Temporal changes in nitrogen acquisition of Japanese black pine （Pinus thunbergii） associated with black locust （Robinia pseudoacacia）

The alien woody legume, black locust(Robinia pseudoacacia), has invaded Japanese black pine(Pinus thunbergii) forests located in Japan's coastal plain and hill regions where gaps are formed in pine forests after nematode infestation. Nitrogen fixation by legumes accelerates N cycling in forest ecosystems. We studied temporal change in the annual tree-ring resolution N stable isotope composition(δ15N, a per mil deviation of δ15N/14 N ratio, relative to atmospheric N2δ15N=0‰) at two natural locations of Japanese black pine forest with black locust that differed in the time since black locust establishment(Shohnai in northeast and Kita-Kyushu in southwest Japan). Analyzed tree-rings covered the period from 1990/1992 to 2009. N acquisition by Japanese black pine from black locust N input to the soil was evidenced by temporal shifting of N stable isotope composition on the annual pine tree rings. With progressive development of the forest stand, δ15N values of earlier tree-rings δ15N of-5‰) from black pine associated with black locust shifted towards values similar to those of black locust δ15N values nearly to-1‰), which suggests acquisition of N by N2 fixation(Shohnai site). In contrast, in a forest where black locust had settled for two or three generations, in a black pine stand(Kita-Kyushu site), longer periods of N enrichment in the soil were reflected in the elevated tree-ring δ15N values of newly established black pine trees. Based on tree-ring δ15N data from the Shohnai site, we determined that about 10 years after black locust establishment, soil N had already been enriched by black locust N, this, in turn, contributed to N fertilization of surrounding trees in mixed stands.     

Interspecific hybridization between Bursaphelenchus xylophilus and Bursaphelenchus mucronatus

Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe.Bursaphelenchus mucronatus is closely related to B. xylophilus in morphology and host plant specificity. A longrunning debate has existed regarding whether these two species can successfully produce hybrid offspring. In the present study, we performed in the laboratory, hybridization of two B. xylophilus nematode isolates from China and Japan and three B. mucronatus isolates from China, Japan and France. Nematode isolates of B. xylophilus were successfully crossed with B. mucronatus isolates, and the rate of hybridization was relatively high; however, some hybrid offspring died. Successful hybridization occurred between B. xylophilus and B. mucronatus isolates from China, and 22 generations of hybrids were produced. All F1 hybrids could be backcrossed with their parents and produce offspring. Variation in mucro length among the hybrid offspring and their parents was observed. The hybrid offspring and their parents were inoculated into 3-months-old black pine(Pinus tunbergii) seedlings. Weaker pathogenicity of hybrid offspring was observed compared with that of their parents, and significantly fewer offspring nematodes than parents were reisolated from pines. Therefore, the offspring of B. xylophilus and B. mucronatus may exist in the forest and could influence disease epidemics.     

杉木、马尾松裸根苗水分关系研究

Water relation parameters of bare-root seedlings of Chinese fir (Cunninghamia lanceolata Hook.)and Masson pine (Pinus massoniana Lamb.)were measured and changes of root growth potential as well as field survival rate of both species were studied after the bare-root seedlings were exposed in a sunny field condition.the results showed that masson pine had a lower osmotic potential(-2.07Mpa) at turgor loss point and at full turgor(-1.29Mpa),compared with Chinese fir(-1.80Mpa and -1.08Mpa respectively).The parameter Vp/Vo(63.27%) of Masson pine was higher than that of chinese fir (58.03%).This means that Masson pine has a stronger ability to tolerate desiccation,compared to Chinese fir according to analysis of above water relation parameters.Root growth potential and field survival rate decreased with prolonging duration of exposure.The field survival rate of both species was reduced to less than 40% after the seedling being exposed only two hours.Water potentials of -1.60 Mpa and -1.70 Mpa were suggested to be critical values for Chinese fir and Masson pine respectively in successful reforestation.     

Effects of Pulsed Magnetic Field on Biochemical and Physiological Characters and Ultrastructure of Pine Wood Nematode

In this paper,we employed the pulsed magnetic field(PMF) processing to investigate the effect of different pulse rise time and treatment time on the survival,reproduction,cellulase activity and surface characteristics of the pine wood nematode (PWN).The results showed that the wider pulse and the longer treatment time were able to reduce the survival,and inhibit the cellulase activity and reproduction of PWN.The 4th instar and females had a strong resistance to the pulsed magnetic field. With pulse rise time of 10 ms and the treatment of 60 min,the adjusted mortality of PWN was 100%. After the PMF treatment,the cellulase activity of PWN increased within a short time,and then declined with the treatment time.The observation with a scanning electron micrograph(SEM) revealed that there was no significant change in morphology of PWN,but the quantity of rod-shaped bacteria carried by PWN was reduced.     

Fecundity and egg hatchability of Dastarcus helophoroides adults fed on different types of artificial diets

Both fecundities and egg hatchabilities were compared among three populations of Dastarcus helophoroides Fairmaire adults(Coleoptera: Bothrideridae) fed on three types of artificial diets(Diet of formula 1 composed of silkworm pupa powder, dried yeast powder,sucrose, peptone, egg yolk powder and poplar branch powder. Diet of formula 2 composed of silkworm pupa powder, dried yeast powder, sucrose, egg yolk powder,poplar branch powder, cricket powder, benzoic acid and distilled water. Diet of formula 3 composed of pine bark powder and Monochamus alternatus larva powder). for90 days. The three diets showed no significant difference regarding the average number of eggs deposited by all D. helophoroides females(16622.3–23874.7); the average number of eggs per female(1278.6–1836.5); and the average number of eggs per female per day(14.2–20.4).The number of eggs one cluster contained mainly(82.06–82.66 %) lied in 1–100 eggs, and the average number of eggs per cluster ranged from 61.7 to 63.1. In the first 10-day period, the number of eggs deposited by all females fed on formula 1 was significantly larger than that on formula 3. The eggs deposited in the last four 10-day periods were more than in the former five 10-day periods,on formula 3. There were no significant differences in hatchability of total eggs among the three artificial diets,and the average corrected egg hatchability ranged from82.85 to 84.78 %. No significant differences in the adult mortality and mean weight gain of D. helophoroides were found after feeding on three artificial diets. Our results suggest that D. helophoroides adults were not specialized on the diet, and the diet types might have little effect on fecundity and egg hatchability in D. helophoroides, as long as sufficient nutrition was supplied.     

Studies on Electrolyte Conductivity and Activity of Dehydrogenase of Chinese Fir and Masson Pine Bare—Root Seedling under Water and Cold Stress

The electrolyte conductivity and activity of dehydrogenase of bare-root seedlings of both Chinese fir (Cunninghamia lanceolata (Lamb.)Hook.)and Masson pine (Pinus massoniana Lamb.) under freezing and desiccation treatments were studied.The results showed that needle electrolyte conductivity of both speices increase significantly after freezing treatment and there are no significant differences in needle electrolyte conductivity between the two species.The dehydrogenase activity(ARD) of fine roots of both Chinese fir and Masson pine was negatively correlated with increasing freezing and desiccation.The results suggest that both electrolyte conductivity and dehydrogenase activity could be used as quick indicators of Chinese fir and Masson pine bare-root seedling quality.     

Growth response of broom (<Emphasis Type="Italic">Cytisus scoparius</Emphasis>) growing with and without radiata pine (<Emphasis Type="Italic">Pinus radiata</Emphasis>) seedlings to different P levels in soils

A study was carried out to test the effects of three rates of TSP (triple superphosphate) (0, 50, and 100 mg·kg -1 P) on growth of broom with and without radiata pine seedlings and to determine the rela- tionships between P concentrations in the broom shoot and dry matter yields with soil plant-available P (Bray-2 P). A bulk sample of soil was collected from Kaweka forest at soil depth of 0 10 cm, in New Zealand on March 11, 2001. The forest area was not supplied with fertiliser at least 30 years. The results show that TSP application increased P avail- ability in the soil. The P availability concentration in soil of broom with radiata pine seedlings was higher than that in soil of broom alone. Bray-2 P concentrations had a significant logarithmic relationship with P con- centrations of broom shoot and an exponential relationship with dry matter weight of whole broom plant.     

Effect of drying methods on the discoloration of three major domestic softwood species in Korea

1 Introduction Three major softwood species in Korea are Japanese pine (Pinus densiflora), Korean pine (Pinus koraiensis) and larch (Larix leptolepis) which have been used for traditional buildings and furniture for a long period of time. They are easily discolored due to drying and UV irradiation. It has been observed that the discoloration varies with different drying methods and the extent of UV irradiation (Mottonen and Luostarinen, 2001; Kang, 2003). To prevent beech from discolorat…     

Genetic Differentiation of Pinus koraiensis under Different Altitude Conditions in Changbai Mountain

The genetic differentiation of Korean pine (Pinus koraiensis) in different altitudes in Changbai Mountain was analyzed by ISSR technique, and it was found that the level of genetic diversity of Korean pine reduces along with altitude increasing in Changbai Mountain. The variation of Korean pine is mainly from intra-population and there is a positive relativity between genetic distance and vertical geographic distance of Korean pine in different altitudes. The genedc coherence shows that altitude has less insulation to Korean pine. Therefore, it is deduced that the terrain formation of vertical distribution of Korean pine is a result of diffusion from lower altitude to higher altitude in the course of enlarging its adaptability.     

松材线虫伴生细菌的分离鉴定及其致病性

从松材线虫虫体上分离到两个细菌菌株:GD1和R,经鉴定,菌株GD1为坚强芽孢杆菌.利用水培马尾松离体松枝作接种材料,接种消毒后的松材线虫(Bx)、GD1、R、Bx GD1和Bx R.结果表明,松材线虫和坚强芽孢杆菌混合接种,松枝发病,松枝流脂减少至停止,蒸腾作用降低,单独接种松材线虫或坚强芽孢杆菌,松枝不发病.菌株R对松材线虫病的发生没有影响.提出松材线虫及其伴生细菌均是松材线虫病不可缺少的致病因素.     

松材线虫侵染对松树苯丙氨酸解氨酶及酚类物质的影响

以湿地松（Pinus elliottii Engelm）、日本黑松（Pinus thunbergii Parl）为材料,研究松材线虫[Bursaphelenchus xylophilus（Steiner＆Buhrer,1934）Nickle]感染对苯丙氨酸解氨酶和酚类物质的影响.两种松树的苯丙氨酸解氨酶的活性在发病过程中都有明显增加,并且伴随着酶活性的变化,各种苯丙烷次生代谢产物,如总酚、类黄酮的含量也发生明显的变化.但湿地松在苯丙氨酸解氨酶活力和酚类物质的积累上的变化比黑松要大些.结果表明,松材线虫病的发生、发展与寄主植物苯丙氨酸解氨酶活性和酚类物质含量变化有关.     

一种利用黑松枝条筛选杀松材线虫剂的生测方法

该文介绍了一种利用黑松枝条进行化合物对松材线虫作用的生测方法。通过研究枝条的接种线虫数量、含水量以及灭菌处理后对松材线虫繁殖的影响,确定了合适的生测条件,并对几种生测方法的优缺点进行了讨论。     

松材线虫入侵的黑松内栖真菌区系初步研究

松材线虫（Bursaphelenchus xylophilus（Steiner ＆ Buhrer）Nickle）是毁灭性森林病害——松材线虫病的病原物，主要危害针叶树种，尤其是松属（Pinus spp．）树种。黑松（Pinus thunbergii Pad．）原产日本及朝鲜半岛东部沿海地区，因其耐海雾、抗海风、可在海滩上生长等特性，在我国辽宁、山东、河北、江苏、安徽、浙江、福建、湖北、广东等省大量栽植，总面积约159300hm^2。研究证明，黑松是松材线虫病的高度感病树种，一旦松材线虫入侵，后果是毁灭性的，将给森林造成严重的、不可挽回的损失。     

马尾松抗松材线虫病候选无性系的抗病性测定

为筛选抗松材线虫病强的马尾松无性系,以前期筛选获得的抗松材线虫病强的马尾松实生苗为接穗,使用湿地松作为砧木培育嫁接苗,开展无性系2次接种松材线虫抗病性测定。结果表明:使用湿地松作为砧木培育马尾松抗性无性系苗木,经过对马尾松无性系嫁接苗2次接种松材线虫测定,获得健全率较火炬松高的无性系。抗病性第1次、第2次测定的健全率超过火炬松的合格无性系分别为77.7%、66.2%,平均健全率分别为81.4%、94.5%,对照树种火炬松平均健全率分别为61.3%和82.1%,获得的无性系抗病性显著提高。为了减小误差,应该选用嫁接成活苗数量相对多的无性系间进行抗病性强弱次序评价。采用了10株以上无性系间抗病性强弱次序评价进行对照,减少了抗性强弱无性系两极分化,抗性能力中等的无性系相应增多,在选拔植株营建抗性种子园过程中应给予重视,尽量选择接种测定数量较多的高抗无性系。     

Identification of Cylindrocladium sp. causing damping-off disease of Japanese black pine (Pinus thunbergii) and factors affecting the disease severity in a black locust (Robinia pseudoacacia)-dominated area

The regeneration of Japanese black pine (Pinus thunbergii) seedlings is inhibited in a black locust (Robinia pseudoacacia)-dominated area. We examined the presence of pathogenic fungi in Japanese black pine seedlings in the area in order to determine the effect of pathogenic fungi on the inhibition of regeneration. When Japanese black pine seedlings were planted in the soil obtained from a black locust-dominated area, all of the seedlings died under low-intensity light conditions, whereas 84% of the seedlings survived in the soil obtained from a Japanese black pine-dominated area under the same light conditions. One fungus was isolated from 48.7% of the dead pine seedlings and was identified as Cylindrocladium pacificum Kang, Crous & Schoch, based on the morphological characteristics, growth, and DNA analysis. This fungus was also isolated from 50% of the dead pine seedlings in 2005 and 66.7% of the seedlings in 2006—both were planted in a black locust-dominated area. The virulence of this fungus increased under high-nitrogen and/or low-intensity light conditions. These results reveal the possibility that the soil eutrophication and shading by the black locust are conducive to a severe damping-off disease and threaten the survival and regeneration of Japanese black pine seedlings.     

The effects of long‐term exposure to simulated acid rain on the development of pine wilt disease caused by Bursaphelenchus xylophilus

To elucidate the synergetic effects of acid rain on the development of pine wilt disease, we measured the sap flow rate in the stems and the chlorophyll content in the needles of 10‐year‐old Japanese black pine trees, Pinus thunbergii and 12‐year‐old Japanese red pine trees, Pinus densiflora, after exposure to simulated acid rain (SAR, pH 3) or tap water (TW, pH 6.3) as a control. The heat pulse method was used for the estimation of the sap flow rate. No apparent difference was found in the sap flow rate between the trees exposed to SAR and TW, but the chlorophyll content of needles at the end of the treatment was significantly higher in the trees exposed to SAR than in those exposed to TW. When the pinewood nematode, Bursaphelenchus xylophilus, the causal agent of pine wilt disease, was inoculated onto the Japanese black pines that had been exposed to SAR repeatedly for 1 year, the period to death was shortened. Japanese red pines that had been exposed to SAR for 2 years, however, did not show any development of symptoms after the nematode inoculation, suggesting that acid rain only affects pine wilt disease slightly, if at all.     

保松灵防治松墨天牛的林间试验

松材线虫病 [Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle]严重威胁我国的森林资源。浙江等地每年因该病造成大量松树枯死 ,防治松材线虫病刻不容缓。当前 ,我国防治该病主要措施是清理枯死松树 ,降低媒介昆虫松墨天牛 (Monochamus alternatus Hope)密度 ,减缓病害扩散蔓延。但在风景名胜区的松林和古树名木等 ,一旦发生该病 ,仅清理死树是不够的 ,必须采取保护性措施 ,防止因病害导致大量宝贵松树枯死。在日本 ,长期以来主要措施是在松树树冠进行空中或地面喷洒杀螟松、倍硫磷、西维因等农药 ,杀灭松墨天牛成虫 ,从而防治松…     

几种物质对松材线虫的作用

松材线虫病是松树的一种毁灭性病害。本文选用了几种物质，采用浸泡生测法和棉球生测法测定了其对松材线虫的作用。结果表明，阿维菌素对松材线虫的杀线活性较强，米乐尔次之，狼牙刺种子粗提物和氯化铵的杀线活性均较弱，氯化钙则无杀线活性。阿维菌素和米乐尔对松材线虫繁殖均有较强的抑制作用，狼牙刺种子粗提物的抑制作用较弱，氯化铵无抑制作用，而氯化钙对松材线虫的繁殖具有促进作用。     

Different development of pine wilt disease in artificially infectedPinus thunbergii seedlings potted together with different tree species

To evaluate the effect of adjacent tree species on the susceptibility of Japanese black pine (Pinus thunbergii) to pine wilt disease, an inoculation experiment was conducted usingP. thunbergii seedlings potted with seedlings of six tree species,i. e. Alnus sieboldiana, Eurya japonica, Lespedeza bicolor formacutifolia, Pinus thumbergii, Robinia pseudo-acacia andSarothamus scoparius. About ten months after planting, they were inoculated with the pinewood nematode (Bursaphelenchus xylophilus) in early July 1992. After that, the proportion of pine seedlings with completely discolored foliage increased more quickly when the seedlings were potted withR. pseudo-acacia, S. scoparius orA. sieboldiana than when potted withP. thunbergii, L. bicolor orE. japonica. At the end of the study period, 17 weeks after inoculation, it reached 90.6%, 90.0%, 87.5%, 72.7%, 63.3%, and 59.4% when the pine seedlings were potted withR. pseudo-acacia, S. scoparius, A. sieboldiana, P. thunbergii, L. bicolor andE. japonica, respectively. This indicated that the susceptibility ofP. thunbergii seedlings to pine wilt disease was influence by the species of adjacent trees.