Search results for "photoperiodism"
showing 4 items of 54 documents
Deregulated Copper Transport Affects Arabidopsis Development Especially in the Absence of Environmental Cycles
2010
Abstract Copper is an essential cofactor for key processes in plants, but it exerts harmful effects when in excess. Previous work has shown that the Arabidopsis (Arabidopsis thaliana) COPT1 high-affinity copper transport protein participates in copper uptake through plant root tips. Here, we show that COPT1 protein localizes to the plasma membrane of Arabidopsis cells and the phenotypic effects of transgenic plants overexpressing either COPT1 or COPT3, the latter being another high-affinity copper transport protein family member. Both transgenic lines exhibit increased endogenous copper levels and are sensitive to the copper in the growth medium. Additional phenotypes include decreased hypo…
Somatic Embryogenesis and Plant Regeneration from Hypocotyl Cultures of Digitalis obscura L.
1986
Summary Hypocotyl sections from 20-day-old seedlings of Digitalis obscura L. were used to examine the effect of IAA on somatic embryogenesis. Although embryogenesis was obtained with all IAA concentrations (0.1, 0.5 and 1 ppm) and under both illumination conditions tested (16 h photoperiod and darkness), incubation in photoperiod increased yield of embryos and shortened the embryo induction time. Optimum results were obtained with 1 ppm IAA. About 30 % of the embryos obtained developed into complete plantlets when transferred to basal medium without growth regulators.
Northern Drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause
2013
Reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. In the present paper we have documented variation in the critical day length (CDL) for adult reproductive diapause and the steepness of photoperiodic response curves (PPRCs) in seven clinal populations of Drosophila montana in Finland between the latitudes 61 and 67°N, paying special attention to variation in these traits within and between cline populations. The isofemale lines representing these populations showed a sharp transition from 0% to 100% in females' diapause incidence in the shortening day lengths, indicate…
Transcriptional study of photoperiodic response in aphids and characterization of candidate photoperiodic photoreceptors
2020
Acyrthosiphon pisum es una especie de pulgón altamente estacional. Durante la estación favorable, únicamente se producen hembras partenogenéticas vivíparas (virginóparas). En otoño, cuando hay menos luz (el fotoperiodo es más corto), A. pisum percibe la diferencia y las virginóparas paren machos y luego hembras sexuadas (ovíparas). Tras aparearse, las ovíparas ponen huevos que resisten el invierno y eclosionan en primavera, reiniciando el ciclo. Algunos mutantes que ocurren de forma natural no responden al fotoperiodo y se reproducen asexualmente durante todo el año. Se denominan anholocíclicos en contraposición a los holocíclicos, que tienen fase sexual. Se desconocen los mecanismos molecu…