大花序桉幼苗营养吸收及分配规律研究

对大花序桉幼苗生物量及营养元素进行测定,结果表明,大花序桉苗木平均单株生物量大小排序为茎>根>叶。幼苗主要营养含量和吸收积累规律为K>N>P>Fe>Mn>Zn>B>Ca>Cu>Mg。大量元素N、P、K贮量最高的部位均为茎,根部和叶中含量相近。大花序桉苗期叶片对主要营养元素N、P和K的吸收分配间存在相互促进的关系;Mg与Ca,Cu与P、K,Zn与N、K、Cu、Fe,Fe与N呈现互相促进关系;Mn与N、Fe、K、Cu,B与P、Cu为相互抑制关系。据此,大花序桉苗期以氮、磷、钾肥为主,其中要求养分K₂O>N>P₂O₅,并有针对性地添加铁肥、锌肥和铜肥。     

油松侧枝的节间特征及其变异规律

【目的】为阐明油松侧枝的节间特征及其变异规律,了解当年生节间枝条和针叶的异速生长关系,揭示侧枝空间构型、活力和光合产物分配的主要影响因子。【方法】本研究在35 a生油松林内选取了5株标准木的标准枝,通过枝条解析截取了372个节间,采用统计分析和模型模拟等方法对相关问题进行了研究。【结果】结果表明:油松枝条多分为3级,近90%的节间分布在2级和3级枝,直径生长周期为1~4 a、具有针叶着生和光合功能的节间占节间总数的83%;节间直径和长度均随枝级增加而显著下降,均随节间生长周期(或形成时间)的增加而显著增加,后者在枝级间及枝级内的变异均远高于前者,后者受枝级和着生位置光照环境的影响明显高于前者。全枝70%以上的枝条生物量分布在1级枝节间,80%以上的针叶分布在2级和3级枝节间;1级和2级枝的生物量以枝条为主,3级枝以针叶为主。直径生长周期为1~3 a的节间生物量以叶为主,4 a的以枝条为主,4 a以上的以完全以枝条为主。当年生节间的不同特征变量间均成显著的异速生长关系,而非成比例变化。【结论】节间是侧枝的基本单元,其数量、质量、生长发育及其在不同枝级和形成时间的变异,以及其主要构件的异速生长关系是影响侧枝空间构型、活力和光合产物分配的主要因子。     

生物质基SiC陶瓷材料制备及应用研究进展

生物质基SiC陶瓷是一种环境友好的新型材料，具有硬度高、抗氧化、耐腐蚀、力学性能优异等特点，因而受到越来越广泛的关注。文中主要阐述了国内外学者对生物质基SiC陶瓷材料制备方法及应用的研究进展，包括以木材、竹材、稻壳、纸张、废弃棉绒等生物质材料为碳模板，运用液态渗硅法、溶胶凝胶-碳热还原法、气相渗透法3种方法制备生物质基SiC陶瓷方面的研究现状，以及对其作为电磁屏蔽材料、防弹材料、电容器、电极材料、催化剂材料等方面的应用进行了探讨，并分析了当前SiC陶瓷研究存在的问题及未来发展趋势。     

Estimation of biomass change in montane forests in Norway along a 1200 km latitudinal gradient using airborne laser scanning: a comparison of direct and indirect prediction of change under a model-based inferential approach

The current study compared two approaches for estimating change of aboveground biomass (AGB) in montane forests in Norway using field- and remotely sensed data from airborne laser scanning (ALS) from two points in time (four-year interval). The first was an indirect method that involved modeling and prediction of AGB at two points in time using ALS metrics as predictors, estimating the change from differences between AGB predictions. The second was a direct method, where change was modeled and predicted directly using differences between corresponding ALS metrics derived at the two measurement occasions as predictors, and the estimate was based on the predicted differences. Both methods were applied over a 1500?km long and 250?m wide transect from south to north in Norway comprising 250?m² grid cells. The results showed that the indirect method was more precise than the direct method. The indirect method estimated 0.65?Mg?ha^?1 change in AGB over the observation period, with a corresponding 95% confidence interval of ±0.27?Mg?ha^?1. The corresponding figures for the direct method was 0.54 and ±0.51?Mg?ha^?1. The direct method has been recommended previously. We conclude that the indirect method is both more precise and versatile.     

生物质炭添加对重金属污染稻田土壤理化性状及微生物量的影响

分析了生物质炭添加对红壤性水稻土理化性状、重金属含量及微生物生物量的影响。通过田间小区长期定位试验,一次性施入不同量生物质炭(0,10,20,30,40t/hm2),于2017年9月采集各处理表层土样(0—15cm),研究土壤理化性状、重金属含量及微生物生物量的变化。结果表明:生物质炭添加对土壤理化性状、重金属含量及微生物生物量均有显著影响。与对照相比,供试土壤的pH、EC和有机质含量随生物质炭添加量的增加而增大,增幅分别为5.11%~18.43%,37.62%~104.31%和1.72%~22.41%,而有效磷和铵态氮含量随生物质炭添加量的增加呈先增大后减小趋势,分别在生物质炭添加量为10t/hm2和30t/hm2时达到最大值。随生物质炭添加量的增加,土壤有效态Cd和有效态Pb含量均呈降低趋势,而土壤有效态As含量呈先增加后减少的趋势,三者均在生物质炭添加量为40t/hm2时达到最小值。土壤微生物生物量碳、氮和微生物商随生物质炭添加量的增加均呈先升高后降低的趋势,均在生物质炭添加量为20t/hm2时达到最大值。相关分析表明,生物质炭添加量分别与土壤有效态Cd和Pb含量之间呈极显著负相关(P0.01);通径分析表明,生物质炭主要是通过直接作用影响土壤有效态Cd含量,而土壤pH、EC、有机质、微生物生物量碳、氮和有效磷主要是通过间接作用影响土壤有效态Cd含量。因此,添加适量生物质炭不仅可以改善土壤重金属污染现状和土壤理化性状,提高土壤养分含量,还可以改良土壤生物学性质,增加土壤微生物量。研究结果可为提高稻田土壤肥力和改善土壤重金属污染状况提供科学依据。     

作物模型中单叶最大光合作用速率的温度响应修订

作物的光合作用对温度变化敏感,其温度依存性随品种、生长环境的变化而改变。基于光效率模型的作物生长模型,在应用中很少对光合作用的温度影响参数值进行订正,且在全生育期使用相同的参数值,难免会增加干物质模拟的误差。为此,本文以ORYZA2000模型为例,提出了一种修订光合作用温度影响参数值的方法。为确定方法的有效性,结合2012年和2013年水稻品种两优培九的温度梯度控制实验,首先利用抽穗开花期光合作用观测曲线提取了不同温度水平的光合作用参数值,然后结合Arrhenius方程和Peaked方程建立了温度敏感性参数的温度影响方程。将这些方程代入机理性光合作用模型,模拟了单叶最大光合作用速率与温度的曲线关系。最后,以归一化后的曲线关系修订作物模型参数值,并利用两年地上部分生物量(WAGT)观测值对其验证。结果显示,两优培九单叶最大总光合作用速率随温度的变化关系不同于ORYZA2000的默认设置,修订后的最适温度为38~40°C,高于默认值。在10~20°C的低温段,修订后的温度影响系数低于默认值。从WAGT模拟值的相对误差看,修订后较修订前平均降低约3.3%。本研究为改进干物质模拟精度和分析不同品种光合作用的温度依存性提供了重要参考。     

3种植物对镉污染土壤修复的试验研究

为探究植物修复技术在济源镉(Cd)污染土壤的应用特征和效果,笔者以不同Cd污染程度的实际土壤为对象,采用盆栽试验,对比三叶鬼针草、黑麦和印度芥菜对Cd的耐受、富集、转移能力及修复效率。结果表明:污染组植物的生物量无显著下降,供试植物均具有较强的Cd耐性。3类植物富集特征不同,地上部分富集Cd浓度顺序依次是:三叶鬼针草印度芥菜黑麦。3种植物中黑麦地下部分Cd含量最高,轻、重度污染组的Cd含量分别达到11.95、28.56 mg/L。三叶鬼针草对Cd具有较强的转移能力,其中在轻度污染土壤中转移系数(TF=2.23)最大。此外,三叶鬼针草修复效率最高,轻、重度污染组分别为2.04%、1.59%。综上所述,三叶鬼针草的生物量、富集转运系数和修复效率均高于黑麦和印度芥菜。因此,三叶鬼针草可作为济源Cd污染土壤修复植物之一,为当地土壤Cd污染治理提供理论参考和技术依据。     

Nutrient Accumulation in Faba Bean Varieties

Increasing the amount of nutrients in plant-based foods will help to improve the nutritional status of people in the World. Faba bean (Vicia faba L.) as a staple food in developing countries has the potential to provide many nutrients in human diets. The objective of this study was to characterize the nutrient concentrations in leaf, pod, and seed of faba bean varieties. A field study was conducted with six faba bean varieties. Variation in the elemental concentrations of nutrients and protein occurred among varieties and different parts of the plants. The highest concentrations of nitrogen, phosphorus, potassium, zinc, or copper and protein were in the seeds. However, the highest accumulation of calcium, magnesium, iron, or manganese was in the leaves. We recommend that faba bean can be considered as a valuable crop in the diet of nutrient-deficient consumers due to high concentration nutrients in edible parts of the plant.     

Growing media for horticultural bedding plants yield under agriculture organic systems

The aim of this experiment was to test on-farm growing after composting the mixture of following legume plants Crotalaria juncea, Cajanus cajan, Mucuna aterrima with the grass Sorghum bicolor. The treatments were compared to commercial growing medium (CGM) and CGM+NPK to produce bedding plants of lettuce, broccoli, kale, and cabbage. The nutrient contents in CGM and CGM+NPK were higher than the values found in the mixture of the legumes plants with the grass. The pH was higher in the growing media from legume plants as well as the electrical conductivity in the combination CroSor and CajSor. The water retention capacity was higher in the treatments MucSor and CGM. The chemical attributes indicated that CroSor, CajSor, MucSor and CGM+NPK were better than CGM. The growing media from the mixture of legume with grass are an affordable alternative to produce bedding plants of lettuce, broccoli, kale and cabbage under organic agriculture system.     

Potassium accumulation,partitioning, and remobilization in high-yield spring maize in Northeast China

Potassium (K) plays an important role in maize yield, but K accumulation characteristics in high yielding maize is still not well documented. A two-year field experiment was conducted to investigate the K accumulation characteristics of high yield (HY)（>15 t ha^?1）spring maize compared with medium yield (MY)（10–15 t ha^?1), and low yield (LY)（<10 t ha^?1). The maximum K accumulation stage in maize appeared between V6 and V12 stage (LY, MY, and HY was 125.46, 138.05, and 146.22?kg ha^?1, respectively). Most of the K (94.27–97.13%) was accumulated during vegetative stages. HY exhibited a significantly higher K accumulation than either MY or LY. For different organs, the K remobilization amount of leaf was the highest, and the remobilization amount of stalk was the lowest, the K remobilization amount of leaf and stalk showed as HY?<?MY?<?LY, same as the total K remobilization amount, but the K remobilization amount of sheath and husk plus cob showed the opposite order. These results indicated that sufficient nutrient supply for maize can not only accumulate more K but also delay leaf senescence and maintain high photosynthetic activity, resulting in reduced K remobilization from vegetative organs, and reduced K loss in whole plant.