Influence of alternating temperature preculture on cryopreservation results for potato shoot tips

Cryopreservation is the most suitable long-term storage method for genetic resources of vegetatively maintained crops like potato. In the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) the DMSO droplet method is applied, and so far more than 1000 accessions are cryopreserved with an average regeneration rate of 58%. New experiments with four potato accessions using alternating temperatures (22/8°C day/night temperature, 8 h photoperiod, 7 d) prior to cryopreservation showed improved regeneration. The influence of this preculture on the shoot tips was studied for two wild, frost resistant species Solanum acaule and S. demissum and for two cultivated, frost sensitive potatoes S. tuberosum ‘Désirée’ and ‘King Edward’. Comparison of liquid and solid media after cryopreservation showed improved regeneration on solid media with higher regeneration percentages, less callus formation and better plantlet structure. In comparative analyses biochemical factors like soluble sugars, starch, and amino acid concentrations were measured. Shoot tips after constant and after alternating temperature preculture were analyzed. Total concentrations of soluble sugars (glucose, fructose, and sucrose) were higher for all accessions after the alternating temperature preculture, which could be the reason for improved cryopreservation results

EFFECT OF GROWTH CONDITIONS AND VARIETY ON DAMAGE SUSCEPTIBILITY OF SUGAR BEET ABREGE -L'IMPACT DES CONDITIONS DE RECO L TE ET DE VARIETE SUR LA SENSIBILITE DES BETTERAVES AUX DOMMAGES

ABSTRACT Damage to sugar beet causes sugar losses either by loss of beet tissue during harvest, by increased respiration of sugar due to wound healing during storage or by leaching to the wash water during processing. One way to reduce damage is the careful handling of beet at harvest and transport However, efforts to reduce soil tare often have the opposite effect Another possible strategy to reduce beet damage is to grow less susceptible beet This may be achieved by choosing the right variety or growth conditions. Therefore, we want to know more about the effect of these factors on damage susceptibility. During a three-year collaborative study this has been investigated in a number of field trials in The Netherlands and Belgium Manually harvested beet samples were treated on a turbine to inflict damage in a standardized way and were then visually examined for root tip breakage and surface damage. In other beet samples from the same plots, the internal quality and the elasticity were assessed. Significant effects of beet weight, variety, N fertilizer, year and harvest period on damage susceptibility were found. Multiple regression showed that a considerable part of the root damage could be attributed to beet weight, elasticity and composition. However, the predictive value of individual parameters was poor From the results it can be concluded that variety and growing conditions affect damage susceptibility of sugar beet. Further research will have to focus on simple and reliable methods for assessing this property

Temperature dependence at various intrinsic a-Si:H growth rates of p-i-n deposited solar cells

With a cascaded arc expanding thermal plasma intrinsic solar grade amorphous silicon can be deposited at growth rates varying from 2 to 100 Å/s. The temperature above which good material is obtained becomes higher for higher growth rates. Higher deposition temperatures affect the p-layer within p-i-n grown solar cells, which will result in other optimum deposition temperatures of the i-layer. In this paper we will address the dependence of the p-i-n solar cell performance on the deposition rate and deposition temperature.</p

Non-permselective membrane reactor for the selective catalytic reduction of NOx with ammonia

A novel type of reactor is developed for the catalytic reduction of NOx with NH3. In this reactor a porous membrane is noted to keep the reactants separated from each other and to carry out the reaction in a controlled way inside the membrane. As the rate of reaction is fast compared to the diffusion rate of the reactants, the molar fluxes of both reactants are in stoichiometric ratio and slip of reactants to the opposite side of the membrane is prevented. The advantage of this reactor is the possibility to obtain high conversions of NOx despite fluctuating concentrations of NOx without severe slip of NH$-3/. This membrane reactor has been tested experimentally and it is demonstrated that it is able to cope with a varying ratio of concentrations of NOx and NH3 without detectable slip of NH3 or NOx at a temperature of 569 K