氮磷钾肥对马铃薯营养状况及块茎产量的影响

试验分别在甘肃省景泰县、内蒙古自治区达拉特旗和河北省沽源县3个马铃薯生产基地进行,在基地常规N、P2O5、K2O肥施用量分别为300、345、375kg/hm2的基础上,研究改变磷、钾、氮肥用量对马铃薯营养状况、块茎产量以及土壤养分的影响。试验结果表明,氮、磷、钾肥用量分别从N300、P2O5345、K2O375kg/hm2降低到180、180、225kg/hm2,对植株干物质累积量没有显著影响,3个基地都呈相同的趋势;3个基地不同处理的块茎产量也没有显著性差异。因此,在试验条件下,氮、磷、钾肥用量和比例为180-180-225的施肥处理,其经济效益较高。施肥对土壤养分含量有较大的影响,特别是磷肥,当施用磷肥后,土壤速效磷含量显著提高,而且主要存在于表层土壤(0￣20cm),这说明缺磷土壤通过施用磷肥,可提高土壤有效磷水平。     

野菊花蕾的组培与快繁技术研究

利用组织培养的方法,首次以野菊花蕾作为外植体,借鉴前人组织培养观赏菊花的经验,找到一种使野菊能够快速增殖的方法.以MS为基本培养基,添加BA 1.0 mg/L和NAA0.2 mg/L作为外植体的分化与继代培养基,得到愈伤组织和大量的丛生芽;用MS培养基进行增殖培养;用1/2MS+BA 1.0 mg/L+NAA 0.2 mg/L进行生根培养,生根率在98%以上.最后通过驯化练苗得到大量的野菊再生植株.     

加工型茎用芥菜适应性研究

通过对6个春榨菜品种进行植物学和瘤状茎性状的比较研究.结果表明:‘甬榨2号'具有植株生长势强,瘤状茎经济性状好等特性,具有较好的适应能力,可以在生产上推广应用.     

木蝴蝶的研究进展

目的研究木蝴蝶不同部位化学成分组成及相对含量,为木蝴蝶药用成分开发以及药理评价提供理论依据。方法以木蝴蝶为试验材料,利用GC-MS技术分析其须根、主根、根基部、茎一、茎二、侧枝一、侧枝二和果实8个不同部位挥发油的化学成分。结果木蝴蝶挥发油的主要化学成分是醇类、酚类、酮类和醛类,其中含量最多是醇类物质,在木蝴蝶8个部位均有发现且相对含量较高;部分木蝴蝶部位中发现了该部位特有的或者较其他部位相对含量明显高的物质,如茎一挥发油中的L-丙氨酸、侧枝一中的羟基脲、侧枝二中的苄醇以及果实中的1-金刚烷乙胺和二甲胺。结论研究结果为木蝴蝶化学成分提取利用提供了理论依据。     

马铃薯薯形发育的组织细胞学研究

薯形是马铃薯重要的农艺性状之一,马铃薯块茎形状在块茎发育的早期就已确定。选取长、圆薯形的马铃薯,在匍匐茎弯钩期、次顶端膨大期、块茎形成初期、块茎形成期4个块茎发生时期,制备石蜡切片并进行组织细胞学观察,研究长、圆薯形块茎发生时内部的形态变化。结果表明:匍匐茎弯钩期髓部组织的细胞层数差异可能是造成长、圆薯形差异的主要原因,而匍匐茎弯钩期可能是造成薯形差异的关键时期。     

高变性芝麻富硒蛋白特性研究

本文研究了高变性芝麻饼粕中含硒量、生物效能、溶解性、分布及存在形式等特性,并采用 D 型大柱凝胶电泳分析其可溶性蛋白硒络合分子量范围为21KD-30KD。     

铜排斥型植物黄花月见草(Oenothera glazioviana)对铜胁迫的响应以及在铜污染土壤上的合理利用

为探究Cu对铜排斥型经济植物黄花月见草生长和生理特性的影响,以铜积累型植物海州香薷和铜敏感植物芝麻为对照,通过水培试验研究了Cu(50μmol·L-1)胁迫对三种植物根系生长、根尖质膜完整性、叶片叶绿素含量、膜透性、渗透调节物质含量、有机酸含量、必需营养元素吸收的影响。结果表明:Cu胁迫下三种植物根系生长均受到显著抑制,但黄花月见草和海州香薷的根尖质膜完整性较好,而芝麻的根尖质膜完整性受到严重伤害;Cu胁迫导致芝麻叶片细胞膜透性增加了130%、叶绿素含量相对于对照降低了6.9%,但对黄花月见草和海州香薷叶片膜透性、叶绿素含量没有影响。Cu胁迫下,三种植物体内苹果酸含量均显著增加;海州香薷和芝麻叶片中脯氨酸含量分别上升了37%和73%,而黄花月见草叶片脯氨酸含量变化不大。三种植物体内Cu积累与Zn、Fe、Mn的积累呈显著正相关,与Ca、K积累呈负相关。此外,通过盆栽试验发现,土壤中总铜含量不高于700 mg Cu·kg-1土对黄花月见草种子千粒重、种子油含量、油中γ-亚麻酸含量均没有显著影响,且种子铜含量符合国家食品卫生标准(GBT 5009.13—2003)。低廉的生产成本和较高的经济效益使得黄花月见草在合理利用Cu污染土壤中具有推广价值。     

Impact and Interaction of Nitrogen and Phytophthora infestans as Yield-limiting and Yield-reducing Factors in Organic Potato (Solanum tuberosum L.) Crops

For organic potato producers, the two main challenges are disease and nutrient management. Both are limited by regulations that on the one hand prohibit the use of chemical fertilizers, especially nitrogen, and on the other hand prohibit most synthetic pesticides. Late blight caused by Phytophthora infestans is commonly thought to be the most yield-reducing factor. However, because there is no really effective fungicide available to control late blight, there are virtually no yield loss data available for organic farming conditions. In this paper, the state of the art of organic potato tuber growth under on-farm conditions with respect to disease and nutrient management is summarized by field trials and on-farm surveys on commercial organic crops carried out in the years 1995–1998. Soil nitrogen (N) levels, plant N uptake, disease development of P. infestans and potato yield were measured. Results indicated that N availability was most important in limiting yields in organic potato crops. From on-farm data, a model including disease development, growth duration of the crops until foliage decay and different parameters related to N status of the crop could explain 73% of the observed variation in yield. Only 25% of this variation in yield could be attributed to the influence of late blight. Differences in N availability explained 48%. In conclusion, several points emerged from the results. In organic farming, yields are mainly limited by nutrient availability in spring and early summer. The effects of late blight on yields may often be overestimated and cannot be deduced from results in conventional farming because of the strong interaction with nutrient status. Depending on N availability, tubers stop growing between mid-July (70–90 kg N ha⁻¹ uptake), the end of July (110–140 kg N ha⁻¹ uptake) and mid-August (140–180 kg N ha⁻¹ uptake) due to N limitations. The higher the N status of a potato crop, the longer the growing period needed to achieve the attainable yield and the higher the probability that late blight stops further tuber growth and becomes the key tuber-yield-limiting factor. In the second part of this paper, the interactive effects of soil N availability and the impact of P. infestans on yield in the presence and absence of fungicides from 1996 to 1998 for mid-early main crops are reported. An empirical schematic model of disease impact depending on N availability was developed.     

Potato and Human Exploration of Space: Some Observations from NASA-Sponsored Controlled Environment Studies

Future space exploration by humans will require reliable supplies of food, oxygen and clean water to sustain the expeditions. Potato is one of several crops being studied for such a “life support” role. Tests sponsored by the US National Aeronautics and Space Administration (NASA) confirmed the well-known short day tendencies for tuberisation, but also revealed that some cvs. (e.g., Norland, Denali and Russet Burbank) could tuberise well under continuous high light. Horticultural tests showed that plants grew well and tuberised readily using a nutrient film technique (NFT). CO₂ enrichment studies with potato showed typical C₃ responses in photosynthesis and yield, with maximum rates occurring near 1000 μmol mol⁻¹. The highest tuber yields from these controlled environment studies reached 19.7 kg FM m⁻² or equivalent to nearly 200 t ha⁻¹. This equated to a productivity of 38 g m⁻² DM m⁻² day⁻¹. Stand evapotranspiration (ET) rates ranged from 3.4 to 5.2 l m⁻² day⁻¹ throughout growth, while maximum ET rates for canopies could approach 10 l m⁻² day⁻¹. Harvest indices (tuber DM/total DM) typically ranged from 0.7 to 0.8, indicating that waste (inedible) biomass from potato would be less than that from many other crops. An experiment was conducted in 1995 on NASA’s Space Shuttle using excised potato leaves to study tuber formation at axillary buds during spaceflight. The results showed that tubers formed equally well in space as in the ground controls, indicating that reduced gravity should not be an impediment to tuberisation.     

Role of continuous nitrogen fertilization on nutrient composition of leaves sampled at various stages of growth and on yield of yam (Dioscorea rotundata)

Abstract

White yam (Dioscorea rotundata cv. Olonko) was grown consecutively for three growing seasons, i.e. from February to October of 1975, 1976 and 1977, and treated with six levels of nitrogen, viz: 0, 40, 60, 120, 160 and 200 kg N/ha in the field. Leaf samples were taken at four stages of growth as follows: vegetative, tuber formation, tuber development and tuber maturation, and analyzed for NO₃‐N, P, K, Ca and Mg.

Increasing nitrogen fertilization consistently increased leaf‐NO₃‐N, particularly at the vegetative stages of growth, while no consistent trend was established for leaf‐P. Leaf‐K was increased at low rate of nitrogen fertilization during tuber formation and maturation whereas leaf‐Ca increased only at tuber maturation in the presence of higher rates of nitrogen fertilization. There was a marked increase in leaf‐Mg at all stages of growth when N treatment was increased to 200 kg N/ha. A positive correlation (r = 0.84???) was obtained for leaf‐K at the vegetative growth stage with tuber yield, while leaf‐Mg was positively correlated with tuber yield at vegetative (r = 0.46?), tuber formation (r = 0.50?) and tuber development (r = 0.67??) stages. All other elements were negatively correlated with yield at all stages of growth. Tuber yield was highest at the 200 kg N/ha treatment.