湘南地区烟稻轮作和不同年限烟薯套种对土壤微生物的影响

对湘南地区烟稻轮作和不同年限烟薯套种的烟田土壤中细菌、真菌、放线菌进行分离培养,对微生物不同种群的数量进行分析,结果表明：烟薯套种在10年内土壤中可培养细菌与放线菌数量均为递增趋势,10年以后又呈递减的变化趋势,通过与水稻轮作,烟田土壤中可培养细菌、放线菌数量又呈明显增加;烟薯套种中随着套种年限的延长土壤中可培养真菌数量呈明显的递增状态,通过与水稻轮作,土壤中可培养真菌数量有了较为明显的减少.对微生物量C/N分析结果表明,烟薯套种10年内土壤中微生物量碳与微生物量氮均呈递增趋势,在10年以后为递减趋势;烟稻轮作相较烟薯套种明显使土壤中微生物量碳与微生物量氮增加.     

烟田免耕直播套种秋玉米栽培技术

烟田免耕直播套种秋玉米,是针对湖南双季稻烟区探索出的一种保护性栽培技术,是以烟叶生产为主的新型种植模式,比传统烟稻轮作减少成本,增加收益,农民节本增收.烤烟套作秋玉米共生期以15～20 d为宜,种植密度因玉米品种和植株类型而定,一般为每公顷52 500～67 500株.介绍了烤烟和玉米的配套栽培技术.     

烟田养殖黑眶蟾蜍对烟草农艺性状和病虫害发生的影响

明确烟田养殖黑眶蟾蜍对烟草农艺性状、烟田病虫危害的影响，探讨烟田引入黑眶蟾蜍后对烟草生长和烟田病虫害发生的规律，为烟田养殖黑眶蟾蜍的可行性提供理论依据。结果表明：养殖黑眶蟾蜍的烟田(处理)，烟草农艺性状除了团棵期的株高、成熟期的节距和腰叶长外，其余的农艺性状指标均显著高于未养殖黑框蟾蜍的烟田(对照)。对照与处理烟田的斜纹夜蛾虫口密度分别为1.39只/m2和0.09只/m2，豆天蛾为0.41只/m2和0.09只/m2，二者的虫口密度对照烟田显著高于普通烟田。试验地烟草的病害较轻。可利用黑眶蟾蜍的捕食性建立生     

郴州植烟区除草剂危害情况调查及治理对策

调查了郴州烟稻轮作区水稻及烤烟的除草剂使用情况,烟田应用的除草剂主要有草甘膦等13种.对桂阳、嘉禾、安仁、宜章、永兴5个烟区疑似除草剂药害的烟田进行调查,产生的症状主要有烟株畸形、叶片卷曲、叶片小而薄、轻微萎蔫、烟株异常矮小、芽扭曲、叶片发黄等.除草剂药害田烟株农艺性状较正常烟株差.对烟田土壤的检测结果表明：郴州地区烟草出现药害主要是二氯喹啉酸和二甲四氯引起的.对除草剂药害产生的原因进行了分析,并提出了治理对策.     

收获后烟秆不同处理方式对烟草病害发生的影响

为了探讨烤烟收获后烟秆不同处理方式对烟草病害的影响，采用多点单因素田间小区实验，研究了2种基本烟秆处理方式下烟田青枯病、黑胫病与病毒病的发生情况。结果表明：烟秆离田上岸处理比砍断还田处理的烟田青枯病、黑胫病与病毒病的始发期分别推迟14、35、23 d；盛发期发病率分别降低21.58%、17.02%、16.35%，病指降低8.89、7.95、6.80；定案调查期发病率分别降低32.15%、17.68%、22.10%，病指降低19.77、10.09、10.10；离田上岸处理烟田青枯病、黑胫病与病毒病发病增长率（定案期-盛发期）分别为1.33%、1.23%、0.19%，病指增长（定案期-盛发期）分别为0.39、0.55、0.20。试验表明，烟秆离田上岸处理可以推迟黑胫病的始发期，降低青枯病的发病率与病指，可以更好地减缓病毒病的扩散。     

高效棉田间套种模式

高效棉田间套种模式张运胜，向安华湖南安乡县农技中心４１５６００湖南安乡县地处洞庭湖西北部，１９９３年植棉１５６６ｈｍ２。为提高棉田整体效益，棉农在棉花与其它作物间作套种等方面进行了探索，涌现出了多种棉田高效间套模式。１棉花大蒜套种即在棉花生育后期套种...     

棉田间套有技巧 立体种植效益高

盐城市棉田立体种植由过去从单一麦子套种,发展到多品种、多层次、多格局的立体种植模式,2001年全市棉田秋冬套种经济作物3 52万公顷,占棉田面积22 2%,春夏间作经济作物9 84万公顷,占棉田面积的62 3%,每公顷平均生产皮棉1431ｋｇ,每公顷增收15000元以上,部分高产高效田增收达37500元以上,东台春马铃薯套种棉花,每公顷增收16500元以上,大丰三龙镇刘如干0 41公顷棉田套种阳春白菜收入就达1 2万元,仅2000年棉田立体种植全市农民计增纯收入5 4亿元,有效地提高棉田综合效益。为适应市场经济,推进农业产业化,加快棉田种植业调整,提高农民增收增效,…     

赣北棉田套种生姜栽培技术要点

由于棉田间套种可以直接提高棉田经济效益,还有利于农业可持续发展.多年来,一大批棉田高产高效的间套种模式已在生产上大面积推广应用.近年来,生姜种植效益良好.棉田套作生姜平均产生姜30 000 kg/hm2,按1.3元/kg计算,收入可达39 000元/hm2;可产籽棉3 450 kg/hm2,按市场价4.8元/kg计算,收入可达16 560元/hm2,合计收入55 560元/hm2以上,而较纯作棉花增收39 000元/hm2.目前江西省湖口县已发展棉田套种生姜66.7 hm2,为进一步提高棉田套种生产效益,现将棉田套种生姜栽培技术要点介绍如下,以供参考.     

潍坊山区烤烟适宜移栽期初探

由于潍坊烟区内地形差异较大,西部山区具有其独特的气候条件,探究适应山区烟田的移栽时间很有必要。试验设置4月20日、5月1日、5月10日、5月20日4个移栽期处理。结果表明,5月10日移栽的烟株田间长势长相正常,病害较轻,烤后上等烟比例、产值明显高于其他处理,化学成分更加协调。因此,潍坊山区烟田较为适宜的移栽时间为5月10日左右。     

棉田套种冬瓜高产栽培技术

棉田套种冬瓜高产栽培技术①杨国喜江西省丰城市棉花生产办公室３３１１００冬瓜是丰城市传统种植的经济作物，近几年来由于经济效益好，冬瓜栽培已开始转向棉田，实行棉田套种。目前，丰城市棉田套种冬瓜面积已达１３３．３３ｈｍ２，特别是小港镇北港村２３．３３ｈｍ２...     

兜兰离体快繁技术研究进展

由于生境破坏和人工过度采挖及繁殖的障碍,兜兰已是世界上最濒危的植物物种之一,所有野生种均被列入《濒危野生动植物种国际贸易公约》附录I而被禁止交易。突破其种苗繁殖技术瓶颈有利于兜兰种质资源的保护和可持续利用。本文对兜兰属植物无菌播种、共生萌发和组织培养技术等离体快繁技术的进展进行综述,并提出了目前存在的问题和解决方法,以期为兜兰属植物离体繁殖技术的深入研究和优质种苗的规模化生产提供参考。     

High variation in frequency of infection by endophytes in cultivars of meadow fescue in Finland

Systemic and asymptomatic Neotyphodium fungal endophytes infect numerous species of the Poaceae. The frequencies of Neotyphodium endophyte infection in Finland were investigated among and within seven Nordic cultivars of meadow fescue, Schedonorus pratensis (Huds.) P. Beauv., which is a widely grown pasture and forage grass species in Scandinavia. The cultivars were Kasper, Salten, Antti, Fure, Ilmari, Inkeri and Kalevi. Frequencies of infection of cultivars varied from endophyte-free cultivar Fure to highly infected cultivar Inkeri [mean (standard deviation of mean) of 0·95 (0·023)]. Mean frequencies of infection of three cultivars remained lower than 0·10, and two of the cultivars, Kasper and Salten, were intermediately infected. In most of the cultivars, frequencies of infection varied only slightly among seed lots. In cultivar Kasper, however, the frequency of endophyte infection was highly variable (0–0·96) among the 45 seed lots examined. The relative importance of cultivar, seed lot and infection by Neotyphodium endophyte to the aphid Rhopalosiphum padi L. was studied experimentally, using both endophyte-free and endophyte-infected plants of four seed lots of the two intermediately infected cultivars. Endophyte infection increased plant resistance to R. padi , overriding the influences of seed lot and cultivar. It is proposed that variation caused by endophyte infections in cultivars of meadow fescue should be taken into account in assessing plant breeding programmes in Europe.     

Investigation of Polymorphisms in Coding Region of OsHKT1 in Relation to Salinity in Rice

Rice(Oryza sativa) is sensitive to salinity, but the salt tolerance level differs among cultivars, which might result from natural variations in the genes that are responsible for salt tolerance. High-affinity potassium transporter(HKTs) has been proven to be involved in salt tolerance in plants. Therefore, we screened for natural nucleotide polymorphism in the coding sequence of Os HKT1, which encodes the HKT protein in eight Vietnamese rice cultivars differing in salt tolerance level. In total, seven nucleotide substitutions in coding sequence of Os HKT1 were found, including two non-synonymous and five synonymous substitutions. Further analysis revealed that these two non-synonymous nucleotide substitutions(G50T and T1209A) caused changes in amino acids(Gly17Val and Asp403Glu) at signal peptide and the loop of the sixth transmembrane domain, respectively. To assess the potential effect of these substitutions on the protein function, the 3D structure of HKT protein variants was modelled by using PHYRE2 webserver. The results showed that no difference was observed when compared those predicted 3D structure of HKT protein variants with each other. In addition, the codon bias of synonymous substitutions cannot clearly show correlation with salt tolerance level. It might be interesting to further investigate the functional roles of detected non-synonymous substitutions as it might correlate to salt tolerance in rice.     

马铃薯试管苗组织培养及微型薯诱导技术的研究

通过加入不同浓度的BA、NAA和KT,以探讨外源激素对马铃薯试管苗生理性状的影响,发现低浓度的外源激素较适合用来进行试管苗的增殖。本试验利用香豆素进行微型薯的诱导,结果表明低浓度的香豆素对提高薯重和大薯率有利,而高浓度有利于提高微型薯的结薯数量。     

Role of invertase in the accumulation of sugars in cold-stored potatoes

Freshly harvested potatoes contain low levels of total invertase and high levels of invertase inhibitor. Total invertase increases sharply when potatoes are placed in cold storage, but the inhibitor is not depleted in all varieties. The absence of basal invertase activity in Norchip tubers indicates that an excess of invertase is not required for reducing sugar formation. Analyses of 37 varieties and seedlings after 3 months cold storage revealed that the reducing sugar content is not proportional to the invertase activity. High sugar contents are associated with low inhibitor levels, but low sugars are not necessarily associated with high inhibitor levels. The results indicate that invertase participates in reducing sugar formation, but other factors are responsible for the regulation of starch-sugar conversion in potatoes during cold storage.     

Quantitative assessment of metals in local brands of tea in Pakistan

In present study, Mn, Fe, Zn, Cu, Co, Pb, Cr, Ni and Cd were analyzed by FAAS in green and black tea samples of locally available in the Pakistani market. Na and K were also determined by Flame Photometer. Tea leaves can be the source of mineral components and trace elements, as well as some undesirable substances due to exposure to the environment. Among the metals tested, K was the most abundant one followed by Na, Mn and Fe. Fortunately, toxic heavy metals, Pb and Cd, had the lowest contents in tea samples and also in tea aqueous extracts. Concentration of heavy metals in tea aqueous extract was markedly lower than their total contents except that of K. The solubility of studied metals in tea aqueous extract varied widely and ranged from 0.0-95%. The lowest ranges of solubility were listed for toxic heavy metals Pb and Cd. The possible uptake of metals by the human body from tea aqueous extract has also been determined. The amounts of metals that one may take up through consumption of tea aqueous extract were found to match the acceptable daily intake even taking into account exposure from air, food and drinking water.     

玉米耐盐性研究进展

综述了玉米耐盐生理机制和耐盐育种的研究进展。     

用蛭石做马铃薯快繁培养基支持体的初步研究

1　前　言目前 ,马铃薯脱毒快繁技术已广泛应用于科研与生产中 ,快繁过程中脱毒苗培养基支持体通常采用琼脂或直接采用液体培养。然而这两种培养基存在着诸多问题 ,例如琼脂培养基中的琼脂价格昂贵、成本高 ,而且胶体不利于营养物质的扩散、透气性差 ,导致瓶苗生长不良。因此 ,该实验在本着降低成本的同时 ,又能保证瓶苗正常生长的前提下 ,以蛭石代替琼脂 ,分析其在实际生产中的应用价值。2　材料与方法2 1　材料供试品种为郑薯 6号脱毒苗 ,试验于 2 0 0 2年在郑州市蔬菜研究所马铃薯脱毒实验室内进行。2 2　方法本试验设两个处理 :处理 1…     

Matlab在玉米子粒灌浆特性分析中的应用

利用Matlab软件对玉米子粒灌浆过程用Richards方程进行拟合后,通过编程实现灌浆次级特征参数计算,并对不同播期子粒灌浆特征进行分析和探讨。结果表明,在黑龙港地区生态条件下,不同播期玉米各部位子粒灌浆均符合"S"形生长曲线,可用Richards方程很好地拟合。不同播期条件下,早播处理子粒起始势最高,达到灌浆盛期时间最早,平均灌浆速率及最大灌浆速率最大,活跃灌浆期较长,粒重最高。各播期玉米不同部位子粒,穗下部与上部相比,子粒的起始生长势较大,平均灌浆速率较高,达到灌浆高峰期时间较短,粒重较高。