Influence of calcium carbide formulations on growth,yield and nitrogen uptake of wheat under field conditions

Field experiments were conducted in 2006–2007 and 2007–2008 to evaluate the effects of three calcium carbide (CaC₂) based formulations (slow release sources of acetylene and ethylene) - matrix-1 [(M-1)(21% CaC₂, 58% polyethylene and 21% plaster of paris)], matrix-2 [(M-2)(42% CaC₂, 48% polyethylene and 10% plaster of paris)] and paint coated [(PC)(35% CaC₂, 44% paint and 21% plaster of paris)] - on nitrification inhibition; growth, yield and nitrogen (N)-uptake of wheat. All the three CaC₂ formulations (CCF,s) inhibited nitrification, reduced plant height, and improved N-uptake, spike bearing tillers, 1000-grains weight and yield of Inqulab-91 and Bhakhar-02 wheat cultivars. Increase in grain yield was found maximum (22% over the control) with M-1 applied at 30 kg CaC₂ ha^?1; followed by M-2 and PC. Furthermore, CaC₂ significantly reduced lodging in Bhakhar-02 plots. It is concluded that grain yield of wheat can be enhanced by the application of CaC₂ formulations particularly M-1 along with NPK fertilizers.     

CaCl_2对盐胁迫下大豆幼苗渗透调节物质含量的影响

[目的]为土壤盐渍化地区的大豆种植提供合理化建议,提高大豆产量。[方法]采用盆栽法培养大豆,分析10、15和20 mmol/L外源CaCl_2对150 mmol/L Na Cl胁迫下大豆幼苗渗透调节物质含量的影响。[结果]三叶期大豆幼苗施加150 mmol/L NaCl胁迫后,可溶性糖和可溶性蛋白的含量与空白对照组相比均显著升高(P0.05),而脯氨酸含量显著下降(P0.05);喷施10 mmol/L CaCl_2处理组与盐对照组相比,可溶性糖和脯氨酸含量显著升高(P0.05),可溶性蛋白含量显著下降(P0.05);喷施15 mmol/L CaCl_2处理组与盐对照组相比,3种渗透调节物质含量均升高,其中可溶性糖、脯氨酸含量升高显著(P0.05),可溶性蛋白含量升高不显著(P0.05);喷施20 mmol/L CaCl_2处理组与盐对照组相比,可溶性糖、可溶性蛋白含量降低,但未达到显著水平(P0.05),而脯氨酸含量显著升高(P0.05)。[结论]综合分析外源CaCl_2对盐胁迫下大豆幼苗渗透调节物质含量的影响表明,15 mmol/L CaCl_2的缓解效果最好。     

硝酸钙对网纹甜瓜果实成熟衰老相关生理因素的影响

为明确钙在调节网纹甜瓜果实成熟衰老中的生理作用,以网纹甜瓜果实圆片为材料,研究了不同浓度硝酸钙(1,3,5 mmoL/L)处理4,8,12,16,20和24 h情况下,甜瓜果实成熟衰老相关生理指标的变化.结果表明:硝酸钙具有明显延缓甜瓜果实衰老的作用,使果肉硬度显著高于对照,并提高过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,同时降低果肉乙烯释放量、可溶性蛋白含量、外渗电导率的升高速度和脂氧合酶(LDX)活性的作用.但不同处理浓度和处理时间对果实软化的作用效果存在一定差异.与1 mmol/L和3 mmoL/L的硝酸钙相比,5 mmol/L的硝酸钙处理更能显著延缓果实的衰老进程;与处理4 h和8 h相比,处理12 h硝酸钙对以上各成熟衰老指标的促进或抑制作用效果更加显著,但是随着处理时间的延长至处理24 h时,POD、SOD、CAT活性反而下降,对可溶性蛋白的合成、外渗电导率和LOX活性升高速度的抑制效应显著降低.因此,5 mmol/L硝酸钙,并且处理12 h具有较好地减缓网纹甜瓜果实衰老的作用.     

Adaptation to exploit nitrate in surface soils predisposes yellow-cedar to climate-induced decline while enhancing the survival of western redcedar: A new hypothesis

Yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) and western redcedar (Thuja plicata Donn), two valuable tree species of Pacific Northwest forests, are competitive in low productivity forests on wet, nearly saturated soils with low nitrogen (N) availability and turnover. We propose a mechanism where cedar trees survive in marginal conditions through exploiting a coupled Ca–NO₃⁻ nutrient cycle where trees assimilate N as nitrate (NO₃⁻), but must accumulate a counter-ion to NO₃⁻ such as calcium (Ca⁺²) to control their internal cell pH and provide electrochemical balance. The availability of NO₃⁻ in cedar forests is favored by increased microbial activity and shifts in microbial community composition that is conducive to N mineralization and nitrification at higher pH. Cedars influence the soils under their canopy by enriching the forest floor with calcium compounds leading to increases in pH. Cedars are also prone to precocious dehardening in the spring when N is released from freeze–thaw events in the soils and conditions appear to favor nitrifying microbial communities. Cedars must concentrate fine-root biomass near the soil surface to access Ca and NO₃⁻, but this beneficial physiological adaptation also creates a vulnerability to periodic root freezing injury that is leading to the decline and mortality of at least one of them—yellow-cedar.     

The potential of kales as a promising vegetable crop

Sixty varieties of kale (Brassica oleracea acephala group) from Galicia (northwestern Spain) were evaluated in two locations along with four commercial kale varieties. Data on 26 agronomic and morphological traits and five nutritional traits (crude fibre, acid detergent fibre, crude protein, calcium and potassium) were recorded. The objectives of this work were (i) to know the potential ability of kale as an horticultural crop, (ii) to assess the characteristics of local varieties of Galician kale in order to select those with the highest yield and a good adaptation to obtain improved varieties. In most traits, significant differences between locations were found, while varieties × location interaction was not significant for most of them. Significant differences were found among varieties and a high intravarietal variability was noticed in some traits. Galician kale germplasm displayed variability in the most important agronomic traits. They are characterized by their long cycles, their susceptibility to Lepidoptera pests, their good yield and adaptation to Galician conditions and their high calcium content. Four local varieties (MBG-BRS0468, MBG-BRS0476, MBG-BRS0477 and MBG-BRS0494) were the most promising for vegetal and fodder use. One of them showed the best early vigor (MBG-BRS0366) and two of them were the most resistant to Lepidoptera pest (MBG-BRS0060 and MBG-BRS0223). Kale varieties showed a high crude fibre content, and also a high acid detergent fibre, crude protein and calcium content. The varieties MBG-BRS0106, MBG-BRS0281, MBG-BRS0335 and MBG-BRS0464 could be candidates for future breeding programs since they had a good agronomic performance and a high calcium content.     

不同钙磷水平对新扬州(蛋)鸡生产性能、蛋壳质量及骨代谢的影响

选用36周龄新扬州(蛋)鸡600只,按2×2因子安排的完全随机设计分为4组(高钙低磷组、高钙高磷组、低钙低磷组、低钙高磷组),每组5个重复,分别饲喂不同钙磷水平的玉米-豆粕型日粮,饲养42d,研究饲粮不同钙磷水平对新扬州(蛋)鸡生产性能、蛋壳质量、内分泌、胫骨质量的影响。高钙高磷组平均产蛋率显著高于两低钙组,试验期体增重显著高于其他3组(P<0.05),蛋比重、蛋壳强度、蛋壳厚度、蛋壳比例等蛋壳质量指标也均显著高于其他3组(P<0.05),高钙高磷组E2水平显著高于低钙低磷组(P<0.05),BGP、PTH、CT各组间差异不显著,各组间胫骨系数及密度差异不显著。研究结果表明,饲粮钙磷水平分别为3.5%、0.32%,二者比例约11∶1时,蛋鸡生产性能、蛋壳质量最佳,内分泌及骨代谢最为理想。     

硅肥和磷肥配合施入对水稻土吸附镉的影响

以辽宁不同地区水稻土为供试土壤,采用静态恒温培养法,研究钢渣和钙镁磷肥配合施入对土壤吸附镉的影响.结果表明:与施用单一肥料相比,配合施入钢渣和钙镁磷肥,大大增强了土壤对Cd2 的吸附能力;土壤对镉的等温吸附曲线符合Langmuir方程;由于各地区的土壤理化性质不同,施用混合肥料的最佳比例也各不同.     

Calcination Method of 45Ca Samples for Isotope Ratio Analysis via Liquid Scintillation

This study was designed to optimize calcium-45 (⁴⁵Ca) sample preparation method in a Liquid Scintillation Counter (LSC) for use with vegetables and soil samples. Different tests were conducted on fruit and soil samples to determine the best conditions related to drying, time and centrifuge speed (rpm) after calcination at 450°C and 550°C for vegetable and soil samples, respectively. The homogeneity of samples, linearity, detection and quantification limits were also determined. The quench curve was calculated to establish the parameters to program the LSC. Six ⁴⁵Ca sample replicates were measured with a coefficient of variation (CV) of 1.74%, which indicates good sample homogeneity. The method is linearity over the range of activity studied for 0–30,000 disintegrations per minute (dpm). Our results suggest that the optimum homogenized sample preparation for calcination purposes was lyophilization. Techniques using ⁴⁵Ca applied to soil and plant tissues are promising tracers of Ca in plants, which can be very useful for the study of Ca kinetics in plants and can serve to guide efficient fertilization programs.     

Accumulation of Ions in Shoot and Seed of Quinoa (Chenopodium ‎quinoa Willd.) Under Salinity Stress

Quinoa (Chenopodium quinoa Willd.) is a high-nutrient halophyte suitable for ?cultivating in semi-arid climates and saline soils. The current study investigated the ?effect of various water salinities (EC_i) (i.e., 0.3, 10, 15, 20, and 25 dS m^?1) and different ?irrigation methods (IMs) on accumulation of calcium (Ca), magnesium (Mg), ?sodium (Na), and chloride (Cl) ions in shoot (stem+leaves) of quinoa at the end of vegetation (onset of flowering) and seed at the end of seed-filling. Therefore, 30 pots (five EC_i and two IM in three replications) were prepared with similar conditions. Considering that the salinity threshold value (STV) of quinoa varies during growth and is 8, 20 and 15 dSm^?1 at each of ?establishment, flowering, and seed-filling growth stages, the two IMs consisted of considering STV at each growth stage (T) and permanent irrigation by ?constant levels of EC_i(P). Results indicated that by increasing the EC_i from 0.3 to 25 dSm^?1 the amount of Na, Cl, and Mg in shoot increased 82.2%, 75.8%, and 8.7%, respectively, while Ca decreased 37.2%. In seeds, Na and Cl increased 43.3% and 50%, respectively, while Mg increased 8% and Ca did not change significantly. An increase in EC_i ?significantly changed ion accumulation content, especially at EC_i higher than STV, ?because it is the onset of damage due to salinity stress and particularly in? ??shoot compared to seed due to the halophytic properties of quinoa. The T ?method of irrigation was preferred due to less accumulation of Na and Cl in ?shoot and seed, and therefore less damage and loss, especially at higher ?salinities.?     

Leaf water potential and gas exchange of eucalypt clonal seedlings to leaf solar protectant

This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla×Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed on the seedlings at weekly intervals. Water stress was induced by suspending irrigation until the soil reached 30% available water and water was then replaced so that it returned to field capacity. Gas exchange and leaf water status were measured after 50 days. The experiment was set up in a 4×2 factorial randomized block design in four distinct environments:(1) temperatures less than 21.2℃ and vapor pressure deficit of 0.15 kPa;(2) intermediate temperatures of 24.2℃ and vapor pressure deficit of 0.69 kPa;(3) high temperatures of 27.0℃ and high vapor pressure deficit of 1.4 kPa; and,(4) high temperature of 27.0℃ and vapor pressure deficit below 1.10 kPa. Two leaf sun protector treatments were used, with five replications each. High atmospheric demand acted as a stress factor for the seedlings during the initial growth phase.Applications of leaf sunscreen protector provided beneficial effects in maintaining optimum water status and gas exchanges of the plants under water stress.