Expression of Circaseptan and Circannual Rhythmicity in the Imbibition of Dry Stored Bean Seeds

Abstract

ABSTRACIWater uptake of seeds of Phaseolus vulgaris L. cv Limburg was monitored in a controlled atmosphere every day at solar noon for a period of 2 years. The imbibition rate, determined as the mean of five replicas, was related to the lunar cycle, maximal water uptake occurring between the new phases of the cycle. The monthly mean value of imbibition rate, calculated from the daily measurements, displayed a circannual rhythm reaching maximal values in August-September and minimal values in February-March. These monthly values were positively correlated with the mean of the maximal temperatures recorded daily outside.Since the (presumably) first mention of rhythmic phenomena in plants, made by Androsthenes, a soldier in the expedition army of Alexander the Great (5), this topic has been studied intensively as is obvious from the numerous review papers (e.g. 13, 27) and text books (11,21). Rhythms have been observed in many morphological, physiological, and biochemical parameters of plant development. They illustrate the wide range of possible wavelengths (ultradian, circadian, infradian, circalunar, and (30), and in the rate ofseed imbibition (26). In this last paper an effect ofthe moment of onset of imbibition on the rate of water uptake of bean seeds was demonstrated pointing to an ultradian rhythm with a period length of 6 h.We now report on the relation between the moment of imbibition onset and the rate of water uptake by the seeds on a longer time scale, searching for the occurrence of circalunar or circannual rhythms.MATERIALS AND METHODS Seeds. Phaseolus vulgaris L. cv Limburg seeds were obtained at the 'Verenigde tuinbouwers' seed company in Roeselare, Belgium. A large stock was purchased and stored at 4°C in darkness. At regular intervals, part of the stock was transferred into an incubator at 25°C in darkness, so that seeds were kept in these conditions for at least 1 month prior to the experiments. The experiments were also carried out in an incubator at 25°C in the basement ofthe building. The temperature ofthe incubator was regularly controlled and never found to oscillate. The ambient temperature in the basement room was fairly constant throughout the year at about 20C. The utmost care was taken to perform identical manipulations every day for the measurements of water uptake.Imbibition. Seeds were imbibed in prewarmed distilled water of25°C. A fixed amount of 30 g (about 100 seeds) was submerged in 250 ml of water in a Petri dish with a diameter of 28 cm. Seeds were weighed to the nearest 0.1 mg with a Sartorius 1601 analytical balance before and after imbibition. Seeds were wetted before imbibition started. Before weighing, the seed coats were dried with laboratory paper towels.Experimental Arrangement. Water uptake was determined every day over a period of more than 2 years. Five replicas were carried out each time. Imbibition started 2 h before solar noon and ended 2 h after solar noon. Water uptake of the seeds was expressed as the percent (w/w) increase of weight compared to the initial...

Influence of temperature on the infradian growth rhythm inUlva lactuca(Chlorophyta)

“…Various schemes have been proposed for dividing the infradian rhythms further into subgroups, such as periods of about 2 days, half a week (circasemiseptan), 1 week (circaseptan), 10 days, 14 days (circasemilunar), 1 month (circatrigintan), 1 year (circannual), and even longer (Reinberg & Smolensky, 1983;Spruyt et al, 1987;Yamashita et al, 1999;Chumakov et al, 2000;Buda et al, 2003;Halberg et al, 2003;Vignoles et al, 2006).…”

“…There are also some reports of infradian rhythms in higher plants; clear examples are the description of circaseptan rhythms of water uptake in Phaseolus vulgaris seeds (Spruyt et al, 1987) and circumnutation intensity in Helianthus annuus (Buda et al, 2003). However, information about such infradian rhythms in seaweeds is sparse and the majority of reports concern reproduction.…”

“…According to the majority of scientists semilunar and weekly rhythms are entrained by moonlight and (or) lunar gravity (Franke, 1985;Neumann & Heimbach, 1985;Spruyt et al, 1987;Neumann, 1989;Andersson et al, 1994;Lüning et al, 2008). However, there is no easy explanation for the origin of infradian modulation with periods of less than 1 week.…”

Spontaneous ultra-weak light emissions from wheat seedlings are rhythmic and synchronized with the time profile of the local gravimetric tide

“…Impressive data, first presented in 1998, indicated that the diameter variation of a tree stem (Picea abies) varied in accordance with the local lunisolar tidal cycle (Zürcher et al 1998), and further analysis has uncovered similar corroborative evidence as well as additional indications of a temporal correlation with geomagnetic activity (Barlow et al 2010), which may itself be governed by the lunar tide. In addition, tidally modulated rhythms have been found for the imbibition and germination of bean seeds (Brown and Chow 1973;Spruyt et al 1987) as well as the nastic movements of bean leaves (Barlow and Fisahn 2012;Barlow et al 2008).…”

Lunar Rhythmicities in the Biology of Trees, Especially in the Germination of European Spruce (Picea abies Karst.): A New Statistical Analysis of Previously Published Data

“…Two publications can nevertheless be cited in relation to the apparently fluctuating plant-water relations at issue, where the time factor "Moon" plays an essential role in living plants, especially their germinating behavior. Experimentally-based, large scale studies with Bean seeds (Phaseolus vulgaris), a dormant reproductive material, demonstrated a spectacular lunar-cycle-dependent water uptake during immersion (Brown & Chow, 1973, who tested 7931 series of 20 seeds; Spruyt, Verbelen & De Greef, 1987, after a trial during 25 lunations). Short term fluctuations with a period of a lunar week (7.4 days) had a relative amplitude of up to 20% in the tested series of Brown et al (1973), and of up to 13% in the series of Spruyt et al (1987).…”