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.     

桐麦间作系统内光量分布及其对小麦产量的影响

对桐麦间作系统内外各点光量与小麦产量对比研究表明：对照区的入射光量和小麦截获光量一直大于系统内各点,系统内各点离树行越近截获的光量越小．小麦截获光量与入射光量的比值在系统内各点变化不大,在开花期、灌浆期和成熟期,系统内的平均比值分别是０７８,０６９和０４５,系统外分别是０９４,０８８和０６３．就小麦产量来讲,系统内平均比系统外低５１２％,系统内冠下各点平均较冠外点平均低１９％,东冠下各点平均较西冠下各点平均低２４４％．单位面积小麦种粒数和千粒重与产量的变化趋势相同,系统内较系统外平均分别低３５５％,２５３％,冠下各点平均较冠外各点平均分别低１１３％,７４％,东冠下两点平均较西冠下两点平均分别低１３１％,１３４％．系统内外各点小麦产量可用其开花期至成熟期的截获光量进行预测．单位面积小麦的种粒数与开花期截获光量,种子千粒重与灌浆期所截获光量的相关关系十分紧密．     

泡桐农田防护林带单株树冠结构特征

冠层结构控制着叶面积及其分布,影响树木的生长,冠层分布影响林带的防护效益。为了解泡桐不同林带树冠的特性,2009年8月选取8年生单行、双行白花泡桐林带,研究其单木冠形、生长量、生物量、叶面积及其分布。结果表明,单行、双行林带单木的树高、胸径、冠长、冠幅、叶量、叶面积均无显著差异,而树干生物量有显著差异(P<0.05)。双行林带单木树冠外偏,呈非对称卵圆型。2个林带单木叶面积在冠内变化规律一致,由上层到下层,内层到外层均逐渐增加。单木叶面积是树高、胸径及冠长的函数。对单木冠层结构的分析可为林带冠层的变化及调控林带结构提供理论支持。     

泡桐属不同种和种源对丛枝病抗性调查

调查表明，泡桐属所有的种和无性系均感染丛枝病（Phytoplasma-MLO），但感染的程度不同。在调查中发现一种高抗类型，其特征是叶背毛密而高大，毛为具长柄的树状毛、具长柄大腺细胞的腺毛、长柄叉状毛和单枝毛，这类毛粘性很大。该类型泡桐抗病的主要机制是抗传毒的媒介昆虫之故。     

泡桐下侧芽萌发成枝与上侧芽萌发接干间关系

该文研究了自然状态下1年生泡桐下侧芽萌发成枝与上侧芽萌发接干间的关系.结果显示:在高密度林分的接干单株中,上侧芽萌发成枝接干与下侧芽萌发成枝间关系密切.接干侧芽的对生侧芽萌发不利于接干枝高生长,并降低接干形率;接干处向下数第1对侧芽萌发成枝倾角越小接干形率越高,第1、2对侧枝长度和粗度仅与胸径生长正相关;第3对侧枝倾角与接干处主干直径和接干基径呈负相关.增加成枝数量,减少单枝生长量,而枝长、基径合计不减少,能增大接干高度和接干处主干直径;第4对侧枝长度、粗度与主干、接干粗生长正相关;第5对侧枝长度、粗度与胸径生长正相关,而其以下侧枝对主干和接干的生长影响较小.      

泡桐无性系间木材性状的差异

对泡桐不同无性系木材性质进行了研究.结果表明,泡桐是一种低湿涨性木材,不同无性系在木材干缩性、纤维长、纤维宽、木材颜色等性状间存在显著差异.径向和弦向干缩率比较接近,最大纤维长和白度值分别为1 144μm和40.76.     

白花泡桐叶片中元素含量年动态变化分析

为研究白花泡桐叶片中大量和微量元素年动态变化,本文选取3个种源,从展叶期到落叶始期,每隔15 d采集1次叶片,进行观测。结果表明:白花泡桐不同种源间叶片中三大元素的变化趋势较为一致,4月中下旬叶片其养分含量偏高;N元素含量一直处于较高水平,随着叶片脱落损失较严重,而P、K元素在叶片枯黄期其含量降至较低;叶片中微量元素钙和镁元素含量相对较高,锰和铜元素在整个生长过程中均保持较低水平,铁和镁元素在叶片掉落时仍保持较高含量;为保证林木快速增长,应重施N肥,并及时补充铁镁肥。     

泡桐生长停止和顶芽死亡过程中的光合特性研究

以毛白33泡桐为研究对象,通过外部形态观察研究泡桐生长停止和顶芽死亡过程,同期观测其光合特性,并分析影响光合速率的主要因素。结果表明:泡桐的高生长停止于9月下旬;9月底10月初,多数泡桐顶芽已经由绿变褐而干枯;地径生长的停止期晚于高生长;泡桐光合速率的日变化是双峰型,存在光合午休现象; 叶片净光合速率与蒸腾速率、光合有效辐射、气孔导度呈极显著正相关性;叶片净光合速率与叶温呈显著正相关性;非气孔因素可能是诱导泡桐顶芽死亡的主要原因;9—10月泡桐的光合速率有所下降,但仍维持较高的水平,且主要用来粗生长和休眠侧芽的形成;泡桐顶芽枯死是进化过程中采取的一种适应策略。      

Some of the properties of particleboard made from paulownia

The objective of this study was to determine some of the properties of experimental particleboard panels made from low-quality paulownia (Paulownia tomentosa). Chemical properties including holocellulose, cellulose, lignin contents, water solubility, and pH level of the wood were also analyzed. Three-layer experimental panels were manufactured with two density levels using urea–formaldehyde as a binder. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB), screw-holding strength, thickness swelling, and surface roughness of the specimens were evaluated. Panels with densities of 0.65 g/cm³ and manufactured using a 7-min press time resulted in higher mechanical properties than those of made with densities of 0.55 g/cm³ and press times of 5 min. Based on the initial findings of this study, it appears that higher values of solubility and lignin content of the raw material contributed to better physical and mechanical properties of the experimental panels. All types of strength characteristics of the samples manufactured from underutilized low-quality paulownia wood met the minimum strength requirements of the European Standards for general uses.     

红头芫菁防治竹蝗的研究

红头芫菁防治竹蝗的研究张太佐（江西省靖安县林业局靖安３３０６００）关键词红头豆芫菁，褐边齿爪芫菁，黄脊竹蝗，泡桐黄脊竹蝗是竹子的重要害虫，大发生时常造成重大经济损失。肖刚柔教授在湖南进行黄脊竹蝗的研究时，就已发现红头芫菁幼虫取食竹蝗卵块［１］，但未进...