Successful <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Populus tomentosa</Emphasis> with apple <Emphasis Type="Italic">SPDS</Emphasis> gene

The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.     

Antibacterial activity of moso bamboo shoot skin (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>) against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

This study examined the antibacterial activity of moso bamboo shoot skin (Phyllostachys pubescens). Bamboo shoot skin itself and its dichloromethane extract had antibacterial activity against Staphylococcus aureus. Results suggest the possibility of effective utilization of antibacterial materials from bamboo shoot skins that are mainly discarded at present.     

Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Cultivation of <Emphasis Type="Italic">Pleurotus eryngii</Emphasis> on umbrella plant (<Emphasis Type="Italic">Cyperus alternifolius</Emphasis>) substrate

Mycelial growth and mushroom yields of three strains of Pleurotus eryngii produced on wheat bran-supplemented umbrella plant (Cyperus alternifolius) substrate were assessed using surface brightness, bromophenol blue color reactions, ergosterol and glucosamine contents, and water potential as indicators of strain performance. Mycelial growth was 31%–46% greater, depending on strain, on the umbrella plant substrate compared with the mushroom industry standard sugi (Cryptomeria japonica) substrate. Mushroom yields on the first flush were 20%–23% higher, depending on strain, on the plastic bottle-contained umbrella plant substrate. However, yields on the second break were lower from the umbrella plant substrate. Because many growers in Japan only harvest one flush, production of P. eryngii on umbrella plant substrate may offer commercial producers an alternative basal ingredient to diminishing supplies of sugi sawdust.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002.     

Enzymatic saccharification and ethanol production of <Emphasis Type="Italic">Acacia mangium</Emphasis> and <Emphasis Type="Italic">Paraserianthes falcataria</Emphasis> wood,and <Emphasis Type="Italic">Elaeis guineensis</Emphasis> trunk

We examined the saccharification and fermentation of meals from Acacia mangium wood, Paraserianthes falcataria wood, and Elaeis guineensis trunk. The levels of enzymatic hydrolysis of cellulose and ethanol production were highest for P. falcataria wood and lowest for A. mangium wood. Ultrasonication pretreatment of meal further increased the rates of hydrolysis and ethanol production in meal from P. falcataria wood. Through this pretreatment, hemicelluloses (xylan and xyloglucan) and cellulose were released in the meal from P. falcataria wood. Loosening of hemicellulose associations can be expected to make P. falcataria wood more useful for bioethanol production.     

Fluorescein-labeled wheat germ agglutinin stains the pine wood nematode, <Emphasis Type="Italic">Bursaphelenchus </Emphasis><Emphasis Type="Italic">xylophilus</Emphasis>

Pine wilt disease, caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus), is a major threat to pine forests throughout East Asia. Nonetheless, its mechanism of invasion has not yet been described in detail. To better understand the pathology of this disease, it is important to examine the distribution of PWNs within pine tissue during the course of disease development. We attempted to stain nematodes with fluorescein-conjugated wheat germ agglutinin (F-WGA) as a means to locate and track the spread of PWNs. Although PWNs proliferated on Botrytis cinerea fungus were successfully stained only on their vulvas and spicule holes, PWNs extracted from inoculated Pinus thunbergii seedlings were stained on their surface. Stainability, or the percentage of PWNs stained with F-WGA over more than half of their surface, was about 20% by 1 day after inoculation, but increased to 80% at 10 days. The stainability of PWNs extracted from a 5-cm main stem segment that included the inoculation site was less than that of PWNs extracted from other parts of the main stem farther away (i.e., those that had dispersed). These results suggest that stainability is related to dispersal activity in time. Thus, to raise the stainability of PWNs at shorter timeframes after inoculation, PWNs with more than 80% stainability were re-inoculated into pine seedlings. This resulted in more than 70% stainability from 1 to 6 days after inoculation. In F-WGA stained thin paraffin sections of pine tissue of re-inoculated seedlings, PWNs brightly fluoresced under epifluorescence and were easily detected against the dark background of pine tissue. This staining technique with F-WGA is an excellent tool for detecting PWNs in pine tissue.     

Bioremediation of CCA-treated wood by brown-rot fungi <Emphasis Type="Italic">Fomitopsis palustris</Emphasis>, <Emphasis Type="Italic">Coniophora puteana</Emphasis>, and <Emphasis Type="Italic">Laetiporus sulphureus</Emphasis>

This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at     

Cloning of <Emphasis Type="Italic">XET</Emphasis> gene from <Emphasis Type="Italic">Anthocephalus chinensis</Emphasis> and its plant expression vector construction

A full-length cDNA sequence of xyloglucan endotransglycosylase gene (XET), abundantly expressed in the cambium of Anthocepha-lus chinensis was cloned by conserved PCR, rapid-amplification of cDNA ends and by chromosome walking. Analytical results of the DNA sequence show that a 912 bp complete open reading frame (ORF) encoded a 303-amino acid protein was in the 1205 bp full cDNA sequence. The deduced amino acid sequence of AcXET, which contained the conserved specific EIDFE catalytic site sequence to XETs was homologous to the other known XET proteins. In order to study the gene function of AcXET and obtain transgenic plants, a plant expression vector pBIAcXET was constructed by recombinating the AcXET fragment from the cloning vector pMD19AcXET and the binary vector pBI121 between the XbaI and SmaI sites. The fragment of AcXET gene was inserted between the CaMV 35S promotor and the coding region of the GUS gene in pBI121. The identification results show that the plant expression binary vector pBIAcXET was constructed successfully. These results lay the foundation for studying the molecular mechanism of AcXET gene during wood formation.     

The changes of understory plant diversity in continuous cropping system of <Emphasis Type="Italic">Eucalyptus</Emphasis> plantations,South China

The assessment of biodiversity in managed plantations has become an important issue for long-term sustainability of the ecosystem. The continuous cropping system (CCS) is common practice in Eucalyptus plantations in southern China. In order to clarify the effects of such a practice on species compositions, species diversity, and functional type compositions of understory vegetation, a field trial was installed in the first and second rotations of Eucalyptus plantations. The treatments were replicated three times and arranged in a simple completely randomized design. Vegetation surveys were performed in 1998–2005 following the treatments. Although the CCS had no significant effect on the composition structures in terms of life-form, growth-form, seed dispersal strategies and breeding strategies, there were significant differences in percent coverages of shrub (SLC) and herbaceous layer (HLC) between two types of stand. The CCS reduced the species richness and species diversity remarkably, and was also particularly favorable for r-strategy herbaceous species at the expense of k-strategy woody species in understory vegetation. The repeated disturbances to soil and vegetation including clear-cutting followed by prescribed burning and mechanical plowing maybe the main factor which results in the negative change of understory plant diversity. Although more comprehensive studies on disturbance and a long-term monitoring of a broad-scale project will be required, we suggest that alternative silviculture, consisting of practices other than clear-cutting and prescribed burning, should be introduced to conserve species composition and diversity of Eucalyptus plantations.     

<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Aboveground biomass equations for individual trees of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>, <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> and <Emphasis Type="Italic">Larix kaempferi</Emphasis> in Japan

Generic equations are proposed for stem, branch and foliage biomass of individual trees in even-aged pure stands of Cryptomeria japonica, Chamaecyparis obtusa and Larix kaempferi. Biomass data was collected from a total of 1,016 individual trees from 247 stands throughout Japan, and five regression models were assessed by root mean square error, mean bias, fit index (FI), and AIC. The results show that a power equation using diameter at breast height (dbh) and height is the most suitable for all species and components. This equation is more accurate than the familiar power equation that uses ‘dbh² height’, and it expresses the greater volume of branch and foliage mass of trees with a lower height/diameter ratio. A power equation using dbh is more reasonable for models with dbh as the only independent variable and more accurate than a power equation using ‘dbh² height’ for estimating branch and foliage mass. Estimating error for branch and foliage mass is larger than that for stem mass, but the entire aboveground biomass can be estimated with an error of less than 19%, except in the case of small trees with dbh less than 10 cm.     

Environmentally benign methods for producing green culms of ma bamboo (<Emphasis Type="Italic">Dendrocalamus latiflorus</Emphasis>) and moso bamboo (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>)

The objective of this study was to find an effective method for treating ma bamboo (Dendrocalamus latiflorus) and moso bamboo (Phyllostachys pubescens) using new water-based reagents containing copper. The effects of green-color protection using various treatments on bamboo culms were examined in this study. Two methods were used: heating in a water bath and ultrasonic dipping. The results revealed that excellent green-color protection (a* value of −6.2) was obtained when ma bamboo culms were treated with 0.25% ammoniacal copper quaternary compound-type B (ACQ-B) in a water bath at 100°C for 2 h. It was also found that the wettability of bamboo epidermis increasedsignificantly after pretreatment in a mixture of 1% KOH and surfactant in a water bath at 100°C for 30 min. Furthermore, pretreated moso bamboo culms exhibited excellent green-color protection after they were treated with 0.25% ACQ-B at 100°C for 2 h (a* value of −8.2). This novel treatment method definitely endows the bamboo culms with a fascinating green skin color and consequently could increase the economic value of bamboo products. No improvement in green-color protection was found when ultrasonic energy was added to the water bath at ambient temperature.     

Lignification in developing culms of bamboo <Emphasis Type="Italic">Sinobambusa tootsik</Emphasis>

Bamboos are among the largest woody grasses and grow very rapidly. Although lignin is a crucial factor for the utilization of bamboo biomass, the lignification mechanism of bamboo shoots is poorly understood. We studied lignification in the bamboo Sinobambusa tootsik during culm development. Elongation growth began in May and ended in late-June, when the lignin content was approximately half that in mature culms. Thioacidolysis analysis indicated that p-hydroxyphenyl units in lignin formed even at late stages of lignification. The syringyl/guaiacyl ratio varied during culm development. Various lignin precursors were detected in developing culms by liquid chromatography–mass spectrometry. The ferulic acid content decreased from May to June, indicating that ferulic acid was utilized in early stages of cell wall formation. Monolignol glucosides were detected at early stages of lignification, whereas the contents of monolignols, coniferaldehyde, sinapaldehyde, p-coumaric acid, and ferulic acid peaked at later stages of lignification. Therefore, lignin precursors may be supplied differentially during the lignification process. In August, the rate of lignification decreased, although the contents of various lignin precursors peaked, implying that the rate-limiting step in the cessation of lignification in bamboo is transport or polymerization of lignin precursors, rather than their biosynthesis.     

Pathogenic effects of <Emphasis Type="Italic">Xenorhabdus nematophilus</Emphasis> and <Emphasis Type="Italic">Photorhabdus luminescens</Emphasis> (Enterobacteriaceae) against pupae of the Diamondback Moth, <Emphasis Type="Italic">Plutella xylostella</Emphasis> (L.)

The relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40?% mortality with LC₅₀ values of 5?×?10⁴ and 5.5?×?10⁵ cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.     

Leaf-level responses to light in two co-occurring <Emphasis Type="Italic">Quercus</Emphasis> (<Emphasis Type="Italic">Quercus ilex</Emphasis> and <Emphasis Type="Italic">Quercus suber</Emphasis>): leaf structure,chemical composition and photosynthesis

We studied morphological, biochemical and physiological leaf acclimation to incident Photon-Photosynthetic-Flux-Density (PPFD) in Quercus ilex (holm oak) and Quercus suber (cork oak) at Mediterranean evergreen oak woodlands of southern Portugal. Specific leaf area (SLA) decreased exponentially with increasing PPFD in both species. Q. ilex had lower SLA values than Q. suber. Leaf nitrogen, cellulose and lignin concentration (leaf area-based) scaled positively with PPFD. Maximum rate of carboxylation (V_cmax), capacity for maximum photosynthetic electron transport (J_max), rate of triose-P utilization (V_TPU) and the rate of nonphotorespiratory light respiration (Rd) were also positively correlated with PPFD in both Quercus species, when expressed in leaf area but not on leaf mass basis. Q suber showed to have higher photosynthetic potential (V_cmax, J_max^m and V_TPU^m) and a higher nitrogen efficient nitrogen use than Q.ilex. Leaf chlorophyll concentration increased with decreasing PPFD, improving apparent quantum use efficiency (Φ) in both Quercus species. We concluded that, in Q.ilex and Q.suber, leaf structural plasticity is a stronger determinant for leaf acclimation to PPFD than biochemical and physiological plasticity.     

A novel cold-inducible promoter,P<Emphasis Type="Italic">ThCAP</Emphasis> from <Emphasis Type="Italic">Tamarix hispida</Emphasis>, confers cold tolerance in transgenic <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Our previous studies have revealed that the ThCAP gene plays a vital role in transgenic Populus (P. davidiana × P. bolleana) in response to cold stress. However, the regulatory mechanism of ThCAP gene expression has been unclear. In this study, the 5′ flanking region of the ThCAP promoter (PThCAP) was cloned using a genome-walking method. By analyzing cis-acting regulatory elements of PThCAP, a DRE motif and MYC and MYB elements were found to be located in the promoter. To identify the regulatory elements that control the expression of the ThCAP gene promoter, a series of deletion derivatives of PThCAP, P1–P5, from the translation start code (?1538, ?1190, ?900, ?718 and ?375 bp), were fused to the GUS reporter gene, and then each deletion was stably introduced into Arabidopsis thaliana plants. Deletion analysis of the promoter suggested that only the P2 fragment had strong GUS expression in leaves and roots of A. thaliana exposed to low temperature stress. These results suggest that this 290-bp region (?1190 to ?900 bp), as an important part in PThCAP, was associated with cold tolerance of A. thaliana. Our results provide evidence for the regulatory mechanism of ThCAP gene involved in the response to cold stress, and that the gene is promising candidate gene for genetic improvement of crops.     

Morphological characteristics of <Emphasis Type="Italic">Quercus</Emphasis><Emphasis Type="Italic">variabilis</Emphasis> charcoal prepared at different temperatures

The morphology of charcoals was investigated by scanning electron microscopy. Charcoal of Quercus variabilis was prepared in an electric furnace under nitrogen gas atmosphere at 400, 600, 800 and 1,000°C. Charring temperature greatly affects the structure of charcoal. In charcoal prepared at 400°C, most of the morphological characteristics remained relatively unchanged with the exception of the cell-wall layering. The cell walls appeared homogenous and glass-like. Above 400°C, there was an increase in cell-wall thinning and volumetric shrinkage with an increase in the charring temperature. These two factors were responsible for most of the observed changes in structure. Fracture surfaces became increasingly rough and disrupted. Vessel elements were increasingly distorted and tyloses disintegrated with increases in temperature. Parenchyma cells exhibited greater shrinkage except at the pits. This resulted in the appearance of distinctive small protuberances over the surface of the parenchyma cells. Rhomboidal calcium crystals were found to be abundant at all the temperatures studied, but at 800 and 1,000°C the crystals had a sponge-like appearance.     

High level expression of glucose-6-phosphate dehydrogenase gene <Emphasis Type="Italic">PsG6PDH</Emphasis> from <Emphasis Type="Italic">Populus suaveolens</Emphasis> in <Emphasis Type="Italic">E. coli</Emphasis>

In order to investigate the functions of the gene PsG6PDH and the mechanisms underlying freezing tolerance of Populus suaveolens, the recombinant expression vector pET-G (pET30a-G6PDH), which contained full encoding region of PsG6PDH gene, was established. The recombinant was identified by lawn-PCR and double enzyme digestion and then transformed into expression host XA90 and induced by isopropyl-â-D-thiogalactoside (IPTG) to express 100 kD polypeptide of G6PDH fusion protein. The results showed that the expressed amount of the fusion protein culminated after 1 mmol&#8226;L^–1 IPTG treatment for 4 h and that pET-G product was predominately soluble and not extra-cellular secreting.     

Early establishment of broadleaved trees after logging of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> and <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> plantations with different understory treatments

We studied the effects of the amount of advanced regeneration before logging and different understory treatments on forest recovery, particularly the establishment of lucidophyllous (evergreen broadleaved) species, following the logging of conifer plantation with a focus on the sprouting ability. The establishment of lucidophyllous tree and shrub species originating from advanced regeneration was closely related to the total amount of these elements in the advanced regeneration, regardless of understory treatment. The understory-left treatment could preserve understory as surviving individuals by high proportion (60% or more of the understory) compared with the understory-cleared practice after logging. However, half of the surviving individuals were damaged to some extent by logging and skidding. Relatively large trees were likely to survive with no damage, indicating that they face a lower risk than smaller trees. In understory-cleared stands, a high proportion (60% or more) of the understory regenerated by resprouting. However, the resprouting ratio depended on tree size and species. Therefore, as well as the amount of the understory, the tree size of understory before logging would be also an important factor for early forest recovery. Further, the infrequent (low-density) species could easily disappear after logging because of their low resprouting ratio and low density. Thus, recovery from resprouting alone would risk simplification of the species composition after logging. We concluded that leaving the developed understory intact before logging can enhance the speed and biodiversity of forest recovery.