Glucanohydrolase enzyme activity in embryos of Scots,Corsican and lodgepole pines infected in vitro with Heterobasidion annosum

Embryos of Scots pine (Pinus sylvestris), Corsican pine (P. nigra var. maritima) and Lodgepole pine (P. contorta) were infected in vitro with Heterobasidion annosum and the activities of 1,3-β-glucanase, chitinase and β-glucosidase were monitored. Both the infected and control embryos of the three pine species showed the presence of the enzymes. Statistical analysis showed no significant increase (P > 0.05) in the levels of 1,3-β-glucanase in infected embryos for all the three pine species. However, there was a significant increase in levels of chitinase in infected embryos of P. contorta and P. nigra var. maritima and also in levels of β-glucosidase in infected embryos of all three of the pine species. The study has therefore revealed that constitutive levels of glucanohydrolase enzymes exist in the embryos of the three pine species and that the induction of chitinase and β-glucosidase was a factor in the response of the embryos to stimulation by H. annosum infection.     

Height growth of Korean pine plantation sapling in Benxi, Liaoning Province, China

The height growth of Korean pine plantation was investigated for different ages of saplings in Benxi city of the eastern Liaoning, China. The sapling and seedling age were determined by branch annuals. Results show that the mean height of third- to eight-year Korean pines ranges from 13.31 cm to 111.73 cm and only 19.4% of the saplings reached the height above 130 cm. The height (Y) of eight-year-old Korean pine increases linearly with the increment of ground stem (x) (Y=3.1x+35.15). The relation between height and age can be described by an exponential equation. The second year after planting of the Korean pine is considered as the key period of Korean pine growth really adapting to the local environment; plantation management should be strengthened in this year. The Korean pine seedlings need two years to adapt to the local environment, thus early care and management should be taken in the second year.     

Aboveground biomass of three conifers in the Qianyanzhou plantation, Jiangxi Province, China

Regressive models of the aboveground biomass for three conifers in subtropical China—slash pine (Pinus elliottii), Masson pine (P. massoniana) and Chinese fir (Cunninghamia lanceolata)—were established. Regression analysis of leaf biomass and total biomass of each branch against branch diameter (d), branch length (L), d ³ and d ² L was conducted with functions of linear, power and exponent. A power law equation with a single parameter (d) was proved to be better than the rest for Masson pine and Chinese fir, and a linear equation with parameter (d ³) is better for slash pine. The canopy biomass was derived by adopting the regression equations to all branches of each individual tree. These kinds of equations were also used to fit the relationship between total tree biomass, branch biomass, foliage biomass and tree diameter at breast height (D), tree height (H), D ³ and D ² H, respectively. D ² H was found to be the best parameter for estimating total biomass. However, for foliage biomass and branch biomass, both parameters and equation forms showed some differences among species. Correlations were highly significant (P<0.001) for foliage biomass, branch biomass and total biomass, among which the equation of the total biomass was the highest. With these equations, the aboveground biomass of Masson pine forest, slash pine forest and Chinese fir forest were estimated, in addition to the allocation of aboveground biomass. The above-ground biomass of Masson pine forest, slash pine forest and Chinese fir forest was 83.6, 72.1 and 59 t/hm² respectively, and the stem biomass was more than the foliage biomass and the branch biomass. The underground biomass of these three forests which estimated with others’ research were 10.44, 9.42 and 11.48 t/hm², and the amount of carbon-fixed were 47.94, 45.14 and 37.52 t/hm², respectively. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(8): 1382–1388 [译自: 应用生态学报]     

White spruce recruitment distances relative to lodgepole pine in southern Yukon,Canada

Eleven seral, postfire forest stands in southern Yukon (Canada) were sampled to determine where western white spruce (Picea albertiana ssp. albertiana) seedlings occurred with respect to distance to the nearest lodgepole pine (Pinus contorta var. latifolia) tree. Seedling-to-nearest tree distances were assessed at 10-cm increments up to 220?cm. On average, seedlings occurred 54?cm from the nearest pine (n?=?490), but peak frequencies were 20–50?cm away, compared to a potential separation distance of 103?cm. Greatest average seedling density occurred 10–20?cm from pine (0.81?m^?2), with values between 10 and 120?cm decreasing logarithmatically with increasing distance from pine (r?=?0.994, p?n?=?11). Spruce seedling densities were <0.02?m^?2 beyond 120?cm. The differences in frequency, which represented moderately strong aggregation (Clark-Evans Index 0.34–0.52), and density suggest greater spruce recruitment near lodgepole pine was facilitated by more favorable ecological conditions than further away, for example, greater nutrient availability. The bias in seedling-to-nearest tree distances occurred regardless of stand age (57–165 years), pine density (1599–5935 stems?ha^?1), or understory vegetation type, although the bias may be weakened by the abundant presence of feathermosses (Hylocomium splendens) on the forest floor.     

Pathogenic fungi associated with pre‐ and post‐emergence seedling blight of pine and cypress in Fars Province,Iran

Seed and root rot of pine and cypress seedlings cause heavy annual losses to forest nurseries in Fars Province. Root and crown samples of various species of conifers, such as Tehran pine (Pinus eldarica), brutia pine (Pinus brutia), Arizona cypress (Cupressus arizonica), Shirazian cypress (Cupressus sempervirens var. fastigiata), common cypress (C. sempervirens var. horizontalis) and oriental arborvitae (Thuja orientalis), showing chlorosis, necrosis, stunted growth, defoliation and root and crown rot symptoms were collected from pine and cypress nurseries across Fars province at various time intervals. Infected tissues were washed and cultured on acidified potato dextrose agar (PDA) and corn meal agar (CMA) amended with Delvocide and ampicillin, with and without surface sterilization, respectively, and incubated at 25°C for 3–5 days. Decaying seeds of all plant species were also collected from nursery seed stocks and cultured on PDA. Hyphal tip isolates were used for further studies. Species of Phytophthora, Pythium, Rhizoctonia and Fusarium were isolated from symptomatic seedlings of pine and cypress at different times during the growing season. Pathogenicity of isolates of Phytophthora, Pythium and Rhizoctonia was confirmed on seedlings of all plant species, whereas Fusarium sp. isolated from the seeds of Tehran pine was only pathogenic on seedlings of Tehran pine and Arizona cypress. Virulent isolates identified as Phytophthora nicotiana var. parasitica, Pythium ultimum, Pythium paroecandrum, Rhizoctonia solani and binucleate Rhizoctonia‐like fungus caused root and crown rot of pine and cypress seedlings. Pathogenic isolates of Fusarium identified as Fusarium proliferatum also caused pre‐emergence seed decay of pine and cypress. Isolates of Phytophthora and Pythium were the most virulent of these fungal isolates.     

我国南方杂交松生长和材性的研究

对广东湛江 15年生和广西东门林场 7年生的杂交松试验林的生长和材性进行研究 ,结果表明 :广东湛江 15年生最优良杂交松组合 (正种加勒比松河 6×湿地松混合花粉 )的材积较对照正种加勒比松材积大 1.66倍 ;广西东门林场 7年生杂交松 (湿地松×洪都拉斯加勒比松 ) 3个家系的平均材积较湿地松 60个家系的大 2倍 ,最优良杂交松 (家系 62号 )的材积较湿地松大 2 .88倍。以上优良杂交松可分别在我国热带及南亚热带推广。杂交松的年轮平均密度和晚材率大致处于正种加勒比松和湿地松之间 ,年轮平均密度的差异主要是由于晚材率差异所致。 3种松木的变异模式都是从髓心起逐渐增高 ,到第 8～ 9年变化趋缓 ;杂交松在近树皮处的纤维长度介于两个亲本之间 ,近髓心处的纤维长度略大于两个亲本的纤维长度     

Ozone,Acid Deposition,and Mycorrhization Effects on Loblolly Pine and White Oak

Abstract

Above- and below-ground responses of juvenile loblolly pine (Pinus taedaL.) and white oak (Quercus albaL.) to tropospheric ozone (0.0, 0.06, and 0.12 μL L^-1 O₃), acid precipitation (pH 4.8, 4.2, and 3.6), and induced ectomycorrhizal colonization (Pisolithus tinctorius [Pers.] Coker & Couch vs. natural mycobiont), alone and in combination, were examined. After 30 weeks, the filtered air treatment (ozone 0.0) reduced foliar injury but also produced smaller stem diameters, lower total foliage and total shoot dry weights, decreased needle density, and shorter root systems in inoculated pine, growth responses not found in uninoculated pine. Height growth of inoculated oak was increased by the filtered air treatment while leaf density was reduced by 0.12 μL L^-1 O₃, results also not found in uninoculated oak. Ectomy-corrhizal colonization percentages in pine decreased with increasing O₃ concentration regardless of mycorrhizal treatment, and the filtered air treatment produced the highest infection percentages in inoculated oak as well. Rains of pH 4.2 stimulated height growth in inoculated pine while diameter decreased in inoculated oak but increased in uninoculat-ed oak with declining pH. Also, pH 4.2 rainfall increased root weight in inoculated oak while that of pH 4.8 reduced foliar injury but also shoot weight in oak regardless of mycorrhizal treatment. Generally, the my-corrhization response to increasing rainfall acidity was reduced colonization. Independent of the other treatments, inoculation produced a substantial increase in above- and below-ground growth of both pine and oak, and also increased foliage density but reduced specific root length in each species. Overall, these results indicate that the growth responses to O₃ and acid deposition of loblolly pine and white oak are strongly influenced by mycorrhization, but that the magnitude of these responses is exceeded by those to mycorrhization alone. However, the propensity revealed here for both O₃ and acid precipitation to suppress mycorrhizal colonization in these two species may indicate the potential for a gradual reduction in long-term forest productivity in the southeastern United States.     

Damage caused by Lygus rugulipennis Popp. (Heteroptera,Miridae), to Pinus sylvestris L. seedlings

The tarnished plant bug (Lygus rugulipennis) and occasionally L. punctatus were found to feed on pine seedlings in central Finland. Both the nymphs and adults of Lygus bugs injured the apical meristem of the seedlings. This led to the death of the apex, and the opening of the lateral buds, resulting in a seedling with multiple leaders. L. rugulipennis may also oviposit on pine seedlings and the development from egg to adult on pine alone is possible. In laboratory experiments it was shown that the main factor in the apical meristem injury is the mechanical damage caused by the bug's stylet. The feeding damage and artificial mechanical damage caused by needles to the apical meristem of pine seedlings resulted in increased numbers of multiple‐leader seedlings and reduced shoot length and dry weight of the shoot and root.     

Effects of Acidic Precipitation and Ectomycorrhizal Inoculation on Growth,Mineral Nutrition,and Xylem Water Potential of Juvenile Loblolly Pine and White Oak

Abstract

Individual and interactive effects of simulated acidic rainfall and mycorrhizal inoculation on growth and nutrient and water relations of loblolly pine (Pinus taedaL.) and white oak (Quercus albaL.) grown in a loam soil were examined. Seedlings of each species inoculated with basidiospores of the ectomycorrhizal fungus Pisolithus tinctorius(Pers.) Coker and Couch, a known my-cobiont of both loblolly pine and white oak, and uninoculated control seedlings received two simulated rains per week of either pH 3.6, 4.2, or 4.8 for 26 weeks. Higher acidity rainfall reduced the growth but increased mycorrhizal colonization of loblolly pine, while both loblolly pine and white oak exposed to these rains exhibited greater foliar injury. Inoculation with P. tinctoriusincreased growth and reduced foliar injury of both species. Foliar concentrations of P, S, and Cu in loblolly pine and white oak, Ca in loblolly pine, and Fe and Zn in white oak decreased with increasing rain acidity while the Al concentration of both species increased. Higher rainfall acidity also reduced soil pH and Ca and Mg concentrations while increasing soil AI. Foliage of inoculated seedlings of both species had higher N and P concentrations and lower Al concentrations than control seedlings. Following the final rain applications, a drought cycle was simulated by withholding irrigation for two weeks during which seedling xylem pressure potential and soil water potential were measured. One day after cessation of irrigation, xylem pressure potential of loblolly pine that had received pH 3.6 rains was lower than that of other treatments. Thereafter, xylem pressure potential and soil water potential of the inoculated treatment decreased below those of the control treatment in both species. These results suggest that acid deposition is detrimental to juvenile loblolly pine and white oak, but the magnitude of this effect is less than the positive response to ectomycorrhizal inoculation.     

Fine root biomass,distribution, and production in young pine-hardwood stands

Patterns of fine root biomass, production, and distribution were estimated for pure stands and mixtures of three-year-old loblolly pine (Pinus taeda L.) with red maple (Acer rubrum L.) or black locust (Robinia pseudoacacia L.) on the Virginia Piedmont to determine the role of fine roots in interference between pine and hardwood tree species. Estimates were based on amounts of live and dead fine roots separated from monthly core samples during the third growing season after planting. Live and dead fine root biomass and production varied by species, but mixtures of loblolly pine and black locust generally had greater fine root biomass and fine root production than pure stands or loblolly pine-red maple mixtures. Hardwood species had greater live fine root biomass per tree in mixtures with pine compared to pure stands. Greater live fine root biomass in pine-locust stands may be attributed to differential utilization of the soil volume by fine roots of these species. For all stands, approximately 50% of live five root biomass was located in the upper 10 cm of soil.     

Long-term effect of different planting proportions on forest landscape in Great Xing’an Mountains, Northeast China after the catastrophic fire in 1987

A landscape model (LANDIS) was used to study the long-term forest dynamics under five planting types (100% larch (P₁); 70% larch and 30% Mongolian Scotch pine (Pinus sylvestris var. mongolica) (P₂); 50% larch and 50% Mongolian Scotch pine (P₃); 30% larch and 70% Mongolian Scotch pine (P₄); 100% Mongolian Scotch pine (P₅)), which were also employed in severely burned area under current planting intensity, and under natural regeneration (as a comparison) in Tuqiang Forest Bureau in the northern slopes of Great Xing’an Mountains after the catastrophic fire in 1987. Results showed that different planting types had a significant influence on the abundance of larch, Mongolian Scotch pine and white birch. The abundance of larch increased with time, whereas the abundance of Mongolian Scotch pine was in a converse way. The abundance of larch and Mongolian Scotch pine under these planting scenarios was higher than that under natural regeneration. Under these planting scenarios, the abundance of larch increased with the increasing proportion of larch, and the abundance of Mongolian Scotch pine was in a similar way. Contrary to larch and Mongolian Scotch pine, white birch had higher abundance under natural regeneration than that under these planting scenarios. Also, the different proportions of larch and Mongolian Scotch pine had an influence on the abundance of white birch. White birch had higher abundance with the increasing proportion of Mongolian Scotch pine. As for the total abundance of larch and Mongolian Scotch pine, the difference was not significant under P₂, P₃ and P₄ scenarios, but was higher than that under P1 and P5 scenarios, which indicated that individual-species planting should not be used in the forest landscape. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(5): 855–861 [译自: 应用生态学报]     

Comparative susceptibility of pine,spruce and larch to sapstain

Summary This study compared the susceptibility of five UK‐grown conifer species to colonization by sapstain fungi in two trials carried out in consecutive years. The conifers consisted of Sitka spruce (Picea sitchensis), Japanese larch (Larix kaempferi), Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta). Freshly cut 1‐m logs were exposed to the available inoculum of sapstain fungi from April to August in a woodland environment in the south east of England. Logs of each species were removed after 1‐, 2‐ and 4‐month exposure and sampled destructively to assess the amount of sapstain. In the second trial, per cent moisture content and concentrations of nitrogen, carbohydrate and phenolic compounds in the sapwood were also measured at the start and end of the trial. After 2 months, only the sapwood of both pine species had significant levels of sapstain; mean values of 37% and 19% for lodgepole pine (year 1 and year 2 respectively) and 12% and 1% for Scots pine. After 4 months, the levels of sapstain in both pine species exceeded 60% in both years. By contrast, very little sapstain developed in the other conifer species with maximum mean values of 10% for Norway spruce, 3.5% for larch and less than 1% for Sitka spruce. Overall, the moisture content of the logs decreased progressively in all species over the length of the trial. However, pine logs tended to retain higher levels of moisture throughout the trial compared with spruce or larch. The relatively higher moisture content of pine sapwood may be closer to the optimal moisture content that sapstain fungi require for infection and colonization, thereby contributing to the increased susceptibility of pine compared with the other conifer species. The pine logs also suffered from some colonization by bark beetles (Ips sexdentatus), which increased the inoculum potential and the opportunity for colonization by sapstain fungi. In addition, particular phenolic compounds in conifer sapwood may play a role in determining the resistance of some species to sapstain. Notably the most resistant species, Sitka spruce, was the only softwood that still retained detectable levels of phenolics in the sapwood to the end of the trial.     

Seedling shoot,needle and bud development in three provenances of Pinus sylvestris and Pinus contorta cultivated in northern Sweden

The patterns of current‐year shoot, needle and terminal bud elongation in seedlings of three Scots pine (Pinus sylvestris L.) and three lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) provenances were compared during the third and fourth growing seasons after planting. Lodgepole pine produced longer shoots and buds than did Scots pine, mainly because lodgepole pine formed more stem units and elongated at a faster rate. Stem unit length and the duration of shoot and bud elongation differed relatively little between species and provenances. Lammas or polycyclic growth occurred in some lodgepole pine provenances, but not in any Scots pine provenance, and was associated with enhanced shoot elongation. Needle elongation commenced earlier, proceeded at a faster rate, and was greater in lodgepole pine than in Scots pine, but ceased about the same time in all species and provenances. The heat sum required to attain 50% of final length was lower for shoots and needles in lodgepole pine than in Scots pine, and for shoots in northern provenances than in southern ones. Mitotic activity in the apical meristem of the terminal bud, which occurred less than one week after the seedlings were free from snow, started and ceased about the same time in each species, but was higher in lodgepole pine than in Scots pine early in the shoot elongation period.     

Impact of fixation/drying conditions on fixation rate, teachability and bioefficacy in CCA-C treated red pine and southern pine

Red pine (Pinus resinosia Ait) and southern pine (Pinus spp.) sapwood blocks were pressure treated with CCA-C at retention of 6.4, 2.0, 1.5 kgm^-3 followed by fixation using 11 post-treatment schedules ranging from 50–70 °C and 5 different relative humidity conditions. The effect of these post-treatment schedules on fixation rate, chemical leachability and decay resistant once were evaluated to better understand the effects of fixation/drying conditions on leachability and biodeterioration. Southern pine blocks fixes slightly slower than red pine. Fixation of CCA at high temperature high humidity, essential initially fixation at high humidity for fixation/drying schedules, resulted in lower leaching of chromium and arsenic elements than high temperature low humidity or initially fixation at the high temperature low humidity conditions. Copper leaching was indicated no significant difference under 11 fixation/drying conditions for both species. Weight losses for southern pine byChaetomium globosum was lower than red pine byGloeophyllom trabeum. There were some different capacities of decay resistance for both species under those post treatment conditions.     

Field ready: Development of a rapid LAMP-based colorimetric assay for the causal agent of white pine blister rust,Cronartium ribicola

The invasive fungal pathogen Cronartium ribicola causes white pine blister rust which is considered one of the most destructive diseases of five-needle (white) pines in North America. The disease has a life cycle that requires two hosts: white pines and Ribes spp., although other non-Ribes species, including Castilleja and Pedicularis, have been demonstrated as alternate hosts as well. Detection of this disease can be difficult because of the ephemeral nature of sporulation on pine hosts with ambiguity in other symptoms, and the alternate hosts for C. ribicola can also be an alternate host for other pine rust species. We used the previously published C. ribicola genome and species-specific real-time PCR assay to develop a field-ready loop-mediated isothermal amplification (LAMP) specific colorimetric assay for this pathogen. Specificity results across regionally identified pine rust pathogens showed the assay is highly specific to C. ribicola and can detect as little as 40 pg of pathogen DNA. We also developed a simple DNA extraction method that works with several tissue types (bark/phloem, aeciospores, and urediniospores/telia) to prepare the DNA samples for the LAMP assay. The DNA extraction and LAMP assay take ~70 min to complete and require a relatively small investment in equipment. This tool enables quick and efficient detection of white pine blister rust.     

Direct PCR‐based method for detecting Bursaphelenchus xylophilus,the pine wood nematode in wood tissue of Pinus massoniana

Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, leads to serious losses to pine forestry around the world. Pinus massoniana, which is vulnerable to be attacked by the PWN, is the dominant species used in pine forestry in China. The objective of this study is to develop a direct PCR‐based method for detecting B. xylophilus in the wood of P. massoniana without a separate nematode extraction step. A simple procedure was first developed for isolating B. xylophilus DNA in 5 mg pine wood tissue samples harbouring PWN for detection by PCR amplification. A B. xylophilus‐specific amplicon of 403 bp (DQ855275) was generated by PCR from the infested wood tissue. The entire procedure can be completed within 5 h with one pair of primers. This assay can serve as a rapid, cheap and environmentally friendly method to detect B. xylophilus in samples of P. massoniana.     

Response of Japanese red pine to inoculation with a blue stain fungus,Ceratocystis piceae

To confirm the pathogenicity of a blue stain fungus,Ceratocystis piceae (Münch) Bakshi to the Japanese red pine (Pinus densiflora Sieb. et Zucc.), the responses of healthy young pine trees and stressed trees which were girdled by the half-circumferential girdling technique were investigated by the fungal inoculation test. Although neither of the pine trees inoculated withC. piceae in the non-girdled treatment nor the controls died, mortality of the trees girdled and inoculated withC. piceae was 28.6%. In the pine trees inoculated withC. piceae, the mean area of the necrotic lesion of the sapwood was significantly larger than that of the controls, and the mean of the water pressure potential of the xylem decreased, regardless of the girdling treatment. TheC. piceae was reisolated from the wood pieces near the inoculation points on the inoculated trees, but not from the controls. These results suggest that under strongly stressed conditions, the Japanese red pine trees might have been killed by heavy infestations ofC. piceae carried by bark beetles. A part of this paper was presented at the 103rd Annual Meeting of the Japanese Forestry Society (1992).     

Impact of invasion of pine wood nematode on the growth of dominant shrub Pleioblastus amarus in Pinus massoniana communities

When pine trees are invaded by pine wilt diseases, the severely infected pine trees will die and fall down, or they will be removed when found to be damaged by the disease. It gives rise to the invasion of other species in these empty niches originally occupied by pine trees, i.e., competing surrounding trees or understory shrubs will invade the empty niches during the following years. As a result, the spatial distribution and pattern of the main tree species in a pine forest will change, and a niche variety in the main population will occur. In the end, the direction of the succession and restoration of the pine forest ecosystem will be affected. In our study, a Pinus massoniana forest with the dominant shrub, Pleioblastus amarus, was invaded by pine wood nematode and was clear cut. Selecting this community as our research object, we studied the effect of the invasion of the pine wood nematode on the growth of the dominant shrub, P. amarus, in this Pinus massoniana forest. Our results show that, after the attacked pine trees were removed, the niche was occupied by Pleioblastus amarus and other shrubs, which benefited the growth of P. amarus to its climax. Growth of P. amarus at the climax stage was greater compared with the unhealthy pine forest and the control group.     

Associations between Tomicus destruens and Leptographium spp. in Pinus pinea and P. pinaster stands in Tuscany,central Italy

The association between Tomicus destruens and fungi of the genus Leptographium was studied in Pinus pinea and P. pinaster forests in Tuscany, central Italy. Fungi were isolated from adult beetles and from pine tissues from infested trees. On average, Leptographium spp. were associated with 18% of beetles in breeding galleries, 35% of emergent brood beetles and 18% of beetles undergoing maturation feeding in pine twigs. The fungal species most frequently identified were Leptographium wingfieldii and L. lundbergii while L. guttulatum and L. serpens were also found.