Selection of Plant Cell Lines with Enhanced Chilling Resistance.

Cell cultures of Nicotiana sybestris and Capsicum annuum, both without and following exposure to the mutagen, EMS, have been submitted to chilling for 21 days at —3 CC and +5 °C respectively and the cell lines derived from the surviving cells tested for their subsequent resistance to the chilling treatment. Some of the cell lines when again submitted to the chilling stress showed no enhanced survival, others retained their resistance after an extended period of growth at 24 °C. The application of the mutagen promoted the isolation of such stable resistant cell lines. Studies of the response of the respiratory activity of isolated mitochondria to temperature from a resistant and from a sensitive cell line of C. annuum revealed a difference similar to that previously reported from studies on isolated mitochondria from chilling-sensitive and chilling-resistant plants of various species

Energy loss due to defect formation from 206Pb recoils in SuperCDMS germanium detectors

The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of (6:08 ± 0:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7+0.6−0.5 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches

Selection of Plant Cell Lines with Enhanced Chilling Resistance.

Cell cultures of Nicotiana sybestris and Capsicum annuum, both without and following exposure to the mutagen, EMS, have been submitted to chilling for 21 days at —3 CC and +5 °C respectively and the cell lines derived from the surviving cells tested for their subsequent resistance to the chilling treatment. Some of the cell lines when again submitted to the chilling stress showed no enhanced survival, others retained their resistance after an extended period of growth at 24 °C. The application of the mutagen promoted the isolation of such stable resistant cell lines. Studies of the response of the respiratory activity of isolated mitochondria to temperature from a resistant and from a sensitive cell line of C. annuum revealed a difference similar to that previously reported from studies on isolated mitochondria from chilling-sensitive and chilling-resistant plants of various species

Selection of Plant Cell Lines with Enhanced Chilling Resistance.

Cell cultures of Nicotiana sybestris and Capsicum annuum, both without and following exposure to the mutagen, EMS, have been submitted to chilling for 21 days at —3 CC and +5 °C respectively and the cell lines derived from the surviving cells tested for their subsequent resistance to the chilling treatment. Some of the cell lines when again submitted to the chilling stress showed no enhanced survival, others retained their resistance after an extended period of growth at 24 °C. The application of the mutagen promoted the isolation of such stable resistant cell lines. Studies of the response of the respiratory activity of isolated mitochondria to temperature from a resistant and from a sensitive cell line of C. annuum revealed a difference similar to that previously reported from studies on isolated mitochondria from chilling-sensitive and chilling-resistant plants of various species

Effects of p-Flourophenylalanine(PFP)on the Growth of Cell Lines Differing in Ploidy and Derived from Nicotiana Sylvestris

The growth inhibitory activity of p-fluorophenylalv~ine (PFP) (concentration range 25--75 µg/ml) has been tested on callus initiation and early callus growth and on suspension cultures derived from one diploid and three haploid plants of Nicotiana syloestris. All the culture lines contained cells at more than one level of ploidy; the cultures of haploid origin contained a high level of haploid cells. Under conditions of partial growth inhibition by PFP there was, despite the reduced sensitivity of the cultures of haploid origin, no preferential growth of haploid cells in these cultures. Genotype not ploidy level determined sensitivity to growth inhibition by PFP

The physiology of flowening plants/ Street

267 hal.: ill.; 24 cm

Ethylene production and plantlet formation by Nicotiana anthers cultured in the presence and absence of charcoal

Anthers of Nicotiana tabacum produce ethylene when cultured for plantlet production. The rate is at a maximum 1–2 weeks after the onset of culture. Charcoal in the medium increases the proportion of androgenic anthers in N. tabacum and several other Nicotiana species. The level of ethylene in culture vessels is reduced by charcoal. However, complete removal of ethylene does not significantly alter the incidence of androgenesis, nor does continuous flushing of cultures with air. It is concluded that although charcoal reduces ethylene in the gas phase of the cultures its effect on androgenesis is exerted through some other mechanism