入侵植物加拿大一枝黄花对小麦光合生理的影响

本研究以入侵植物加拿大一枝黄花和土著植物一枝黄花为供体材料,并以小麦为受体植物,分析两种供体的浸提培养液对小麦叶片光合生理的影响。结果表明加拿大一枝黄花和对照一枝黄花的浸提培养液中麦苗叶片总叶绿素含量下降,叶绿素a荧光诱导动力学参数改变,光系统Ⅱ活性受抑制,光合作用效率降低,其中具化感作用潜力的加拿大一枝黄花浸提培养液对小麦叶片光合生理抑制的程度较一枝黄花大。     

加拿大一枝黄花对土壤微生物区系的影响研究

以外来入侵杂草加拿大一枝黄花和土著种一枝黄花为研究材料，检测了这两种植物的根部土壤中微生物区系和微生物生理类群的变化。结果表明，具化感作用潜力的加拿大一枝黄花明显影响了土壤中根部微生物群落多样性。具体表现在加拿大一枝黄花根部土壤中的真菌数量低于对照土，而细菌和放线菌的数量则有增多。土著种一枝黄花对根部土壤中微生物的生长均为抑制效应。进一步分析显示，加拿大一枝黄花的根系分泌物对土壤的亚硝酸细菌、好气性自生固氮菌、硫化细菌、氨化细菌和好气性纤维素分解菌的数量具有促进作用，而对反硝化细菌、嫌气性纤维素分解菌和反硫化细菌的生长有抑制效应。据此，文中还探讨了影响外来入侵植物扩散力的生态机制。     

取食加拿大一枝黄花的白条银纹夜蛾生物学特性及食性研究

中国首次发现白条银纹夜蛾（Argyrogramma albostriata Bremeret Grey）幼虫大量取食加拿大一枝黄花（Solidago canadensis）,本研究重点为确定该虫寄主范围。野外采集该虫幼虫,试验室饲养、观察与鉴定,确定其生活史;调查发现地以及合肥其他加拿大一枝黄花分布区的植物,并饲喂其6科13种代表植物,进行寄主专一性研究。人工饲喂该虫加拿大一枝黄花,该虫可单独依赖其正常完成生活史,新一代幼虫也能继续取食;调查及食性研究表明,合肥地区该虫的寄主植物全为菊科植物,分别为：马兰（Kalimeris indica）、小飞蓬（Conyza canadesis）、一年蓬（Erigeron annuus）、钻叶紫菀（Aster subulatus）、加拿大一枝黄花;以上5种植物同时存在时,该虫优先取食加拿大一枝黄花。加拿大一枝黄花已成为该虫寄主的稳定组成部分;该虫在本地原寄主均为杂草,其食性条件有利于加拿大一枝黄花的防治。     

加拿大一枝黄花水浸提液对3种植物种子萌发的影响

加拿大一枝黄花（Solidago canadenis L.）是一种外来入侵恶性杂草，研究加拿大一枝黄花的化感作用，有助于了解该植物对其他植物的抑制作用，并对农业生产具有重要的指导意义。该研究采用不同浓度的加拿大一枝黄花地上部分的水浸提液，对3种植物[早熟禾（Poa annua L.）、圆白苋菜（Basella rubra L.）和青王子（Brassia campestris L）]进行了种子萌发处理实验，分别测定了不同植物种子的萌发速率，终萌发率和种子萌发趋势。结果表明：（1）加拿大一枝黄花地上部分的化感作用是存在的；（2）高浓度的加拿大一枝黄花水浸提液对3种植物种子的萌发特性（终萌发率、发芽速率和发芽动态）均有明显的抑制作用，其中Poa annua和Brassia campestris受到的影响比Basella rubra较为明显。通过加拿大一枝黄花地上部分水浸提液处理3种植物种子的实验，初步揭示了该植物的化学入侵机制。     

假色槭种子透水性及内源抑制物质的初步研究

为研究假色槭种子透水性及种子不同部位甲醇浸提液生物活性,初步探讨假色槭种子休眠原因,比较了假色槭完整种子和剪裂种皮种子的吸水率,测定了种子各部位浸提液对小麦种子萌发及幼苗生长的抑制强度。结果表明,种皮透水性良好,对假色槭种子休眠影响较小。假色槭种子的果皮、种皮、胚浸提液处理后,对小麦种子发芽率影响较小,但却严重影响了小麦苗高、苗鲜重、根长、根鲜重的生长,降低了叶绿素含量、淀粉酶活性,抑制了小麦种子对自身淀粉和可溶性糖的吸收利用,而且随着各部位浸提液浓度比例的不断提升,其抑制活性也表现得愈加强烈。在各部位浸提液浓度比例相同的情况下,胚浸提液对小麦种子发芽率、苗高、苗鲜重、根长、根鲜重的生长以及各项生理指标的抑制影响强于种皮和果皮。说明假色槭种子果皮透水性不是其休眠的主要原因,种子各部位存在发芽抑制成分,尤其是胚的抑制活性最强可能是其休眠期较长、不易发芽的主要原因。     

H_2S处理下对小麦根蛋白质组表达谱分析的研究

小麦是人类的主要粮食作物之一。硫化氢(H2S)被认为是细胞内第3种气体信号分子,关于H2S对植物的调控机理的研究越来越多,主要集中在参与植物形态建成,调节生理生化活动,应答非生物胁迫,应答生物胁迫4个方面,但外源H2S对小麦根系生理生化及蛋白质表达调控作用机制的研究鲜有少见,研究其具有重要意义。采用硫氢化钠作为硫化氢的外源性供体,研究不同浓度硫氢化钠(0,0.05,0.10,0.20,0.40,0.80,1.60,3.20 mmol/L)对小麦根蛋白质差异表达谱的影响,以探寻H2S对小麦幼苗生长发育的机制。通过对小麦根部的比较蛋白质组学分析发现,不同浓度的硫氢化钠处理引起了涉及光合作用、糖代谢和能量代谢、氧化还原平衡、蛋白质合成、加工与降解,以及信号转导等途径的蛋白质的差异表达。初步推测,硫化氢可能通过调节参与上述代谢途径的功能蛋白质的表达量,进而相应地影响到植株生理与生物量等指标,从而引起植株表型的变化。     

刺槐、木荷水浸液对马尾松幼苗生理活性的化感效应

用枯落物浸提液生物鉴定的方法,研究了刺槐、木荷对马尾松幼苗生理活性的化感影响。结果表明,两供体植物对受体光合色素含量和质膜相对透性的影响,总体表现为促进作用;对受体光合速率和蒸腾速率的影响,表现为抑制效应。供体木荷对氮、磷吸收的影响表现出低促高抑的作用趋势,对钾元素的吸收,均表现出一定的促进效应;而供体刺槐对氮、钾吸收的影响,则表现出高促低抑的作用趋势,对磷吸收的影响则相反。     

绍兴"通缉""加拿大一枝黄花"

它有一个美丽的名字——“加拿大一枝黄花”,它有一种歹毒的秉性——能迅速导致其他植物灭亡,带来严重的生态失衡。日前,这种曾经一度被当作观赏植物的“加拿大一枝黄花”成为绍兴县紧急“通缉”的对象。绍兴县政府日前召开专题工作会议,要求各镇、街道紧急搜查,及时清除这一有害植物。据了解,“加拿大一枝黄花”原产北美,为多年生的根茎植物。据记载,1935年作为观赏植物引进“落户”上海、南京一带, 80年代扩散蔓延成为河滩、荒地、道路两侧、农田旁边、平原城镇住宅旁甚至绿化地带的杂草。“加拿大一枝黄花”在上海蔓延后,在近20年来导致…     

赤霉素提高烤烟种子活力的研究

以烤烟种子为材料,研究外源赤霉素对种子发芽势、发芽率、生理生化活性、种子浸提液的电导率、烟苗干鲜重等方面的影响。结果表明,烤烟种子经过赤霉素浸种处理后,种子发芽指数和活力指数提高,种子TTC还原力增强,POD酶活性提高,种子浸提液的电导率降低,烟苗高度增长,干物质积累增多,种子活力显著高于对照,且最佳处理浓度为300～500mg／L。     

葫芦科植物单倍体离体诱导研究进展

重点对葫芦科植物离体诱导单倍体的研究进行综述,包括花药培养、离体雌核培养、辐射花粉诱导单倍体培养等在育种中的应用,以及供体基因型、培养基、预处理方式、胚囊发育时期等因素对离体诱导再生频率的影响。关于离体培养发育机制的生理生化研究主要集中在离体雌核发育的形态及细胞学过程以及培养早期生理、生化的变化研究。同时总结了葫芦科植物DH育种研究进展,指出葫芦科植物离体诱导单倍体研究中存在的问题并提出思路和建议     

Herbicidal Potential and Quantification of Suspected Allelochemicals from Four Grass Crop Extracts

Unknown compounds in crop plants are inhibitory to seed germination and early seedling growth of weed plants. A Petri dish assay showed that barley (Hordeum vulgare L.), oats (Avena sativa L.), rice (Oryza sativa L.) and wheat (Triticum aestivum L.) extracts significantly reduced root growth of alfalfa (Medicago sativa L.), barnyard grass (Echinochloa crus‐galli, Beauv. var. oryzicola Ohwi.) and eclipta (Eclipta prostrata L.). As the concentration of crop extracts increased, root growth of the test plants were significantly reduced. A high‐performance liquid chromatography analysis with nine standard phenolic compounds showed that the concentrations and compositions of allelopathic compounds depend on the extracted plant extracts. Caffeic acid, hydro‐cinnamic acid, ferulic acid, m‐coumaric acid, p‐coumaric acid and coumarin were present in all the crop plant species, and hydro‐cinnamic acid were detected as the highest amount. Coumarin at 10^?3 m significantly inhibited root growth of alfalfa and barnyard grass more than that of eclipta. The research suggests that extracts of barley, oats, rice and wheat have an allelopathic effect on alfalfa, barnyard grass and eclipta and that the findings of bioassay were considerably correlated with the type and amount of causative allelochemicals, indicating that the allelopathic effects on three test plants were ranked in order of wheat (highest), barley, rice and oats (lowest). The results may have value in enabling weed control based on natural plant extracts or crop residues in the fields.     

入侵植物马缨丹叶片挥发物的化感作用

采用室内模拟试验,研究入侵植物马缨丹叶片挥发物对伴生入侵种三叶鬼针草、伴生土著种鬼针草,以及萝卜、生菜2种农作物种子萌发和幼苗生长的影响。结果表明：马缨丹叶片挥发物能够抑制4种受试植物的种子萌发和幼苗生长,不同浓度的马缨丹叶片挥发物均显著降低了4种植物的萌发势、萌发率、苗高和根长,且随着挥发物浓度的增加,其抑制作用不断增强。但同一浓度的马缨丹叶片挥发物对4种植物的化感抑制程度不同,其对土著植物鬼针草以及萝卜、生菜2种农作物的化感抑制作用较强,而对伴生入侵种三叶鬼针草的化感抑制效应较弱。     

Aluminium tolerance in wheat: correlating hydroponic evaluations with field and soil performances*

The objective of this study was to correlate root length of wheat (Triticum aestivum L.) genotypes grown in Al-containing, acidic hydroponic solutions, with root weights from acid-soil experiments and field scores from Brazilian acid-field trials. A total of 43 wheat genotypes, primarily from Brazil, were evaluated by growing seedlings for 4 days in hydroponic solutions containing 0.0–4.0 mg/l Al. The root growth rate of all the genotypes was reduced with the addition of Al to the solution and the Al-sensitive and Al-tolerant wheat genotypes were clearly identified. Genotypes with intermediate Al-tolerance levels showed variable root lengths in response to Al stress. Correlations between root length or a root tolerance index (RTI) in the Al solutions versus acid-soil experiments and acid-field trials were highly significant (r = 0.71–0.85, P < 0.01). The most significant correlation was observed among seedlings grown in 1 mg/1 Al. This study presents evidence that this short duration and simple screening technique provides a highly significant correlation with previous acid-soil Al-tolerance evaluations. Furthermore, the data obtained suggest that hydroponic screening of wheat seedlings for Al tolerance may be used in breeding programmes or in screening germplasm collections.     

DROUGHT STRESS: Soil Water Availability Alters the Inter‐ and Intra‐Cultivar Competition of Three Spring Wheat Cultivars Bred in Different Eras

Competition for water generates a classic aspect of the tragedy of the commons, the ‘race for fish’, where crops must allocate more resource to acquisition of the limiting resource than is optimal for crop yield allocation. A pot experiment using a simple additive (target–neighbour) design was conducted to examine the above‐ground and below‐ground growth of three spring wheat (Triticum aestivum L.) cultivars when grown alone and in mixtures at three levels of water availability. The effects of competition and water availability were compared by observing patterns of growth, biomass allocation and below‐ground outcomes. Competitive interactions were investigated among cultivars ‘HST’, ‘GY602’ and ‘LC8275’, target plant of each cultivar grown without neighbouring plants are referred to herein as control plant and one target plant of each cultivar sown surrounded either by same or another cultivar as intra‐ or inter‐cultivar competition. Competitive ability was assessed as the response ratio (lnRR) between the target plant surrounded by six other plants and the target plant in isolation. Our results showed that the cultivar ‘HST’, released over a century ago, produced a higher biomass and grain yield than the more recently released cultivars ‘LC8275’ and ‘GY602’ when grown as isolated plants with sufficient water supply. However, competition for resources from neighbours led to target plant biomass and grain yield being significantly reduced relative to controls in all three cultivars, particularly in ‘HST’. When subjected to intra‐cultivar competition, the two recently released cultivars ‘LC8275’ and ‘GY602’ had higher grain yields and water use efficiency for grain than ‘HST’ in all three water regimes. The landrace ‘HST’ had better and significantly linear relationships between biomass and biomass allocation, root length and specific root length, whereas the recent and modern cultivars had much more water‐related species‐specific changes in root morphology and allocation patterns. These results suggest that crop traits that influence competitive ability, such as biomass allocation to roots and root plasticity in response to drought have changed in modern wheat cultivars because of breeding and selection.     

剪根与水分胁迫对小麦单根和细胞导水率及TaPIP基因表达的影响

剪去小麦部分根系能瞬间打破其水分平衡,研究根系导水特性对剪根的响应有助于解释静水压对作物根系吸水的调节机制。通过对苗期小麦(Triticum aestivum)剪根与水分胁迫处理,用压力探针技术测定单根和细胞两种尺度上的根导水特性变化,以及根中TaPIP1;2和TaPIP2;5的转录调节变化。结果显示,剪根处理或水分胁迫处理使叶片蒸腾速率和气孔导度均显著低于对照,而单根导水率和细胞导水率均与对照无显著差异。剪根处理的叶片蒸腾速率、气孔导度、叶水势、单根导水率和细胞导水率均显著高于水分胁迫处理,而剪根且水分胁迫处理的各参数均显著低于其他处理。各处理的单根导水率与细胞导水率显著正相关。各处理根中TaPIP1;2和TaPIP2;5相对mRNA含量的变化规律与单根和细胞导水率的变化规律相似。剪根处理显著上调了TaPIP1;2和TaPIP2;5转录,水分胁迫处理显著下调了其转录,但TaPIP1;2和TaPIP2;5在剪根且水分胁迫处理中的转录水平最低。这些结果表明,小麦的根导水特性在单根尺度和细胞尺度上具有一致性;剪根短期内能够增加小麦幼苗的水分敏感性。推测TaPIP1;2和TaPIP2;5参与了静水压对小麦根导水特性的调节过程。     

Assessing Allelopathic Index for Estimating Allelopathic potential of Ajowan Extracts

Allelopathy is a procedure in which secondary metabolites are produced by plants. Some plants may beneficially or antagonistically affect other plants through allelochemical compounds which may be released directly or indirectly from live or dead parts and cause allelopathic and phytotoxic effects. The aim of the present study was to investigate the allelopathic possibility of ajowan (Carum copticum) extracts in different concentrations on morphological indices (germination and growth) of wheat (Triticum sativum), barley (Hurdeum vulgare), corn (Zea maize S.C 704), and safflower (Carthamus tinctorius L.) seedlings as proceeding crops and to develop a comprehensive formula for measuring the negative and positive effects of allelochemicals on growth indices such as shoot and root length, as well as the germination percentage on donor plants. It was demonstrated that increasing concentrations of ajowan extracts significantly decreased the Allelopathic Index, percent of germination, and other growth related indices of all seedlings. Based on the proposed Allelopathic Index of experimental plants, it was revealed that ajowan has posed a higher risk to corn and barley especially at the early stages of the growing cycle, while safflower and wheat indicated more tolerance to growth inhibition effects of ajowan in rotational sequence.