A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot ...A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas （GHG） emissions following organic fertilizer application in energy maize cultivation. We hypothesized that cattle slurry application enhanced CO2 and N20 fluxes compared to biogas digestate because of the overall higher carbon （C） and nitrogen （N） input, and that higher levels of CO2 and N20 emissions could be expected by increasing soil organic C （SOC） and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH＋-N ha-1, were incorporated into 3 soil types with low, medium, and high SOC contents （Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively）. The GHG exchange （CO2, CH4, and N20） was measured on 5 replicates over a period of 22 d using the closed chamber technique. The application of cattle slurry resulted in significantly higher CO2 and N20 fluxes compared to the application of biogas digestate. No differences were observed in CH4 exchange, which was close to zero for all treatments. Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N20 emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.展开更多
Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate ...Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate the distribution profiles of cell production, cell length and the duration of cell elongation in the growing zone of the wheat leaf during the steady growth phase. Plants were grown in loamy soil with or without 120 mmollL NaCI in a growth chamber, and harvested at day 3 after leaf 4 emerged. Results show that the elongation rate of leaf 4 was reduced by t20 mmollL NaCI during the steady growth phase. The distribution profile of the lengths of abaxial epidermal cells of leaf 4 during the steady growth stage shows a sigmoidal pattern along the leaf axis for both treatments. Although salinity did not affect or even increased the length of the epidermal cells in some locations in the growth zone compared to the control treatment, the final length of the epidermal cells was reduced by 14% at 120 mmollL NaCI. Thus, we concluded that the observed reduction in the leaf elongation rate derived in part from the reduced cell division rate and either the shortened cell elongation zone or shortened duration of cell elongation. This suggests that more attention should be paid to the effects of salinity on those properties of cell production and the period of cell maturation that are related to the properties of cell wall.展开更多
Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat g...Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels （control and 150 mmol/L NaCI） in a greenhouse. The physiological traits （ion contents in leaves and stems, i.e. Na^＋, Cl^-, K^＋, Ca^2＋）, the ratios of K^＋/Na^＋ and Ca^＋/Na^＋ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content （SPAD value）, and leaf water relations, were measured at different growth stages. The physiological traits except for Na^＋ and Cl^- in stems and the leaf transpiration rate at 150 mmol/L NaCI showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca^2＋ and Ca2^＋/Na^＋ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca^2＋ in plant tissues.展开更多
We agree with Schnyder et al. （2009） that ＂Cell division rates cannot be estimated with the continuity equation if independent measurements of displacement velocity and cell length distribution are not available＂....We agree with Schnyder et al. （2009） that ＂Cell division rates cannot be estimated with the continuity equation if independent measurements of displacement velocity and cell length distribution are not available＂. To our knowledge, there is still a lack of information on the effect of salinity on the cell division rate in the division zone of grass leaves in published reports. Based on the study of the salt effect on the epidermal cell number in the mature wheat leaves （Hu and Schmidhalter 2007）, the results showed that, depending on the cell types, the total cell number in the abaxial epidermis was reduced by 16-23%. However,展开更多
文摘A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas （GHG） emissions following organic fertilizer application in energy maize cultivation. We hypothesized that cattle slurry application enhanced CO2 and N20 fluxes compared to biogas digestate because of the overall higher carbon （C） and nitrogen （N） input, and that higher levels of CO2 and N20 emissions could be expected by increasing soil organic C （SOC） and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH＋-N ha-1, were incorporated into 3 soil types with low, medium, and high SOC contents （Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively）. The GHG exchange （CO2, CH4, and N20） was measured on 5 replicates over a period of 22 d using the closed chamber technique. The application of cattle slurry resulted in significantly higher CO2 and N20 fluxes compared to the application of biogas digestate. No differences were observed in CH4 exchange, which was close to zero for all treatments. Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N20 emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.
文摘Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate the distribution profiles of cell production, cell length and the duration of cell elongation in the growing zone of the wheat leaf during the steady growth phase. Plants were grown in loamy soil with or without 120 mmollL NaCI in a growth chamber, and harvested at day 3 after leaf 4 emerged. Results show that the elongation rate of leaf 4 was reduced by t20 mmollL NaCI during the steady growth phase. The distribution profile of the lengths of abaxial epidermal cells of leaf 4 during the steady growth stage shows a sigmoidal pattern along the leaf axis for both treatments. Although salinity did not affect or even increased the length of the epidermal cells in some locations in the growth zone compared to the control treatment, the final length of the epidermal cells was reduced by 14% at 120 mmollL NaCI. Thus, we concluded that the observed reduction in the leaf elongation rate derived in part from the reduced cell division rate and either the shortened cell elongation zone or shortened duration of cell elongation. This suggests that more attention should be paid to the effects of salinity on those properties of cell production and the period of cell maturation that are related to the properties of cell wall.
基金a scholarship from ICSC-World Laboratory,Switzerland to S.E.El-Hendawy.
文摘Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels （control and 150 mmol/L NaCI） in a greenhouse. The physiological traits （ion contents in leaves and stems, i.e. Na^＋, Cl^-, K^＋, Ca^2＋）, the ratios of K^＋/Na^＋ and Ca^＋/Na^＋ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content （SPAD value）, and leaf water relations, were measured at different growth stages. The physiological traits except for Na^＋ and Cl^- in stems and the leaf transpiration rate at 150 mmol/L NaCI showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca^2＋ and Ca2^＋/Na^＋ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca^2＋ in plant tissues.
文摘We agree with Schnyder et al. （2009） that ＂Cell division rates cannot be estimated with the continuity equation if independent measurements of displacement velocity and cell length distribution are not available＂. To our knowledge, there is still a lack of information on the effect of salinity on the cell division rate in the division zone of grass leaves in published reports. Based on the study of the salt effect on the epidermal cell number in the mature wheat leaves （Hu and Schmidhalter 2007）, the results showed that, depending on the cell types, the total cell number in the abaxial epidermis was reduced by 16-23%. However,
