不同玉米基因型吸钾和耐低钾能力的研究

利用植物对环境的遗传多样性,充分发掘优良基因型,筛选和利用吸钾能力强以及对土壤和肥料中钾利用效率高的作物品种,以适应低钾土壤条件,节约钾肥资源,缓解钾肥短缺矛盾[1 - 3].玉米是需钾量较多的作物,开展不同玉米基因型吸钾和耐低钾能力研究,挖掘玉米优良种质资源,以期为筛选吸钾能力强和耐低钾的玉米基因型,缓解我国钾肥不足提供依据.     

水稻耐低钾基因型的筛选及吸钾特性的研究

筛选水稻耐低钾基因型最直接、客观方法是在低钾土壤上进行田间实验直接筛选,其结果可作为其他方法的比较标准.但该方法需时较长、工作量大,不能满足大批量快速、高速筛选的要求.因此,近年来国内外许多学者在探索用液培的方法进行筛选[1,2].     

矿质镁对水稻产量及品质影响的研究

镁对作物正常生长发育、生理代谢、提高产量、改善产品品质具有重要作用.我国有关镁素的研究始于60年代,多见于南方红壤地区土壤镁素状况调查和镁肥肥效的研究报道.谢建昌等调查结果表明,我国广东、广西、福建等大部分植胶地的胶树出现不同程度的缺镁症状,在生产实践中镁肥效果得到了进一步的验证[1].随着农业高产品种的应用和氮、磷、钾化肥施用量的增加,作物产量不断提高,土壤养分的供给与作物对养分的需求,出现了不平衡的矛盾.为了达到平衡施肥,促进我省优质高效农业的发展,利用黑龙江省东宁县丰富的蛇纹石资源,通过特殊工艺处理,生产可被植物吸收利用的矿质镁肥,为水稻科学施肥提供依据.     

不同基因型大麦对钾的吸收、积累及分配特性

通过不同供钾水平的土培试验,研究了钾高效基因型大麦Sandrime和钾低效基因型大麦ACWestech对钾素的吸收、积累和分配特性。结果表明：在各生育期,钾高效基因型Sandrime株高和生物量均大于钾低效基因型AC Westech,根冠比小于低效基因型,但钾低效基因型缺钾症状比高效基因型严重;不同钾效率基因型大麦各器...     

耐低钾冬小麦基因型筛选方法的研究

通过液培实验及低钾土壤上的田间实验,比较,讨论了耐低钾冬小麦基因型的筛选指标,时期及钾浓度,结果表明：液培筛选的评价指标,吸钾量优于钾利用指数,筛选的适宜时期为拔节期,钾浓度以１．０ｍｍｏｌ／ＬＫ＾＋为宜,低钾土壤７种基因型的经济产量与植株地上部吸钾量间存在极显著正相关（ｒ＝０．９４５,ｎ＝２１）。冬小麦吸收的钾主要来自于１ｍｏｌ／Ｌ热ＮＨＯ３不能提取的非交换性钾,吸钾量亦可作主田间筛选的评价指标     

不同钾营养效率玉米品种的筛选

采用营养液培养和土壤盆栽试验相结合的方法,对40个玉米杂交种进行了典型钾营养效率的筛选,同时综合考虑品种的吸收和利用特性,以生物量、吸钾量、钾利用指数、钾敏感度为指标采用聚类分析方法,结合品种稳定性,筛选出典型钾营养效率玉米品种.结果表明,蠡玉18、永研4号、冀单31为高效敏感型,豫玉23为高效不敏感型,纪元1号、兴农998为低效敏感型,这为后续深层钾素高效吸收和利用机理的研究提供了基础材料,也对实际生产中因地制宜选择玉米种植品种有一定指导意义.     

不同基因型小麦钾离子吸收动力学分析

在日光温室营养液培养条件下,研究了经筛选的不同钾效率基因型小麦在不同钾营养状况下K+的吸收动力学。结果表明,采用不同钾营养状况小麦K+吸收动力学参数Km和Imax对不同基因型小麦钾效率分类,结果与经筛选的不同基因型小麦的钾效率特征相一致,Km和Imax可用来评价和筛选高效吸钾基因型小麦。但不同基因型小麦Km和Imax在不同钾营养状况下表现规律不相同,Km和Imax值的大小受到小麦本身钾营养状况反馈调节,植物钾营养状况越高,Km越大,Imax越小;有的基因型受本身钾营养状况影响较大,有的受其影响较小,但总体上还是相一致的。结果还看出,温6-986和周麦13是钾高效基因型,予农015是钾低效基因型;同一基因型小麦在不同钾营养状况下是以不同机制吸收钾的。     

籼稻不同基因型对钾、钠的反应

本研究用微区试验研究了4种典型基因型在田间条件下对钾、钠反应的遗传差异。这4种基因型是经液培方法从近300种基因型中筛选得到的。结果表明,在低钾条件下,钾高效基因型的钾素利用效率、钾素经济利用效率、对胡麻斑病的抗性等都显著高于钾低效基因型;不同基因型对钠的反应差异明显;茎叶的钾钠含量互成显著的反相关。     

嫁接对不同棉花基因型钾效率的影响

采用全生育期土培盆栽试验,在研究2个棉花基因型钾吸收效率和利用效率的基础上,对未嫁接和经嫁接的自根苗(接穗和砧木为同一基因型)处理的棉花干物质和钾的积累、分配进行比较。结果表明:自根苗植株与未嫁接植株相比,不同棉花基因型在不同钾水平下干物质和钾的积累及分配不同。高效基因型103经过嫁接后营养器官中的干物质和钾比例增加,生殖器官中的干物质和钾减少,产量和钾利用指数下降;低效基因型122经过嫁接后营养器官中的干物质和钾比例减少,生殖器官中的干物质和钾增加,产量和钾利用指数升高。吸收效率因钾水平而异,高效基因型103嫁接后施钾时吸收效率降低,缺钾时升高;而低效基因型122嫁接后施钾时吸收效率升高,缺钾时降低。嫁接对不同棉花基因型产生的效应不同,通过嫁接使不同棉花基因型物质分配趋于平衡。     

作物不同基因型对土壤环境中某些因素影响的研究进展

近年来,随着植物营养研究的发展和对资源环境综合管理的日益重视,国内外许多学者以植物本身的遗传特性为切入点,研究作物不同基因型与环境因素的相互影响,从而使资源得到合理的有效利用.综述了作物不同基因型对土壤磷、钾、土壤酶、土壤微生物的影响,以及根系分泌物的差异,为开展相关研究提供参考.     

Microassay for rapid screening of alpha-amylase activity

A microassay was developed for measuring the activity of alpha-amylases in the nanogram enzyme concentration range, based on the use of dye-labeled cross-linked starch as the substrate, and the release of soluble colored fragments formed in enzyme hydrolysis. Reaction conditions were optimized to generate a linear correlation between the increase in absorbance and a reaction time of 0-10 min, as well as enzyme concentrations in the range of 0-50 ng. A standard curve for the conversion of absorbance to enzyme activity units was constructed. The protocol developed was applied to monitoring the production of ultralow concentrations of recombinant barley alpha-amylase in yeast cells.     

Rapid screening method for detection of deoxynivalenol

A rapid method for detecting deoxynivalenol (DON), also known as vomitoxin, was developed. DON was extracted from grains and other samples with acetonitrile-4% potassium chloride solution (9 + 1). Impurities that would interfere with detection were removed on a C18 silica gel reverse phase column. Water was removed from eluates on a hydrophilic matrix column. DON was detected by thin layer chromatography using an aluminum chloride solution to develop the blue response characteristic of the mycotoxin. Total time involved is approximately 30 min. The method was applicable to corn, wheat, and barley at detection levels of 1 ppm, and oats at 1.5 ppm. It is applicable to environmental samples (soil, green plants, and water) at detection levels of 0.75 ppm.     

Practical screening procedure for sulfathiazole in honey

A simple, inexpensive procedure is described for rapidly screening small samples of honey for sulfathiazole (ST), a drug formerly used but not approved in the United States for the prophylactic treatment of American foulbrood disease of bees. The method uses 2 plastic tubes arranged in tandem. The upper tube contains a bed of alumina, which removes some interfering pigments. The lower tube contains a very small bed of anion exchange resin in the HSO4- form, which traps the ST. The drug is eventually eluted and detected using the Bratton-Marshall diazotization-coupling reagents. Honey containing 0.1 ppm ST can be readily detected. An optional dye concentration step permits the detection of as little as 25 ppb ST.     

Penetrometer measurements for screening soil physical variability

Spatial variability of soil physical conditions can easily be assessed by means of a penetrometer. This is demonstrated at a reforestation site near Hannover on a Podzol-Cambisol (FAO). Reafforestation was performed after deep ploughing to a depth of 80–100 cm. Penetration resistance was measured as kg cm⁻² with a dial penetrometer. The data showed recompaction after deep ploughing. Furthermore, it became evident that measuring penetration resistance is a simple and inexpensive way to obtain a preliminary impression of the area to be examined. Based on these results, locations with minimum, maximum and average values can be chosen for further investigations, depending on the aim of the investigation. For screening purposes it is not important whether penetration resistance is expressed in physical units or other values, such as the number of blows per unit depth with a falling-weight penetrometer. In these circumstances the low specificity of penetration resistance is not a disadvantage, but enables any change in soil physical conditions to be detected.     

Antimicrobial screening of Mentha piperita essential oils

Essential oils of peppermint Mentha piperita L. (Lamiaceae), which are used in flavors, fragrances, and pharmaceuticals, were investigated for their antimicrobial properties against 21 human and plant pathogenic microorganisms. The bioactivity of the oils menthol and menthone was compared using the combination of in vitro techniques such as microdilution, agar diffusion, and bioautography. It was shown that all of the peppermint oils screened strongly inhibited plant pathogenic microorganisms, whereas human pathogens were only moderately inhibited. Chemical compositions of the oils were analyzed by GC and GC/MS. Using the bioautography assay, menthol was found to be responsible for the antimicrobial activity of these oils.     

Enzyme immunoassay for screening of sulfathiazole in honey

A simple enzyme immunoassay (EIA) was developed to screen honey samples for sulfathiazole (ST) adulteration. Honey samples required only a 30-fold dilution before use in the procedure. Because 96 well microtiter plates were used and only 100 microL of diluted honey sample was required per well, numerous replicates or samples could be tested simultaneously. The EIA was able to detect at least 0.3 ppm levels of ST in honey and also provide a rough quantitation of ST amounts.     

Phlorin screening in various citrus species and varieties

Phlorin (3,5-dihydroxyphenyl beta-D-glucopyranoside), an orange peel marker, has been searched in 45 species and varieties of Citrus. The phlorin content was determined by high-pressure liquid chromatography in juices and aqueous peel extracts of these different fruits. The phlorin content in C. reticulata peel extract varies from 0 to 1012 mg L(-)(1) with a mean of 162 mg L(-)(1). On the contrary, phlorin was not found in mandarin and clementine juices except for mandarin "Commune" and "Beauty" (33 and 30 mg L(-)(1), respectively). In the 14 species of oranges and varieties, phlorin was detected in juices and peel extracts with a mean of 22 and 492 mg L(-)(1), respectively, while for grapefruits, means were 108 mg L(-)(1) in juices and 982 mg L(-)(1) for peel extracts. Tangors and tangelos which are hybrids (C. reticulata x C. sinensis and C. reticulata x C. paradisi, respectively) are characterized by the systematic presence of phlorin in peels (mean: 406 and 659 mg L(-)(1), respectively) while in juices its presence could be variable (0-73 mg L(-)(1)). These heterogeneity and values may be explained by the genetic variability of these hybrids and the phlorin content of their parentage group.     

水稻化感种质筛选的初步研究

采用砂培法和蒸馏水浸提法对300份水稻品种进行了化感作用初筛，初步发现12份品种分别对稗草或莴苣的幼根、幼苗的生长具有明显的抑制作用，约占总数的4％，主要来源于外国粳稻、籼稻及广西地方晚籼品种；一般情况下，化感物质对稗草幼苗的抑制作用明显强于其对幼根的抑制作用，而对莴苣幼苗的抑制作用则明显弱于其对幼根的抑制作用；对莴苣的化感作用强于对稗草的化感作用，所以初筛时以莴苣为检测植物可提高效率；砂培法和蒸馏水浸提法具有能快速大量测定化感种质的优点，可作为初筛的主要方法，但均需改进，以提高准确性。