中国笋用竹的栽培优选种

在中国534个竹子种类中，遴选了153种笋用竹。其中刚竹属、箭竹属、牡竹属、寒竹属、香竹属和绿竹属占据笋用竹种类的78％。在笋用竹中，56种具有商业价值，其中的16种具有世界市场。通过对所有笋用竹的商业价值、形态特征、生态特征和种植特点的种植潜力指数评价，将笋用竹分为5个类别：第一类（9种）具有很高的商业价值，大面积种植前景，第二类（33种）可以区域性种植。     

Analysis on residue formation during wood liquefaction with polyhydric alcohol

Liquefactions of cellulose powder, steamed lignin, alkali lignin, and their mixtures were carried out to analyze the reaction process of wood using polyhydric alcohol. The liquefaction of wood proceeded immediately and wood components were converted to N,N-dimethylformamide (DMF)-soluble components. After that, the condensation reaction occurred with increasing reaction time. However, none of cellulose powder, steamed lignin, and alkali lignin condensed by themselves during their liquefaction. The mixture of cellulose and lignin was also liquefied, and condensed after a long reaction time. The results of analysis showed that the behavior of the mixture resembled that of wood with respect to molecular weight distribution and the main functional groups. Lignin was converted to DMF-soluble compounds in the initial stage of wood liquefaction, followed by cellulose gradually being converted into soluble compounds. After that, condensation reactions took place among some parts of depolymerized and degraded compounds from cellulose and lignin, and were converted into DMF-insoluble compounds. It was concluded that the rate-determining step of wood liquefaction was the depolymerization of cellulose. Furthermore, it was suggested that the condensation reaction was due to the mutual reaction among depolymerized cellulose and degraded aromatic derivatives from lignin or due to the nucleophilic displacement reaction of cellulose by phenoxide ion.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

Lignans ofLinum flavum var.compactum

A new dibenzylbutyrolactone lignan 7.6-dihydroxybursehernin, together with six known lignans (pinoresinol, lariciresinol, secoisolariciresinol,-peltatin,-peltatin, 5-methoxypodophyllotoxin) were isolated from the methanol extracts ofLinum flavum var.compactum. The enantiomeric analysis of pinoresinol and lariciresinol isolated from the species, which are upstream lignans in the lignan biosynthetic pathway, indicated that they are not optically pure, which is in accordance with our recent findings on lignans occurring in other plant species.Parts of this report were presented at the 42nd Lignin Symposium, Sapporo, October 1997; and the 43rd Lignin Symposium, Fuchu, October 1998     

Potential of Nepalese entomopathogenic nematodes as biocontrol agents against <Emphasis Type="Italic">Holotrichia longipennis</Emphasis> Blanch. (Coleoptera: Scarabaeidae)

Holotrichia longipennis Blanch. (Coleoptera: Scarabaeidae) is a serious pest of commercial crops in Siduwa, Dhankuta, Nepal. Seven indigenous isolates of entomopathogenic nematodes (Steinernema lamjungense LMT5, S. lamjungense SS4, S. everestense DKP4, S. abbasi CS1, S. sp. KL1, Heterorhabditis indica CK2 and H. indica CK6) were used in a series of bioassays against the insect. All isolates showed an increased dispersal in response to H. longipennis. Nematodes were more attracted towards third instar larvae than to second instars. Differences in penetration and multiplication in the insect were observed amongst the seven isolates. Steinernema lamjungense LMT5, S. everestense DKP4 and S. abbasi CS1 caused greater mortality than other isolates to different developmental stages. Pupae and second instar larvae were more susceptible than third instar larvae. Significant differences were observed in LT₅₀ values of the isolates against different stages of H. longipennis. Three isolates (S. lamjungense LMT5, S. everestense DKP4 and S. abbasi CS1) along with a commonly used insecticide (chlorpyrifos) were tested against this insect in pot and field experiments. In pot experiments using maize and cabbage as a host crop, S. lamjungense LMT5 and S. everestense DKP4 performed better than S. abbasi CS1 and yielded a mortality comparable with chlorpyrifos. Similar results were observed in field experiments 3 weeks after nematode application. These experiments overall suggest S. lamjungense LMT5 to be a promising biocontrol agent against H. longipennis followed by S. everestense DKP4 and S. abbasi CS1.     

Estimation of the root colonization of soybean by an arbuscular mycorrhizal fungus,Gigaspora rosea,based on specific fatty acid profiles

Root colonization by arbuscular mycorrhizal (AM) fungi has traditionally been analyzed by microscopy. However, this method is time consuming and it is often difficult to distinguish between AM and non-AM fungi. In this study, we analyzed the fatty acid profiles in soybean roots colonized by AM fungi to determine if specific fatty acids derived from AM fungi can be used as markers for the intensity of the AM fungal colonization. The wild-type Enrei and hypernodulating Kanto100 soybean cultivars were inoculated with an AM fungus (Gigaspora rosea) alone or with Bradyrhizobium diazoefficiens, which nodulates soybean roots. Fatty acids 20:1ω9, 20:4ω6, and 20:5ω3 were specifically detected in the lateral roots of AM fungus-inoculated and dual-inoculated soybean plants. In the second lateral roots, the percentage of AM-specific fatty acids (i.e., 20:1ω9, 20:4ω6, and 20:5ω3) derived from AM fungi was closely correlated with the intensity of the AM fungal colonization. We propose that the AM-specific fatty acids represent useful markers for estimating the degree of AM fungal colonization. The percentage of AM-specific fatty acids was more than twofold higher in the second lateral roots than in the first lateral roots. Thus, the degree of AM fungal colonization is probably twofold higher in the second lateral roots than in the first lateral roots.     

Involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization in soybean roots

Soybean plants autoregulate to suppress excessive nodulation. It has been revealed recently that the autoregulation of various legumes controls both nodulation and arbuscular mycorrhizal (AM) fungal colonization. We investigated the involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization. We used a wild-type soybean cv. Enrei and its hypernodulating mutant Kanto100, defective in the autoregulation. We included four different treatments: an uninoculated control, inoculation with rhizobium Bradyrhizobium japonicum alone, inoculation with AM fungus Gigaspora rosea alone, and dual inoculation with rhizobium and AM fungus. In both Enrei and Kanto100, AM fungal colonization enhanced the weight and N₂ fixation of nodules, suggesting that autoregulation of host plant is not involved in the stimulatory effect of AM fungal colonization on rhizobial nodulation. In plants with the AM fungus alone, the AM fungal colonization of Enrei was comparable to that of Kanto100. In plants with dual inoculation, however, this was significantly (P?<?0.05) lower than in Kanto100. To confirm the control of AM fungal colonization by the autoregulation of host plant, a reciprocal grafting experiment was performed between Enrei and Kanto100. In plants with the AM fungus alone, AM fungal colonization was comparable among Enrei (shoot)/Enrei (root), Enrei/Kanto100, Kanto100/Enrei, and Kanto100/Kanto100 grafts. In plants with dual inoculation, however, AM fungal colonization of Enrei/Enrei and Enrei/Kanto100 grafts was significantly (P?<?0.05) lower than that of Kanto100/Enrei and Kanto100/Kanto100. These results indicate that rhizobial nodulation suppresses AM fungal colonization, and the autoregulation of host plant, initiated by nodulation, is involved in this phenomenon.     

Effect of stocking density and addition of proteins on larval survival in Japanese flounder, Paralichthys olivaceus

The effects of larval density, rearing media, and protein additions on fish larval survival were tested by rearing larvae in small containers. Yolk-sac larvae of Japanese flounder, Paralichthys olivaceus, were transferred 1 day after hatching to plastic dishes and cell-culture microplates by Pasture pipette at densities ranging from 0.3 to 30 individuals/ml and incubated at 16 °C without food. Dead larvae were removed and counted every 12 h. Three peaks of larval mortality were observed: the first peak appeared just after the transfer, the second corresponded to the completion of yolk absorption, and the third occurred 10–12 days after the transfer. Since about 50% of larvae survived until the third peak, it was clear that mortality at the second peak (completion of yolk absorption; equivalent to the first feeding) was not due to starvation. At the first mortality peak, better survival was unexpectedly recorded at higher larval densities (30 individuals/ml), suggesting that some material beneficial for survival is derived from the larvae. This idea was further supported by the improved survival in media previously used to rear larvae at high densities. The addition of bovine serum albumin (BSA) at 10 μg/ml effectively reduced mortality in microplates and in 30-l tanks. To reduce the larval mortality just after handling, addition of egg white at a dilution rate of 1/30,000 (vol/vol) or less is recommended as a practical alternative to BSA. Since the addition of polyethylene glycol 6000 (1 μg/ml) also effectively reduced mortality, reduction in mortality could not be attributed to a specific mechanism. The precise determination of the magnitude and timing of larval mortality was attained through the use of small containers, and a method to prevent mortality due to handling was identified in this study. These types of tests may allow the logical evaluation and establishment of better rearing procedures for seed production in aquaculture.     

Enzyme-linked immunosorbent assay with monoclonal and single-chain variable fragment antibodies selective to coplanar polychlorinated biphenyls

Coplanar polychlorinated biphenyls (Co-PCBs) consisting of non-ortho and mono-ortho-chlorinated PCBs are dioxin-like compounds and cause wide contamination in the environment. To monitor Co-PCB residues, it was attempted to establish an enzyme-linked immunosorbent assay (ELISA) with monoclonal and recombinant antibodies selective to Co-PCBs. When 3,3',5,5'-tetrachlorobiphenoxybutyric acid (PCBH)-keyhole limpet hemocyanin conjugate was immunized into mice, two monoclonal antibodies, Mab-0217 and Mab-4444, were obtained. 3,3',5,5'-Tetrachlorobiphenyl (PCB80) was determined with an IC(50) value of 2.6 and 0.46 ng mL(-1) in ELISA based on Mab-0217 and Mab-4444, respectively. Mab-4444 cross-reacted with Co-PCB congeners, except for PCB77 and PCB81. Mab-0217 reacted with PCB80 and cross-reacted with PCB111. A single-chain variable fragment (scFv) antibody derived from Mab-4444 was produced in recombinant Escherichia coli cells. The scFv antibody showed nearly the same sensitivity toward PCBH as the parent monoclonal antibody in ELISA. These results clearly suggested that Mab-4444 and its scFv antibodies were suitable for monitoring the representative congeners of Co-PCBs.     

First report of triploidy in Ailanthus altissima,an invasive tree species

Ailanthus altissima is a woody plant that has become invasively naturalized in many countries. Using nuclear SSR markers, we studied specimens of this species collected throughout Japan and found an individual (labeled Aa-1) that was not diploid. We examined pollen morphology and ploidy level of Aa-1 by optical microscopy and flow cytometry (FCM), respectively. Some pollen grains were morphologically abnormal and much larger than normal. FCM analysis demonstrated that Aa-1 was triploid. Formation of abnormal pollen indicates that Aa-1 may well have reduced fertility compared to normal diploids. If this were the case, vegetative progeny Aa-1 could be used as ornamentals without attendant risks of future naturalization.