为探讨北京平原不同人工林叶片、凋落物以及土壤的碳(C)、氮(N)和磷(P)化学计量特征及其差异,进一步了解北京平原造林工程实施7年人工林生态系统的养分供求现状,选取北京大兴区永定河边造林区4种不同人工林:人工刺槐林(Robinia pseudoacacia)、油松林(Pinus tabuliformis)、千头椿林(Ailanthus altissima)、旱柳林(Salix matsudana)为实验样地,在每个样地内随机选取3个20 m×30 m实验样方,在每个样方内,按照"S"形布点法进行5点采样,采集叶片、凋落物和土壤样品,土壤采集0—10、10—20 cm土壤样品,分析其碳(C)、氮(N)和磷(P)含量,并计算其化学计量比.研究结果表明:油松林和旱柳林叶片的C含量显著高于刺槐林和千头椿林.叶片和凋落物N含量呈现刺槐林>千头椿林>旱柳林>油松林的变化,叶片P含量为千头椿林最大,油松林最小;凋落物C?P和C?N均表现为油松林>旱柳林>千头椿林>刺槐林,且两两间差异显著;人工林土壤C和N含量以及C?P和C?N均表现为刺槐林最高,土壤N?P值呈现出油松林最高,显著性差异主要集中在土壤表层(0—10 cm);枯落物与土壤的化学计量比无显著相关性;刺槐林不同组分中N?P均为最高,其中叶片和凋落物N?P均显著高于土壤,刺槐、千头椿和油松凋落物C?N、C?P均大于叶片.该研究揭示了刺槐、油松和旱柳人工林的生长受到"磷限制",而千头椿生长受到"氮限制",建议在北京平原林人工林经营管理时应考虑减少除草割灌,并适当增加凋落物有利于C、N的积累,以促进人工林土壤质量的提升.

[目的]土壤重金属污染日益严重,重金属对植物的影响备受关注.目前,研究多限于重金属单一胁迫对植物的影响,但土壤重金属污染存在形式并不是只有一种重金属,而是由多种重金属复合而成,研究重金属单一胁迫与复合胁迫对植物生长及光合作用的影响与差异很有必要.[方法]本研究以桑树幼苗为实验材料,通过添加不同质量分数的Pb2+和Cd2+进行桑树幼苗土培实验,分析单一胁迫与复合胁迫对桑树幼苗生长指标、光合色素含量和光合作用指标的影响与差异.[结果]Pb2+单一胁迫降低了桑树叶绿素含量和类胡萝卜素含量,Cd2+单一胁迫对叶绿素含量是"低促高抑",对类胡萝卜素而是随Cd2+含量的增加抑制作用增强.复合胁迫对桑树光合色素含量起到抑制作用,且程度强于单一胁迫.桑树叶片的光饱和点(LSP)、最大净光合速率(Pnmax)、暗呼吸速率(Rd)及表观量子效率(φ)均受到重金属胁迫的抑制作用,且随含量增大,抑制作用增强.单一胁迫和复合胁迫对桑树叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)以及蒸腾速率(Tr)均起到抑制作用,从而显著地限制了桑树的生长.[结论]重金属单一胁迫及复合胁迫对桑树幼苗的生长指标、光合色素含量以及光合作用均有抑制作用,且重金属含量越高,桑树幼苗受到的抑制作用越强,复合胁迫对桑树幼苗的抑制作用存在协同效应,毒害程度强于单一胁迫;在重金属胁迫条件下,桑树表现出了较强的耐重金属性.

利用SSR分子标记对不同派别的48个杨树无性系进行遗传分析,计算不同无性系间的遗传距离.结果表明:16对引物共检测到81个多态性位点(从100～600 bp),不同无性系间的分子遗传距离在0.061 7 ～0.5309,平均距离为0.250 4.派内种间遗传距离平均值变化范围为0.148 2 ～0.274 1,派间遗传距离平均值变化范围为0.330 2～0.401 2.聚类分析结果表明在聚类分析自检举值为0.70时,可以清晰的将48个无性系分成白杨派(Leuce)、黑杨派(Aigeiros)、青杨派(Tacamahaca)、大叶杨派(Leucoides)和胡杨派(Turanga)等5类.本研究利用分子手段检测不同派别杨树的遗传距离,为杨树杂交育种、分子育种等提供理论依据.

以金丝楸优系苗木温室催芽的半木质化芽苗为材料,研究了IBA与NAA处理下扦插生根过程中可溶性糖和可溶性蛋白质2种营养物质的动态变化,分析了其变化规律与生根的关系.结果表明,金丝楸嫩芽扦插生根过程分为3个阶段.营养物质动态变化与金丝楸生根进程密切相关,嫩芽经外源激素处理促进了其营养物质动态转换,有助于金丝楸不定根的形成.

以10个转TaLEA小黑杨无性系和1个对照无性系为材料,对无性系苗期苗高和地径生长过程进行测定并构建Logistic模型,探讨不同无性系苗期生长过程的变异情况.结果表明:转基因小黑杨无性系苗高和地径生长过程高度符合“S”型曲线,所有Logistic模型拟合系数超过0.9,表明拟合效果显著.方差分析结果表明不同无性系苗高和地径间差异均达到极显著水平(P＜0.01).参试无性系苗高平均速生期持续期为48天,速生期内平均生长量为1.85 cm,地径平均速生期持续时间为70天,速生期内平均生长量为0.09 mm.苗高、地径均与速生期内生长量、速生期内平均日生长量间呈极显著正相关.转基因无性系XL-1和XL-9苗期生长较快,苗高(地径)分别比对照高16.37％ (32.82％)和10.92％ (22.68％),表明转LEA基因对无性系生长具有一定的影响.此研究为小黑杨苗期管理提供理论依据.

The propagation of hard-branch cuttings of tetraploid Robinia pseudoacacia (black locust) is restricted by the low rooting rate; however, etiolated juvenile tetraploid black locust branches result in a significantly higher rooting rate of cuttings compared with non-etiolated juvenile tetraploid branches. To identify proteins that influence the juvenile tetraploid branch rooting process, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectra (MALDI-TOF/TOF-MS) were used to analyze proteomic differences in the phloem of tetraploid R. pseudoacacia etiolated and non-etiolated juvenile branches during different cutting periods. A total of 58 protein spots differed in expression level, and 16 protein spots were only expressed in etiolated branches or non-etiolated ones. A total of 40 highly expressed protein spots were identified by mass spectrometry, 14 of which were accurately retrieved. They include nucleoglucoprotein metabolic proteins, signaling proteins, lignin synthesis proteins and phyllochlorin. These results help to reveal the mechanism of juvenile tetraploid R. pseudoacacia etiolated branch rooting and provide a valuable reference for the improvement of tetraploid R. pseudoacacia cutting techniques.

In order to learn effects of different rootstocks on photosynthesis characteristics in walnut,taking 4-year-old trees of Shang 14 strains in the field as materials,which grafted taking Zhongningyi,Zhongningqiang,Zhongningqi,Juglans nigra and seeding walnut as rootstocks,the effects of the five rootstocks on photosynthetic characteristics of walnut leaves were researched,and the relationship between environmental factors and photosynthetic indicators was discussed.The results show that the diurnal variation of net photosynthesis rate(Pn) of walnut in five rootstock treatments present a single peak curve,but the peak values are significant different,Pn values of Zhongningqi and Zhongningqiang are significantly greater than that of seeding walnut,and light and temperature are major influencing factors of photosynthesis.The Pn-Par curves of five rootstock treatments are S type,and accord with quadratic curve model.Under the conditions of saturated luminous intensity,the order of the five rootstocks based on Pn value from high to low is Zhongningqi(23.12 μmol·m-2s-1),Zhongningyi(22.38 μmol·m-2s-1),seeding walnut(21.23 μmol·m-2s-1),Zhongningqiang(21.09 μmol·m-2s-1),Juglans nigra(20.14 μmol·m-2s-1).Therefore,Zhongningqi,Zhongningqiang and Zhongningyi are rootstock resources of walnut which can improve photosynthetic characteristics of walnut scion.

Walnut has great value for development,which is an important woody oil tree species.Now Walnut In dustry was advanced in breeding,seedlings,cultivation,Processing and utilization.To bring out the great potential of Walnut Industry and Promote it large development,we should strengthen the government's policy support and guidance,market positioning,industrial planning,construction of industrial technology platform and processing and utilization of technology research.

The experiment was conducted to study the contrast of the abilities of rooting during the cuttage between etiolated and non-etiolated Tetraploid Robni ia psedu oacacia shoots.Colorimetryand indirect enzyme-linked immunosorbent assay( ELI-As) were used to detect the level of three kinds of oxidase including indole acetic acid oxidase ( IAAO) , polyphenol oxi-dase enzyme ( PPO) and peroxidase ( POD) , and four kinds of endogenous hormone including indole acetic acid ( IAA) , abscisic acid (ABA), gibberellic acid ( GA3 ) and zeatin riboside ( ZR) in Tetraploid Robinia pseudoacacia etiolated shoots and non-etiolated shoots after the cuttage.Through the contrast of the differences and variation of oxidase activity and endogenous hormones content in the two kinds of materials, etiolated shoots are significantly superior on rooting rate, average root number and average root length .Three kinds of oxidase activities and four kinds of endogenous hormones un-der two treatments roughly have the same variation trends , but the etiolated shoots can form more IAA to promote the for-mation of roots, and have a higher levels of oxidase enzyme activity as well as IAA/ABA values.Therefore, the etiolated shoots can improve the oxidase activities, regulate endogenous hormones and the formation of adventitious roots.

To enhance the rooting rate of tetraploid Robinia pseudoacacia by hardwood stem cutting,cuttage of hardwood treated by low temperature sand storage with plant growth tegulator and upended were researched.The results showed that cuttage of hardwood treated by sand storage in winter and two-step hormone treatment was the best treatment,the survival rate reach 66.67 percent or more,500 mg·kg-1 ABT was the best hormone condition of treatment in three density of IBA,NAA and ABT,the survival rate of hardwood cuttage was appreciably increased by storaged in greenhouse and upended in sand.

Tetraploid robinia pseudoacacia clone K2 was a superior clone,which was selected from the clones.To enhance the rooting rate of tetraploid Robinia pseudoacacia clone K2 by juvenile stem cutting,different parts of scions,plant growth regulators as well as their concentrations and treatment time,types of substrate and scions collecting periods were researched to find the best combination of these techniques.The results showed that the optimum part of scions from tetraploid Robinia pseudoacacia clone K2 for rooting were canopy shoots,the efficient treatment in the plant growth regulators were IBA at 1500 mg/L combination with a dipping time 30s,the most favorable substrate was vermiculite,the best suitable scions collecting time was June.

提高校园绿化植物的物种多样性和保护力度是优化校园环境的核心。通过对校园植物生长情况、环境的调查和认真分析,为学校建设提出可行的合理化建议。

杨树是我国平原绿化主要树种之一,自20世纪80年代以来,林业科研单位经过多年研究,选育出一大批白杨派优良无性系.为实现优中选优、适地适树的研究目标,1990～1993年,先后从大专院校和科研单位引进15个白杨派优良无性系,以易县雌株作为对照,于1994年3月开始在魏县苗圃场定植建立无性系对比试验林.现将进行11年的试验研究结果,简报如下.

本文着重对影响林木扦插成活率的几个主要因素进行了分析。影响林木扦插成活率的主要因素包括树木品种、插穗年龄和位置、穗条规格和状态、扦插时间、扦插基质和外源激素。