滨海沙地尾巨桉人工林凋落物及碳氮养分归还

对滨海沙地10年生尾巨桉人工林凋落物数量及其碳氮归还量进行为期1年的定位监测.结果表明：尾巨桉人工林年凋落量为6 739.92 kg/（hm2·a）,叶是凋落物的主要形式;凋落物量具有明显的季节动态,表现为“双峰”型,即5月和7月出现2次高峰;凋落物各组分碳含量差异不明显,介于45％～50％;凋落叶的氮含量是皮和枝的2倍多,氮含量大小排序为碎屑＞叶＞果＞枝＞皮.碳氮元素养分年归还量为3 325.86 kg/（hm2·a）,其中：碳归还量为3 267.48 kg/（hm2·a）,氮归还量为58.39 kg/（hm2·a）;C/N值为55.96,高于同试验区其他树种,大小排序为皮＞枝＞果＞叶＞碎屑.     

Nondestructive determination of paper properties of Populus × euramericana with near infrared spectroscopy

Five Populus x euramericana wood samples representing three different sites were selected and nearinfrared （NIR） spectra were obtained. For these sections, basis weight, brightness and three mechanical properties （tensile index, tearing index and bursting index） were determined by standard analytical methods. Calibrations were developed for each paper property using the NIR spectra, data on paper properties, using partial least squares （PLS） regression. The results show that the coefficients of correlation of calibration and validation for basis weight were 0.8824 and 0.8299, respectively; the standard error of calibration （SEC） and prediction （SEP） were 1.150 and 1.170, respectively. In testing for brightness, the correlation coefficient of calibration was 0.9621 and for validation 0.9612, while the SEC and SEP were 0.997 and 1.300, respectively; paper brightness and NIR spectroscopy were highly correlated. NIR spectroscopy can be used to predict tensile, tearing and bursting indices of paper samples rapidly. We found that the paper properties fitted by NIR and GB methods were highly correlated. The coefficients of correlation of calibration and validation for basis weight exceeded 0.8000, while the SEC and SEP were very small. These results reveal that the five paper properties of Populus x euramericana and those predicted by the NIR model were highly correlated. We conclude that the NIR models can be used for the prediction of paper properties.     

巨尾桉扦插繁殖技术研究

以巨尾桉半木质化当年生枝条为插穗,采用不同插穗长度、不同基质配比、不同激素处理对其进行扦插繁殖试验。结果表明：巨尾桉在扦插过程中应选用5-10cm长的穗条,在质量分数为10×10^-4的ATB溶液中浸泡2h之后,扦插到黄心土和碳化谷壳以3：2混合的基质上,生根率最高可达93．68％,苗高适宜,苗木生长良好且根系呈辐射状分布,具有一定的抗性。     

湖北红安县花生“2+x”试验总结

通过小区试验获得花生最佳施肥量、施肥时期,筛选、验证土壤养分测试技术,建立施肥指标体系。摸清土壤养分校正系数、土壤供肥能力、肥料利用率等基本参数,为花生施肥分区和肥料配方提供科学依据。     

Hard seed breakdown patterns of unprocessed forage legume seed sown into dry soil in summer in southern Australia

The patterns and extent of hard seed breakdown of dormant seeds and pods following burial in the soil in February (summer) varied for up to 19 accessions of 12 species of annual forage legumes. The experiments, at six sites across southern Australia, were designed to identify legumes whose patterns of hard seed breakdown would suit them to agronomic evaluation in a summer sowing research program. For a subset of accessions, sufficient hard seed breakdown was demonstrated between February and April to allow a high proportion of seed to germinate in late autumn—a desirable pattern for summer sowing. Although there was a large G x E interaction, some cultivars of Ornithopus sativus Brot., O. compressus L. and Trifolium spumosum L. had a pattern that was reproducible at all sites. The experiments also identified accessions of Biserrula pelecinus L. and T. glanduliferum Boiss., which had the desirable pattern in regions of south‐eastern Australia, but not Western Australia. A pragmatic approach for selection of forage legume accessions in situ for evaluation within a summer sowing program was demonstrated.     

The Effect of Calcium Sprays and Fruit Thinning on Bitter Pit Incidence and Calcium Content in ‘Honeycrisp’ Apple

‘Honeycrisp’ is a recently released cultivar of apple (Malus x domestica) developed by the University of Minnesota, now in high demand by growers and consumers. This cultivar is susceptible to bitter pit, especially when the trees are young and the fruit load is low. The effects of calcium (Ca) sprays, fruit thinning, vegetative growth, fruit and leaf nutrient concentration on bitter pit incidence, and two sampling methods for nutrient analysis were studied. Bitter pit incidence was associated with several variables, including Ca and phosphorus (P) concentrations in leaves and fruits, magnesium (Mg) concentration in leaves, and yield parameters. Fruit Ca concentration and content for the growing season were modeled, which allowed the determinations of Ca levels associated with bitter pit incidence. Our data suggest that plug analysis was less sensitive than fruit-segment analysis for finding differences in Ca concentrations.     

Effect of Sulfur on the Yield and Essential and Nonessential Element Composition of Alfalfa Determined by Polarized Energy Dispersive X‐ray Fluorescence

Alfalfa crops were grown in the field at the University of Ankara (473939 E, 4385149 N), over two seasons between 2001 and 2003 with sulfur (S) supplied at two different rates. The experimental design was a randomized complete block with five replicates and three cutting dates in each season. Sulfur was applied at rates of 0 (control), 160 (S₁), and 240 (S₂) kg ha^?1 as gypsum. Alfalfa hay was harvested three times each year, and the concentrations of elements in the hay were measured by polarized energy dispersive x‐ray fluorescence (PEDXRF). Sulfur fertilization increased S concentrations and improved alfalfa hay yield for both years. Applied S slightly reduced phosphorus (P) and magnesium (Mg) concentrations in the first year and had no significant effect on the potassium (K) and calcium (Ca) concentrations of alfalfa hay for either year. The highest S (240 kg ha^?1 S) level increased sodium (Na) concentrations in the first year but decreased them in the second year. Sulfur application also decreased chloride (Cl) concentration in the first year. Molybdenum (Mo) concentration of the alfalfa was significantly reduced by S₁ treatment in year 1. Iron (Fe) concentration was increased by S₂ treatment in the second year, and zinc (Zn) concentration was increased by S₁ treatment in the first year. However, applied S had no effect on manganese (Mn), copper (Cu), titanium (Ti), vanadium (V), cobalt (Co), nickel (Ni), barium (Ba), uranium (U), and lead (Pb) concentrations for either year. Applied S decreased aluminum (Al) and silicon (Si) and increased bromine (Br) and rubidium (Rb) concentrations of alfalfa in the first year. In addition, strontium (Sr) concentration was increased by S₂ treatment in the first year but was decreased in the second year. The stage of cutting greatly affected mineral concentrations. Compared with the first cutting, S concentrations were higher in the second and third harvest for both years. In general, the concentrations of P, Mg, Na, Cl, Mo, Ti, V, Br, Co, Ba, Sr, Rb, U, and Pb were increased, whereas the concentrations of Fe, Zn, Mn, Cu, and Ni were decreased with later cutting. The concentrations of K and Ca did not vary between cuts.     

Analysis of cationic elements in liquid samples by x‐ray

Abstract

Plant analyses methods have expanded immensely to document plant mineral element deficiency and toxicity disorders and to note mineral element interactions. Experiments were conducted to determine the feasibility of using cation exchange papers for the extraction of cationic elements from solutions to be analyzed by x‐ray fluorescence. The cationic elements Al, Fe, Mn, Zn, and Cu were effectively extracted from solutions by one exchange resin paper disk if solutions were passed several times through the exchange resin paper. Calcium and Mg were extracted from solutions if two or three separate exchange papers were used, and K was not extracted from solutions with the use of up to five separate exchange papers. The relatively high concentrations of K in solutions and the relatively low exchange capacity of ion exchange resin papers apparently prevented the effective removal of K from solution. The detectability limits on the exchange resin disks by this technique were <2.8 μg Al, 0.5 μg Fe, 0.10 μg Mn, 0.10 μg Zn, and 0.08 μg Cu. Extraction of cationic elements from solutions for x‐ray analysis appeared practical and relatively rapid for Al, Fe, Mn, Zn, and Cu, less practical for Ca and Mg, and impractical for K.     

杂交相思组织培养研究初报

【目的】筛选杂交相思组织培养不同培养阶段的培养基配方,为实现杂交相思工厂化育苗提供技术参考。【方法】用杂交相思嫩茎为外植体,探究生长调节剂6-BA、NAA、IBA对其诱导出芽、继代增殖和诱导生根的效果。【结果】在不添加6-BA的情况下,添加0.2mg/LNAA时芽诱导率为60.0%,当添加0.2mg/L的6-BA后,诱导率为42.0%。当NAA为0~0.5mg/L时,随着6-BA的增加,增殖系数随之增加,6-BA为0.8mg/L时,增殖系数为4.2;当6-BA为1.0mg/L以上时,继代苗的增殖系数为1.0。以改良MS为基本培养基,在NAA1.0mg/L的条件下添加0.5、1.0mg/L的IBA生根诱导率分别为17.5%、24.0%;以改良1/2MS为基本培养基,在NAA1.0mg/L的条件下,添加0.5mg/L的IBA生根率为91.7%,当添加IBA为1.0mg/L时,生根率降到50.0%;生根苗移栽基质以黄心土与河沙或蛭石混合较好,移栽成活率在85.0%以上。【结论】改良MS＋NAA0.2mg/L培养基是较适宜芽诱导的培养基;改良MS＋6-BA0.8mg/L＋NAA0.5mg/L培养基较利于继代苗的生长;改良1/2MS＋NAA1.0mg/L＋IBA0.5mg/L培养基较改良MS培养基有利于诱导生根。