Deltoides Marsh Research Articles

Effects of Sulfur Dioxide Fumigation on Photosynthesis, Respiration, and Chlorophyll Content of Selected Lichens

Four lichens-Parmelia bolliana Mull. Arg., Physcia stellaris (L.) Nyl., Xanthoria fallax (Hepp) Am., and Physconia grisea (Lam.) Poelt--listed in order of decreasing mesophytism, were fumigated for 4 hr at 0.01, 0.1, 1.0, and 2.5 ppm sulfur dioxide to determine the effects on photosynthesis, respiration, and chlorophyll content. The lichens had been collected from Populus deltoides Marsh or Tilia americana L. in northeastern South Dakota near a lignite-fired power generator. Photosynthesis decreased after fumigation at 1.0 and 2.5 ppm, but significant decreases occurred only after fumigation at 2.5 ppm. Expressed on the basis of per unit weight chlorophyll content, photosynthesis of Physconia grisea was most sensitive followed by that of Xanthoria fallax, Physcia stellaris and Parmelia bolliana. Expressed on the basis of per unit dry weight of lichen sample, photosynthesis of Physconia grisea was most sensitive followed by Xanthoria fal- lax, Physcia stellaris, and Parmelia bolliana. In both cases, the more xerophytic species were more sensitive. Chlorophyll content in these species was not mea- surably altered by fumigation. Comparison of chlorophyll a and b absorption spec- tra peaks for fumigated and control samples indicated that no phaeophytinisation occurred. Insignificant and inconsistent differences in chlorophyll a/b ratios were observed. Respiration of Physcia stellaris and Parmelia bolliana decreased signif- icantly following fumigation with 2.5 ppm S02; both species were more sensitive than Xanthoria fallax. Physconia grisea was not tested for respiratory responses. The effects of S02 fumigation on measured metabolic rates differed with the species. Photosynthetic rates of the xerophytic Xanthoria fallax and Physconia grisea were more sensitive than the more mesophytic Parmelia bolliana and Phy- scia stellaris. In contrast, respiratory sensitivities to S02fumigation were greater for P. bolliana and P. stellaris. It is well known that lichens are sensitive to air pollution, particularly to sulfur dioxide. Field studies from a variety of locations have reported evidence of the phytotoxicity of sulfur dioxide. Hawksworth's (1971) review of the literature is comprehensive; studies done since 1971 have left his basic conclusions unchanged. Experimental studies to examine the basis of lichen sensitivity have produced inter- esting results, which in some cases are not altogether consistent with field observations. Summaries of experimental studies have been presented by Gilbert (1973) and Nieboer et al. (1976). Experimentally, lichens have been exposed to both low and high concentrations of sulfur dioxide. In studying the effects of exposure on photosynthesis, Pearson & Skye (1965) used concentrations ranging from 102 ppm to 105 ppm. Puckett et al. (1973) used

Regrowth Control by Injection of Growth Regulators in Seedlings of Four Tree Species1

Abstract Topped 1- and 2-year-old seedlings of silver maple (Acer saccharinum L.), American sycamore (Platanus occidentalis L.), cottonwood (Populus deltoides Marsh.) and American elm (Ulmus americana L.) were treated with each of 10 growth regulating chemicals in the greenhouse by chemical injection. Daminozide [butanedioic acid mono (2,2-dimethylhydrazide], maleic hydrazide [l,2-dihydro-3,6 pyridazinedione] and the soldium salt of dikegulac [2,3:4,6-bis-0-(l-methyl-ethylidene)-L-xylo-2-hexulofuranosonic acid] controlled regrowth at appropriate concentrations without causing unacceptable phytotoxicity.

The Origin of Populus deltoides and Salix interior zones on Point Bars along the Minnesota River

An investigation was made to ascertain the nature and origin of the separate and distinctive zones of Populus deltoides Marsh, and Salix interior Rowlee commonly occurring on point bars along the Minnesota River. These vegetation zones are primarily monospecific, have high stem densities, possess well-defined boundaries and are restricted to specific contour intervals on the point bars. A method was devised to determine past river elevations at ungauged locations between two gauging stations along the lower Minnesota River. Comparisons of calculated river elevations with sur- veyed vegetation-zone elevations have illustrated two mechanisms by which the zones originate. During years of zone establishment the river elevation remained fixed for periods ranging from 13-22 days near the contour line marking the lower boundary of the zones, thereby limiting the area available for colonization during the dispersal period of a pioneer species. The second and less common mechanism involves the stunt- ing, by a constant river elevation, of the lower portion of a zone previously established by the above mechanism. The plants in the upper portion of the zone initiate normal spring growth but the lower, submerged plants must await a drop in river elevation be- fore growth can begin. Thus the development of what appears to be two vegetation zones from one previously established zone may occur. Both mechanisms require the maintenance of an appropriate river elevation during the waning period of general flooding.

Introduction and Improvement of Poplars in Australia

SUMMARY Poplars have been sporadically introduced into Australia since the mid 1800s. The first systematic introductions were made in 1947 as part of a large-scale species introduction program. Systematic provenance studies of the main plantation species, Populus deltoides Marsh, were started in 1967 with the introduction of a large number of seedlots from throughout the natural range of this North American species. After the involuntary establishment of poplar leaf rusts in 1972 and 1973 work has concentrated on the selection of rust resistant, fast-growing poplar clones, and con-siderable progress has been made in this field. In the southern parts of the plantation area selection against damage by honey bees has also been necessary. Breeding of poplars has, in Australia, concentrated on producing rust-resistant hybrid clones, adapted to growth at low latitudes. The total plantation area of poplars in Australia is 2 600 ha with a projected future planting area of 350 ha/year.

Phytotoxic Effects of Several Bark Extracts on Mung Bean and Cucumber Growth1

Abstract Mung bean (Phaseolus aureus Roxb.) cuttings and cucumber (Cucumis sativus L. cv. Marketer) seedlings were cultured in water extracts of bark from silver maple (Acer saccharinum L.) hackberry (Celtis occidentalis L.), sycamore (Platanus occidentalis L.) and cottonwood (Populus deltoides Marsh.). Extracts of fresh silver maple bark inhibited root elongation of cucumbers and the adventitious rooting of mung bean. Composting the silver maple bark for 30 days prior to preparing the water extracts reduced inhibition. Pretreatment of fresh silver maple bark extracts with insoluble polyvinylpyrrolidone (PVP) reduced inhibition and indicated that the inhibitory compound was phenolic in nature. Chromatography and spectral analysis of common phenolic compounds and silver maple bark extracts revealed the toxic substance was similar to tannic acid.

Successional Stages in a Hardwood Bottomland Forest near Dallas, Texas

Forested bottomland areas associated with the Trinity River, near Dallas, Texas, have for many years been exploited for their gravel content leaving many seres represented at present by variously aged stages of plant succession. Data obtained by the plot method from excavated 3-, 5-, and 47-year-old gravel pits and an unexcavated forested area were compared to determine successional trends. Her- baceous and vine species, particularly Heterotheca latifolia Buckl. and Smilax Bona- nox L. respectively, were prevalent in the 3-year-old gravel pit whereas the trees, Populus deltoides Marsh. and Salix nigra Marsh. dominated the 5-year-old gravel pit. Principal woody species in the 47-year-old gravel pit were Celtis laevigata Willd., Juniperus virginiana L., Ulmus alata Michx., and Rhus Toxicodendron L. The grass Bromus commutatus Schrad. was the dominant herbaceous species. The unexcavated forested area exhibited a rather dense upper canopy composed pri- marily of Ulmus alata Michx., Quercus stellata Wang. and Prunus mexicana Wats. Panicum laxiflorum Lam. and Carex amphibola Steud. were prominent understory plants.

Biosystematics of the genus Populus L. II. Chemotaxonomy, phenology, fertility, and segregates of native Manitoba species and variants

Chemotaxonomical, phenological, fertility, and hybrid segregation characteristics have further elucidated the relationships of Populus species and variants in southern Manitoba.Species chromatograms, made with bark collections from widely separated localities, were consistently uniform and proved reliable for species identification. Chromatograms of variant individuals were unlike those of any species examined. Flowering and seed shedding in P. balsamifera L., P. deltoides Marsh. var. occidentalis Rydb., and variants occurred together and about 2 weeks and 4 weeks later than respective dates for P. tremuloides Michx.Hybrid fertility, measured by seed set was lower than the expected values for fully fertile hybrids of P. balsamifera and P. deltoides var. occidentalis. All variant populations, except from Grand Beach, produced greater than 90% vigorous seedlings. Seedling progenies from several apparent F1 hybrids segregated towards P. balsamifera and P. deltoides var. occidentalis. No segregates similar to or approaching P. tremuloides were recovered.

Biosystematics of the genus Populus L. I. Distribution and morphology of native Manitoba species and variants

Twenty-four morphological characters of native Manitoba Populus were studied in an attempt to delineate species and variants and provide keys for correct identification. The results support the hypothesis that the variants have originated from intersectional hybridization of P. balsamifera L. (section Tacamahaca Spach.) and P. deltoides Marsh. var. occidentalis Rydb. (section Aegeiros Duby). Populus × jackii Sarg. encompasses the collective group of individuals resulting from this hybrid cross. The hybrid individuals are widely distributed and occur commonly where the two parental species are growing together.

Comparative Effects and Concentration of Picloram, 2,4,5-T and Dicamba in Tissue Culture

In nutrient agar comparative concentrations (10−3 to 10−5M) of (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) were generally more inhibitory to the growth of tissue cultures of soybean (Glycine max (L.) Merrill cv. Acme) and cottonwood (Populus deltoides Marsh.) than were either 4-amino-3,5,6-trichloropicolinic acid (picloram) or 3,6-dichloro-o-anisic acid (dicamba). Compared to untreated tissue dicamba or picloram at 10−6M in the nutrient agar resulted in a 200 % increase in the growth of soybean tissue. At 10−5 and 10−6M dicamba also produced an increase in the growth of cottonwood tissue. Greatest absorption of picloram and dicamba by tissue cultures from agar occurred during the first 24 h after treatment. However, absorption remained nearly static thereafter for 14 days. More dicamba was absorbed by soybean and cottonwood tissue cultures than either picloram or 2,4,5-T.

Effect of Gibberellic Acid in Fertilizer Packets on Growth of Cottonwood and Silver Maple

AbstractAddition of fertilizer packets containing 0.5% or 2% gibberellic acid to potted soil significantly increased height growth rates of cottonwood (Populus deltoides Marsh.) cuttings over that for packeted fertilizer alone. Plant weight increases were significantly higher for 0.5% gibberellic acid in the two‐packet treatment but not in the one‐packet treatment. Similar treatments with gibberellic acid in the field did not increase the height or diameter growth rates of cottonwood cuttings, and caused a significant decrease in growth rate of silver maple (Acer saccharinum L.) plantings for the two‐packet treatment with 0.5% gibberellic acid. The latter treatment reduced survival of this species to 60% from 95% for fertilizer alone.

Fertilizer Release from Packets and its Effect on Tree Growth

AbstractA study was made of various factors affecting the release of fertilizer from polyethylene packets. Movement of water from the soil into the packets was almost entirely in the form of vapor and was closely related to both the area and perimeter of the pinholes in the packets. Absorption of water vapor by saturated salt solutions from air maintained near 100% relative humidity was directly related to both the solubility of the salts used and to their vapor pressure lowering values. The length of time required to release the fertilizer was directly related to the size of packet and inversely related to the number of pinholes. The more soluble fertilizer constituents were released faster than the less soluble ones. The use of packets of 19‐5‐17 (N, P, K) fertilizer in the field generally increased by 10 to more than 100% the rates of growth in height and diameter of cottonwood (Populus deltoides Marsh.), silver maple (Acer saccharinum L.), sugar maple (Acer saccharum Marsh.), and white ash (Fraxinus americana L.).

THE RELATIONSHIP OF GELATINOUS FIBERS TO WOOD STRUCTURE IN EASTERN COTTONWOOD (POPULUS DELTOIDES)

Wood samples from Populus deltoides Marsh. were used to investigate the relationship of gelatinous fibers to the size and number of other wood elements. An increase in the amount of gelatinous fibers was related to a decrease in diameter and an increase in wall thickness of non‐gelatinous fibers. The relative sizes of rays, vessels, and fibers were inter‐related, but all of these wood elements decreased in size with an increase in the amount of gelatinous fibers. Apparently environmental conditions controlling the differentiation of gelatinous fibers also influence the development of associated wood elements. Thus, the adverse physical properties of reaction wood must be attributed to all of these structural differences in the wood and not merely to the presence of large numbers of gelatinous fibers.

The Relationship of Gelatinous Fibers to Wood Structure in Eastern Cottonwood (Populus deltoides)

Wood samples from Populus deltoides Marsh. were used to investigate the relationship of gelatinous fibers to the size and number of other wood elements. An increase in the amount of gelatinous fibers was related to a decrease in diameter and an increase in wall thickness of non-gelatinous fibers. The relative sizes of rays, vessels, and fibers were inter-related, but all of these wood elements decreased in size with an increase in the amount of gelatinous fibers. Apparently environmental conditions controlling the differentiation of gelatinous fibers also influence the development of associated wood elements. Thus, the adverse physical properties of reaction wood must be attributed to all of these structural differences in the wood and not merely to the presence of large numbers of gelatinous fibers.

White Cedar Ecotypes in Wisconsin

Within its natural range in Wisconsin, white cedar (Thuja occidentalis L.) displays the ability to persist in a wide range of habitats. Figure 1 indicates the range of white cedar in Wisconsin. It forms dense swamps on low, poorly drained topography and is commonly found on upland, well drained sites as well. This ability of white cedar has long been recognized and has been attributed to a wide degree of adaptability possessed by the species. Potzger (1941) has suggested that white cedar in northern Michigan possesses ecotypes because of its presence on upland and lowland sites in that area. There has not been, as yet, any critical investigation made of this phenomenon to substantiate the idea that ecotypes exist in white cedar. Taxonomically, there are no subspecies or varieties recognized in this species, there being no distinguishable morphological differences between white cedar found on any site. This study was undertaken to determine whether ecotypic variants exist in the white cedar population in Wisconsin. In northern and eastern Wisconsin, the extremes in white cedar habitats can often be found geographically close together, sometimes within a few hundred feet. Wide geographical distances are involved in many demonstrations of ecotypes in other species. Pauley and Perry (1954) have shown that ecotypes occur in the wide ranging species of Populus deltoides Marsh. and P. trichocarpa Torr. & Gray in response to photoperiodicity. Vaartaja (1954) has determined the presence of photoperiodic ecotypes within Pinus sylvestris L. and Alnus incana (L.) Moench. as a result of studies on material collected from northern and southern latitudes in Finland. Wright (1944a, 1944b) found three ecotypes in both white ash (Fraxinus americana: L.) and red ash (F. pennsylvanica Marsh.). These ash ecotypes are rather widely separated geographically and are differentiated on their ability to withstand cold. Within a much smaller geographical area, central California, McMillan (1956) has indicated that important edaphic ecotypic variation exists in species of Cupressus and Pinus whose ranges include serpentine and nonserpentine soils. Ecotypes occurring rather close together on different soils are probably of greater ecological importance than those existing hundreds of miles apart on the same soil. The recognition of local ecotypes is of particular importance in phytosociological studies. The procedure used in this study involved the collection, for transplantation purposes, of naturally occurring white cedar seedlings from both upland and lowland habitats throughout the white cedar range in Wisconsin, and also the collection of seed from the same sites for germination tests and growth experiments. A presentation of the methods and results will be given first for the seedling transplants, followed by a similar outline for the seed germination and growth experiments. This work was supported in part by the Wisconsin Conservation Department, with Federal Aid to Wildlife Restoration funds under PittmanRobertson Project Number W-79-R. The author wishes to extend his appreciation to Dr. J. T. Curtis for critical reading of the manuscript.

Fiber Size in Populus deltoides Marsh. In Relation to Lean of Trunk and Position in Trunk

Fiber Size in Populus deltoides Marsh. In Relation to Lean of Trunk and Position in Trunk