Vegetative propagation of Inga feuillei from shoot cuttings and air layering

Cuttage and air layering were evaluated as means of vegetative propagation of the tropical woody tree, Inga feuillei. Effects of moisture management systems, leafiness, auxin application, and stem diameter on rooting of semihardwood cuttings were investigated. Cuttings were taken from 2-year-old seed-propagated, greenhouse-grown stock plants. Compound leaves were either reduced in area or removed entirely before auxin pretreatment with 0, 0.3, or 0.8% indolebutyric acid (IBA) followed by sticking under mist or in a polyethylene enclosure. Leafless cuttings did not root regardless of moisture management system or auxin pretreatment, whereas 55% rooting of leafy cuttings was observed. Leafy cuttings rooted significantly better under mist than in a polyethylene enclosure. Auxin treatment at the higher level increased rooting percentage approximately two fold for larger diameter cuttings (8.1 to 20 mm), but had no effect on the smaller cuttings (2 to 8 mm), and resulted in an approximately three fold increase in the number of roots/rooted cutting for both stem diameter classes. Auxin treatment did not affect rooting percentage of leafy softwood cuttings under fog, however it did increase the number of roots per rooted cutting. One hundred percent of air layered shoots rooted within 5 weeks with or without auxin pretreatment, and all rooted layers survived transplanting to soil. Possible implications of this research on agroforestry, selection, genetic improvement, and conservation are discussed.     

大花蕙兰的嫩根与根兜组织快繁技术研究

取大花蕙兰的的嫩根和根兜为外植体在MS培养基上用不同浓度的细胞分裂素BA和生长素NAA进行了研究。结果表明：根兜的分化率比嫩根高,而最适合的培养基配方为MS＋BA1.5 mg/L＋NAA0.5 mg/L＋蔗糖30 g/L＋琼脂8 g/L。可直接分化成小苗,增殖的同时可获得健壮的再生植株。最适的生根培养基为：MS＋NAA0.3 mg/L＋活性碳1.0/L＋蔗糖25 g/L＋琼脂7 g/L。     

生物助长剂浸根处理对红皮云杉幼苗生长影响的研究

采用天津大学研制的生物助长剂对红皮云杉 1年生换床苗进行不同时间的浸根处理 ,发现采用生物助长剂处理的苗木苗高、主根长度、侧根条数和苗木的生物量都明显增加 ,并得出了不同浸根时间对红皮云杉 1年生换床苗生长影响的差异 ,为生物助长剂在育苗生产中的应用提供了可靠的依据。     

In vitro rooting and early greenhouse growth of micropropagated Paulownia elongata shoots

Experiments focused on improving methods for rooting micropropagated Paulownia elongata shoots and enhancing the quality of plants grown from rooted shoots transferred to the greenhouse. Micropropagated shoots rooted on basal Murashige and Skoog medium, but inclusion of 0.2 mg/l naphthaleneacetic acid and 0.4 mg/l indole-3-butyric acid during a 10-day rooting treatment resulted in a shorter rooting time, a greater number of roots per shoot, and shorter roots that were more easily manipulated during transfer to the greenhouse. Shoots with a greater initial height had greater rooting success than short shoots. Shoots from 1.1 to 2.0 cm in height were preferable to taller shoots because: (1) less time is required to produce them, (2) their smaller leaf size makes them easier to handle, (3) they root with about the same frequency, (4) rooted shoots are more easily transferred to the greenhouse, and (5) once in the greenhouse they attain a height that is indistinguishable from shoots that were classified as very tall at the start of the rooting process. Inclusion of sucrose in the rooting medium promoted rooting as compared to shoots rooted without sucrose. Of the fertilizer treatments applied to plants newly transferred to the greenhouse, 17-17-17 (N-P-K) and 0-44-0 each applied at 1 g/l with each watering resulted in the highest portion of plant fresh mass allocated to roots (49%).     

杂草对激素类除草剂抗药性研究进展

农田杂草严重影响作物的产量和品质,对除草剂的过度依赖和长期使用,使杂草对除草剂的抗性问题日益突出。目前已有262种杂草(152种双子叶和110种单子叶)的512个生物型对23类中的167个除草剂产生抗性。激素类除草剂作为除草剂的重要成员,为禾谷类作物田的杂草防除提供了保障,然而在使用了几十年后,44种杂草对此类除草剂产生了抗药性。本文对激素类除草剂的分类应用、除草机理、抗性现状、抗性机理等进行了综述,以期为激素类除草剂的应用和抗激素类除草剂杂草的防除提供参考。     

植物激素受体的三维结构及其分子识别机制研究进展

许多研究表明,第一次"绿色革命"与植物激素的相关基因编码是密不可分的。植物激素是一类具有调节植物生长发育功能的有机内源物质,激素受体是植物激素调控生长的中心环节,一直备受关注,而激素受体结构的发现可以使人们更深入地了解其调节植物生长的分子机制。综述了生长素、赤霉素和脱落酸3种经典植物激素受体结构的发现及其作用机制的最新研究成果,旨在为开展基于结构的新型人工植物激素的生物合理设计提供参考。     

低钾胁迫下外源生长素对烟草根系生长及钾吸收的影响

【目的】探明生长素参与低钾胁迫下植株根系的生长发育及吸钾机制,同时为提高植物体内钾素水平提供理论依据。【方法】采用室内水培法,以模式植物烟草为试验材料,通过设置2个钾浓度(5、0.15 mmol/L)和5个外源生长素(3–吲哚乙酸)浓度(0、5、10、20、40μmol/L),对植物根系生理特征、内源生长素浓度、钾素累积及钾吸收动力学和相关钾离子通道基因转录表达进行比较研究。【结果】1)与正常钾水平相比,在低钾胁迫条件下,植株地上部干重显著降低15.6%;根系扫描8项指标中,除根平均直径外,其余7项指标值均显著降低;ATPase活性显著降低43.3%;主根尖、侧根尖及叶片内源生长素浓度显著升高;钾吸收动力学参数Vmax、Km值分别显著降低了89.2%、99.6%;植株根系、叶片钾浓度分别显著降低了93.0%、62.2%;根系中内流型钾离子通道基因Ntkc1的表达量显著降低56%。2)添加外源生长素后,正常供钾植株的根系干物质重、根系活力、主根尖及侧根尖内源生长素浓度有增加的趋势,Vmax值和内流型钾离子通道基因NKT2、NtKC1的表达量明显增加;低钾条件下,植株表现出和正常供钾相似的规律,除此之外,低钾植株的根系生长得到明显改善,ATPase活性和地上地下部钾素浓度明显增加,外流型钾离子通道基因Ntork1的表达量明显降低。3)当添加生长素浓度为10μmol/L时,与未添加生长素相比,正常供钾植株的地上地下部干重显著增加了6.05%、8.54%;根体积及根系交叠数显著增加16.5%、23.2%;根系活力显著增加了298%;Vmax值显著增加了118%;低钾植株地上地下部干重与不添加相比显著提高了5.61%、28.6%;根系活力达到113μg/(g·h), FW,为无添加生长素时的3.3倍;根系ATPase活性相对增加了87.5%;根系钾浓度显著增加250%;钾离子通道基因NKT2在根系中表达量显著增加了7.04倍,Ntork1在根系及叶片中表达量显著降低了49.5%、72.5%。【结论】低钾胁迫影响烟草根系生长及植株对钾素的吸收累积,添加适当浓度外源生长素可改善植株根系生长发育状况,增加内流型钾离子通道基因NKT2、NtKC1的表达量,降低外流型钾离子通道基因Ntork1的表达量,且提高植株钾吸收动力学参数Vmax值、降低Km值,从而提高了植株对钾离子的吸收能力与亲和力,进而增加植株钾素浓度。     

禾本科植物中不定根的发生发育研究进展

不定根是许多高等须根系植物中根系的主体,是植物固定在土壤中以及吸收利用养分和水分的重要器官,在禾本科植物中有着重要的意义.介绍了不定根的形态和生理特征以及发生发育过程,综述了近年来不定根发育方面的研究成果,总结了生长素信号及运输路径、乙烯和细胞分裂素对植物不定根发育的影响.     

百子莲生长素受体基因TIR1的全长cDNA克隆及功能分析

采用cDNA末端快速扩增(rapid amplification of cDNA ends,RACE)方法获得百子莲生长素受体TIR1基因cDNA全长序列,对该序列进行生物信息学分析的结果显示,TIR1基因的mRNA序列全长为2 235bp;5’非编码区296bp,3’非编码区172bp;该基因的ORF全长为1 764bp,编码一个含有588个氨基酸的蛋白。百子莲TIR1推导蛋白序列与葡萄(Vitis vinifera)、二穗短柄草(Brachypodium distachyon)、高粱(Sorghum bicolor),玉米(Zea mays)等植物均具有较高的同源性,同源性最高的是葡萄,可达78%。系统进化树表明,百子莲与葡萄距离最近。由α-螺旋,随机卷曲和延伸链组成一个磁状结构,为亲水蛋白,疏水性值为-0.092,在百子莲体细胞胚胎发生过程中,实时荧光定量PCR结果表明TIR1基因表达量在愈伤组织中含量最低,在胚性愈伤组织和体细胞胚胎中含量均有所升高,而在体胚幼苗中表达量最高,表明该基因介导的生长素信号在体细胞胚胎发生过程中发挥着非常重要的作用。     

生长素促进拟南芥AtNRT1.1基因表达增强硝酸盐吸收

为研究生长素信号对植物硝酸盐营养吸收的调控作用,采用扫描离子选择电极技术 (SIET) 和实时荧光定量 PCR 技术(qRT-PCR),测定拟南芥野生型Col-0、生长素过表达突变体yuc1-D以及生长素通路缺失突变体axr1-12 3种株系初始根中硝酸根离子(NO-3)吸收速率以及硝酸盐转运蛋白基因AtNRT1.1表达量的差异,并进一步检测Col-0株系以及硝酸盐转运蛋白突变体nrt1.1株系在正常条件(CK)或施加外源IAA及生长素极性运输抑制剂2,3,5 三碘苯甲酸(TIBA)处理下的NO-3流速和AtNRT1.1基因表达量的差异。结果表明:yuc1 D株系的NO-3吸收速率以及AtNRT1.1基因表达量相比野生型均有大幅增加,而axr1-12株系的 NO-3吸收速率以及AtNRT1.1基因表达量相比野生型显著降低;在Col-0株系中施加外源IAA对NO-3吸收速率以及AtNRT1.1基因表达量有明显促进作用,而施加TIBA的效果反之,说明生长素对硝酸盐吸收有增强效应。nrt1.1株系在CK、IAA、TIBA处理下NO-3吸收速率差异较野生型不明显,揭示了AtNRT1.1基因在生长素促进硝酸盐吸收途径中所起的重要作用。