谷子成熟胚诱导愈伤组织及植株再生的研究和条件的优化

选用4个谷子品种,"冀谷11"、"豫谷2号"、"铁谷5号"和"十里香"研究在不同条件下谷子成熟胚的再生能力及其影响因素。研究表明谷子的再生能力受基因型影响较大,不同谷子品种诱导愈伤和愈伤分化能力不同,4个品种中以"冀谷11"的再生能力最好。后续试验用"冀谷11"研究不同培养基、不同激素配比以及培养基的添加物对谷子再生能力的影响。结果表明LS培养基适合谷子的愈伤组织诱导,MSB5培养基适合谷子的分化;所试验的碳源中麦芽糖适合愈伤的诱导和分化;谷子诱导愈伤较好的激素配比是2,4-D+ZT,愈伤分化较优的激素配比为NAA和6-BA的组合。另外,硝酸银、酸水解酪蛋白、脯氨酸及山梨醇等添加物会提高谷子的再生能力。     

不同水肥和光照条件对水稻化感特性的影响

采用盆栽实验对水稻化感品种华航1号在不同水肥和光照条件下的化感潜力和化感物质进行了研究。结果表明,华航1号在较高水肥条件下化感潜力较强,而在较低水肥条件下化感潜力下降,进一步对华航1号的化感特征物质的含量测定表明,在较低水肥条件下其化感物质没有显著的变化,只是次生物质的种类有所增加,尤其是一些具有抗病功能的次生物质的含量有所增加,在弱光照条件下华航1号的化感特征物质含量比在较强光照条件下要低,而且具有抗病功能的次生物质含量则保持较高水平,结果还发现,不论水、肥或光照条件的变化,华航1号对非伴生杂草的化感潜力都比伴生杂草要强。     

谷子秸秆不同部位水浸液对3种杂草的化感作用

通过测定种子萌芽期生物学指标和盆栽苗期生理指标,研究谷子不同部位(叶片、茎秆)不同浓度(原液、10倍稀释液、50倍稀释液、100倍稀释液)浸提液对反枝苋、藜、狗尾草3种谷田恶性杂草的化感作用。结果表明: 谷子叶片、茎秆水浸提液对3种杂草均存在显著化感作用,且不同浓度浸提液化感作用存在差异,总体表现为原液有抑制作用,稀释液(10、50、100倍)有促进作用。叶片、茎秆浸提液原液处理下,反枝苋、藜、狗尾草的发芽率分别下降了63.9%、37.3%和41.7%,根长仅为对照的27.8%、37.8%和18.4%,芽长仅为对照的34.5%、27.7%和17.6%,净光合速率为对照的66.6%、89.9%和88.2%,蒸腾速率为对照的69.0%、87.5%和56.1%,原液对3种杂草的综合化感效应指数为-0.699、-0.716和-0.795,表现出较强的化感抑制作用。稀释液处理下化感促进作用随稀释倍数增加呈先上升后下降趋势,其中50倍稀释液促进作用最强,3种杂草的发芽率、根长和芽长均与对照达到差异显著水平,综合化感效应指数分别为0.261、0.217和0.165。谷田伴生杂草大量生长与谷子秸秆中化感物质淋溶有关。     

不同化感物质对西瓜幼苗生长的影响

西瓜是受连作障碍影响最为严重的作物之一,由化感物质引起的自毒作用被认为是造成连作障碍的主要原因。为阐明化感物质对西瓜种子萌发及生长发育的影响,本研究选择4种最为普遍的化感物质——苯甲酸、肉桂酸、阿魏酸与丁香酸处理6个品种的西瓜种子,利用平底圆柱玻璃瓶培养法直接观察测量西瓜种子萌发以及幼苗根系与下胚轴生长动态变化。结果表明,浓度超过10 mg/L的化感物质处理显著抑制了西瓜种子的萌发和幼苗的生长,其中幼苗根系受化感物质的影响最大。不同西瓜品种对化感物质的响应差异显著,苯甲酸、肉桂酸处理后,‘郑麻10号’受到的抑制作用最强,‘利丰3号’与‘新优16号’受到的抑制作用较弱;‘晋抗6号’和‘中优杂1号’受阿魏酸、丁香酸的抑制作用最强,但这2种化感物质对‘新优16号’的抑制作用相对较弱。总体上,化感物质对西瓜抑制效果从强到弱依次为苯甲酸肉桂酸阿魏酸丁香酸。在所研究的材料中,‘利丰3号’与‘新优16号’对化感物质相对不敏感,可能在连作障碍防控中有一定的应用价值。     

不同谷子（Setaria italica(L.)Beauv）品种对除草剂的耐药性

试验对34个谷子品种进行盆栽试验,研究两种土壤处理除草剂扑草净、速收对谷子安全性的影响.测定相关的生理和生化指标,通过聚类分析比较不同谷子品种之间的耐药性的差异.试验结果表明:这两种除草剂对大部分谷子的株高、叶面积有一定的抑制作用.不同除草剂对同一种谷子的生理指标影响是有差异的.大部分谷子品种对扑草净(0.07g/m2)有一定的耐药性,扑草净药剂处理后,大部分谷子品种的POD酶活性有所提高,可溶性糖含量提高,蒸腾强度、气孔导度也有一定程度的提高.大多数谷子品种施用速收(0.015g/m2)后其SOD酶活性下降,其蒸腾强度、气孔导度有所提高.同一种除草剂对不同谷子品种的生理指标影响也是不同的,对其进行聚类分析后,聚类结果各为四大类,表明不同谷子品种之间存在耐药性差异.     

豌豆根系中分泌物质的分离鉴定及其化感效应的研究

本文实验采用GC-MS分析法对豌豆组培苗、土培苗重茬两代的根系分泌物进行鉴定。实验结果表明,能被二氯甲烷提取的豌豆根系分泌物有醇类、脂类、醛类、苯类、烃类等。用不同浓度的豌豆化感物质2,4-二叔丁基苯酚(2,4-DB)和2,6-二叔丁基对甲酚(2,6-DM)处理豌豆、绿豆、小麦和玉米4种作物种子,进行萌发和幼苗生长的化感效应研究。结果表明,0~2 mmol·L~(-1) 2,4-DB和2,6-DM处理对豌豆和绿豆种子萌发呈促进作用,而3~5 mmol·L~(-1) 2,4-DB和2,6-DM处理则呈抑制的作用。随浓度的增大,2种化感物质对小麦和玉米种子萌发的抑制作用逐渐增强。对于豆科作物豌豆和绿豆,2,4-DB对绿豆萌发时根系的抑制作用较强;而对于禾本科作物玉米和小麦,则2,4-DB对小麦萌发时根系的抑制作用最强。     

水稻关键化感物质稻壳酮的研究综述

杂草给水稻(Oryza sativa)生产带来严重损失,利用水稻自身化感作用被认为是对环境友好的杂草控制方法。稻壳酮A和B是水稻抑制杂草的主要化感物质,其中稻壳酮B是至今发现最高效的天然除草剂之一,具有很好的应用潜力。稻壳酮B可以从水稻根系释放到土壤中抑制周围稗草等植物的种子萌芽和生长。稻壳酮B的浓度大于3 nmol·mL^-1时就能抑制水芹和莴苣的根和胚轴生长,同时稻壳酮A和B是水稻重要的植保素,可有效抑制水稻病原菌比如稻瘟病菌(Magnaporthe grisea)等。此外,稻瘟病菌感染可诱导水稻合成更多的稻壳酮。该文主要对国内外有关水稻化感物质稻壳酮的性质、分布状况、化感作用、生物合成途径、检测方法、人工合成方法和影响因素等方面的研究进行了综述。在此基础上进一步探讨稻壳酮研究过程中简捷检测方法、诱导因子和人工合成等问题。     

谷子对干旱胁迫的生理生态响应

干旱少雨严重限制了我国西北地区谷子的产量,为明确谷子响应干旱的生理特征,以干旱敏感谷子品种安04和不敏感品种豫谷1号以及xiaomi为材料,通过盆栽试验,研究了谷子不同生育期叶片光合参数、叶绿素含量、非结构性碳、β-淀粉酶基因表达对水分亏缺的响应。结果表明,正常水分条件下安04产量高于豫谷1号,干旱胁迫严重限制了两个谷子品种的产量形成,安04和豫谷1号分别减产71.2%和56.0%,豫谷1号产量显著高于安04。正常水分条件下,安04具有比豫谷1号更高的净光合速率（P<0.05）,干旱胁迫下,豫谷1号叶片净光合速率显著高于安04;叶片蒸腾速率结果同光合结果一致。干旱条件下,豫谷1号具有更高的叶片相对含水量。干旱胁迫显著降低了两个谷子品种花期的叶绿素a、叶绿素b及总叶绿素含量,且安04降低幅度均大于豫谷1号。干旱胁迫均显著增加了豫谷1号拔节期和开花期的叶片可溶性糖含量,而安04叶片可溶性糖含量并没有发生显著性变化,同时干旱胁迫显著增加了豫谷1号β-淀粉酶基因SiBAM1的表达水平。施用β-淀粉酶活性抑制剂α-环糊精,xiaomi叶片可溶性糖及脯氨酸含量显著降低,进一步加重了干旱对xiaomi的生长抑制。综上所述,干旱胁迫诱导谷子β-淀粉酶基因表达和β-淀粉酶活性升高从而水解淀粉形成可溶性糖,高可溶性糖含量对谷子提高抗旱性起重要作用。     

2，4-D二甲胺盐对草鱼、鲢鱼和鲫鱼的急性毒性

【背景】2,4-D二甲胺盐是一种选择内吸性除草剂,用于清除果园、牧场、水域等环境中的藜、苋等阔叶杂草。本文明确了2,4-D二甲胺盐在防除鱼塘杂草过程中对淡水鱼类的毒性。【方法】采用半静态法测试了2,4-D二甲胺盐对草鱼、鲢鱼和鲫鱼的急性毒性,并明确了2,4-D二甲胺盐对草鱼、鲢鱼和鲫鱼的安全浓度。【结果】随着供试鱼苗在药液中暴露时间的延长,LC50。值逐渐减小。2,4-D二甲胺盐对草鱼、鲢鱼和鲫鱼的96hLC50值分别为369．27、339．20和438．47mg·L^-1。2,4-D二甲胺盐对草鱼、鲢鱼和鲫鱼的安全浓度分别为36．93、33．92和43．85mg·L^-1。【结论与意义】2,4-D二甲胺盐对草鱼、鲢鱼和鲫鱼表现低毒。本研究为合理使用2,4一D二甲胺盐防除水生杂草提供了依据。     

稗草潜在化感物质的排查

针对已报道属于羟基肟酸(丁布)、酚酸和酞酸酯类的稗草潜在的化感物质,本文以水稻、稗草和莴苣为试验材料,对2,4-二叔丁基酚、对羟基扁桃酸2种酚酸以及3种酞酸酯类物质的化感活性进行了研究.采用高效液相色谱法( HPLC)研究了上述5种物质以及丁布在稗草组织、根区土壤和种子萌发液的含量.结果表明:在100μg·ml-1作用浓度下,对羟基扁桃酸对莴苣、水稻以及稗草的种子萌发和幼苗生长的综合抑制活性最弱,2,4-二叔丁基酚化感抑制活性相对最强.酞酸二甲酯、酞酸二异辛酯和2,4-二叔丁基酚这3种物质对稗草的抑制活性大干水稻.通过HPLC只在稗草苗期叶、根和种子萌发液中检测出对羟基扁桃酸,其含量分别为9.72 μg·g-1、7.29 μg·g-1和0.24 μg·ml-1,而其他生长期组织以及根区土壤中均未检出.所有样品均未检测出2,4-二叔丁基酚、丁布和3种酞酸酯类物质.对羟基扁桃酸的浓度-效应试验显示,接近实测浓度(20 μg·g-1)时其对3种受试植物没有显著的化感抑制效应.本研究表明,对羟基扁桃酸不是稗草中主要的化感物质;通过HPLC-标准物质比对方法可以准确分析上述6种化合物,并证实了稗草不含有2,4-二叔丁基酚、丁布和酞酸酯类物质.     

2,4-D和干燥处理对谷子成熟胚离体再生体系的影响

谷子离体再生体系不够稳定、转化效率低，已成为谷子功能基因研究和品种改良的瓶颈。为了建立谷子成熟胚稳定的离体再生体系，以当地高产优质的6个谷子品种成熟胚为外植体，以不同2,4-二氯苯氧乙酸（2,4-dichlorophenoxyacetic acid，2,4-D）浓度及对胚性愈伤的不同干燥处理时间为变量，通过单因素实验和正交实验考察各因素对谷子愈伤组织分化及成苗的影响。结果表明，晋谷21在2,4-D浓度为9 μmol·L-1、4 h干燥处理的条件下所建立的再生体系最好，分化率为64.35%，成苗率为29.06%。研究通过探索谷子组织培养的最适条件，为谷子高效稳定遗传转化体系的建立和利用基因工程手段进行品质改良提供了依据。     

Influence of four herbicides on the algal flora of a prairie soil

Summary Four herbicides (2,4-D, trifluralin, MCPA and TCA) were applied at two concentration levels to isolated cores of a grassland loam soil. After herbicide contact times of 1, 5, and 20 days, samples were taken and the algal population estimated both quantitatively and qualitatively using two selective mineral salts media. Thirty one genera of algae were identified as occurring in the soil. Of these, Chlamydomonas, Chlorococcum, Hormidium, Palmella, and Ulothrix proved to be so sensitive to the four herbicides that they were rarely isolated from the cores after treatment. Other algal genera were found to be less sensitive, and the theoretical percentile sensitivity of fifteen genera was calculated. Chlorella, Lyngbya, Nostoc, and Hantzschia were found to be the most resistant algae, having percentile sensitivity to all four herbicides of less than 50%. Some algal genera varied in their sensitivity to each of the herbicides. Scytonema was sensitive to all of the herbicides except 2,4-D, while Tolypothrix showed a greater tolerance to MCPA. In the top cm of the soil, the reduction in cell numbers experienced by many algal genera after herbicide treatment was offset by an increase in the population of Chlorella. Stichococcus, Oscillatoria, and Spongiochloris all exhibited the ability to recover rapidly after a reduction in cell numbers resulting from the application of one of the herbicides. An overall reduction in cell numbers was noted for the algae growing preferentially on a nitrogen-free medium (i.e. potential nitrogen-fixers). re]19760511     

Effects of Selected Herbicides on the Germination and Infection Process of Puccinia lagenophora,a Biocontrol Pathogen of Senecio vulgaris

The herbicides 2,4-D, glyphosate, linuron, and MCPP at rates of 1X (recommended field rate), 0.25X, 0.025X, and 0.0125X were evaluated in vitro for their effects on the rust fungus Puccinia lagenophorae, a biocontrol agent for the annual weed Senecio vulgaris. Herbicides applied at 1X and 0.25X completely prevented aeciospore germination. Glyphosate was toxic even at 0.0125X and 0.025X. Aeciospores germinated in linuron, 2,4-D, and MCPP at 0.025X and 0.0125X at rates similar to the water control. Abnormal germ-tube growth was observed with 2,4-D at 0.25X and 0.025X, with linuron at 0.025X, and with glyphosate at 0.0125X. Further in planta studies were perfomed with two inbred lines of S. vulgaris inoculated with aeciospores of P. lagenophorae and treated with water, linuron, and 2,4-D at 0.025X at different times of application. Quantitative analysis of the infection process revealed that both herbicides reduced spore deposition on the leaves and altered leaf morphology. The herbicides had no effect on disease severity at this low rate although linuron significantly reduced the formation of infection peg. Timing of herbicide application had no influence on the infection process, and the effect of the herbicides on fungal development did not differ between the two plant lines. Thus, the herbicides applied at 0.025X did not increase plant susceptibility to the rust fungus, and the rates of 1X, 0.25X, and 0.025X would prevent, inhibit, or delay fungal development. Therefore, joint application of P. lagenophorae with these herbicides to control S. vulgaris cannot be recommended.     

除草剂对冬小麦光合特性、籽粒产量及品质的调控效应

通过田间试验研究了4种除草剂(2,4-D丁酯、‘巨星’、‘世玛’和‘骠马’)对2个小麦品种(‘临优145’和‘临汾138’)光合特性、籽粒产量和品质的影响。结果表明:2,4-D丁酯使小麦灌浆期间旗叶的叶绿素相对含量(SPAD值)和净光合速率(Pn)一直较低,千粒重和籽粒产量显著低于对照;‘巨星’使灌浆前期的SPAD值和Pn较高而中后期快速下降,灌浆持续时间缩短,产量与对照相近;‘世玛’使灌浆前中期SPAD值和Pn较低但后期下降缓慢,灌浆持续时间延长,千粒重和籽粒产量显著高于对照和其它处理;‘骠马’对光合特性和产量影响较小。2,4-D丁酯和‘骠马’使籽粒的蛋白质含量、湿面筋含量、沉降值、吸水率、评价值显著或极显著提高,稳定时间延长,而形成时间与对照相近;‘巨星’和‘世玛’处理的品质指标大多低于或接近对照。研究发现,除草剂通过调控小麦旗叶光合特性和灌浆进程来影响其千粒重和籽粒产量,且除草剂和品种间存在差异;2,4-D丁酯虽能明显改善小麦品质但却显著降低籽粒产量,‘骠马’使小麦品质特性改善的同时也使籽粒产量有所提高,‘世玛’虽能显著提高籽粒产量却使品质特性变差。     

不同除草剂的田间杂草防效及对糜子生长发育的影响

筛选糜子适宜除草剂来防范农田药害,是糜子高效安全生产和改善生态环境亟待解决的关键问题。本研究以粳性糜子品种‘榆糜2号'为材料,探究22种除草剂对糜子田间杂草的防除效果及对糜子生长发育的影响。结果表明: 1)喷施土壤封闭型除草剂谷友、丁草胺、莠去津、苄嘧·丙草胺和茎叶型除草剂苯唑·二甲钠、阔世玛、藤净、陶氏·优先、阔菲后,基本无药害作用,糜子幼苗生长正常,其余除草剂均对糜子有不同程度的药害影响;2)参试的22种除草剂在糜子田中对杂草均表现出一定的防除效果,总体而言,土壤封闭型除草剂的杂草防效相对优于茎叶型除草剂,但所有参试除草剂对糜子株高、功能叶片叶绿素含量、单株穗重均造成不同程度的影响;3)与人工除草相比,参试除草剂均导致糜子产量有不同程度的下降;但与不除草对照相比,部分除草剂有明显的增产增效作用。土壤封闭型除草剂中,谷友、丁草胺、莠去津、苄嘧·丙草胺的杂草防效较好,较不除草对照增产60%以上;茎叶型除草剂中,阔世玛、苯唑·二甲钠的杂草防效较好,较不除草对照增产50%以上。因此,在糜子出苗前可用38%莠去津或44%单嘧磺隆进行土壤封闭处理,或在出苗后喷施茎叶型除草剂3.6%二磺·甲碘隆或55%苯唑·二甲钠,农田杂草防效较好,且对糜子生长发育的负面影响较小。     

Effect of certain herbicide treatments on pasture composition and inoculum of the take-all fungus

The improvement of pastures by the use of a range of herbicides to eliminate grasses, and their effect on populations of the take-all fungus (Gaeumannomyces graminis vartritici=Ggt) were studied in the field (at Esperance Downs, on the south-coast of Western Australia) from 1982 to 1985. Field trials were conducted to evaluate three herbicide treatments (2,4-D amine+propyzamide; 2,4-D amine+paraquat; paraquat/ diquat) and an unsprayed control. A pot trial involving these treatments with two levels of nitrogen was undertaken to confirm treatment effects observed in the field trial. All herbicide treatments resulted in reduced grass composition of pastures, in both the year of spraying and in the second year of pasture, but reduced dry matter production in the year of spraying. In the year of spraying, however, inoculum ofGgt was reduced (P<0.1) only following the 2,4-D amine+propyzamide treatment and was greater (P<0.1) after 2,4-D amine+paraquat treatment than the unsprayed treatment. Despite reduced grass levels in the herbicide-treated plots in the second year of pasture,Ggt inoculum did not differ between treatments, nor did it after a wheat crop which followed a second year pasture. There was high correlation (P<0.001) between disease levels and dry weights of grasses in the pot trial. There was significantly less (P<0.001) grass in pots treated with herbicides compared to the unsprayed control but no difference (P>0.05) was evident between treatments. Inoculum levels were lower (P<0.05) in the treated pots than the unsprayed control with no evidence of differences among treatments (P>0.05). Nitrogen level had no effect on disease (P>0.05). All herbicide treatments tested reduced grass level and total dry matter, both in the field and in pots. Whereas in the pot trial reduced grass levels resulted in reducedGgt inoculum, in the field such a reduction occurred only with the 2,4-D amine+propyzamide treatment and only in the year of spraying. Herbicide treatments had no effect onGgt inoculum in second year of pasture or crop. Unknown soil and environmental factors in the field precluded a simple relationship between grass level in pasture and subsequent level ofGgt inoculum, and where such a relationship did occur (2,4-D amine+propyzamide treatment) it appeared to be shortlived.     

Comparative effects of the herbicides dicamba, 2,4-D and paraquat on non-green potato tuber calli

The effects of the herbicides 1,1'-dimethyl-4,4'-bipyridylium dichloride (paraquat), 3,6-dichloro-2-metoxybenzoic acid (dicamba) and 2,4-dichlorophenoxyacetic acid (2,4-D) on cell growth of non-green potato tuber calli are described. We attempted to relate the effects with toxicity, in particular the enzymes committed to the cellular antioxidant system. Cell cultures were exposed to the herbicides for a period of 4 weeks. Cellular integrity on the basis of fluorescein release was strongly affected by 2,4-D, followed by dicamba, and was not affected by paraquat. However, the three herbicides decreased the energy charge, with paraquat and 2,4-D being very efficient. Paraquat induced catalase (CAT) activity at low concentrations (1muM), whereas at higher concentrations, inhibition was observed. Dicamba and 2,4-D stimulated CAT as a function of concentration. Superoxide dismutase (SOD) activity was strongly stimulated by paraquat, whereas dicamba and 2,4-D were efficient only at higher concentrations. Glutathione reductase (GR) activity was induced by all the herbicides, suggesting that glutathione and glutathione-dependent enzymes are putatively involved in the detoxification of these herbicides. Paraquat slightly inhibited glutathione S-transferase (GST), whereas 2,4-D and dicamba promoted significant activation. These results indicate that the detoxifying mechanisms for 2,4-D and dicamba may be different from the mechanisms of paraquat detoxification. However, the main cause of cell death induced by paraquat and 2,4-D is putatively related with the cell energy charge decrease.     

Ames assays and unscheduled DNA synthesis assays on 2, 4-dichlorophenoxyacetic acid and its derivatives.

2,4-dichlorophenoxyacetic acid and several of its derivatives (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. The genetic toxicity in vitro of 2,4-D and seven of its salts and esters were examined by employing gene mutation in bacteria (Ames test) and induction of DNA damage and repair in rat hepatocytes. In addition, an in vivo unscheduled DNA synthesis (UDS) assay was performed on 2,4-D. There were no indications of genotoxic potential for 2,4-D acid, or any of its derivatives, in these assays. These results are consistent with the reported lack of carcinogenic potential for 2,4-D in both mice and rats.     

In vitro assay for 2,4-D resistance in transgenic cotton

Summary 2,4-Dichlorophenoxyacetic acid (2,4-D) resistant plants of transgenic cotton (Gossypium hirsutum L.) were produced using Agrobacterium tumefaciens containing a plasmid carrying the neomycin phosphotransferase II (npt II) and 2,4-D monooxygenase (tfd A) genes. An in vitro assay was performed to determine the sensitivity of seed germination, and the growth of seedlings of transgenic and non-transgenic cotton to various concentrations of kanamycin and 2,4-D. The results indicated that kanamycin caused the cotyledons of non-transgenic plants to turn white, but transgenic plants grew normally. Seed germination and seedling growth of non-transgenic plants were strongly inhibited by 2,4-D, but only slightly for transgenic plants. Transgenic plants and non-transgenic plants can be clearly distinguished by the use of 2 mg l⁻¹ 2,4-D in seed germination medium. There was a high correlation between the response of seed germination and the growth of seedlings to kanamycin or 2,4-D, based on the germination ration, albino ratio, dry weight or fresh weight. On this basis, we development a rapid method for identifying transgenic plants that has been verified in the field. These findings will allow identification of cotton transformants at an early stage of plant development, saving time and improving cultivars containing the 2,4-D resistance trait.