氮素形态对烤烟成熟过程中抗坏血酸-谷胱甘肽循环的影响

探讨了氮素形态对烤烟成熟过程中抗坏血酸-谷胱甘肽循环系统的影响。结果表明,烟叶自移栽后60 d开始,抗坏血酸过氧化物酶(APX)活性和抗坏血酸(ASA)含量逐渐上升,到70~80 d达到最高峰,随后稳定在一定的水平。3种不同氮素形态处理的APX活性和ASA含量变化规律相似,均随着硝态氮比例的增加而增大;谷胱甘肽还原酶(GR)活性在移栽后90 d达最大值,此后逐渐下降,谷胱甘肽(GSH)含量随着烟叶的成熟持续下降。烟叶成熟过程中各处理GR活性和GSH含量随着铵态氮比例的增加而增大。     

Morphology, chemical properties, and radiocarbon dating of eutrophic peat in Turkey

Morphologies, classifications, chemical properties and radiocarbon dates of Akgöl–Sakarya peatland located in the northwestern part of Turkey, which has never been studied up to now, were investigated. Three representative profiles were excavated in the study area and soil samples were taken based on soil horizons. Additionally, soil samples were taken at the different depths in each profile for radiocarbon dating. Accretion rates changed between 1.40 and 1.69 mm year^− 1 according to ¹⁴C measurements. Radiocarbon ages ranged between 365 ± 90 and 195 ± 50 years depending on sampling depth. Profile I was Sapric Haplohemist, profile II was Hydric Haplohemist and profile III was Typic Haplosaprist. Soil properties varied widely depending on the profiles. Fibre contents were between 9.4% and 34.7% due to degree of organic matter decomposition. pH and ECe values varied between 4.20–6.62 and 0.51–2.50 dS m⁻¹, respectively. The cation exchange capacity (CEC) ranged from 100 to 140 cmol kg⁻¹. Total nitrogen and phosphorus ranged from 0.78% to 1.82% and from 0.45% to1.03%, respectively. Total calcium contents were between 1.44% to 3.25%, and magnesium contents varied from 0.22 to 0.71%. Both nutrients were higher in the surface horizons of profiles I and II. Total Fe, Mn, Zn, Cu and B contents varied considerably among profiles. It was found that total amounts of Fe, Zn, Cu and B in samples were between 4660–16220 mg kg^− 1, 89–451 mg kg^− 1, 16–57 mg kg^− 1, 3–11 mg kg^− 1 and 12–37 mg kg^− 1, respectively. Cr, Ni and Pb contents in peat samples were 22–55 mg kg^− 1, 24–58 mg kg^− 1, and 3–93 mg kg^− 1, respectively. However, there was no Cd and Hg detected. It was observed that seasonal ground water fluctuations, eutrophic formation and differences in decomposition degrees have a substantial effect on changing of morphological and chemical properties of organic soils in the study area.     

裕固族的草原游牧文化（I）——裕固族民族的形成、宗教信仰与语言文字

研究裕固族的游牧文化对保护祁连山生态环境、巩固民族团结、促进少数民族地区经济发展和中华民族和谐统一具有十分重要的意义。通过查阅资料,分析裕固族的民间传说和族源的史料记载表明：裕固族的族源是多元的,是由古代回鹘的一支和古代蒙古的一支共同融合形成的一个新的民族共同体,1953年正式定名为裕固族。裕固族曾经信仰过多种宗教,如...     

建立保障蔬菜供应价格稳定的长效机制——宁波城区主要蔬菜供应价格形成机制研究对策与建议

蔬菜为主要菜篮子商品,其供应价格的稳定事关城乡居民的切身利益.本课题组在对宁波城区主要蔬菜供应价格形成的现状、存在的问题进行了深入调研、分析的基础上,重点针对宁波城区主要蔬菜供应自给力弱、季节性倾向明显、菜市场管理机制欠完善以及蔬菜产销信息不对称等问题,提出建立保障宁波市蔬菜供应价格稳定的长效机制的对策与建议.     

5个籼稻品种的产量形成特点和库源类型研究

采用疏花、降密、去叶等改变库源比例的方法，对5个籼稻品种的库源类型进行了研究。结果表明：水稻库的接纳能力对抽穗后干物质生产量有一定的调控作用；华矮21的结实率随抽穗后同化产物供应量的增减而急剧升降，为源限型品种：扬稻6号和景龙6号的结实率不因抽穗后颖花数的减少和密度的减低而提高，为库限型品种；在一定范围内，库－源比例的改变对嘉育948和988的结实率的影响明显小于华矮21而略大于扬稻6号和景龙5号，二者为库源互作型品种。     

限根条件下混配基质对甜樱桃生长发育的影响

以甜樱桃品种“抉择”/本溪山樱为试材,研究在限根条件下7种人工混配基质对植株生长发育的影响。结果表明:基质中添加草炭、炉渣后,容重变小,固、液、气三相比例适宜,甜樱桃生长发育好,植株成花比例高、产量高,易获得早期丰产;基质中添加炭化稻壳,植株生长量小,产量低,综合效果较差。     

不同环剥(割)处理对四季蜜芒夏季成花结果的研究

对四季蜜芒进行半圆环剥、螺旋环剥及两道环割等措施处理,研究环剥(割)对夏季促花的影响,结果表明:半圆环剥成花率最高,达到80.2%;单花序花期9～10d;开花期间前期两性花比例高而后期降低;日开放两性花占两性花总量比率的变化与日开花量占小花总量百分率的变化相似,以第5、6d的最高;螺旋环剥两性花比例最高,达到62.0%;当成花率高于60%时,座果率随着成花率的增高而呈下降的趋势;高产植株理想的成花率为60%～70%;综合衡量以两道环割处理的成花率和座果率较理想.     

细菌磁小体形成机制和应用研究进展

趋磁细菌(magnetotactic bacteria,MTB)可以在细胞内形成磁小体(magnetosome,MS)并在磁场作用下定向运动。MTB的MS合成是一个多基因参与的复杂过程。MS由于其优良的性能而有着广阔的应用前景。本文对MS的合成机制和应用的研究进展进行了初步的概述。     

云南省低产用材林成因及改造途径

论述了云南省低产用材林的现状及改造试点情况,取得的成绩和存在的问题,针对现实问题提出了解决的办法.     

小麦籽粒建成过程的光合特性及内源激素研究

以不同粒(重)型小麦品种为材料连续测定籽粒建成过程中的光合特性和内源激素的变化,结果表明:开花7日前后,各品种的叶片光合速率均有不同程度回升,该回升与蒸腾速率的高峰、籽粒中内源 IAA,Z+ZR 及 ABA 的含量高峰相吻合,而后进入籽粒快速增重期。不同粒型品种间在旗叶、倒2叶的光合速率高值持续期及叶片功能期间的叶源量上存在显著的差异,大粒显著高于中粒和小粒品种。在籽粒增重尤其是快速增重期,不同粒型间上述几种激素含量亦有明显差异。以上可能足导致不同基因型间粒重差异的重要生理原因。