Enzyme Solutions and H_2O_2 on Somatic Embryogenesis of Fraxinus mandshurica Rupr. (Oleaceae)

[Objective] This study aimed to explore the effects of treatments with three types of exogenous oxidase solutions and H2O2.solution on the somatic embryogenesis of Fraxinus mandshurica Rupr. （Oleaceae）. [Method] The immature zygotic cotyledons were treated with PPQ （polyphenol oxidase） solution, GQD （glucose oxidase） solution, SOD （superoxide dismutase） solution and H202 （hydrogen peroxide） at different concentrations to explore the effects on the growth, browning and somatic embryogenesis on cotyledon explants in the somatic embryogenesis of F. mandshurica. Through comparative analysis on the effects of different treatments on somatic embryogenesis of F. mandshurica, the relationship between explants browning and somatic embryogenesis was uncovered during the somatic embryogenesis of F. mandshurica. [Result] H2O2 treatment not only advanced the explants browning, but also inhibited the growth and somatic embryogenesis of explants; different concentrations of PPQ promoted the growth and browning of explants, as well as improving the incidence of somatic embryogenesis; both GOD and SOD treatment could raise the explants browning rate; when somatic embryogenesis of explants treated with enzyme solutions advanced, the incidence of somatic embryogenesis was low; however, when the disparity of the incidence of somatic embryogenesis between 30 and 60 d treatments reached its peak, the incidence of somatic embryogenesis was also high. [Conclusion] The results of this study provide basis for raising the incidence and improving the status of somatic embryogenesis of F. mandshurica, as well as optimizing the somatic embryogenesis system of F. mandshurica.

ENDOGENOUS INHIBITORS IN SEED OF FRAXINUS MANDSHURICA RUPR AND THEIR EFFECT ON GERMINATION AND REGENERATION

Bioassay and GC-MS determination indicated that inhibitors of seeds of Fraxinus mandshurica Rupr were distributed mainly in zones of β-inhibitors (including ABA) and of high and low Rf value. The inhibitory activity of outer seed coat of the dormant seed (control treatment) was higher than that of seeds with only the inner coat attached e.g. ABA was 114 and 54ng/g fresh weight respectively. The inhibitory effect of No. 12 zone was even higher than ABA. The inhibitory activity of all the zones decreased after stratification (St) and burying (AO) treatment, especially that of the outer seed coat, whose ABA content decreased to 7(St) and 11(AO) ng / g(fw). However, the decrease in inhibition of root growth lagged bchind'thc decrease in germination. It is concluded that burial is advantageous to regeneration. Inhibitors of the outer seed coat and seeds were mostly destroyed under the adverse conditions of natural dissemination (Di treatment) indicating that Di was not conducive to regeneration. MS analysis revealed that the largest peaks of No. 6, 7 and 12 zones were linoleic acid, olcic acid and 17-C, 18-C, and 20-C long chain fatty acids. Several coumarins were found in No. 6 and 7 zones, and cadincncs, farncsol and scsquitcrpcncs were found in No. 6 and 12 zones having common bioorigins with ABA.

Regulation of applied-hormones on tension wood formation in Fraxinus mandshurica Rupr. var.japonica Maxim. seedlings gravitational response

We investigated the role of GA3, uniconazole-P and IAA on tension wood formation, in particular the vessel features, in Fraxinu smandshurica seedlings. Ninety seedlings were used and treated with applications of GA3 and/or IAA to the apical bud of the stem using a micropipette. Applications of GA3 or GA3 plus IAA with uniconazole-P strongly increased cell number of tension wood in comparison to that of no-uniconazole-P-applied, indicated that GA3 is more efficient than IAA on xylem cell production. Wood quality was also regulated by relative concentration ratio of GA3 to lAA, because of the vessel elements differentiation, density and size were controlled by GA3 and/or IAA on the different levels. These results suggested that the relative concentration ratio of GA3 to IAA and interactions of them are essential in regulating both wood quality and wood quantity, and tension wood formation in this species.

Spatial distribution of fine roots of larch and ash in the mixed plantation stand

The spatial distribution of standing fine roots in tree rows of different species in a 12-year-old mixed stand of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) was studied by soil core sampling in early spring, 2001. It is found that ash and larch differ greatly in their belowground biomass distribution. Ash has much higher fine root biomass density in the soil than larch at stand level (with the max value of 4442.3 vs. 2234.9 gm-3). Both tree species deployed more fine roots in their neighboring zone, suggesting a less intensive competition between roots of the two species. Both fine root biomass density and root length density of ash in the zone between larch tree rows are greater than that of larch in zone between ash tree rows, indicating that ash is more powerful than larch in belowground competition. The spatial distribution feature of roots favors the growth of ash in the mixed stand.

水曲柳FmMYB转录因子生物信息学及表达模式分析

MYB蛋白广泛存在于植物中,参与植物生长发育等多种代谢途径。前期研究获得2个FmMYB转录因子cDNA全长序列(FmMYB2和FmMYB20),已上传至NCBI并获得登录号(KT261341和KT261342)。为揭示FmMYB转录因子功能,对这两个MYB转录因子的结构特征、生化特性进行分析,利用实时荧光定量PCR,对FmMYB2和FmMYB20的时空表达模式以及施加应力后的转录水平进行分析。结果表明:FmMYB转录因子的时空表达模式有所差异,FmMYB2基因在7月相对表达量最高,约为最低值5月的60倍;然而在8月,FmMYB20基因的相对表达量最高,约为最低值5月的5倍;同时在叶、木质部、皮3个部位中,FmMYB2和FmMYB20基因在木质部中表达量最高。FmMYB2与FmMYB20基因均对应拉处理有响应,FmMYB20与木质素合成相关基因4CL表达模式相似。研究结果初步说明FmMYB2和FmMYB20可能参与木质素的合成。

Phosphate Availability Alters Lateral Root Anatomy and Root Architecture of Fraxinus mandshurica Rupr. Seedlings

Abstract: Plants have evolved some mechanisms to maximize the efficiency of phosphorus acquisition. Changes in root architecture are one such mechanism. When Fraxinus mandshurica Rupr. seedlings were grown under conditions of low phosphorus availability, the length of cells in the meristem zone of the lateral roots was longer, but the length of cells in the elongation and mature zones of the lateral roots was shorter, compared with seedlings grown under conditions of high phosphorus availability. The elongation rates of primary roots increased as phosphorus availability increased, but the elongation rates of the branched zones of the primary roots decreased. The number of lateral root primordia and the length of the lateral roots decreased as phosphorus availability increased. The topological index (altitude slope) decreased as phosphorus availability increased, suggesting that root architecture tended to be herringbone-like when seedlings were grown under conditions of low phosphate availability. Herringbone-like root systems exploit nutrients more efficiently, but they have higher construction costs than root systems with a branching pattern.

黑龙江省东部地区水曲柳天然林水源涵养功能

对黑龙江省东部地区水曲柳天然林林下灌草层、枯枝落叶层、土壤水分物理性质以及土壤渗透性能的研究表明 :林下灌草层的存在显著增强了林分对水分的调蓄能力 ,最大持水量为 5 .4 2～ 11.2 8t·hm-2 。枯落物的持水量较低 ,仅为 12 .0 0～ 13.0 0t·hm-2 。水曲柳林土壤最大蓄水量为 3344 .0 0～ 345 5 .94t·hm-2 ,有效蓄水量为319.16～ 4 0 0 .6 5t·hm-2 。林地土壤的初渗、稳渗速度以及达到稳渗的时间都较荒地有明显的不同。综合分析表明 ,水曲柳天然林具有显著的水源涵养效益 ,对于保证该地区水资源的可持续利用具有重要意义。

利用正交设计优化水曲柳ISSR-PCR反应体系

利用正交设计L16(45)对水曲柳ISSR-PCR反应体系的5因素(Taq酶,Mg2+,模板DNA,dNTP,引物)在4个水平上进行优化试验,PCR结果用统计软件MINITAB分析:①各因素的不同水平对PCR反应结果都有显著的影响,其中Taq酶量影响最大;②筛选出各反应因素的最佳水平,建立水曲柳ISSR-PCR反应的最佳体系(20滋l)为:Taq酶1.0U,Mg2+2.0mmol/L,模板DNA50￣200ng,dNTP0.15mmol/L,引物0.3滋mol/L。最后,对水曲柳ISSR-PCR最佳反应体系进行梯度退火,得到最佳退火温度为58.3℃。这一优化系统的建立为今后利用ISSR标记技术,研究水曲柳的地理变异提供一个标准化程序。

东北三大硬阔的阻火性能

采用锥形量热仪对黑龙江省主要阔叶树种三大硬阔(水曲柳Fraxinus mandshurica Rupr.,黄波罗Phellodendron amurense Rupr.,胡桃楸Juglans mandshurica Maxim.)的燃烧性进行了系统的测定,通过对3个树种树皮和叶的试样在燃烧时的热释放、质量变化及烟气产生等试验数据的综合对比分析,比较了各树种的抗火能力。结果表明:水曲柳和胡桃楸树皮抗火能力较强,胡桃楸叶抗火能力最强。综合树皮和叶得到3个树种抗火强弱的排序为:胡桃楸>水曲柳>黄波罗。

水曲柳种子主要天然发芽抑制物的鉴定及生物化学研究

休眠水曲柳种子TLC主要抑制区段的生测和GC-MS鉴定表明,在No.7和No.6区段分别发现了来源于莽草酸代谢的6,7-二甲氧基香豆素和3,4,7-三甲氧基香豆素,同未甲酯化比较,前者可能是抑制萌发的东莨菪内酯。在No.6和No.7区段还存在三甲基脲和9-甲基,9-氢芴,其分别与可打破休眠的硫脲和整形素——一种生长延缓剂有基本相似的结构。高Rf值No.12区段检测到许多单萜及倍半萜,单萜中有抑制发芽的香芹醇,这些萜类与ABA具有共同的生源——金合欢醇·三区段的最大主峰是在各区段以不同形式存在的亚油酸,其它有油酸和17-C,18-C和20-C等长链脂肪酸。简单讨论了上述化合物和休眠散发过程的可能相关。

水曲柳人工林直径生长与培育技术

以帽儿山地区20年生水曲柳人工林为研究对象,研究了林木直径生长与立地选择、施氮肥、落叶松混交和林下清除灌木抚育,以及大气温度的关系。结果表明,坡位和混交对林木直径生长有显著影响,坡下大径木(R>10cm)所占的比例均高于坡中和坡上,且与落叶松混交林中的水曲柳大径木比例(28%)也高于纯林(19%);施氮肥和清除林下灌木对水曲柳直径生长影响不明显,这可能与土壤肥力、林木养分需求特性,以及清除林下灌木的处理时间有关;直径的生长与生长季内日最低和最高温度差值存在一定程度的负相关。

温度对经层积处理解除休眠的水曲柳种子萌发的影响

经层积处理解除休眠的水曲柳种子于10种不同温度条件下萌发的结果表明:变温条件下的种子萌发比恒温条件的好,最佳的变温条件为15℃/10℃,最佳的恒温条件是10℃,20℃以上的恒温会诱导种子产生二次休眠。

水曲柳大小孢子发生、雌雄配子体发育及其系统学意义

通过石蜡切片对水曲柳孢母细胞减数分裂和雌雄配子体发育过程进行观察,揭示大、小孢子发生和雌、雄配子体发育的解剖学特征,并通过与相关类群的胚胎学特征比较探讨其系统学意义.结果表明:水曲柳花药4室,药壁发育属双子叶型,腺质绒毡层,小孢子母细胞减数分裂为同时型,成熟花粉为2细胞型.子房2室,每室2个倒生胚珠,具单珠被,薄珠心.大孢子母细胞减数分裂形成的4个大孢子呈直线形排列,其中合点端的大孢子具备继续发育的功能.蓼型胚囊.其雄蕊先熟,散粉时,雌配子体还未发育成熟,处于大孢子母细胞减数分裂阶段.从目前雌、雄配子体形成和发育的资料来看,木犀科的胚胎学特征与玄参目较为接近,与龙胆目系统学关系较远,并就它们的胚胎学特征的系统学意义进行了讨论.

长白落叶松水曲柳混交林增产机理的研究(Ⅱ)——落叶松水曲柳混交林生理特性的研究

研究了长白落叶松、水曲柳混交林(简称混交林)及纯林中长白落叶松(简称落叶松)的净光合速率、呼吸速率和蒸腾速率及其日进程、叶绿素,有机物和矿质元素的含量等。结果表明、混交林中落叶松树冠东、南、西、北四个方向的平均净光合速率和呼吸速率都太子落叶松纯林,在一天中的不同时刻观测值也是如此。混交林中落叶松的呼吸效率(净光合速率/呼吸速率)大于落叶松纯林,前者是2.11,后者是1.59,说明混交林中落叶松的高呼吸速率对其代谢及生长是有利的。混交林宁落叶松的蒸腾速率低于落叶松纯林,水分利用率却高于落叶松纯林。混交林中落叶松的叶绿素含量高,a/b 比低,这与其净光合速率高相关。混交林中落叶松的蛋白质及 N、K、Ca、Mg、Zn 含量高于落叶松纯林。提出了混交林生态环境的改善促进了树木的生理过程,最终导致生长加快的增产机制。

赤霉素对三种白蜡种子发芽率的影响

在不同温度条件下,利用不同浓度的赤霉素对大叶白蜡、绒毛白蜡和水曲柳的种子进行药剂催芽试验,浸种时间均为48 h,分别以经过层积处理60 d的种子作为对照。结果表明,用适宜浓度的赤霉素处理后,在20℃-30℃的变温条件下,可以显著提高大叶白蜡和绒毛白蜡种子的发芽率。催芽大叶白蜡的最佳处理组合为200 mg/L,平均发芽率为71%,催芽绒毛白蜡最佳处理组合为300 mg/L（20℃-30℃）,平均发芽率为73%,发芽率均接近各自的对照,催芽效果十分显著。水曲柳具有相对深的休眠特性,单纯赤霉素处理不能有效打破水曲柳种子的休眠。

长白落叶松水曲柳混交林增产机理的研究(Ⅰ)——落叶松水曲柳混交林生态条件的研究

比较研究了落叶松水曲柳混交林及落叶松,水曲柳纯林的土壤含水量、土壤温度、土壤 pH 值、土壤全量矿质元素含量和树冠中各部位温度、照度和湿度等。结果表明,不同林分的土壤条件不同,同一林分不同土层的土壤条件也不同。混交林的各层土壤含水量、土壤温度、土壤 pH 值均高于纯林;随土壤深度的增加、各林分的土壤含水量、土壤温度、土壤 pH 值降低。与纯林相比,混交林土壤 N、P 含量较高,Cu、Zn、Mn、Ca、Mg、Fe、K 含量较低。不同林分的地上部生态条件也不相同,与落叶松纯林相比,混交林改善了林内的生态条件,使气温降低,湿度升高。这恰好有利于树木的生长。可以看出,落叶松水曲柳混交林的增产机制与其对生态条件的改善有关。

坡向和坡位对水曲柳中龄林生长的影响

为了评价地形因子对水曲柳中龄林生长的作用,以帽儿山地区水曲柳(Fraxinus mandshurica Rupr.)中龄人工纯林为对象,研究了坡向和坡位对林木胸径、优势木高以及地上和地下生物量分配的影响。结果表明,坡向对林分平均胸径和优势木高的影响要大于坡位,且坡向对优势木平均高有显著的影响(P<0.05)。综合比较,西向坡林分生长状况好于东向坡,而且坡下与坡上林分生长状况的相对优劣,受到坡向的影响。林分总生物量和地上、地下各组分,均以西向坡高于东向坡。林木个体的径级分布,对林分水平上的生物量分配格局有重要影响。虽然幼龄阶段水曲柳林分在阴坡下坡位生长不良,但在中龄林时期生长较好。这些结果表明坡向和坡位等立地因子对水曲柳林木生长的重要影响,同时也表明了林分生长与立地条件之间的关系也会随林龄而发生变化。

黑龙江椴树属植物叶表皮形态学观察

利用扫描电子显微镜对紫椴(Tilia amurensis Rupr.)及糠椴(T.mandshurica Rupr.et Maxim.)叶片的微观形态结构特征进行观察,并进行微观形态结构的比较研究。研究结果表明紫椴与糠椴叶片上表皮微观形态相同,而下表皮气孔器的形态类型、蜡质纹饰和角质膜的形态特征、单位面积上星状毛的数量均表现出很大的差异。这些微观形态差异可作为区分紫椴和糠椴的分类学依据。

长白落叶松和樟子松等五种树种抗旱性的比较

为研究树木的抗旱机制，文中对长白落叶松、樟子松、红皮云杉、油松和水曲柳的抗旱性进行了探讨。结果表明，自然失水不同时期，各树种的水分参数不同，其变化速率也不同。各时期均以水曲柳和落叶松失水速率最大，红皮云杉次之，樟子松和油松失水速率最小；与之相关的各树种其它水分参数变化由快到慢的顺序也如此。落叶松和水曲柳的质膜相对透性较小，樟子松和红皮云杉较大，油松质膜相对透性居中；脱水对各树种叶绿素代谢的影响由强到弱依次为水曲柳、红皮云杉／油松、樟子松和落叶松。落叶松与樟子松的抗旱机制不同，落叶松属于忍耐脱水耐旱树种，而樟子松属于延迟脱水耐旱树种，水曲柳与落叶松相似，油松与樟子松相似，红皮云杉抗旱机制属中间类型。

水曲柳种子次生休眠的预防和解除

以解除休眠和经高温诱导产生次生休眠的水曲柳种子为材料,探讨预防和解除水曲柳种子次生休眠的方法。结果表明:GA_3和乙烯利不能阻止已解除休眠水曲柳种子在25℃下萌发时诱导的次生休眠。干燥和短时间低温解除水曲柳种子次生休眠的效果不明显,较长时间(大于2周)的低温对解除水曲柳种子的次生休眠有一定的效果。综合来看,10^(-3)mol·L^(-1)的乙烯利或GA_(4+7)解除水曲柳种子次生休眠的效果较好。