Responses of Pinus clausa, Pinus serotina and Pinus taeda seedlings to anaerobic solution culture. II. Changes in tissue nutrient concentration and net acquisition

Fifteen or 30 days of anaerobic growth conditions significantly reduced shoot and root nitrogen, potassium, phosphorus, iron and manganese concentrations in seedlings of pond pine ( Pinus serotina Michx.), sand pine [ P. clausa (Engelm.) Sarg.] and drought-hardy and wet-site loblolly pine ( P. taeda L.) grown in a culture system using non-circulating, continuously flowing solution. Calcium and shoot magnesium levels were least affected by anaerobic growth conditions – largely reflecting the passive nature of their uptake. Shoot and root nutrient content (mg nutrient pot^-1) followed similar trends, with wet-site loblolly and pond pine seedlings least affected by anaerobic solution culture. Shoot biomass of wet-site loblolly and pond pine seedlings was not affected by anaerobiosis, suggesting an increase in shoot nutrient utilization efficiency. Root biomass was significantly reduced by 15 or 30 days of anaerobiosis, with sand pine exhibiting the largest reduction in root dry weight (57%).
These results suggest that anaerobiosis interferes with net nutrient acquisition, even under the high nutrient conditions provided by solution culture. Sand pine suffered the largest reductions in shoot and root biomass and nutrient concentrations, showing earlier symptoms of waterlogging injury and nutrient stress than drought-hardy loblolly pine seedlings. Whether net nutrient acquisition decreased because of the reduction in root surface area available for absorption and/or reduced uptake efficiency cannot be ascertained from these data.     

Does It Make Sense to Restore Wildland Fire in Changing Climate?

Forest restoration guided by historical reference conditions of fire regime, forest structure, and composition has been increasingly and successfully applied in fire‐adapted forests of western North America. But because climate change is expected to alter vegetation distributions and foster severe disturbances, does it make sense to restore the ecological role of wildland fire through management burning and related activities such as tree thinning? I suggest that some site‐ and date‐specific historical conditions may be less relevant, but reference conditions in the broad sense are still useful. Reference conditions encompass not only the recent past but also evolutionary history, reflecting the role of fire as a selective force over millennia. Taking a long‐term functional view of historical reference conditions as the result of evolutionary processes can provide insights into past forest adaptations and migrations under various climates. As future climates change, historical reference data from lower, southerly, and drier sites may be useful in places that are higher, northerly, and currently wetter. Almost all models suggest that the future will have substantial increases in wildfire occurrence, but prior to recent human‐caused fire exclusion, fire‐adapted pine forests of western North America were among the most frequently burned in the world. Restoration of patterns of burning and fuels/forest structure that reasonably emulate historical conditions prior to fire exclusion is consistent with reducing the susceptibility of these ecosystems to catastrophic loss. Priorities may include fire and thinning treatments of upper elevation ecotones to facilitate forest migration, whereas vulnerable low‐elevation forests may merit less management investment.     

Attraction to monoterpenes and beetle‐produced compounds by syntopic Ips and Dendroctonus bark beetles and their predators

• 1 Bark beetles are significant mortality agents of conifers. Four beetle species, the pine engraver Ips pini, the six‐spined pine engraver Ips calligraphus sub. ponderosae, the southern pine beetle Dendroctonus frontalis, and the western pine beetle Dendroctonus brevicomis, cohabitate pines in Arizona.
• 2 A pheromone trapping study in ponderosa forests of Arizona determined the attraction of beetles to conspecific and heterospecific pheromone components in the presence and absence of host volatiles, and tested whether predators differ in their attraction to combinations of pheromone components and tree monoterpenes.
• 3 All four bark beetle species differed in their responses to heterospecific lures and monoterpenes. Ips calligraphus was the only species that increased in trap catches when heterospecific lures were added. Heterospecific lures did not inhibit the attraction of either Dendroctonus or Ips species. The replacement of myrcene with α‐pinene increased the attraction of Dendroctonus, whereas the addition of α‐pinene had mixed results for Ips. The prominent predators Temnochila chlorodia and Enoclerus lecontei were more attracted to the I. pini lure than the D. brevicomis lure, and the combination of the two lures with α‐pinene was most attractive to both predator species.
• 4 Cross attraction and limited inhibition of bark beetles to heterospecific pheromones suggest that some of these species might use heterospecific compounds to increase successful location and colonization of trees. Predator responses to treatments suggest that tree volatiles are used to locate potential prey and predators are more responsive to Ips than to Dendroctonus pheromone components in Arizona.

     

皮下接种松墨天牛卵及幼虫致死松树的研究

为了探明松墨天牛MonochamusalternatusHope直接致死松树的作用 ,作者采用在健康松树皮下接入松墨天牛卵或初孵幼虫方法做了试验和观察。结果表明 ,接入卵或初孵幼虫的松树平均枯死率为41 . 7%。松树枯死取决于松墨天牛幼虫取食时对松树韧皮部的破坏程度。每株接入 5个单位 (1单位指1粒卵或条初孵幼虫 ) ,松树枯死率达 85. 7% ;接入 1个单位 ,枯死率为 1 0 %。初步结论是 ,松墨天牛是引起松树枯死的主要原因之一 ;大力防治松墨天牛是保护我国松林的关键。     

Predators and competitors of the mountain pine beetle Dendroctonus ponderosae (Coleoptera: Curculionidae) in stands of changing forest composition associated with elevation

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Mountain pine beetle host-range expansion threatens the boreal forest

The current epidemic of the mountain pine beetle (MPB), an indigenous pest of western North American pine, has resulted in significant losses of lodgepole pine. The leading edge has reached Alberta where forest composition shifts from lodgepole to jack pine through a hybrid zone. The susceptibility of jack pine to MPB is a major concern, but there has been no evidence of host-range expansion, in part due to the difficulty in distinguishing the parentals and their hybrids. We tested the utility of a panel of microsatellite loci optimized for both species to classify lodgepole pine, jack pine and their hybrids using simulated data. We were able to accurately classify simulated individuals, and hence applied these markers to identify the ancestry of attacked trees. Here we show for the first time successful MPB attack in natural jack pine stands at the leading edge of the epidemic. This once unsuitable habitat is now a novel environment for MPB to exploit, a potential risk which could be exacerbated by further climate change. The consequences of host-range expansion for the vast boreal ecosystem could be significant.     

萧氏松茎象危害与松树松脂量关系研究初报

萧氏松茎象HylobitelusxiaoiZhang是近年来暴发性松树害虫 ,主要危害 3种松树 :湿地松 (PinuselliottiiEngelm)、火炬松 (P .taeda)、马尾松 (P .massoniaanaLamb) ,其中以湿地松受害最为严重。为明确萧氏松茎象的危害与松脂流量的关系 ,作者对萧氏松茎象危害前后 3种松树 (湿地松、马尾松、火炬松 )松脂流量变化进行了研究。结果显示 ,在松树受害植株和未受害植株间松脂总流量间存在一定差异 ,其中以马尾松松脂流量变化最大 ,对受害株和未受害株松脂流量t-测验 ,差异达到显著水平 ;而湿地松和火炬松松脂总流量在受害植株和未受害植株间没有显著差异。对上述 3种松树松脂流量随时序动态变化的分析显示 ,松脂流量在 1年中以 5月到 6月之间为松脂流量高峰期 ,此后逐渐下降 ,到 3月中旬以后松脂流量又开始上升。就松脂流量时序动态而言 ,萧氏松茎象为害对马尾松松脂流量影响最大 ,对其它2个松树影响不明显。另外 ,不同松树树种在松脂流量及其时序动态上也存在一定差异 ,其中以马尾松脂流量较高。     

Identifying southern yellow pine cross sections from the southeastern United States using quadratic discriminant analysis on pith and second annual ring diameters

Southern yellow pine specimens collected from historical structures, stumps, and coarse woody debris in forests have been difficult to identify at the species level due to similar wood anatomy. This can be problematic for dendrochronologists when identifying the correct species used in the construction of historical structures, or reconstructing forest history on the landscape and using those specimens in the context of that history. We applied a quadratic discriminant analysis (QDA) to update a century-old method plotting pith diameters against second annual ring diameters to discern one species of southern yellow pine from others. Our analysis estimates error rates for false positive and false negative determinations when comparing longleaf pine (Pinus palustris Mill.) to shortleaf (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.). The cross-validated false positive error rates for the smallest dataset (n = 46), was nearly twice (9.52%) that determined as a simple proportion by counting errant observations (4.76%). QDA of the largest dataset (n = 206) gave a flatter zero contour and false positive rate (3.13%) like the proportionally determined value (1.56%), despite one additional observation being falsely assigned to longleaf pine by QDA. An unknown, unearthed southern pine specimen from southeastern Virginia was radiocarbon dated up to 500 years prior and assigned as longleaf by our method (probability ≥ 0.9998). Thus, through a QDA, it is possible to greatly improve confidence in identifications of key unknown specimens that can provide evidence of discerning one species, longleaf pine, from other southern yellow pines.     

In vitro adventitious shoot formation from embryonic and cotyledonary tissues of Pinus brutia Ten.

Adventitious buds were induced when isolated whole embryos, and excised cotyledons from treated seeds of Calabrian pine (Pinus brutia Ten.) were cultured on a cytokinin-supplemented medium. The adventitious buds formed directly from the cotyledons. The highest number of bud primordia were formed, with both embryos and excised cotyledons, after 6 weeks on a BAP — supplemented Schenk and Hildebrandt medium under a 16 h photoperiod. The buds, when separated and maintained individually on a full-strength medium without growth regulators, developed into well-formed shoots within 4 weeks. The average number of harvested shoots obtained (>1 cm in height) per seed over 24 weeks was 55; however, a maximum number of 152 shoots was obtained from one individual over the same period. The shoot forming capacity of the meristematic tissue was not lost after seven harvests.     

Responses of Pinus clausa, Pinus serotina and Pinus taeda seedlings to anaerobic solution culture. I. Changes in growth and root morphology

Seedlings of pond pine ( Pinus serotina Michx.), sand pine [ P. clausa (Engelm.) Sarg.] and two edaphic seed sources of loblolly pine ( P. taeda L., dry- and wet-site seed sources) were grown in non-circulating, continuously flowing solution culture under aerobic (250 μ M O₂) and anaerobic (≤ 23 μ M O₂) conditions. Survival was 100% for all seedlings at 11 weeks. Although shoot height, biomass and leaf emergence of loblolly and pond pine seedlings were not significantly affected by 15 or 30 days of anaerobic growth conditions, root biomass was significantly reduced. Sand pine suffered the largest reduction in biomass, showing extensive root dieback and shoot chlorosis with retarded leaf development. These anaerobically induced symptoms of flooding injury were less severe in dry-site loblolly pine, and absent in wet-site loblolly and pond pine seedlings. Adventitious or new, secondary roots, and stem or taproot lenticels were particularly abundant under the 30-day anaerobic treatment in wet-site loblolly and pond pine seedlings, present to a lesser degree in dry-site loblolly pine, and nearly absent in sand pine seedlings. These results indicate that much of the immediate damage from flooding is due to the anoxic condition of the root rather than to the build-up of phytotoxins or soil nutrient imbalances. On the basis of overall seedling vigor, root plasticity and growth, we suggest the following flooding-tolerance/intolerance species (seed source) gradient: pond pine ≥ wet-site loblolly pine > dry-site loblolly pine > sand pine.     

适用于微卫星标记的湿地松、加勒比松DNA快速提取法

以湿地松(Pinuselliottii,PEE),包括古巴加勒比松(P.caribaea var.caribaea,PCC)、洪都拉斯加勒比松(P.caribaea var.hondurensis,PCH)、巴哈马加勒比松(P.caribaeavar.bahmaensis,PCB)3个变种在内的加勒比松,侧枝顶芽为试验材料,使用RETSCHMM400混合球磨仪破碎植物组织,然后利用改良CTAB法提取基因组DNA,完成48个样品仅用1h,1个工作日可提取300个样品以上,DNA分子量大于20kb,0.3g样品可提取DNA20-60μg,能够满足几百次PCR反应;利用所提DNA进行SSR分析,条带清晰,多态性好,说明该方法提取的DNA完全可以满足SSR反应的需要。本研究为SSR标记用于湿地松、加勒比松分子标记辅助选择育种提供了经济、高效、可靠的DNA提取方法。     

Initiation of somatic embryogenesis in Pinus banksiana, P. strobus, P. pinaster, and P. sylvestris at three laboratories in Canada and France

During 2002–2004, three laboratories in Canada and France collaborated to improve initiation of somatic embryogenesis (SE) in jack pine (Pinus banksiana Lamb.), eastern white pine (P. strobus L.), maritime pine (P. pinaster Ait.), and Scots pine (P.␣sylvestris L.), giving particular attention to the effects of (1) N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) versus various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and benzyladenine (BA), (2) differences in basal nutrient media, i.e., macro- and microelements, and (3) gelling agent concentration. The work was carried out separately at␣each laboratory, but the details of media compositions were shared and tested on their respective species. Results indicate that the developmental stage of the zygotic embryo (ZE) and genotype effects had a large influence on SE initiation, and that genetic effects were consistent over time. Different species responded differently to PGR types and concentration, basal nutrient media, trace elements, and their combinations. Currently, our best initiation rates based on a selected group of genotypes, optimal development stage of ZE, and medium are 3.9% for jack pine, 54.6% for eastern white pine, 76.2% for maritime pine, and 19.7% for Scots pine.     

Changes of 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Activity in Stressed Pinus Sylvestris Needles

Stimulation of ethylene biosynthesis in pine needles by hydrogen peroxide and sodium bisulfite coincided with the activation of ACC oxidase at the level of protein synthesis. Decrease in ethylene production at high concentrations of sodium bisulfite (above 7 mM) was apparently due to inhibition of ACC oxidase activity. Treatment of pine needles with aminotriazole caused an inhibition of both ethylene production and ACC oxidase activity. Both methylviologen and methyl jasmonate stimulated ACC oxidase activity in a concentration-dependent manner with no parallel changes in ethylene production. The presented results suggest that ACC oxidase plays an important role in regulation of ethylene formation in pine needles in response to different stimuli.     

Transmission of Bursaphelenchus xylophilus between Monochamus alternatus and Monochamus saltuarius through interspecific mating behaviour

Cerambycid adults of the genus Monochamus transmit the pine wood nematode (Bursaphelenchus xylophilus [Steiner et Buhrer] Nickle), the causative agent of pine wilt disease. To confirm the transmission of B. xylophilus between vector species, nematode‐infected Monochamus alternatus Hope and nematode‐free Monochamus saltuarius (Gebler) adults were paired and their behaviour was observed for 107–220 min. In three pairs that exhibited mounting without copulation, nematode transmission occurred, whereas it was not found in another pair without mountings. The effect of nematode transmission between different vector species on the invasion biology of B. xylophilus is discussed.     

Host selection behaviour of the banded pine weevil,Pissodes castaneus (Coleoptera: Curculionidae)

1. Pissodes castaneus represents an emerging pest species for Pinus spp. production in Latin America. This species attacks all the cultivated pine species in Patagonia Argentina causing wood damage and tree death. The objectives of this work were to describe the host preference behaviour of P. castaneus and the influence of wood damage by conspecifics on its host selection.
2. In two-choice bioassays, P. castaneus showed a feeding preference for Pinus contorta over P. ponderosa. However, percent weight gain when feeding on either species was similar.
3. In other bioassays, P. castaneus spent more time in areas with twigs on which other conspecifics had recently fed, although they were able to successfully feed on twigs without previous damage.
4. These results show that while P. castaneus can successfully colonize different pine species, P. contorta may be more susceptible to attack than P. ponderosa. Silvicultural management should be prioritized considering the weevil's preference for attacking damaged hosts.

     

Components of juvenile-mature correlations in forest trees

Summary Juvenile-mature correlation has played an important role in indirect selection for size traits in forest trees. The juvenile size of a tree is a part of the mature size, and the juvenile-mature correlation is an example of a part-whole type of correlation. As is the case with any other part-whole type of correlation, the juvenile-mature correlation can be subdivided into two components; one is a function of variance only, and the other a function of variance and covariance. In this paper the components of the juvenile-mature correlation is described, the basic properties and the dynamics of its components analyzed, and the role of these components in explaining the gain from indirect juvenile selection discussed. Six forest tree populations were used to review the various properties of the model. The most important applied conclusions were: (1) even if two populations have the same juvenile-mature correlations, different selection strategies can be used depending on the nature of correlation components. (2) Choosing the proper mature age is as important as choosing juvenile age. (3) Understanding the growth curves of mean and variance is essential to developing selection strategies Annotation: Describes a new way of interpreting juvenile-mature correlation in forest tree species.     

影响松毛虫种群动态的因素

综述了影响松毛虫种群动态的因素。气候、天敌、食料、林业技术措施等都不同程度地影响着松毛虫种群的变动。当气候条件适宜 ,天敌数量减少 ,食料丰富 ,林业技术措施缺乏时 ,松毛虫种群就会出现暴发的趋势。反之 ,当气候条件恶劣、天敌数量较多 ,食料植物缺乏或营养恶化 ,林业技术措施得当时 ,松毛虫种群就会得到遏制。尽管松毛虫的种群变动受到多种因素影响 ,但是对松毛虫自身调节能力的研究尚缺乏。     

The enemy of my enemy is still my enemy: competitors add to predator load of a tree‐killing bark beetle

1 The mountain pine beetle Dendroctonus ponderosae is a major tree‐killing bark beetle in North America. We evaluated how the subsequent arrival of a competing bark beetle Ips pini influences the arrival of predators and their impact on both species. 2 The predators Temnochila chlorodia and Enoclerus sphegeus were strongly attracted to pheromones of D. ponderosae. By contrast, Enoclerus lecontei was mostly attracted to I. pini pheromones. The host compound myrcene synergized attraction of both D. ponderosae and E. sphegeus to the pheromone of D. ponderosae. However, it inhibited attraction of both I. pini and E. lecontei to I. pini’s pheromone. 3 Dendroctonus ponderosae were more attracted to trees than logs treated with its pheromones, whereas I. pini were more attracted to logs than trees treated with its pheromones. Some 78% of T. chlorodia were captured at hosts baited with D. ponderosae pheromones, whereas 83% of E. lecontei were captured at hosts baited with I. pini pheromones. We characterized the sequence of arrival to live trees baited with pheromones of D. ponderosae as: D. ponderosae, T. chlorodia, E. sphegeus, I. pini, E. lecontei. 4 Various combinations of I. pini and predators were added to logs colonized by D. ponderosae in the above sequence of arrival observed in live trees baited with D. ponderosae aggregation pheromones. Ips pini reduced D. ponderosae adult brood production. However, the combination of I. pini and E. lecontei did not raise D. ponderosae brood production above that observed with only I. pini present. Similarly, the combination of I. pini and T. chlorodia did not reduce D. ponderosae brood production below that observed with I. pini alone. By contrast, the combination of I. pini, T. chlorodia and E. lecontei caused more brood loss to D. ponderosae than I. pini alone. 5 Enoclerus lecontei did not reduce brood production by T. chlorodia, whereas T. chlorodia substantially reduced brood production by E. lecontei. 6 Secondary bark beetles that exploit the resource created by primary tree‐killing species exert negative effects through both competition and increased predator load. Implications to the population dynamics, ecology and evolution of tree‐killing bark beetles are discussed.     

The bimodal adult activity of Monochamus alternatus (Coleoptera: Cerambycidae) caught in pheromone traps in Jeju can be explained by the competitive attractiveness of dying pine trees

The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), is known to be the primary vector of pinewood nematode Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle that causes pine wilt disease. Adult activity of M. alternatus caught in a pheromone trap on Jeju Island of Korea showed a bimodal form with the first peak in mid to late June and the second peak in mid to late September. The two peaks were separated between mid and late August, showing a valley. Accumulated degree‐days predicted that the emergence of the second generation adults could be possible just before the second peak. But actually no adults of the second generation occurred in the field development experiments of M. alternatus in 2016 and 2017. Pine trees without oleoresin flow (namely dying trees by the infection of pinewood nematode) were abundant during early July to early August. The bimodal adult activity pattern of M. alternatus could be partially explained by the competitive attractiveness of dying trees against pheromone traps, when we accepted the assumption that dying pine trees attract strongly M. alternatus.     

红松阔叶林倒木贮量动态的研究

在森林倒木研究的基础上探讨长白山红松阔叶林倒木贮量的动态,涉及红松阔叶林倒木分解及其贮量的动态规律。研究表明,倒木分解,除心腐木外,均由表及里进行;倒木分解速率在其它生态条件相同时因树种、直径和部位而异。红松阔叶林倒木贮量动态包括现有倒木贮量和倒木年输入量两个分解动态过程,现有倒木贮量在头100年其干重迅速减少,其中椴树比红松尤速,前者分解91%,后者为72%.林地倒木贮量动态与倒木年输入量分解动态相似,但前者在分解初期贮量增加较大,因为部分现有倒木未完全分解;100年后趋于一致,并恒定于16～17t·hm^-2,直至群落的顶极阶段结束.