银白杨与白榆远缘杂交的研究

围绕银白杨、白榆、新疆杨以及银榆杨(银白杨×白榆)这四个树种进行了远缘杂交试验。结果表明:通过花粉蒙导与未成熟胚离体培养技术,克服了科间远缘杂交障碍,获得了银白杨×白榆杂种苗。此外,银白杨×银榆杨、银白杨×新疆杨都得到了种子。银白杨×新疆杨效果较好,银白杨×银榆杨试验所得的成熟种子比较少,只占所得种子总数的25%,且成熟种子的发芽率为66.7%。由于银白杨×银榆杨的杂种苗生长羸弱,没能存活下来。这表明银榆杨花粉可育,只是育性差。形态学标记和AFLP标记结果表明,银榆杨属于偏母本融合型的杂种。银榆杨雌雄同株,且有同花序现象,在早花性、叶背面无毛、侧枝细弱,从这些性状上看,白榆的基因在银榆杨中得到了表达。     

海涂围垦区不同耐盐树种根际土壤团聚体形成及养分分布特征

以温州宋埠围垦区的滨海潮滩盐土为研究对象,种植泌盐乔木——柽柳(Tamarix chinensis)、拒盐灌木——厚叶石斑木(Rhaphiolepis umbellata)和拒盐乔木——白榆(Ulmus pumila),分析植树2 a后各树种根际土壤团聚体形成及养分分布特征。与裸地相比,柽柳、厚叶石斑木和白榆根际土壤pH分别下降0.14、0.43、0.39,电导率分别下降80%、70%、72%。裸地土壤粒径均小于0.053 mm,各树种根际土壤形成的微团聚体(0.25～0.053 mm)占土壤总质量的5.0%～5.9%,大团聚体(2～0.25 mm)占比小于1%。相比粉+黏团聚体(<0.053 mm),微团聚体中有机碳和游离铁含量分别呈现上升和下降趋势,表明微团聚体形成可能是一个脱铁富碳过程。与裸地相比,各树种根际土壤全氮和碱解氮显著增加,而速效钾含量显著下降。各树种根际土壤全氮和碱解氮含量以白榆最高(分别为1.20 g·kg–1和42.6 mg·kg–1),且微团聚体中全氮和碱解氮显著高于粉+黏团聚体。综上所述,植树2a后,各树种根际土壤盐碱度显著下降,且形成团聚体,表明柽柳、...     

Leaf litter selection by detritivore and geophagous earthworms

Summary Litterbag experiments with 10 different kinds of leaf litter showed that detritivore (Lumbricus species) and geophagous (Aporrectodea species) earthworms prefer certain litter types over others, since different numbers of worms were found below the litter after 50–52 days of exposure in a pasture. The detritivores preferred Fraxinus, Tilia, and predecomposed Ulmus and Fagus litter to Fagus litter and paper, while geophages preferred Tilia litter to Alnus and Ulmus litter, so that the two groups of earthworms showed different preferences. The detritivores seemed to be more selective than the geophages. The palatability of the litter was examined in relation to the C: N ratio, the lignin concentration and the initial and final polyphenol concentration. The numbers of detritivores were significantly correlated with the C: N ratio and the final polyphenol concentration, so that selection of litter seems to be related to palatability. The numbers of geophages were not significantly correlated with any of the parameters for palatability. The disappearance of litter after 50–52 days appeared to be due to detritivore activity, since the numbers found below the litter were positively and significantly correlated with the litter disappearance. There was no significant correlation with geophage activity. This indicates that detritivores use litter as food, and therefore influence the composition of the litter layer.     

美国岩榆愈伤组织的诱导及不定芽形成

以顶芽、嫩茎、叶片为外植体,对美国岩榆进行组织培养的初步研究。结果表明,用顶芽作外植体诱导愈伤组织的最佳培养基为MS BA2.0mg·L-1 IBA2.0mg·L-1,诱导愈伤增殖的最佳培养基为MS BA1.0mg·L-1 NAA1.0mg·L-1 IBA1.0mg·L-1;以幼叶为外植体产生愈伤的最佳培养基为MS BA2.0mg·L-1 IBA2.0mg·L-1,诱导其愈伤增殖的最佳培养基为MS BA1.0mg·L-1;用嫩茎段作外植体诱导愈伤组织的最佳培养基配比为MS BA2.0mg·L-1 NAA0.5mg·L-1。诱导不定芽分化产生的外植体是嫩茎段,其最佳培养基组合为MS BA1.0mg·L-1 NAA1.0mg·L-1 IBA1.0mg·L-1。     

白榆深根苗低成本培育技术

为了降低白榆深根苗的培育成本,分别探讨了塑料育苗袋替代PVC导根筒、杨树叶与玉米秸秆腐熟基质替代市售轻基质培育白榆深根苗的有效性,并对培育成本进行了比较分析。结果表明:以塑料育苗袋替代PVC管导根筒、以杨树叶或玉米秸秆等腐熟基质替代市售轻基质材料,完全能够满足培育白榆深根苗的需要。替代后的白榆深根苗培育成本比替代前降低66.7%。     

Propagation method influences first year field survival and growth of Paulownia

Field trials at three locations were used to evaluate survival and early growth of Paulownia elongata, P. fortunei, and P. × 'Henan 1' plants produced from seeds, shoot cuttings, and micropropagated shoots. One year after field establishment, trees produced by either vegetative propagation method survived with higher frequency and were taller and of greater diameter breast height than trees grown from seed. The influence of propagation method was more pronounced in P. elongata and P. fortunei than in P. × 'Henan 1'. Survival frequency was similar for each species/hybrid, but both species were taller than P. × 'Henan 1' across propagation method and site. Field site had a pronounced influence on tree survival and height. Species/hybrid differences were not detected at the site that promoted the greatest tree growth, but P. elongata outperformed P. fortunei and P. × 'Henan 1' at the two sub-optimal sites. Clones within species/hybrid produced through micropropagation differed in survival frequency, height, and diameter breast height. Under the conditions used for this study, Paulownia field survival and early growth in central North Carolina was improved by using P. elongata or P. fortunei produced by rooting shoot cuttings or micropropagated shoots. Significant variation among clones within these species demonstrated the potential benefit of identifying superior clones to improve first year field survival and growth.     

典型榆树疏林碳氮储量及其分配特征

榆树疏林是科尔沁沙地和浑善达克沙地植被演替的顶级群落。以退耕还林后天然恢复的科尔沁沙地榆树疏林和无破坏的浑善达克沙地榆树疏林为研究对象,运用样方调查法、生物量估算法及相关的数理统计方法,比较分析2种典型榆树疏林碳氮储量及其分配特征。结果表明：1）除土壤无机碳储量外,浑善达克沙地榆树疏林各组分的碳氮储量均显著高于科尔沁沙地榆树疏林,其中总的碳氮储量分别为科尔沁沙地榆树疏林的1.97和1.82倍;2）2种榆树疏林碳氮分配特征相似,最大贡献者均为土壤,其所占比例相应地均超过了55%和80%,而最小贡献者则均为枯落物;3）与浑善达克沙地榆树疏林相比,退耕还林后的科尔沁沙地榆树疏林可能具有更大的碳汇潜力和固氮功能。     

长穗偃麦草HKT1;4基因片段的克隆及序列分析

根据已报道的其他植物高亲和钾离子转运蛋白（HKT1;4）基因的保守序列设计一对简并性引物,以长穗偃麦草幼根总RNA为模板,采用RT-PCR方法克隆出长穗偃麦草HKT1;4,基因命名为EeHKT1;4。结果表明：该基因片段长度为614 bp,编码204个氨基酸,所得序列与其他植物氨基酸序列同源性均在80%以上,特别是和一粒小麦TmHKT1;4氨基酸同源性高达92%。这为长穗偃麦草HKT1;4全长基因的克隆及其耐盐分子机制的研究奠定基础。     

三个小麦野生近缘种抗条锈性传递的初步研究

以当前小麦条锈病菌的优势小种条中２９ 号、３０ 号和３１ 号测定了小麦近缘植物长穗偃麦草、簇毛麦和华山新麦草及其各自与小麦的杂交后代的抗条锈性。试验结果表明,３ 个小麦近缘植物均含有宝贵的抗条锈基因,此类基因具有较强的传递性能,可在小麦遗传背景下高度表达,表现出良好的抗条锈性能,具有广阔的应用前景     

疏勒河中游盐质沙丘分布长穗柽柳种群空间格局及种间联结性研究

在中点四分法调查资料的基础上,阐述了疏勒河中游流域盐质沙丘分布长穗柽柳群落结构组成:并采用离散分布模型的理论拟合、聚集强度指标和种间联结测定等方法,研究了该群落类型优势种的空间分布格局和种间生态分布的联结关系.