Gas exchange characteristics of Populus trichocarpa, Populus deltoides and Populus trichocarpa x P. deltoides clones

Responses of net photosynthesis, dark respiration, photorespiration, transpiration, and stomatal conductance to irradiance, temperature, leaf-to-air vapor density difference (VDD), and plant water stress were examined in two Populus trichocarpa clones (one from a moist, coastal climate in western Washington and one from a dry, continental climate in eastern Washington), one P. deltoides clone, and two P. trichocarpa x P. deltoides clones. Light saturation of photosynthesis in greenhouse-grown trees occurred at about 800 micromol m(-2) s(-1) for P. deltoides, P. trichocarpa x P. deltoides, and the eastern Washington ecotype of P. trichocarpa, but at about 600 micromol m(-2) s(-1) for the western Washington ecotype of P. trichocarpa. Average net photosynthesis (at saturating irradiance and the optimum temperature of 25 degrees C) was 20.7, 18.8, 18.2 and 13.4 micromol CO(2) m(-2) s(-1) for P. deltoides, P. trichocarpa x P. deltoides, and the eastern and western Washington clones of P. trichocarpa, respectively. In all clones, net photosynthesis decreased about 14% as VDD increased from 3 to 18 g H(2)O m(-3). Stomatal conductance decreased sharply with decreasing xylem pressure potential (XPP) in all clones except the western Washington clone of P. trichocarpa. Stomata in this clone were insensitive to changes in XPP and did not control water loss. Complete stomatal closure (stomatal conductance < 0.05 cm s(-1)) occurred at about -2.0 MPa in the eastern Washington clone of P. trichocarpa and around -1.25 MPa in the P. deltoides and P. trichocarpa x P. deltoides clones. Transpiration rates were highest in the P. trichocarpa x P. deltoides clone and lowest in the western Washington clone of P. trichocarpa. The P. deltoides clone and eastern Washington clone of P. trichocarpa had the highest water use efficiency (WUE) and the western Washington clone of P. trichocarpa had the lowest WUE. The hybrids were intermediate. It was concluded that: (1) gas exchange characteristics of eastern and western Washington clones of P. trichocarpa reflected adaptation to their native environment; (2) crossing the western Washington clone of P. trichocarpa with the more drought resistant P. deltoides clone produced plants better adapted to the interior Pacific Northwest climate, although the stomatal response to soil water deficits in the hybrid was conservative compared with that of the eastern Washington clone of P. trichocarpa; and (3) introducing eastern Washington clones of black cottonwood into breeding programs is likely to yield lines with favorable growth characteristics combined with enhanced WUE and adaptation to soil water deficits.     

美洲黑杨无性系苗期生长与蒸腾特性研究

对12个美洲黑杨无性系苗期生长、蒸腾速率、水分利用效率及其影响因子的相关性进行研究,结果表明：各无性系的蒸腾速率日变化均呈单峰曲线规律,最大值出现在14：00左右.日平均蒸腾速率的大小次序为：tn01-n58＞ tn02-16＞ tn01-38＞ tn05-n53＞ tn04-n31＞xl-90＞ la06-n30＞ tn01-30＞ tn01-90＞ tn04-n52＞tn02-13＞ tn01-78;水分利用效率的大小次序为：tn01-90＞ la06-n30＞ tn02-13＞ tn04-n52＞ tn01-78＞ xl-90＞ tn01-n58＞ tn05-n53＞ tn02-16 ＞tn01-30＞ tn04-n31＞ to01-38.蒸腾速率与G5、VpdL、Tair和PAR呈正相关,与Ci和RH呈负相关;蒸腾速率与影响因子的相关程度依次为：PAR＞Gs＞ RH＞Tair＞Ci＞ VpdL;苗期的平均地径、苗高与Pn、Cond、RH、PAR呈正相关,与VpdL、Tair呈负相关.     

Effects of induction treatments on flowering in Populus deltoides

Stimulation of early flowering is required to shorten breeding cycles of eastern cottonwood (Populus deltoides Bartr. ex Marsh. var. deltoides), a commercially important and fast-growing hardwood species. A series of experiments was conducted to evaluate the influence of various treatments on flowering in rooted cuttings from mature and juvenile trees. A combined treatment of water stress, root pruning and paclobutrazol was applied to 3-month-old rooted cuttings from mature trees. These cuttings had been subjected to root restriction and long days. All treated plants flowered, whereas no untreated plants formed flower buds. One-year-old rooted cuttings from juvenile trees did not flower when treated with either paclobutrazol, paclobutrazol plus water stress, paclobutrazol plus root pruning, or paclobutrazol plus girdling. This was true both under continuous or periodic growth. Assessment of the lack of flowering in juvenile trees may require an integrated approach that investigates environmental or physiological stimuli, assimilate shift, gibberellic acid type and concentration, and flowering-time gene activity in the new shoots of mature and juvenile cottonwood trees.     

美洲黑杨无性系的苗期生长比较

从美国田纳西州、路易斯安那州引进599个无性系,通过3年苗期试验,对苗期生长表现较好的13个无性系进行生长量测定,结果表明：一根一干苗各无性系之间地径生长存在显著性差异,二根一干苗和三根一干苗各无性系之间地径生长存在着极显著性差异;苗高生长在各无性系之间均存在着极显著性差异;参试无性系的地径、苗高表型变异系数分别为12.638%和5.570%,广义遗传力分别为0.835和0.860,遗传变异系数分别为11.562%和5.150%。说明各性状遗传潜力较大,存在着广泛的遗传变异,具有获得较大遗传增益选择的潜力。     

美洲黑杨抗光肩星天牛品种选育初报

以抗光肩星天牛的南抗杨2号为母本,以抗逆性较强的赤峰美黑为父本,选育美洲黑杨抗光肩星天牛品种。经过封闭环境下的抗虫试验和总酚类物质含量测定,从实践和理论2个方面综合选育了一批抗光肩星天牛性状较强的品种,K6、K8、K10、K13在抗虫性状上优势突出,抗侵染能力比群众杨提高6.3倍以上,K6、K8材性优于群众杨。     

滇杨与美洲黑杨派间杂交育种试验初报

本研究以青杨派中的滇杨为母本,黑杨派中的美洲黑杨为父本,采用人工切枝水培杂交技术进行了滇杨×美洲黑杨的杂交工作,获得了一定数量的杂种苗。今后将结合表型性状和分子标记技术对杂种苗和亲本进行遗传变异分析,探索和研究滇杨×美洲黑杨杂交育种的遗传变异规律,亲子鉴定和早期选育的遗传基础。     

Fine root dynamics in a developing Populus deltoides plantation

A closely spaced (1 x 1 m) cottonwood (Populus deltoides Bartr.) plantation was established to evaluate the effects of nutrient availability on fine root dynamics. Slow-release fertilizer (17:6:12 N,P,K plus micronutrients) was applied to 225-m(2) plots at 0, 50, 100 and 200 kg N ha(-1), and plots were monitored for two growing seasons. Fine root production, mortality, live root standing crop and life span were analyzed based on monthly minirhizotron observations. Fine root biomass was measured in soil cores. Fine root dynamics were controlled more by temporal, depth and root diameter factors than by fertilization. Cumulative fine root production and mortality showed strong seasonal patterns; production was greatest in the middle of the growing season and mortality was greatest after the growing season. Small diameter roots at shallow soil depths cycled more rapidly than larger or deeper roots. The strongest treatment effects were found in the most rapidly cycling roots. The standing crop of live roots increased with fertilizer treatment according to both minirhizotron and soil coring methods. However, production and mortality had unique treatment response patterns. Although cumulative mortality decreased in response to increased fertilization, cumulative production was intermediate at 0 kg N ha(-1), lowest with 50 kg N ha (-1), and highest with 200 kg N ha(-1). Aboveground growth responded positively to fertilization up to an application rate of 50 kg N ha(-1), but no further increases in growth were observed despite a threefold increase in application rate. Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability.     

基因库中21个美洲黑杨无性系的抗寒性

基因库中２１个美洲黑杨无性系的抗寒性徐红，张崎纹，陈一山，解荷峰关键词美洲黑杨无性系，抗寒性，电导率，膜脂脂肪酸不饱和度美洲黑杨（ＰｏｐｕｌｕｓｄｅｌｔｏｉｄｅｓＭａｒｓｈ）无性系具有生长迅速，抗病虫性较强等优良性状。历史上引种成功的几个美洲黑杨无性...     

Diversity of leaf traits related to productivity in 31 Populus deltoides x Populus nigra clones

To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency.     

杨树EST-SSR标记的开发

利用来自美洲黑杨及欧美杨的20 023条EST序列,进行EST-SSR标记开发研究.首先对这些EST序列进行序列拼接,然后在非重复序列中发现由二核苷酸至五核苷酸组成的SSR重复序列.共在10 816个非重复序列中发现1 604个序列含有SSR,占总非重复序列的14.8%.在发现的1 918个SSR重复序列中,二核苷酸重复是最丰富的重复类型,占总类型的62.3%.设计合成48对SSR引物,利用6个不同的杨树品种对其进行验证.结果约90%的引物获得扩增产物,58%的引物在6个不同杨树品种中产生多态性分离.另外,还对重复序列的数量及重复类型进行了讨论.     

Populus deltoides CL“SZ-2”等73个杨树无性系的引进与优选

通过对Populus deltoidesCL"SZ-2"等73个杨树无性系的苗木培育和造林试验,比较分析其造林成活率、胸径、树高和材积生长量,并利用聚类分析法,初选出SZ-2杨、SZ-31杨、SZ-5杨3个优良无性系,其9年生林分生长量均高于目前浙江省表现最好的35/66杨10%以上,其中SZ-2无性系9年生林分平均胸径达37.7cm、树高达24m、单株材积达1.2946m3/hm2,分别为35/66杨的118.93%、116.50和164.69%。     

First report of Curvularia eragrostidis leaf spot on Populus deltoides

Poplars are affected by a large number of foliar pathogens in nurseries and in the field, which result in biomass reductions. Management of these diseases is essential to minimise losses. During field surveys between 2008 and 12, an unrecognized leaf spot disease was observed on several commercial clones of P. deltoides (G‐48, Udai, WSL‐22 & WSL‐39). The pathogen was identified as Curvularia eragrostidis. Pathogenicity was proven on all host clones. This paper is the first report of the pathogen affecting poplars.     

美洲黑杨新无性系的海涂适应性试验研究

１９９２－１９９５年的试验结果表明，在含盐量０．２０８％的海涂上栽植的１１个黑杨无性系中，筛选出５个优良无性系，具有适应性强，生长迅速抗盐和抗病虫害，与Ｉ－６９杨相比，单株材积增长率为４．８６％－６４．６３％，每公倾蓄积增长率为３８．３８％－７４．１７％，增加收入７８００－１５７５元／ｈｍ＾２。     

不同供水条件对Ⅰ-69杨树材质的影响

杨树生长对土壤水分条件的反应非常敏感,虽然不同品种或无性系之间存在着明显的差异,但从总体来看,木材年轮宽度的变化主要是由土壤水分供应条件所决定的。在有条件灌溉的地区,人们除了关心灌溉的花费与木材增长量之间的经济效益外,同时也关心灌溉量与树木材质之间的相互关系。换句话说,木材质量会不会因灌溉量过多而下降?下降多少?这显然是科技工作者应当回答的重要问题。遗憾的是,在国内外繁多的文献中,报道灌溉对树木生长影响的结论很多,但是,关于灌溉对材性影响的研究工作,国外也为数很少,国内更未见有报道。     

辽育3号杨的抗逆性测试

辽育3号杨(Populus deltoides‘L iaoyu3’)是辽宁省杨树研究所选育的新品种,在选育过程中,对其抗寒性、抗病及抗虫能力进行了测试,从测试结果可以看出:该品种能抗-47.84--43.93℃的低温;在抗水泡溃疡病方面,发病率低于小钻杨,与对照达到极显著差异;抗杨干象能力明显高于亲本和对照品种。     

Ⅰ-69杨人工林生长规律与营养特性的研究

1982年以来在湖南省汉寿进行了Ⅰ-69杨人工林生长规律与营养特性的定位研究。前三年(1982～1984年)结果表明,当地的气候、土壤生态因子适于Ⅰ-69杨生长,胸径生长年、月变异极显著。第一年生长慢,8月为高峰期;第三年较第二年次之,6月为高峰期。三年胸径年平均增长4.78 cm。主要营养元素(除Mg外)的月变异极显著,与胸径生长规律一致。年变化无显著差异,年平均含量较高,N为3.25％～3.31％,P_2O_5为0.58％～0.59％,K_2O为1.59％～1.61％,CaO为3.17％～3.28％,MgO为0.54％～0.70％,反映了Ⅰ-69杨生长与主要营养元素吸收、利用以及土壤养分的供给,处于动态平衡的良好状态。     

造林密度对美洲黑杨幼林生长的影响

在昆明市宜良县千亩杨树种植基地内,依据完全随机区组试验设计,设置美洲黑杨3组造林密度试验。通过对5年生引种美洲黑杨不同造林密度幼林的生长指标观测与分析,结果表明,造林密度对美洲黑杨幼林的胸径、树高和冠幅均有极显著影响,胸径、树高和冠幅随着造林密度的减小而极显著地增加,低密度的造林有利于美洲黑杨树木的生长。     

美洲黑杨生长变异与无性系选择

从美洲黑杨原产地密西西比州、得克萨斯州和路易斯安娜州等地引种了104个无性系,并于1998年春在江苏省泗洪县陈圩林场开展无性系对比试验造林。12年生试验结果表明,来自于密西西比州和得克萨斯州7个产地89个无性系长势较好,路易斯安娜州的15个无性系长势较差。树高、胸径和材积等3个生长性状在无性系间差异极显著,性状遗传力(0.552 3~0.658 7)较高,遗传变异系数(8.26%~31.61%)较大。在入选率为5%,选择强度为2.02条件下,材积生长量的选择增益为50.82%。选择的S3412等5个速生无性系12年平均单株材积生长量为1.021 1 m3,超过对照(CK)品种I-69杨15.05%。     

Carbon allocation and nitrogen acquisition in a developing Populus deltoides plantation

We established Populus deltoides Bartr. stands differing in nitrogen (N) availability and tested if: (1) N-induced carbon (C) allocation could be explained by developmental allocation controls; and (2) N uptake per unit root mass, i.e., specific N-uptake rate, increased with N availability. Closely spaced (1 x 1 m) stands were treated with 50, 100 and 200 kg N ha(-1) year(-1) of time-release balanced fertilizer (50N, 100N and 200N) and compared with unfertilized controls (0N). Measurements were made during two complete growing seasons from May 1998 through October 1999. Repeated nondestructive measurements were carried out to determine stem height and diameter, leaf area and fine-root dynamics. In October of both years, above- and belowground biomass was harvested, including soil cores for fine-root biomass. Leaves were harvested in July 1999. Harvested tissues were analyzed for C and N content. Nondestructive stem diameter and and fine-root dynamic measurements were combined with destructive harvest data to estimate whole-tree biomass and N content at the end of the year, and to estimate specific N-uptake rates during the 1999 growing season. Shoot growth response was greater in fertilized trees than in control trees; however, the 100N and 200N treatments did not enhance growth more than the 50N treatment. Root biomass proportions decreased over time and with increasing fertilizer treatment. Fertilizer-induced changes in allocation were explained by accelerated development. Specific N-uptake rates increased during the growing season and were higher for fertilized trees than for control trees.