Liquidambar Research Articles

Diarylheptanoids from Myrica gale var. tomentosa and Revised Structure of Porson.

From the stems of Myrica gale var. tomentosa (Myricaceae), two new diarylheptanoids (3 and 4) were isolated together with myricanone, porson, gallic acid and myricetin 3-O-(6-galloyl)-β-D-galactopyranoside. On the basis of spectroscopic and chemical evidence, the structures of 3 and 4 have been determined as 12-dehydroporson and 12-hydroxymyricanone, respectively. The structure of porson was reinvestigated, and a revised structure, 12-hydroxy-5-O-methylmyricanone, was proposed

The effects of watershed liming on the tissue chemistry of three co-occurring poor fen species

We investigated the impact of watershed liming on elemental concentrations in the shrubs Myrica gale and Chamaedaphne calyculata and the sedge Carex stricta. We analyzed tissues from plants co-occurring in 1-m2 plots in limed and unlimed portions of an Adirondack poor fen for Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, N, Na, Ni, P, Pb, Se, V, and Zn. Within 2 years of liming, we found higher concentrations of Ca, Ni, and Zn and lower N, Na, and Mn in Chamaedaphne foliage; higher Fe, K, Mg, Ni, Pb, and Zn and lower Co and Mn in Chamaedaphne twigs; higher Mo and lower Al, B, Mn, and Ni in Myrica foliage; higher Al, Cr, and Mo and lower Cd, Mn, and Se in Myrica twigs; and higher Al and lower Co and Cr in Carex foliage. Clearly, each species was unique in its uptake and allocation of elements, which will influence the rate these elements cycle in this watershed after liming. Elements in Carex foliage changed the least after watershed liming, while those in Chamaedaphne twigs changed the most. However, the slow decay of Chamaedaphne litter will likely inhibit the release of accumulated elements, including Ca. Key words: peatlands, poor fens, liming, watershed, tissue chemistry, Adirondacks.

Factors Affecting the Acetylene to 15N2 Conversion Ratio in Root Nodules of Myrica gale L.

When nodules of actinorhizal plants are exposed to acetylene, there is often an initial peak rate of acetylene reduction followed by a decline and a partial recovery. Treatment of hydroponically grown Myrica gale L. with water deficiency or dark stress increased the magnitude of the acetylene-induced decline and decreased the extent of the recovery. When N2 fixation was measured with 15N2 in unstressed plants, the ratio of acetylene reduction (peak) to N2 fixation prior to acetylene exposure was 3.73 [plus or minus] 0.14 (mean [plus or minus] SE). This value does not differ significantly (P < 0.05) from the theoretical minimum value of 4.0. In water-stressed plants the conversion ratio for the peak rate was greater (4.32 [plus or minus] 0.10) and in dark-stressed plants it was lower (2.54 [plus or minus] 0.33) than 4.0. The conversion ratio for the recovered rate of acetylene reduction was much lower than 4.0 in all cases, with mean values ranging from 1.16 to 2.60. We conclude that the peak rate of acetylene reduction provides the most reliable estimate of N2 fixation. The recovered rate of acetylene reduction consistently underestimates N2 fixation, sometimes severely, and thus measurements of acetylene reduction made in closed systems also underestimate N2 fixation to varying degrees.

Relative Importance of Mechanisms Determining Decomposition in a Southeastern Blackwater Stream

-Chemical inhibitors were used to separate the effects and determine the relative importance of microbial degradation, flow-related fragmentation, and shredder fragmentation on sweet gum (Liquidambar styraciflua) decomposition rates in Upper Three Runs, in South Carolina. We correlated several abiotic and biotic variables (current velocity, accumulation of inorganic and fine particulate organic matter, water depth, bacterial density and shredder biomass) with the decomposition of individual sweet gum leaf packs. We also surveyed the biomass and density of shredders in natural leaf accumulations and in constructed leaf packs to help determine the importance of shredders in decomposition. Except for accumulated sediments (inorganic and fine particulate organic matter, FPOM), none of the independent variables, including base-flow current velocity and shredder biomass, were significantly correlated with decomposition of individual sweet gum leaf packs. Sediment accumulation was inversely related to decomposition rates. Experimental analyses suggested that microbial degradation dominated the decomposition processes. A constant flow regime characterized by low current velocities, plus a depauperate shredder abundance, accounted for the relatively minor role of shredders and flow-related fragmentation.

Soil conditions affect the occurrence of cluster roots in Myrica gale L. in the field

Roots of Myrica gale L. from 12 field sites in central Maine were examined for extent of cluster (proteoid) root formation and mycorrhizal infection. Cluster roots were abundant (30–66% of total fine root weight) at all 12 sites and leaf P concentrations were consistently low (490–900 μg Pg −1). Extent of cluster root formation was negatively correlated ( r = −0.59) with the amount of available (extractable) soil P and the amount of organic matter ( r = −0.79) in the soil and was greater on mineral soils than on organic soils. Extent of cluster root formation was not correlated with leaf P concentration or soil pH. Mycorrhizas probably contributed little or nothing to the P nutrition of M. gale at these sites because only small amounts of fungal infection were found. The infections were intracellular but probably did not represent functional vesicular-arbuscular mycorrhizas because no arbuscules were seen. Cluster roots probably allow M. gale to obtain sufficient P from wet, nutrient poor soils in the absence of significant mycorrhizal infection.

The wall of the infected cell may be the major diffusion barrier in nodules of Myrica galE L

Nitrogenase activity (C 2H 2 reduction) by single- or two-lobed nodules of Myrica gale L. with long nodule roots was measured at 6 and 8 kPa O 2 in a flow-through system after various treatments. Neither excision of nodule roots nor covering the cut surface with silicone grease after nodule root removal had a significant effect on C 2H 2 reduction, while covering the entire nodule with grease eliminated C 2H 2 reduction. Likewise, covering the nodule lobe while leaving nodule roots uncovered had little effect on C 2H 2 reduction. These results suggest that the diffusion resistance to gases is low at the surface of the nodule lobe and the nodule roots. Nodule slices ( ca 100 μm thick) retained high C 2H 2 reduction rates which were O 2-limited up to 18 kPa, indicating that the diffusion barrier is within the slices. The O 2 gradient from the gas phase to the infected cells in the slices was calculated to be ca 0.65 kPa out of a total gradient of 20 kPa. The addition of 2 kPa CO had little effect on nodule respiration (CO 2 evolution), suggesting that the diffusion barrier is outside the cytoplasm of the infected cells. Thus the major diffusion barrier may be in the wall of the infected cells.

Palynology, paleoclimatology and correlation of middle Miocene beds from Porcupine River (locality 90-1), Alaska

Beds in the Upper Ramparts Canyon of the Porcupine River, Alaska (67° 20' N, 141° 20' W), yielded a flora rich in pollen of hardwood genera now found in the temperate climates of North America and Asia. The beds are overlain or enclosed by two basalt flows which were dated to 15.2 ± 0.1 Ma by the 40 Ar 39 Ar method, fixing the period of the greatest abundance of warm-loving genera to the early part of the middle Miocene. The assemblage is the most northern middle Miocene flora known in Alaska. Organic bed 1 underlies the basalt and is older than 15.2 Ma, but is of early to middle Miocene age. The pollen assemblage from organic bed 1 is dominated by conifer pollen from the pine and redwood-cypress-yew families with rare occurrences of temperate hardwoods. Organic bed 2 is a forest floor containing redwood trees in life position, engulfed by the lowest basalt flow. A pine log has growth rings up to 1 cm thick. Organic beds 3 and 4 comprise lacustrine sediment and peat between the two basalt flows. Their palynoflora contain conifers and hardwood genera, of which about 40% have modern temperate climatic affinities. Hickory, katsura, walnut, sweet gum, wingnut, basswood and elm pollen are consistently present, and beech and oak alone make up about 20% of the pollen assemblage. A warm high latitude climate is indicated for all of the organic beds, but organic bed 3 was deposited under a time of peak warmth. Climate data derived by comparison with modern east Asian vegetation suggest that, at the time of deposition of organic bed 3, the Mean Annual Temperature (MAT) was ca. 9°C, the Warm Month Mean Temperature (WMMT) was ≥ 20°C and the Cold Month Mean Temperature (CMMT) was ca. −2°C. In contrast, the modern MAT for the region is −8.6°C, WMMT is 12.6°C and CMMT is −28°C. Organic beds 3 and 4 correlate to rocks of the middle Miocene—late Seldovian Stage of Cook Inlet and also probably correlate to, and more precisely date, the lower third of the Suntrana Formation in the Alaska Range, beds at Unalaklect, part of the upper Mackenzie Bay sequence in the Beaufort-Mackenzie basin, and the Mary Sachs gravel of Banks Island. This suggests that forests with significant percentages of temperate deciduous angiosperms existed between latitudes 60° and 72°N during the early middle Miocene.

Riverine wetland vegetation: importance of small‐scale and large‐scale environmental variation

Abstract. The purpose of this study was to evaluate the relative importance of small‐scale variation in abiotic factors and large‐scale spatio‐temporal variation on the distribution of wetland vegetation of a section of the Upper St. Lawrence River in Québec. Vegetation data have been classified with agglomerative clustering into 11 community types, from Acer rubrum, Acer saccharinum and Fraxinus swamps, to scrubs dominated by Salix petiolaris, Alnus rugosa var. americana or Myrica gale, to Typha, Typha/Lythrum, Carex lacustris and Calamagrostis canadensis marshes. Canonical Correspondence Analysis (CANOCO) suggested that peat thickness and water level are the most important abiotic variables correlated with plant community composition. As a whole, small‐scale variation accounts for 25.6 % of the species variation. Another 21.6% is explained by large‐scale variation based on location data summarizing large‐scale spatial distribution, and historical landscape dynamics differentiated into (a) no net loss of wetlands, (b) net loss of wetland, and (c) changes within wetlands, which are correlated with the actual variation in herbaceous and scrubby vegetation. The interaction between small‐scale and large‐scale variations explains another 1.7 %. In total, 48.9% of the species variation is explained by the two data sets, leaving 51.1% unexplained. Whereas the omission of some abiotic variables is possible, it is hypothesized that the abiotic conditions measured in this study play an important role, especially in the distribution of forested swamps. In addition, past history, particularly that of human interventions, becomes another important factor leading to the observed importance of large‐scale spatio‐temporal variables. This is particularly true for Alnus rugosa var. americana shrublands. Time lag between a relative stabilization of species distribution and the reduction of natural disturbances (water level fluctuations and fires) could be a possible cause of the importance of spatio‐temporal variables and the undetermined portion of species variation.

Factors affecting formation of cluster roots in Myrica gale seedlings in water culture

The effect of nutrient deficiency, aeration, phosphorus supply, and nitrogen source on the formation of cluster (proteoid) roots was examined in Myrica gale seedlings growing in water culture. Only the omission of phosphorus resulted in the formation of significant numbers to cluster roots when plants were grown in a number of 1/4 strength Hoagland's solutions, each lacking one mineral nutrient. Aeration shortened the time required for cluster root formation and increased the percentage of plants forming cluster roots. The proportion of the root system comprised of cluster roots decreased as the phosphorus concentration in the solution increased and no cluster roots formed in solutions containing 8 mg P/L. Phosphorus supply also affected total plant biomass, proportion of biomass comprising nitrogen-fixing nodules, shoot:root ratio, phosphorus concentration in the leaves and phosphorus content of the plants. The plants showed luxury consumption of phosphorus and were able to produce large amounts of biomass utilizing only stored phosphorus. Nitrogen source also affected cluster root formation. Urea-fed plants produced cluster roots more quickly and devoted a substantially larger proportion of root growth to cluster roots than did nitrate-fed plants. The longest cluster root axes were produced in nitrate-fed plants supplied with no phosphorus and the shortest were in urea-fed plants at 4 mg P L−1. Four methods for expressing the extent of cluster root formation were examined and it was concluded that cluster roots as a proportion of total fine root dry weight is preferable in many cases. Formation of cluster roots in response to phosphorus deficiency coupled with previously demonstrated traits allows Myrica gale to adapt to a wide range of soil conditions.

Growth and water relations of Liquidambar styraciflua L. in an urban park and plaza

Growth and water relations of 10-year-old sweet gum (Liquidambar styraciflua L.) street trees were studied in sites with low and high potential evapotranspiration to determine how these differences are integrated by growth and water relations over time. The trees were located in the parking strip between the curb and sidewalk at a partially vegetated urban park and an urban plaza in Seattle, Washington. Crown size, and seasonal and diurnal stomatal conductance and water potential, as well as diurnal air temperature and humidity, were measured over 2 growing seasons. Yearly trunk growth since transplanting was measured from increment cores. Vapor pressure deficits and air temperatures averaged 18% greater at the plaza, but whole-tree water loss appeared to be much lower than the park trees due to more restricted stomatal conductance and crown size. In addition, yearly diameter increment declined progressively once the plaza trees were established in the existing soil several years after transplanting. Lower water potential in the plaza trees indicated greater internal moisture deficits than the park trees, and tissue analysis revealed lower nutritional status, particularly nitrogen. A manipulative study of water and fertilizer to several additional plaza trees showed an interaction between water and nutrient deficiencies in the coarse and shallow soil that apparently limited growth. Furthermore, soil limitations probably interacted with paved surface conditions over time by reducing nutrient recycling from leaf litter, and generating higher vapor pressure deficits that would contribute to prolonged stomatal closure. Restricted growth and water relations status of the plaza trees represented an equilibrium between chronic high-resource demand above ground and limited below ground.

Hexachloroethane obscurant: Assessing tree foliage injury

AbstractOpen‐top chambers were used to determine the relationships between a hexachloroethane (HC) obscurant, zinc deposition, and foliar injury of tree species indigenous to military training facilities. Eight eastern U.S. tree species were exposed four times to three exposure regimens (0x, 1x, 2x) of the obscurant, measured as Zn, during the 1990 growing season. Plots received ambient or charcoal‐filtered air for comparison purposes. Black locust (Robinia pseudoacacia L.) and black cherry (Prunus serotina Ehrh.) were the most sensitive species, exhibiting significant (p &lt; 0.05) necrotic leaf spot, chlorotic mottle, and marginal necrosis of leaves at the 2x levels throughout the season. Defoliation was also greater (p &lt; 0.05) in exposed vs. unexposed plots. Sugar maple (Acer saccharum Marsh.) injury was different among exposure regimens (p &lt; 0.05) only near the end of the season. Sweet gum (Liquidambar styraciflua L.), eastern white pine (Pinus strobus L.), loblolly pine (Pinus taeda L.), and Virginia pine (Pinus virginiana Mill.) were asymptomatic. Charcoal filtration did not affect severity of symptoms. Zinc deposition was positively correlated (p &lt; 0.05) with most of the symptoms on black locust and black cherry. The HC obscurant in the concentrations used in this study adversely affected these species.

Comparative foliage and twig chemistry of co-occurring Myrica gale and Chamaedaphne calyculata

The deciduous N-fixing shrub Myrica gale L. and the evergreen sclerophyllous shrub Chamaedaphne calyculata (L.) Moench sometimes intermingle in small patches in boreal peatlands. The mineral element composition of adjacent plants and plant parts may differ owing to the distinctive morphology and physiology of each species. We compared the elemental composition and allocation patterns of Myrica and Chamaedaphne co-occurring in 1-m2 plots in a western Adirondack peatland. Current foliage and twigs of each species were analyzed for Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Se, V, and Zn. Fourteen elements differed significantly among tissues. Chamaedaphne foliage was highest in Al, Mn, and P, and Chamaedaphne twigs were highest in Cu, whereas Myrica foliage was highest in K and Ni, and Myrica twigs were highest in Mo and Zn. Elemental differences were interpreted with respect to possible physiological roles in each species. Additionally, a multivariate discriminant function analysis yielded two canonical variables: (i) a structural – functional component correlated with Al, B, Ca, Cu, Fe, and K that distinguished Myrica from Chamaedaphne, and (ii) a metabolic component correlated with Al, B, Mo, P, and Zn that separated foliage from twigs. Key words: peatland, sclerophylly, nitrogen fixer, tissue chemistry, Chamaedaphne calyculata, Myrica gale.

HEXACHLOROETHANE OBSCURANT: ASSESSING TREE FOLIAGE INJURY

Open-top chambers were used to determine the relationships between a hexachloroethane (HC) obscurant, zinc deposition, and foliar injury of tree species indigenous to military training facilities. Eight eastern U.S. tree species were exposed four times to three exposure regimens (0x, 1x, 2x) of the obscurant, measured as Zn, during the 1990 growing season. Plots received ambient or charcoal-filtered air for comparison purposes. Black locust (Robinia pseudoacacia L.) and black cherry (Prunus serotina Ehrh.) were the most sensitive species, exhibiting significant (p < 0.05) necrotic leaf spot, chlorotic mottle, and marginal necrosis of leaves at the 2x levels throughout the season. Defoliation was also greater (p < 0.05) in exposed vs. unexposed plots. Sugar maple (Acer saccharum Marsh.) injury was different among exposure regimens (p < 0.05) only near the end of the season. Sweet gum (Liquidambar styraciflua L.), eastern white pine (Pinus strobus L.), loblolly pine (Pinus taeda L.), and Virginia pine (Pinus virginiana Mill.) were asymptomatic. Charcoal filtration did not affect severity of symptoms. Zinc deposition was positively correlated (p < 0.05) with most of the symptoms on black locust and black cherry. The HC obscurant in the concentrations used in this study adversely affected these species.

Relation of nickel concentrations in tree rings to groundwater contamination

Increment cores were collected from trees growing at two sites where groundwater is contaminated by nickel. Proton‐induced X ray emission spectroscopy was used to determine the nickel concentrations in selected individual rings and in parts of individual rings. Ring nickel concentrations were interpreted on the basis of recent concentrations of nickel in aquifers, historical information about site use activities, and model simulations of groundwater flow. Nickel concentrations in rings increased during years of site use but not in trees outside the contaminated aquifers. Consequently, it was concluded that trees may preserve in their rings an annual record of nickel contamination in groundwater. Tulip trees and oaks contained higher concentrations of nickel than did sassafras, sweet gum, or black cherry. No evidence was found that nickel accumulates consistently within parts of individual rings or that nickel is translocated across ring boundaries.

Long-term human disturbance of an urban park forest, New York City

Development of an urban park forest, the Turtle Pond Watershed, Alley Park, Queens, New York, was analyzed from historical, vegetation, and pollen records. After 1800, the forest began to develop as a hickory ( Carya spp. Nutt.) dominated stand following release of the land from agricultural use. Pollen and sediment analysis of a section from the bog in Turtle Pond showed that before 1900, residential development introduced pine ( Pinus spp. L.) to the area, reduced the hickory population, and caused the Pond to change from bog to fen conditions. From 1908 to 1912, the hickory bark beetle reduced hickory and chestnut blight killed off American chestnut ( Castanea dentata (Marsh.) Borkh.). Although the area containing the Watershed forest was incorporated into Alley Park in 1927, private structures were not removed until 1937. Forest canopy inventory data from 1936 showed canopy gaps left open by the losses of American chestnut and hickory trees permitted flowering dogwood ( Cornus florida L.) to become the forest dominant. Comparison of the 1936 data with an inventory of the forested Watershed in 1987 indicated the flowering dogwood was decimated in the intervening years and the open growing space was occupied by maple ( Acer spp. L.), birch ( Betula spp. L.), American beech ( Fagus grandifolia Ehrh.), sweet gum ( Liquidambar styraciflua L.), black gum ( Nyssa sylvatica Marsh.), black cherry ( Prunus serotina Ehrh.), and oak ( Quercus spp. L.). The pollen record indicates that stresses of recreational use and abuse in the Watershed forest since 1973 have negatively affected reproduction in maple, birch, and sweet gum. The history of human disturbance provides information to guide recreation of past forest types and to increase diversity through the selection of hardy species to plant.

The antifungal activity of the leaf gland volatile oil of sweet gale (Myrica gale) (Myricaceae)

The antifungal activity of volatile oil obtained from the leaves of sweet gale (Myrica gale) has been investigated. Fungi, isolated from the leaves ofM. gale, were grown in liquid medium containing the oil and its effect on biomass production was gauged. The oil inhibited growth of all species of fungi to greater or lesser extent. Sesquiterpenes were more active than monoterpenes, and among the sesquiterpenes germacrone was marginally more active than β-elemenone. These results support the proposition that the volatile oil ofM. gale has a role in resistance to fungal pathogens.

Factors Affecting the Acetylene-Induced Decline during Nitrogenase Assays in Root Nodules of Myrica gale L.

Our goal was to determine why the rate of acetylene reduction by nodules of actinorhizal plants declines after an initial peak value. The decline was eliminated by pretreatment with argon, indicating that the decline is initiated by cessation of ammonia synthesis. When O(2) concentration was decreased during the decline, the rate of acetylene reduction increased. This shows that during the decline there is either O(2) toxicity or competition between respiration and nitrogenase for reductant. The decline was not eliminated when uptake hydrogenase was inactivated by pretreatment with acetylene, showing that cessation of H(2) oxidation is not the primary cause of the decline. The effects of a variety of other treatments on the decline were also studied. Overall, we conclude that the cessation of ammonia formation is the primary cause of the acetylene-induced decline. We hypothesize that the supply of reductant for nitrogenase depends on amino acids that are depleted following cessation of ammonia formation. We also conclude that the initial peak rate of acetylene reduction provides the best measure of nitrogenase activity.

Variation of leaf gland volatile oil within a population of sweet gale (Myrica gale) (Myricaceae)

The leaf gland volatile oils of ten sweet gale plants from a Scottish population were extracted in early summer. The results differed notably from reports of other populations in respect of the sesquiterpenes, β-elemenone and germacrone, which were major components of the volatile oil. Three dihydrochalcones were also detected in the volatile oil. Variation within the population existed, particularly with respect to the relative importance of germacrone. Five plants were resampled in late summer and exhibited a marked reduction in β-elemenone, a lesser reduction in germacrone and changes in the proportions of some monoterpenes.

A study of the effects of leaf extracts on aluminum toxicity to fish

Abstract A study was carried out to find out if leaf extracts from different plants could be used to reduce the toxic effects of aluminum on fish. The types of leaves were pine, oak, sweet gum, willow, alligator grass, pecan and pine. Shiners (Notropis) fish were used for the study. The results obtained showed that if the pH was controlled to pH 4.5 the presence of leaf extracts did not mitigate the toxic effect of aluminum. However at pH 5 and above the presence of leaf extracts reduced aluminum toxicity to fish. When dried leaf extract was added to aluminum solution at pH 4.5 the final pH increased to 6.2 depending on the type of leaves. With no adjustment back to pH 4.5 the toxic effect of aluminum was greatly reduced except when pine or oak were used. 1. The presence of humic and fulvic acids in the leaf extracts were ascertained by the ratio of their absorbances at 465 nm and 665 nm. The results indicated that the presence of humic or fulvic acids depended on type of leaves and the length of time the...

Plant sex and hare feeding preferences.

To evaluate the general extent to which sex-related differences in palatability occur in boreal dioecious woody plants, males and females of five dioecious woody plant species were presented to free-ranging mountain hares (Lepus timidus) during winter. Hares strongly preferred branches from male plants when feeding on Populus tremula and Salix caprea and weakly preferred male S. pentandra. However, they did not show any sex-related preference when feeding on the other two species studied (Myrica gale and Juniperus communis). Nitrogen concentration and, to some degree, digestibility showed strong relationships with hare food preferences. By contrast, the concentration of phenolics was only weakly related to feeding preference. Phenolics could, nevertheless, still be important if only one or a few specific compounds deter hare feeding. These results indicate that sex-related differences in plant palatability in the boreal forest might be more widespread than previously believed, particularly for species of the family Salicaceae. Thus, herbivores might be responsible for the female-biased sex ratios found in willow populations in northern Scandinavia (e.g. Elmqvist et al. 1988).