A new instrument for the recording of leaf movement rhythm is described. Coleus blumei x C. frederici, a short day plant, exhibits a circadian rhythm of leaf movement. The period length of the free running rhythm is shortest in continuous darkness and is increased with an increase in the light intensity. The amplitude of the rhythm tends to damp in continuous bright light.

Cavity ring down absorption spectroscopy with a continuous light souree is used to measure the transition frequencies and absolute absorption coefficient of the weak b ItCv' = 2) +--X I;-Cv" = 0) transition of 02. The absorption spectrum is extracted from a measurement of the magnitude of the phase shift that an intensity modulated continuous light beam experiences upon passing through an unsta...

Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permanently attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar...

Insect behaviors are often influenced by light conditions including photoperiod, light intensity, and wavelength. Understanding pest insect responses to changing light conditions may help with developing alternative strategies for pest control. Little is known about the behavioral responses of leafhoppers (Hemiptera: Cicadellidae) to light conditions. The behavior of the tea green leafhopper, E...

This study investigated the influence of modulated photo-activation on axial polymerization shrinkage, shrinkage force, and hardening of light- and dual-curing resin-based composites. Three light-curing resin composites (SDR bulk-fill, Esthet X flow, and Esthet X HD) and one dual-curing material (Rebilda DC) were subjected to different irradiation protocols with identical energy density (27 J c...

Seeds of lettuce (Lactuca sativa L. cv. Grand Rapids) were imbibed and given either short irradiation with red or far red light prior to drying or dried under continuous red or far red light. Seeds treated with either short or continuous red germinate in darkness, whereas seeds treated with either short or continuous far red require a short exposure to red light, after a period of imbibition, t...

Germination of nine important medicinal plant species from the high altitudes of southern Africa was investigated in relation to different environmental parameters. The seeds were subjected to different constant and alternating temperatures, temperature shifts, light and dark conditions, and cold stratification periods. Temperature regimes of 17–23°C appear most suitable for optimal germination...

A comparative study of the spectral sensitivity of anthocyanin production in dark-grown and light-pretreated systems was carried out in Brassica oleracea L., Lycopersicon esculentum Mill., Secale cereale L. and Spirodela polyrrhiza L. Light pretreatments bring about an enhancement of the inductive, red-far red reversible response in all systems, a decrease of the continuous irradiation response...

The growth and tuberization of potatoes (Solanum tuberosum L.) maintained for 6 weeks under four different regimes of continuous irradiance were compared to plants given 12 hours light and 12 hours dark. Treatments included: (a) continuous photosynthetic photon flux of 200 micromoles per square meter per second cool-white fluorescent (CWF); (b) continuous 400 micromoles per square meter per s...