that fall down during phenological development of plants under both experiment conditions.

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Expression of circadian rhythmicity in Djungarian hamsters under constant light: Effects of light intensity and the circadian system's state

Journal of Comparative Physiology A ◽

10.1007/bf00215865 ◽

1991 ◽

Vol 169 (2) ◽

pp. 185-189 ◽

Cited By ~ 19

Author(s):

W. Puchalski ◽

G.R. Lynch

Keyword(s):

Light Intensity ◽

Circadian Rhythmicity ◽

Constant Light ◽

Light Effects

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Ambient light intensity and direction determine relative attractiveness of yellow traps toRhagoletis indifferens(Diptera: Tephritidae)

The Canadian Entomologist ◽

10.4039/tce.2015.6 ◽

2015 ◽

Vol 147 (6) ◽

pp. 776-786 ◽

Cited By ~ 4

Author(s):

W.L. Yee

Keyword(s):

Light Intensity ◽

Fruit Fly ◽

Ambient Light ◽

Laboratory Results ◽

Yellow Traps ◽

Relative Attractiveness ◽

Variable Light ◽

Sunlight Intensity ◽

Trap Placement ◽

Tephritid Fruit Flies

AbstractUnderstanding factors that influence attraction of tephritid fruit flies (Diptera: Tephritidae) to objects can lead to development of more sensitive traps for fly detection. Here, the objective was to determine if differences in attractiveness between two sticky yellow rectangle traps to western cherry fruit fly,Rhagoletis indifferensCurran, depend on ambient light intensity and direction. The translucent plastic Yellow Sticky Strip (YSS) was compared with the less translucent yellow cardboard Alpha Scents (AS). Flies were released inside a box or cage opposite a trap or traps illuminated from outside at different intensities to generate variable light passage. Regardless of type, the trap with greatest light passage was most attractive. When the same light intensity was shone on both traps, the YSS, which allowed greater light passage, was more attractive than the AS. When the light was inside a cage and shone onto the two traps in the same direction as approaching flies, the AS reflected more light and was more attractive. A field experiment generally supported light passage effects seen in the laboratory. Results suggest trap placement with respect to sunlight intensity and direction affects light passage and the attractiveness of yellow traps toR. indifferens.

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Medicinally Important Secondary Metabolites and Growth of Hypericum perforatum L. Plants as Affected by Light Quality and Intensity

Environment Control in Biology ◽

10.2525/ecb.45.113 ◽

2007 ◽

Vol 45 (2) ◽

pp. 113-120 ◽

Cited By ~ 13

Author(s):

Tetsuro NISHIMURA ◽

Sayed M. A. ZOBAYED ◽

Toyoki KOZAI ◽

Eiji GOTO

Keyword(s):

Secondary Metabolites ◽

Hypericum Perforatum ◽

Light Quality ◽

Hypericum Perforatum L

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Behavioural and physical adaptations of three insects that feed on the phototoxic plant Hypericum perforatum

Canadian Journal of Zoology ◽

10.1139/z90-049 ◽

1990 ◽

Vol 68 (2) ◽

pp. 339-346 ◽

Cited By ~ 26

Author(s):

Paul G. Fields ◽

John T. Arnason ◽

Bernard J. R. Philogène

Keyword(s):

Light Intensity ◽

Hypericum Perforatum ◽

Fourth Instar ◽

Larval Cuticle ◽

St John’S Wort ◽

St John's Wort ◽

Late Instar ◽

Light Part

Chrysolina hyperici, C. quadrigemina (Coleoptera: Chrysomelidae), and Anaitis plagiata (Lepidoptera: Geometridae) all feed on St. John's-wort (Hypericum perforatum), in spite of the presence of the phototoxin hypericin, which has been shown to be toxic to other insects. Fourth instar Chrysolina spp. larvae fed at dawn, then hid in the soil for the remainder of the day. When larvae were forced to remain in the light, mortality was positively correlated with light intensity. This susceptibility to light may be related to the highly transparent larval cuticle which transmitted over 60% of the photosensitizing wavelengths (540–610 nm). Chrysolina adults differed from the larvae in that they were sun loving, fed on St. John's-wort during the day, and basked at the tips of the branches. Adult cuticles only transmitted 0.1–0.2% of the photosensitizing wavelengths. Third instar A. plagiata larvae remained on the plant at all times, feeding both during the day and night. In the 5th instar, larvae burrowed into the soil during the day and fed mostly at night, much like late instar Chrysolina larvae. However, A. plagiata larvae suffered no ill effects if forced to remain in the light. Part of their resistance to photosensitization may be explained by the low transmittance of their cuticle (20%).

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