Solute Accumulation as a Cause for Quality Losses in Sugar Beet Submitted to Continuous and Temporary Drought Stress

Adaptation to low water availability in sugar beet includes the accumulation of solutes relevant for the technical quality of the beet. Two sugar beet genotypes were grown in pot experiments under drought stress of different severity to study effects on taproot composition and concentration of solutes relevant for technical quality, reversibility of drought effects after re‐watering and genotypic differences in drought response. Differences in stress sensitivity between the genotypes were not observed as reductions in taproot and leaf dry weight and white sugar yield were the same. Increasing dry matter concentration with decreasing water supply could, in part, be attributed to an increase in the concentration of cell wall components. The major solutes in the taproot were sucrose, potassium, amino N (the sum of amino acids) and betaine. Sucrose concentration decreased considerably under drought, indicating limited availability of assimilates. In contrast, all further solutes increased in concentration with increasing severity of stress. However, the response of individual solutes varied largely. Changes in amino N and nitrate were most pronounced and probably reflect accumulation of non‐utilized metabolites under limited growth. The drought‐induced accumulation of taproot solutes implicates a considerable decrease in the technical quality of the beet. It was only in part reversible by re‐watering. Genotypic variability for solute accumulation under water deficiency was observed but was not linked to drought tolerance.     

A Self-Learing Chinese Character Recognition System

A method using possibility theory and fuzzy logic is introduced. Possibility functions of each feature are determined during training. Methods of fuzzy logic are used to combine the possibility of different features. This Chinese character recognition system consists of a pre-classifier and a two-level fine classifier. In order to handle deviations of the characters,a fuzzification of features is introduced. This method is used to develop single-font classifiers. The whole system consists of a font-classifiers and four single-font-classifiers.     

Chromosomal location of genes for resistance to powdery mildew in common wheat (Triticum aestivum L. em Thell.). 9. Gene MlZec1 from the Triticum dicoccoides-derived wheat line Zecoi-1

The Triticum dicoccoides-derived wheat line Zecoi-1 provides effective protection against powdery mildew. F₃ segregation analysis of Chinese Spring × Zecoi-1 hybrids showed that resistance in line Zecoi-1 is controlled by a single dominant gene. Amplified fragment length polymorphism (AFLP) analysis of bulked segregants from F₃s showing the homozygous resistant and susceptible phenotypes identified eight markers, of which four were associated with the resistance allele in repulsion phase. Following the assignment of these four repulsion phase AFLP markers to wheat chromosome 2B with the aid of Chinese Spring nulli-tetrasomic lines, they were physically mapped in the terminal breakpoint interval 0.89 (2BL-6)–1.00 (telomere) of chromosome 2BL. Genetic and physical mapping of simple sequence repeat markers from the distal half of chromosome 2BL located the wild emmer-derived powdery mildew resistance gene distal of breakpoint 0.89 in deletion line 2BL-6. Based on disease response patterns, genomic origin and chromosomal location the resistance gene in Zecoi-1 is temporarily designated MlZec1.     

Nitrogen mineralization in loamy arable soils after increasing the ploughing depth and ploughing grasslands

Abstract. Increasing the ploughing depth and ploughing in grassland has been common in Germany during the past 20 years. Incubation studies were conducted with topsoils from luvisols and gleysols at different times after change of management in order to assess its influence on nitrogen mineralization and its kinetic parameters.
The results show that deep ploughing slows the mineralization of nitrogen. The difference between earlier (1967–72) and more recently (1980–82) deepened topsoil has become smaller after a further three years of cultivation, however. The preceding crops (wheat or sugar beet), the amount of N fertilizer as well as clay and nitrogen contents cause a variation in N mineralization. The results indicate a continuing approach of an'equilibrium'organic matter and nitrogen content. The enrichment capacity of intensively managed soils may be replenished within 10 years.
Gleysols formerly under grass mineralize more nitrogen than'traditionally'ploughed soils, even 27 years after the ploughing-in. While nitrogen from easily decomposable materials decreases within the first 10 years, the resistant fraction is a long-lasting determinant for N mineralization. Both processes need to be considered when applying fertilizer to minimize nitrate leaching.     

Soil acidification gradients: Mode of development,status quo and classification

Studies on soil profiles down to a depth of 3.5 m were carried out in the catchment area of the Söse River (western Harz Mts. Germany). The results show that the presence of an acidification front in the soil or unsaturated zone is a normal occurrence. Acidification fronts can be classified on the basis of water flow paths: Type A: front developed under vertical flow conditions, Type B: front developed under conditions of different flow directions, Type C: front developed in the presence of layers of different permeability. Knowledge of the type of acidification front and its depth allows a simple ion-budget calculation to be used to predict whether and when acidification of fresh waters will take place.     

Influence of soil temperature and soil compaction on growth and P uptake of sugar beet

Sugar beet growth is often impaired by cold and compacted soil. The aim of this study was to determine the effect of soil temperature and soil compaction on the growth and function of sugar beet roots. For this purpose a pot experiment with sugar beet (Beta vulgaris) was conducted in a growth chamber in which the soil temperature was kept constant either at 10°C or 20°C and air temperature at 20°C. The soil was uncompacted (1.30 g cm^?3) or compacted to a bulk density of 1.65 g cm^?3. In order to find out whether growth restriction was caused by insufficient P supply of the plant the experiment was run without and with P application (300 mg per kg soil). Root growth was much smaller at 10°C compared to 20°C, whereas root/shoot ratio was not affected by soil temperature. Hence, root and shoot growth was inhibited to the same extent. P content of the plants was not reduced, neither by cold nor by compacted soil, although parameters of acquisition such as root length and morphological root properties were altered. Soil temperature strongly affected P influx, whereas compaction did not. The calculation with a simulation model showed that at 10°C soil temperature the predicted P uptake of the plants agreed with the measured P uptake irrespective of compaction and P application. However, at 20°C the model underestimated the P influx at low soil P availability even if allowance was made for root hairs. It is concluded that under conditions of high shoot P demand and low P availability in soil P has been mobilized by mechanisms not taken into account by the model.     

Longitudinal growth strain as a log and wood quality predictor for plantation-grown <Emphasis Type="Italic">Eucalyptus nitens</Emphasis> sawlogs

Peripheral longitudinal growth strain (LGS) was measured on a total of 81, 22-year-old pruned Eucalyptus nitens trees from five thinning treatments in a plantation thinning trial in Tasmania. Growth strain data were gathered at breast height on each tree using the CIRAD-Forêt method. The effects of thinning treatment and tree diameter on LGS and its relationships to solid-wood traits determined in a processing trial were examined. LGS was significantly higher in the direction of the prevailing wind and was not significantly affected by either thinning treatment or tree diameter. An index of log end splitting was positively related to tree diameter, sawlog position (upper/lower), and LGS, which explained up to an additional 20% of the variance after tree diameter and log position were accounted for in a linear regression model. High LGS and log end splitting were significant indicators of increased board end splitting.     

Einfluß der Mineralstoffversorgung auf die Prädisposition von Phaseolus vulgaris gegen Colletotrichum lindemuthianum (Sacc. et Magn.) Br. et Cav. I. Wirkung verschiedener Nährstoffe und des Blattalters auf die Symptomausprägung

Influence of mineral nutrition on the predisposition of Phaseolus vulgaris against Colletrotrichum lindemuthianum (Sacc.et Magn.) Br.et Cav. I. Effects of different mineral nutrients and leaf-age on the disease severity 1. The N-concentration between 2–12 mMol N/I did hardly influence the disease, higher concentrations up to 52 mMol/I led to a severe disease increase. Potassium at concentrations of 5–10 mMol/I showed little effect on disease, higher concentrations up to 50 mMol also strongly increased the predisposition. 2. Calcium had a remarkable influence on symptom expression. Lower concentrations (1.15–0.25 mMol/I) increased the symptoms, higher concentrations up to 4.25 mMol/I reduced the disease, but only at a high disease level resulting from high N- or K-concentration. 3. The influences of Mg, P and Fe were of minor importance. 4. Usually, bean-leaves show resistance against C. lindermuthianum when the leaves are old. This is prevented by high N- and K-concentrations. 5. The change of predisposition related to the N- and K-concentration in the nutrient solution was confirmed with 3 additional bean varieties (‘Comtessa’ ‘Perry Marrow’, ‘Pizzaro’). No further increase of disease severity could be achieed with variety ‘Wavero’ which was generally very sensitive. 6. The monogenic resistance of incompatible combinations (‘Titan’/δ and ‘Titan’/λ) could not be changed with high N- or K-concentrations.