Spotlight 2002 Abstracts
Environmental and Forest BiologyTHE EFFECTS OF CANOPY COVER ON THE OVIPOSITION PREFERENCES OF THE ENDANGERED KARNER BLUE BUTTERFLY
Maija E. Benjamins & Donald J. Leopold, Faculty of Environmental and Forest Biology, 350 Illick Hall, College of Environmental Science and Forestry, Syracuse, NY 13208
Oviposition preference of the Karner blue butterfly, Lycaeides melissa samuelis Nabokov (Lepidoptera: Lycaenidae) was studied in the pine barrens of eastern New York. Female L. m. samuelis oviposite on wild lupine, Lupinus perennis L., the obligate food source of the larvae. In the eastern New York pine barrens, L. perennis is found abundantly dispersed throughout the mosiac of Quercus ilicifolia Wangenh. and Pinus rigida L.. Most current conservation management techniques have focused on restoring the eastern New York pine barrens to a primary successional ecosystem by eliminating a majority of the present woody canopy cover. It has been demonstrated that larval growth of L. m. samuelis was significantly faster on L. perennis that has been grown in moderate shade. By reaching pupation more quickly, larvae avoid senescing L. perennis during the second brood and decreasing rates of predation and parasitism. Do ovipositing L. m. samuelis select for L. perennis in moderate shade to increase the survival of their offspring? Larvae and ovipositing L. m. samuelis were exposed to L. perennis in full sun and various levels of shade. The results of this research show that both the larvae and ovipositing females prefer to reside on L. perennis in moderate shade, independent of the density and center of the patch. Although L. perennis grows more vigorously in full sun, this research demonstrates the need to maintain the canopy heterogenity of the natural pine barrens ecosystem to maintain a healthy, sustainable population of the endangered L. m. samuelis.
Brant, Jason, Smart, Lawrence1 Department of Environmental Forestry and Biology 1State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210
Lipid transfer proteins (LTP) are small (9 kD), basic proteins that can non-specifically bind lipids and transport them through an aqueous solution. In Arabidopsis, there are at least twelve LTP-like genes, and the expression of LTP 1 has been well characterized. Although similar in structure, these genes have different patterns of expression, which may indicate different biological functions. LTP 1 is preferentially expressed in epidermal cells of leaves, while other LTP’s seem to be upregulated under drought conditions. In order to gain a better understanding of the expression patterns and in vivo functions of LTP genes, the transcriptional regulation of several LTP’s are being studied. Primers were designed to PCR amplify a 1.8-kb segment of genomic DNA upstream from the start codon of each gene. These fragments were first sub-cloned into TOPO-TA vectors and then into pCAMBIA vectors containing the GUS reporter gene. These promoter:GUS fusion constructs will be used for Agrobacterium mediated transformation of Arabidopsis. The expression pattern of the GUS reporter gene will allow a greater understanding of the expression of the LTP genes, which will provide clues to the function of each gene.
Emily T. Cloyd, John M. Farrell, Donald J. Leopold, Faculty of Environmental and Forest Biology, 423 Illick Hall, SUNY-ESF, Syracuse, NY 13210
Northern pike are a sensitive obligate species of Great Lakes wetlands and an indicator of the general health of their environment. Pike populations in the Thousand Islands region of the St. Lawrence River have been declining, possibly due to changes in the structure and accessibility of their spawning and nursery grounds. The structure of habitats within these coastal wetlands has changed since water level regulation began in 1963. Interruption of the natural flow regime, extensive shoreline development, and expansion of dense cattail stands has altered the composition of the spawning and nursery areas used by northern pike. We are building a model to test how these changes have affected the spatial and temporal distribution of spawning, survival, and growth of pike in the St. Lawrence. Our model uses three habitat types, seasonally flooded backwater (less than 0.5 m depth), shallow marsh (less than 2 m depth), and deepwater submergent vegetation (2-6 m depth) as potential spawning and nursery grounds. We will develop relationships between water level, temperature, availability and suitability of spawning and nursery grounds, season, and prey abundance. We will be able to predict spawning success, survival, and growth of pike within each wetland by applying these relationships to habitat-specific egg deposition rates, survival rates, and growth models for several stanzas of life history (egg, yolk-sac fry, swim-up, first piscivory, emigrant). The results of this model can be used to predict how pike will respond to proposed changes in water level regulation and/or restoration of habitat in both the short- and long-term. It will also be useful in guiding discussions and policy making for future water level management.
Sheila Christopher, Shreeram Inamdar, and Myron Mitchell, Faculty of Environmental and Forest Biology, 6 Illick, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Recently there has been considerable interest in investigating the mechanisms responsible for the export of solutes. Few studies have examined topography and its influence on hydrologic flowpaths in regulating the export of DOC and NO3-. The knowledge of flowpaths derived from the topographic index (ln [a/tanB]) in combination with the potential solute source areas within the soil profile can be used to characterize the potential for leaching of solutes. We explored the use of TOPMODEL to characterize surface water chemistry for a suite of subcatchments of the 135 ha Archer Creek Catchment. The assemblage of subcatchments represented a range in topography and drainage. Headwater subcatchments had steep hillslopes, bench-step topography, and surface springs. Subcatchments located lower in the watershed were poorly drained with a greater share of wetland areas. We hypothesized that the potential for export of DOC and NO3- from these subcatchments can be expressed as a function of the topographic index and hydrologic flowpaths. We tested this hypothesis by comparing subcatchment ln [a/tanB] distribution and flow partitioning against solute concentrations measured in surface and subsurface water. TOPMODEL results suggested that subcatchment 11, a lower elevation subcatchment, had surface runoff contribution nearly an order of magnitude greater than the headwater subcatchments and highest mean ln [a/tanB]. This subcatchment also had the highest mean annual stream DOC (816.7 umol/l) and lowest mean annual stream NO3- (11.7 ueq/l) concentration indicating the dominance of near surface flowpaths on solute availability and flushing since near-surface soil solution was the controlling end-member for stream water DOC. In contrast, subcatchment 14, located in the headwaters, had a much greater percentage of deep subsurface flow contribution and lowest mean ln [a/tanB]. Subcatchment 14 also had the lowest mean annual stream DOC (137.2 umol/l) and highest NO3- (56.1 ueq/l) concentration, suggesting the controls of deep flow paths on solute export since groundwater was the controlling end-member for stream water NO3-. Intermediate surface water chemistry values observed for other subcatchments could not be explained by topographic and hydrologic controls. Results from this study suggest that although TOPMODEL can capture some of the spatial variability in solute concentrations, other controls such as catchment geology can also have significant influence on stream solute concentrations.
David H. F. Coder and Prof. Dudley Raynal
Most tree growth or dendrochronological studies have concentrated only on the growth rings at breast height. While looking only at these rings can give a fair interpretation of the overall tree, a more detailed approach would yield greater results. Using converted tree ring data from many heights in a tree, we compiled a growth layer profile graph (GLP, see definition box below) to view a complete representation of the tree. The next step in this project is to turn these data into a true 3D representation of an actual tree. This research project was conducted over a one semester period.
Debora Endriss, Department of Environmental Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210. Stacy McNulty Haulton, Adirondack Ecological Center, State University of New York College of Environmental Science and Forestry, Newcomb, NY 12852.
Terrestrial salamanders are sensitive to disturbances and therefore are good indicators of ecosystem health and biodiversity, but differences in environmental variables such as temperature and soil moisture may affect salamander abundance. Terrestrial salamanders have characteristics that are especially useful in monitoring ecosystem health such as small territory size, high densities, and low sampling costs. We monitored terrestrial salamanders at Huntington Wildlife Forest in the central Adirondack Mountains of New York. We checked 32 sets of artificial cover objects in 5 habitat types, 5-7 times per year, from May to October 1998 to 2001. Total daily precipitation and minimum and maximum daily temperature were recorded. We investigated the relationship between habitat type, climatic variables, and salamander abundance. Mean abundance (+SD) over all years and habitat types was 0.95 ± 1.15 for redbacked salamanders, 0.57 ± 1.08 for dusky salamanders, 0.12 ± 0.42 for two-lined salamanders, and 0.10 ± 0.41 for red-spotted newts (eft stage). There was no trend in abundance for any species over the four-year period. Redback abundance on HWF was higher in mixed wet sites, while deciduous wet sites had higher dusky abundance. Neither two-lined nor dusky salamanders were found in coniferous sites. Redbacks were less abundant as both maximum and minimum daily temperatures increased, whereas dusky salamanders were more abundant. Salamander abundance was also negatively related to precipitation on the day of sampling. Environmental variables and habitat type are important to terrestrial salamander distribution and abundance under artificial cover objects and should be included in interpretations of abundance data.
Kemal Gökkaya, Dudley J. Raynal and Todd M. Hurd, Faculty of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Biological nitrogen fixation is a unique process achieved only by certain groups of living organisms such as free living bacteria or plants that have symbiotic relationships with microbes that possess the nitrogen fixing enzyme, nitrogenase. Alder is a group of nitrogen fixing woody plants known as actinorhizal plants. Actinorhizal plants fix nitrogen through a root nodule symbiosis with the actinomycete Frankia. Speckled alder is one of the defining species of riparian shrub wetlands in the Adirondack Park. It is an early successional species that grows along lakeshores and stream edges.
Nitrogen fixers have inherently high phosphorus demands. The effect of phosphorus supply on nodule growth and nitrogen fixation in legumes has been studied, but information about the effects of phosphorus on nitrogen fixation of actinorhizal plants is very limited. This study was undertaken to test the hypothesis that phosphorus limits nitrogen fixation in speckled alder.
Four blocks with a reference and phosphorus addition treatment plot in each were established at each of two wetlands at Huntington Wildlife Forest. Specific nitrogenase activity was measured in situ by the acetylene reduction assay on three dates after the treatment application. Ion exchange resins were used to capture phosphate and nitrate in the substrate. Specific nitrogenase activity increased with the treatment but the difference between the treatment and reference plots was not significant over the course of sampling period even though a significant difference on the second sampling date was observed (alpha=0.05). The phosphate amount captured by the ion exchange resins in treatment plots was consistently higher than the reference plots, but the difference was not significant over the course of sampling period. Nitrate concentrations were consistently higher in reference plots compared to treatment plots and showed an increasing pattern both for the treatment and reference plots over the sampling period although the difference between them was not significant over time. These preliminary findings indicate that there is a stimulation initiated by phosphorus addition on nitrogenase activity. Higher rates of P addition and longer sampling period spread over the entire growing season, coupled with multiple seasons of sampling may be necessary to better detect the sensitivity of response of nitrogen fixation activity of speckled alder in these riparian systems.
Nicole E.M. Hotaling and Donald J. Leopold, Environmental and Forest Biology, 350 Illick Hall
We are studying wetlands in eight embayments along the southern and eastern shores of Lake Ontario as part of a multi-institutional project involving researchers at Cornell University, Syracuse University, and SUNY-ESF funded by the National Science Foundation Biocomplexity Program. The overall project hypothesizes that hydrologic residence time is the key variable determining the degree to which each embayment is either self-organized or controlled by influences from the watershed. Our specific interest is in examining the effect of watershed hydrology and water chemistry on the structure and function of embayment wetlands, and how the wetlands’ structure and function influence the aquatic habitats in these bays. Last summer, we sampled wetland vegetation at all eight sites using a systematic sampling design. The relative amount of each of five wetland community types (graminoid herbaceous, non-graminoid herbaceous, shrub, tree, and water) varied among the sites based on line-intercept data. The most important species in these sites based on relative important values calculated from plot data (density, percent cover, and frequency) also varied, as did species richness (total and per square meter). This summer we will investigate nutrient dynamics in these wetlands to look for patterns that could correspond to known patterns in wetland vegetation communities, and embayment and watershed characteristics.
Juan Lin1, Lee E. Gunter2, Richard F. Kopp1, Gerald A. Tuskan2, and Lawrence B.Smart1
1Faculty of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Illick Hall, Syracuse, NY 13210
2Environmental Sciences Division, Oak Ridge National Lab, Oak Ridge, TN 37831
Some varieties of Salix matsudana are characterized by extensive bending of the stems and curling of the leaves. These varieties are often named ‘tortuosa’ or commonly corkscrew willow. We made a controlled cross between a corkscrew female (Salix matsudana var. ‘tortuosa’) and a straight-stemmed male (Salix alba clone 99010) and are growing 77 of the progeny in the field. Among the progeny are 39 with straight and 38 with twisted stems and curled leaves, suggesting that a dominant allele at a single locus controls this phenotype. As a first step in characterizing this locus, we searched for AFLP and RAPD markers linked to the tortuosa allele using bulked segregant analysis. DNA samples from 20 F1 individuals were pooled to produce two bulks, one with ten displaying the corkscrew phenotype and the other with ten straight individuals. Amplification using 56 AFLP primer combinations and 640 RAPD primers was attempted and many bands putatively present in the corkscrew pool and absent in the straight pool were identified. We have identified one RAPD marker that is amplified in 35 of 38 corkscrew progeny and in only 3 of 39 straight progeny. We have also found 2 AFLP fragments that are present in 10 individuals of the corkscrew pool and absent in 9 of 10 individuals of the straight pool. Results of AFLP analysis with all the progeny in this family will be presented.
Jennifer Lund1, Stephen A. Teale1, Joseph Francese1, Michael J. Bohne1, Jian-guang Li2, You-ju Jin2. 1College of Environmental Science and Forestry, State University of New York, Syracuse, NY 13210, USA, 2 College of Biology Science and Technology, Beijing Forestry University, 100083, PR China
In the United States, the Asian Longhorned Beetle (Anoplophora glabripennis) is an invasive, exotic pest of hardwoods, including maples, poplars and willows. Originally from Asia, the beetle has established populations in New York City and Chicago. Potential damage in the United States is estimated at over 500 billion dollars. In 1997, volatiles produced by host materials and beetles were isolated and identified. Subsequently, several host and one beetle-produced volatiles have elicited antennal responses in male A. glabripennis. In laboratory, paired choice tests, male beetles preferentially selected females and host volatiles over blanks. Frass extracts have also been tested for similar volatile production and behavioral responses. In field tests, both males and females were attracted to synthetic host compounds. In 1999, cis-3-hexen-1-ol baited traps attracted a significantly higher number of beetles then unbaited traps. In 2000, cis-3-hexen-1-ol also attracted a significantly high number of beetles. Traps baited individually with 1-butanol, 1-pentanol, or 2-pentanol caught few beetles, but the combination of the three compounds attracted a significantly more beetles than all other treatments, including cis-3-hexen-1-ol. The 2001 field tests showed similar trends but without statistical significance. Long-term applications of this research include the development of a semiochemical-based control method for A. glabripennis and the development of a monitoring system to evaluate the progress and effectiveness of this and other control methods.
William A. Moskal Jr.1, Yuval Eshed2, John L. Bowman2, Lawrence B. Smart1
1. Faculty of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry. Syracuse, NY 13210.
2. Section of Plant Biology, University of California Davis, California 95616.
Guard cells are a highly specialized and differentiated cell type that play an important role in plant physiology. The objective of our research is to gain a better understanding of the unique aspects of stomatal physiology by identifying guard-cell-specific genes from the model plant Arabidopsis thaliana. To accomplish this, we have screened several thousand lines of promoter tagged Arabidopsis from two enhancer trap collections for guard-cell-specific reporter gene expression. From our screening of these collections, we have identified nine lines in which the reporter gene (GUS) is expressed in guard cells or guard mother cells. The tagged locus has been identified in four lines. Two of these, GCA2 and GCA4, display a mutant morphological phenotype. We are currently working to elucidate the function of the tagged genes, as well as their role in stomatal physiology.
Margaret H. Murphy, Michael J. Connerton, and Donald J. Stewart. Environmental and Forest Biology, 106 Illick Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Many factors regulate survival, growth, and reproduction of Atlantic salmon throughout their life. Both abiotic and biotic factors interact at each life stage to influence overall survival, such as temperature, habitat constraints, competition, predation, and food availability. One critical period during Atlantic salmon life history is survival through the first winter. A major factor involved in mortality may be the loss of energy content that occurs over winter resulting in reduced body weight. We hypothesize that winter survival of Atlantic salmon is regulated by body size and condition in late fall and by the severity of winter conditions. We tested this hypothesis with a laboratory and field study conducted over two winters in Central New York. A 2x2x2 factorial design (temperature, food, genetic strain) was used in the laboratory to evaluate differences in over-winter survival. Temperatures were held constant at 3-4oC in one treatment (2 tanks) and fluctuated weekly between 3-4oC and 1oC in the other treatment (2 tanks). Two feeding treatments, starved fish and fed fish, were conducted to assess influence of feeding on survival and growth rates between fed and unfed fish during winter. Two strains, a landlocked and a sea run were used in each treatment. Three respirometry trials were conducted over the winter to assess basal metabolism in individuals in each treatment. Plastic cages with six Atlantic salmon per cage were placed in three stream locations to assess instream survival during the winter. Cages were removed at monthly intervals to assess survival and growth during early, mid- and late winter. There were no significant differences in growth rates between the strains in the laboratory. Survival was highest in the unfed, constant temperature treatment while growth rates were highest in the fed, constant temperature treatment. Negative growth rates were recorded in both fed and unfed, fluctuating temperature treatments. Respirometry data indicate a significantly higher metabolic rate in the constant temperature, fed treatment compared to the other three treatments. The two winter field seasons were two extremes with the first one of the snowiest on record (2000-2001) and the next one of the driest (2001-2002). There were no mortalities in any of the field cages as a result of winter stress. Fish in the majority of field sites lost weight over winter, with highest losses occurring early in the winter. Differences in growth rates were observed between sites within years and within sites between years. Fish in the field cages were actively feeding during the winter although this was not converted to positive growth during this period.
Ingrid S. Phillips1, Richard F. Kopp1, Peter O. Greeno2, Charles A. Maynard2, Lawrence P. Abrahamson1,2, and Lawrence B. Smart1, 1Faculty of Environmental and Forest Biology, 2Faculty of Forest and Natural Resources Management, 418 Illick Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Shrub-form willows (Salix spp., including S. eriocephala) have been studied as a potential biomass source for bioenergy and biobased products. These fast-growing species are grown under a coppice system, where stems are cut after the first year of growth, and the resprouted stems are then harvested every three years. The goal of this study is to determine the heritability of a number of growth characters of S. eriocephala in order to determine what gains can be made when selecting for these characters. For this study, 34 half-sib F1 families were produced in an incomplete half-diallel with seven females and eight males as parents. Six to ten individuals per family were planted in a RCBD on two sites with four blocks per site in four-tree row-plots. Rust (Melampsora spp.) incidence was surveyed after the first year of growth. Stem height, stem number, and stem diameters were measured the first year after coppice. Variance components for these characters were calculated and narrow- (h2) and broad- (H2) sense heritabilities were calculated for these traits. The results indicate low to moderate heritability, suggesting that some improvement can be made in the selection for these characters in a breeding program.
Adam J. Storch, Stephen M. Coghlan Jr., and Neil H. Ringler, Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210
Density-dependent processes, such as competition for food resources, have the potential to structure stream fish assemblages by effecting changes in individual-level fitness. The direction and intensity of competition may depend upon temporal and spatial variation in abiotic factors, such as temperature or stream discharge. The ability to predict the outcomes of these competitive interactions has important implications in conservation biology, specifically in assessing the feasibility of native species restoration given prior naturalization of exotic species. We examined partitioning of food resources among sympatric juveniles of stocked Atlantic salmon (Salmo salar), wild brown (S. trutta) and steelhead trout (Oncorhynchus mykiss) in two tributaries in the Owasco Lake, NY, watershed, during a period of summer drought. All salmonines were dependent upon larval stages of a few ubiquitous families of aquatic invertebrates (Baetidae, Hydropsychidae, Chironomidae, Simuliidae), but regularly ingested less-abundant aquatics and terrestrials. Steelhead showed marked temporal variation in diversity and quantity of ingested invertebrates, becoming highly selective in mid-afternoon. Atlantic salmon demonstrated relative constancy in overall diversity and quantity of food ingested, although diet composition varied temporally. Atlantic salmon fed more and appeared less selective than brown and, especially, steelhead trout. However, diet overlap among the three species was usually highly significant, indicating very little niche partitioning. Our results indicate that Atlantic salmon may dominate interspecific interactions; possible explanations include the presence of strong intraspecific competition among abundant steelhead juveniles and a thermal regime favoring Atlantic salmon metabolic activity. We also suggest that the presence of naturalized exotic salmonines has few depressing effects on resource acquisition by juvenile Atlantic salmon during periods of habitat constriction and elevated temperatures. After sampling under conditions more optimal for salmonine survival and growth (i.e., cooler temperatures and increased streamflow), we will be able to quantify the degree, direction, and seasonality of niche breadth fluctuation. In addition, incorporating results from sites with each species in allopatry will clarify the role of interspecific competition in structuring juvenile salmonine communities, and elucidate potential effects of this competition on Atlantic salmon restoration.
Kristy Szprygada, Environmental and Forest Biology, 339 Jahn Laboratory, Dr. Kimberly Schulz, Environmental and Forest Biology, 456 Illick Hall, and Dr. Gregory Boyer, Chemistry, 320 Jahn Laboratory, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Cyanobacterial blooms produce hepatotoxins and neurotoxins, which can be fatal to humans and animals. Due to the ephemeral nature of these blooms and the high cost of monitoring for these toxins, we are interested in using zebra mussels as biomonitors. To determine the rate of toxin accumulation, zebra mussels (Dreissena polymorpha) were collected from Oneida Lake and grown in a growth chamber in a defined freshwater media. Mussels were removed from their natural substrate and reattached to PVC plates. Coupled with frequent media changes, this practice minimized the growth of nuisance algae. A flow-through fluorescence system was developed and will be used to determine mussel feeding rates on toxic Microcystis aeruginosa and non-toxic Chlorella vulgaris. Toxin content of mussel tissues will be determined using a protein phosphatase inhibition assay and a commercially available ELISA kit. Mussel tissues collected from lakes containing toxic cyanobacteria will be analyzed for toxin content and compared to the tissues from experimentally fed mussels. These results will determine the rates of toxin accumulation and turnover in the mussel. This research is funded by New York State Sea Grant.
Jack T. Tessier, Faculty of Environmental and Forest Biology, 350 Illick Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.
Understory plant species in northern hardwood forests encompass multiple patterns of leaf-longevity. Several authors have called Oxalis acetosella L. (common wood sorrel) a wintergreen herb, meaning that it keeps a cohort of leaves for one full year and as that cohort senesces it is replaced by a new one. I censused and labeled leaves in four populations of Oxalis acetosella in a northern hardwood forest of the Catskill Mountains, New York periodically for one full year beginning in November of 2000 to quantitatively document leaf-longevity in the species. A total of 220 leaves were labeled during the study. Multiple cohorts of leaves developed and senesced in less than one year in each of the four populations. In the extreme cases four leaves survived for at most 16 days while four leaves survived for at least 360 days. Oxalis acetosella did not function as a true wintergreen species during this year in the Catskills. Leaf-longevity in this species is therefore more versatile than previously believed. I suggest that this leaf-longevity strategy be termed ‘continual-green’ to describe the continual production and senescence of leaves throughout the year. The functional significance as well as the geographic and temporal extents of this leaf-longevity pattern in Oxalis acetosella remain to be determined.
Stephanie Turner, Christopher Mauro and Danilo Fernando, Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, 350 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210.
Genetic engineering of plants relies on the development of efficient methods for the regeneration of whole plants from cultured tissues. This study aims to develop protocols for the efficient in vitro regeneration of willow through organogenesis and somatic embryogenesis. To initiate organogenesis, willow seeds were surfaced sterilized and germinated overnight. Hypocotyl segments were excised under aseptic conditions and cultured on callus induction medium (WPBM supplemented with 2,4-D and BA). The calli were allowed to develop for 3 weeks and then subcultured on the same medium for another 3 weeks. They were then transferred onto shoot induction medium (MS basal medium supplemented with zeatin and various vitamins) where they readily proliferated, turned green and red, and formed nodulate structures. The calli were subcultured on the same medium after 3 weeks. After the third subculture, multiple shoots started to develop on some of the calli. Individually separated shoots containing small pieces of callus tissue were transferred onto root induction medium (MS basal medium supplemented with kinetin). Within a week, roots developed from the calli and bases of young stems. Rooted shoots have also been successfully grown in soil with very high rate of survival. To initiate somatic embryogenesis, callus was induced from young anthers and cultured on embryo induction medium (MS basal medium supplemented with either 2,4-D or BA). The calli proliferated profusely, but no somatic embryo has yet been observed. Although the protocols presented here require further optimization, these results already show that callus from hypocotyl explants are amenable to shoot formation with high regeneration frequencies, and therefore, ready to be used for genetic transformation experiments.
Shiliang Zhang and Danilo Fernando, Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, 350 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210.
Our knowledge of reproductive development in plants is essentially confined to herbaceous species. Very few studies deal with woody plants and none on willow. Willow is rapidly coming to the forefront as biomass species not only because it is fast growing, but also because of its high potential for bioproducts and bioenergy. As part of the program on developing willow as a model for reproductive development in woody species, this project specifically describes the structural events leading to the formation of pollen grains. In the course of the study, several developmental abnormalities were observed from Salix discolor clone S365. Abnormalities were based on comparison of histological structures of all developmental stages involved in pollen development using several clones and species of willow. The abnormalities observed in clone S365 includes a combination of the following: delayed tetrad formation, rare occurrence of tetrads, highly variable sizes of pollen grains, almost zero pollen viability, and stickiness of pollen grains resulting in their inability to be released. There were no abnormalities observed on the structure and development of the tapetum and anther wall. The structural analysis led us to examine meiosis and as a result, several meiotic irregularities were observed including delayed meiosis, presence of sticky chromosomes and occurrence of lagging chromosomes. The latter resulting in aneuploidy. Therefore, the sterility in S. discolor (S365) is genetic and not environmental, as previously thought. One dimensional gel analysis of proteins isolated from catkins containing microspore mother cells of normal and male sterile clones revealed an interesting difference that could point to the gene responsible for male sterility in willow.