Observation of Phase Transitions in Intact Leaves by Intrinsic Low‐level Chemiluminescence

Abstract

The Arrhenius plots of a remnant intrinsic ultraweak light emission from dark-adapted leaves of hibiscus, bean, cucumber, tomato and spinach exhibit strong linear behavior, despite the structural heterogeneity of the intact leaf. Well-defined break points within the temperature range from 8°C to 17°C could be found in these plant species, In the case of hibiscus and cucumber an additional feature of a thermotropic phase change around 20°C and 24"C, respectively, could be detected. However, in the case of spinach, a representative of a chilling resistant plant species, the changes in activation energies obtained were only minor. Isolated chloroplasts of spinach leaves did not show identical thermal behavior of luminescence in comparison with the intact leaf. The activation energies were significantly lower and the transition features were different compared to intact leaves. A possible relationship between the thermal behavior of low-level chemiluminescence and the chilling sensitivity of plants is suggested.

Weak microwave can alleviate water deficit induced by osmotic stress in wheat seedlings

“…In addition to lower amylase activity and biophoton emission, higher microwave doses also lead to increases in the surface temperature and in the magnetic Weld intensity of seeds. We suggest that higher doses of microwave radiation may interfere with some cellular physiological processes since biophoton emission has been considered an as indicator of several metabolic pathways, such as membrane transport, growth and diVerentiation (Roschger et al 1993). Therefore the microwave dose of 10-s treatment was applied in the protective experiments.…”

Ultraweak luminescence of the Characeae plants under the circumstances of cyclical changes in temperature

“…The temperature increase in plants causes the UWL increase satisfying in an approximate way the Arrhenius equation (Roschger, Scott, Devaraj & Inaba, 1993). The correlation occurs in the temperature range where no considerable disturbances in the function of the metabolic apparatus are observed.…”

“…The measurements of UWL dependent on temperature are well known for cultivated plants (Slawinski & Popp, 1987;Roschger et al, 1993;Triglia, Grasso, Musumeci, Scordino, Luciani, Battiato, Allegra & Rajfur, 1993;Makino, Kato, Iyozumi & Aoshima, 2005). Results of this type of studies on algae living in water medium are unknown (the authors have failed to find any), although temperature investigations of membrane changes as well as growth and transport processes in Chara are still intensively continued because algae are the sort of plants that is very sensitive to temperature changes (Radenovic, Maksimov, Jeremic & Vuchinich, 2000;Ogata, 2000;Djurisić & Andjus, 2000;Proseus, Zhu & Boyer, 2000;Demidchik, Naidun, Yablontskaya, Sokolik & Yurin, 2001;Hertel & Steudle, 1997;Beljanski, Andjus, HadziPavlović, Srejic & Vucelić, 1997).…”

Spectral Shift of Ultraweak Photon Emission from Sweet Potato During a Defense Response¶

“…Many living organisms generate ultraweak photon emission, referred to as biophotons (1–3). Plants generate a relatively high level of ultraweak photon emission as a response to external changes, such as an anaerobic treatment (4), growth hormone treatments (5,6), saline stresses (7), temperature change (8), herbicide treatments (9) and attack by pathogens (10). Ultraweak photon emission depends strongly on the physiological state of the living organisms (11).…”

“…As a result, some sources of ultraweak photon emission, including enzymatic reactions and reactive oxygen species, have been determined (12), although the total mechanism of ultraweak photon emission is still unclear. ¶Posted on the web site on January 8,2002. *To whom correspondence should be addressed at: Shizuoka Agricultural Experiment Station, 678-1, Tomigaoka, Toyoda, Iwata, Shizuoka 438-0803, Japan.…”