Factors influencing direct shoot regeneration from leaves,petioles, and plantlet roots of triploid hybrid <Emphasis Type="Italic">Populus</Emphasis> sect. <Emphasis Type="Italic">Tacamahaca</Emphasis>

Since the generation of full-sib artificial triploid families, rapid clone establishment and genetic improvements have been needed. Here, we report an in vitro method of direct shoot regeneration of a triploid hybrid poplar [(Populus simonii × P. nigra ‘Italica’) × (P. × ‘popularis’)]. Using different randomized block designs, we selected one triploid to evaluate the explant type, optimal concentrations of plant growth regulators and agar, and culture time under light or dark conditions over 60 days. The highest rate of shoot induction, 80.0%, was obtained using Murashige and Skoog (MS) medium supplemented with 0.2 mg/L benzyladenine, 0.04 mg/L naphthaleneacetic acid (NAA), and 5.5 g/L agar for the first 30 days in the dark, then 3 g/L agar for the next 30 days in light. This last medium yielded the best rate of shoot induction (6.32 shoots/explant). These three media were also used to evaluate the influence of the genotypes of the parents and hybrid triploids on regeneration. Two parents and three of the four full-sib triploids were regenerated successfully; different genotypes and explant types significantly affected the rate of shoot induction and average number of shoots. Leaves but not petioles were a suitable explant. One genotype produced the highest rate of shoot induction of 96.67%. Half-strength MS medium supplemented with 0.2 mg/L indole butyric acid and 0.04 mg/L NAA was the most effective for rooting; rooting rate was 96.67%, survival rate of transplants was 73.33%, and rooting frequency surpassed 85% for each genotype. Overall, this in vitro regeneration system will be useful for the propagation and genetic modification of triploid poplars.     

In vitro regeneration of Populus tomentosa from petioles

A reliable in vitro regeneration procedure for Populus tomentosa is a prerequisite for its trait improvement through genetic transformation. We established a systematic protocol for indirect regeneration of P. tomentosa using in vitro petioles of Chinese poplar cultivar ‘fasta-3'. A high frequency of callus induction([97 %) was obtained from isolated petioles cultured on the modified 1/2MS basal medium supplemented with 0.5 mg/L ZT and 1.0 mg/L NAA, and the tested calli were subsequently plated on1/2MS basal medium supplemented with 0.25 mg/L BA,0.25 mg/L ZT, 0.25 mg/L NAA, 0.01 mg/L TDZ, and0.5 mg/L KT for efficient regeneration of shoots after being cultured for 6 weeks. The regenerated shoots were vigorously rooted on the tested media supplemented with 1.0 mg/L IBA and 0.5 mg/L NAA. These results can facilitate genetic transformation of P. tomentosa for trait improvements in future.     

Callus induction from leaves of differentpaulownia species and its plantlet regeneration

The experiment was carried out on five different species ofPaulownia for callus induction from leaves. MS medium was adopted as basic medium, and from different combinations of NAA and BA the suitable media were determined for callus induction, bud differentiation, and root differentiation of five different species. MS+0.5NAA+4BA, MS+0.3NAA+2BA, MS+0.5NAA+4BA, MS+0.3NAA+6BA, and MS+0.3NAA+8BA were suitable media of callus inductions of leaves, respectively, forPaulownia tomentosa, Paulownia australis, Paulownia fortunei, Paulownia elongata andP. tmentosa x P. fortunei, and MS+0.3NAA+12BA, MS+0.3NAA+12BA, MS+0.5NAA+12BA, MS+0.5NAA+12BA, and MS+0.7NAA+12BA were suitable media for bud differentiation from leaf callus respectively for above five species. The rooting media was determined as 2MS+0.1NAA, 1/2MS+0.1NAA, 1/2MS, 1/2MS+0.3NAA, and 1/2MS+0.5NAA. These results provide reference data for breeding new fine varieties with different kinds ofPaulownia protoplasts fusions. Foundation Item: This paper was supported by National Nature Science Foundation of China (No. 39870631) and Nature Science Foundation of Henan Province (No. 994011100). Biography: Fan Guo-qiang (1964), male Ph. Doctor, Professor in Forestry Department of Henan Agriculture University. Zhengzhou 450002, P. R. China. E-mail: guoqiangf@263.net. Responsible editor: Song Funan     

35杨微繁殖与叶片不定芽再生研究

以35杨茎段外植体为供试材料,对腋芽微繁殖、叶片不定芽再生、生根以及移植的离体培养技术体系进行了研究,结果表明：获得初始无菌苗的取材以4月取田间杨树新枝茎段外植体为最好;茎段外植体的启动培养基以附加NAA0．1mCL、0．5mg／L6-BA及GA,0．5mg／L的WPM培养基为优;腋芽微繁殖最快的培养基为WPM＋0．2mg／L6-BA＋0．1mg／LIAA＋0．1mg／LIBA;生根培养基以3／5WPM＋0．1mg／LIBA为好;叶片不定芽再生培养基以WPM＋0．2mg／L 6-BA＋0．1mg／LIAA＋0．1mg／LIBA再生频率最高,达92．86％;叶片不定芽在生根培养基上培养20d后获健壮生根苗,移栽成活率达100％。     

Cultural factors influencing adventitious shoot and plantlet formation from slash pine cotyledons

Cultural factors affecting in vitro shoot and subsequent plantlet formation of slash pine (Pinus elliotti Engelm.) cotyledons were investigated. Basal media composition, N⁶-benzylaminopurine (BAP) concentration and exposure time significantly influenced bud induction in cotyledons cultured under a continuous photoperiod of 35–40 mol m^–2 s^–1 at 24 ± 1 °C. The largest number of adventitious shoots was obtained after 28 days exposure to 66 M BAP-supplemented modified Gresshoff and Doy 1 (GD1) medium. Relatively high frequencies of large shoots were obtained after a 14-day exposure to 22 M BAP-supplemented Brown and Lawrence (BL) or 66 M BAP-supplemented GD1. Adventitious shoots derived from 21- or 28-day exposures to BAP developed more slowly and were smaller in size than those derived from a 14-day exposure to the cytokinin. Shoot differentiation and subsequent growth were also influenced by basal media, media concentration, and presence of activated charcoal in the medium. The percentage of cotyledons forming shoots was highest on half-strength GD1 medium containing activated charcoal. Rooting was achieved in vitro under a continuous photoperiod of 60–70 mol M^–2 S^–1. Roots were formed when excised shoots were planted on GD 1/2 medium supplemented with 2.68 M 1^–1 a-napthaleneacetic acid (NAA) with or without BAP for 14 days. The proposed technique of slash pine propagation using cotyledon explants can produce up to 100 seedlings per embryo.     

不同种泡桐叶片愈伤组织诱导及其植株再生(英文)

在确定5种泡桐叶片诱导愈伤组织基本培养基为MS的基础上,通过不同的NAA和BA的组合,筛选出了毛泡桐(Paulownia tomentosa)、南方泡桐(Pauiownia australis)、白花泡桐(Paulownia fortunei)、兰考泡桐(Paulownia elongata)和豫杂一号泡桐(P.tomentosa x P. fortunei)叶片愈伤组织诱导、芽分化和根分化的最适培养基。MS+0.5NAA+4BA、MS+0.3NAA+2BA、MS+0.5NAA+4BA、MS+0.3NAA+6BA和MS+0.3NAA+8BA分别为五种泡桐树种叶片愈伤组织诱导的最适培养基,上述树种的叶片愈伤组织诱导芽分化最适培养基分别为MS+0.3NAA+12 BA、MS+0.3NAA+12 BA、MS+0.5NAA+12 BA、MS+0.5NAA+12 BA和MS+0.7NAA+12 BA,最后找出了5种泡桐芽诱导根的最适培养基分别为1/2MS+0.1NAA、1/2MS+0.1NAA、1/2MS、1/2MS+0.3NAA和1/2MS+0.5NAA。这些结果为开展泡桐基因工程研究和利用不同种泡桐叶片原生质体融合培育泡桐新品种提供了参考。     

毛白杨叶片愈伤组织的诱导、芽的分化及不定根的再生

以毛白杨叶片为外植体进行组织培养研究。结果表明:培养基MS 6-BA 1.0 mg/L NAA 1.0 mg/L有利于愈伤组织的诱导;培养基MS 6-BA 0.5 mg/L NAA 0.5 mg/L诱导愈伤组织并且有大量不定芽发生;培养基MS ZT 0.1 mg/L NAA 0.3 mg/L可使叶片生根率达100%。     

小油桐外植体分化及植株再生影响因素的初步研究

研究发现在MS培养基中添加6-BA 3 mg.L-1+IBA 0.5 mg.L-1的激素对小油桐苗质及外植体分化有明显促进作用。15 d苗龄的小油桐幼苗外植体有较高的分化率。正交实验研究最佳分化激素浓度,发现6-BA+IBA组合对小油桐外植体芽苗诱导效果明显优于6-BA+NAA组合。子叶再生芽诱导最佳培养基为MS+6-BA 3 mg.L-1+IBA 0.5 mg.L-1,最高诱导率为82.9%;下胚轴再生芽诱导最佳培养基为MS+6-BA 2 mg.L-1+IBA 0.2 mg.L-1诱导率为23.8%。在子叶和下胚轴再生培养基中添加1 mg.L-1的AgNO3能促进小油桐植株再生,并抑制褐化产生。小油桐再生苗最佳生根培养基为WPM培养基。     

Genetic control of fiber properties and growth in triploid hybrid clones of Populus tomentosa

To better understand the genetic control of fiber properties (fiber length [FL], fiber width [FW] and coarseness [C]) and growth traits (tree height [H], diameter at breast height [DBH] and stem volume [SV]) in triploid hybrid clones of Populus tomentosa carr., genetic relationships among selected fiber properties with growth traits were examined in five-year-old clonal field trials located in Yanzhou, Gaotang and Xiangfen, China. In total, 180 trees from 10 clones were sampled from the three sites. The site had a moderate effect on FW, C and tree growth, and a highly significant (P<0.001) effect on FL and fiber length/width (FL/W). Clonal effects were also significant (P<0.05) for all studied traits except for the DBH and SV. Clone×site interactions were significant for all studied traits (except for FL). The estimated repeatability of clonal mean for FL (0.91) was higher than for FW (0.88), C (0.77), FL/W (0.74), H (0.62), DBH (0.61) and SV (0.55). Intersite genetic correlation estimates indicated that fiber properties were more stable than growth traits. Positively insignificant genetic correlation estimates between FL and growth trait and negatively insignificant genetic correlation estimates between C and growth traits were observed. This suggests that in the triploid hybrid poplar, clones selection for growth traits will not result in a significant increase or reduction in the fiber properties.     

In vitro regeneration of <Emphasis Type="Italic">Populus tomentosa</Emphasis> from petioles

A reliable in vitro regeneration procedure for Populus tomentosa is a prerequisite for its trait improvement through genetic transformation. We established a systematic protocol for indirect regeneration of P. tomentosa using in vitro petioles of Chinese poplar cultivar ‘fasta-3’. A high frequency of callus induction (>97 %) was obtained from isolated petioles cultured on the modified 1/2MS basal medium supplemented with 0.5 mg/L ZT and 1.0 mg/L NAA, and the tested calli were subsequently plated on 1/2MS basal medium supplemented with 0.25 mg/L BA, 0.25 mg/L ZT, 0.25 mg/L NAA, 0.01 mg/L TDZ, and 0.5 mg/L KT for efficient regeneration of shoots after being cultured for 6 weeks. The regenerated shoots were vigorously rooted on the tested media supplemented with 1.0 mg/L IBA and 0.5 mg/L NAA. These results can facilitate genetic transformation of P. tomentosa for trait improvements in future.     

苹果叶片再生体系建立研究

以乔纳金苹果试管苗叶片为外植体诱导不定芽再生，在培养基中添加不同浓度TDZ与NAA或IAA配合，使用琼脂或Polygel作为固化剂。结果表明，较适宜的叶片再生不定芽的培养基为TDZ 2．0mg／L和NAA 1．0mg／L，或TDZ 2．0mg／L与IAA 4．0mg／L。较适宜的组培固化剂为5．0g／L的Polygel。在不同的组培固化剂中，卡那霉素均能抑制不定芽的发生数量，但琼脂和Polygel效果不同。     

The effect of roots and litter of Calamagrostis canadensis on root sucker regeneration of Populus tremuloides

Marsh reed grass (Calamagrostis canadensis (Michx.) Beauv.)is a common, highly competitive grass native to the boreal mixedwoodforest. This grass increases in abundance after clear-cut loggingbut little is known about its effects on trembling aspen (Populustremuloides Michx.) sucker regeneration. The effects of Calamagrostissod and its litter on aspen regeneration were studied in twoseparate greenhouse studies. Calamagrostis sod did not affectthe initiation of suckers, but resulted in 30 per cent fewersuckers emerging above the soil that were smaller and had 40per cent less leaf area. Calamagrostis litter had little effecton the initiation and number of emerged suckers; however, itdelayed emergence by 10 days. The physical barrier by rootsand litter of Calamagrostis reduced or delayed the expansionof suckers and therefore prolonged their dependence on rootreserves. By the time the suckers reached the surface, theyhad to compete for light with Calamagrostis shoots that hademerged a week earlier. This, coupled with low soil temperaturesassociated with Calamagrostis in other experiments, will significantlyreduce the number and growth of suckers. Any reduction and delayin sucker emergence will decrease aspen regeneration and productivitysince the growing season in the boreal forest region is short.     

Genotypic parameters of wood density and fiber traits in triploid hybrid clones of Populus tomentosa at five clonal trials

? Context

A clear understanding of the genetic control of wood properties is a prerequisite for breeding for higher wood quality in Populus tomentosa Carr. hybrid clones.

? Aims

The experiments aimed at unraveling genetic and environmental effects on wood properties among triploid hybrid clones of P. tomentosa.

? Methods

We used 5-year-old clonal trials established in Northern China to assess the heritability of wood density and fiber traits. Two hundred seventy trees from nine clones were sampled in five sites.

? Results

Site had a very significant effect on all recorded traits. Despite this large site effect, a tight genetic control was detected and clonal repeatability varied between 0.53 and 0.95. Significant genotype?×?environment interactions were detected for most of the traits. Moderate to tight correlation were evidenced among traits but they were not consistent with that in several cases that were site-dependent.

? Conclusions

Our results revealed a tight genetic control over several wood properties and therefore breeding programs might be able to improve wood density, fiber length, and coarseness in these hybrids.     

An efficient in vitro shoot regeneration through direct organogenesis from seedling-derived petiole and leaf segments and acclimatization of Ficus religiosa

Prolific and rapid in vitro plant organogenesis via direct regeneration has been obtained from axenic seedling-derived petiole and leaf explants of Ficus religiosa in Murashige and Skoog (MS) medium containing different concentrations of cytokinins in combination with indole-3-butyric acid (IBA). MS medium with 1.5 mg/l 6-benzylaminopurine plus 0.15 mg/l IBA produced the highest shoot induction frequency with an average of 6.26 and 10.13 shoots per leaf and petiole explants, respectively. After 4 weeks, the highest root formation frequency (96.7%), root number (5.73), and root length (4.76 cm) were with MS medium containing 2.0 mg/l IBA plus 0.1 mg/l α-naphthalene acetic acid. In addition, the effect of four sodium nitroprusside (SNP) treatments on acclimatization was also studied. Highest morphological traits such as survival rates, fresh and dry root weights as well as antioxidant enzymatic activities such as superoxide dismutase, peroxidase, and catalase was achieved with 125 ppm SNP. The α-amino acid, proline, content was highest with this treatment while the highest H2O2 (hydrogen peroxide) was in the controls. This study introduces a cost-effective, prolific, and efficient in vitro multiplication system to supply pharmaceutical and ornamental needs. It is the first report of an in vitro organogenesis protocol for F. religiosa by direct regeneration through axenic seedling-derived petiole and leaf explants, which can be efficiently employed for the utilization of active biomolecules.     

Fungi in leaves,twigs and stem bark of Populus tremula from northern Spain

Fungal species were recorded from Populus tremula leaves, twigs and bark (trunk) at eight sites in the northern region of Spain, with the aim of evaluating the effect of sampling site, sampling tissue and isolation method on the frequency and species distribution of the fungi recovered from necrotic and healthy tissues. Two different isolation methods were used: the first consisted of finding fruitbodies on plant tissues after incubating them in wet and warm conditions, and the second included growing mycelia from plant fragments plated on potato dextrose agar (PDA). A total of 48 fungal species were isolated from 960 plant fragments. Cytospora chrysosperma, previously reported to be a pathogen of poplar, was recovered very frequently and was recorded as much in healthy as in dead or dying tissues. Cladosporium maculicola, Elsinoe veneta, Alternaria alternata, Aureobasidium pullulans and Pollaccia radiosa were also frequently isolated. The isolation frequencies from necrotic and healthy plant tissues were significantly different between sites and isolation methods. The incubation in moist chambers revealed significantly more fungal isolates and a higher species richness (38 species) than isolations on PDA. However, 16% of the fungal species were exclusively recorded from cultures. Therefore, a combination of several isolation methods is recommended for surveys of fungal communities associated with trees.     

银白杨×马氏杨杂交子代及亲本的AFLP分析

为了探讨银白杨、马氏杨及银白杨×马氏杨杂交子代间的遗传多样性参数及个体聚类关系,利用8对引物对银白杨、马氏杨及银白杨×马氏杨杂交子代4个样本进行了AFLP分析。结果表明,8对引物共扩增出780条扩增谱带,其中多态性条带数为715条,多态性比例为91.65%,平均有效等位基因数为1.5017,Nei’s平均遗传多样性指数为0.3065,Shannon平均信息指数为0.4679。不同杂交子代在E-AAC/M-CAG引物对上均有特异性位点,这些特异位点可用于品种鉴定。聚类研究发现,在相似系数为0.76时,试验样品分成2个AFLP群,其中马氏杨为1个AFLP群,银白杨及2个杂交子代为1个AFLP群;当相似系数为0.78时,银白杨和2个杂交子代的AFLP群又划分为2个亚群,其中杂交子代1和杂交子代2聚合为亚群1,银白杨为亚群2。本研究的结果多态性比例很高,对样品的区分率达到100%,为杨树AFLP分析检测提供了指导借鉴价值。     

Establishment of high frequency shoot regeneration system in Himalayan poplar (Populus ciliata Wall. ex Royle) from petiole explants using Thidiazuron cytokinin as plant growth regulator

Populus species are important resources for industry and in scientific study on biological and agricul-tural systems. Our objective was to enhance the frequency of plant regeneration in Himalayan popla...     

枣树叶片愈伤组织培养与再生植株的研究

为探讨枣树组织培养育种及快繁技术,以木枣、骏枣和狗头枣组培苗叶片为外植体,通过诱导愈伤组织形成再分化出不定芽,从而建立高效的再生系统。试验结果表明,不同基因型或同一基因型的不同部位的材料其培养效果间有差异;试管枣苗茎尖倒数1～3片叶是合适的外植体材料;6-BA与2,4-D在枣树叶片愈伤组织诱导中有极显著的交互作用,二者的配比浓度水平影响愈伤组织的诱导增殖和质量;枣树叶片愈伤组织诱导和继代增殖培养适宜的培养基是3/4MS+6-BA0.2 mg.L-1+2,4-D 2.0 mg.L-1+琼脂0.55%+蔗糖3%。6-BAI、BA与TDZ在枣树愈伤组织分化培养中有显著的协同作用,不定芽诱导的适宜培养基是CYI+6-BA 1.0 mg.L-1+IBA 0.2 mg.L-1+TDZ 0.015 mg.L-1。