IMPLAN MODELING APPLICATIONS IN STATE AND REGIONAL DEVELOPMENT

Community/Rural/Urban Development,

Embryogenic potential and expression of embryogenesis-related genes in conifers are affected by treatment with a histone deacetylase inhibitor

Somatic embryogenesis is used for vegetative propagation of conifers. Embryogenic cultures can be established from zygotic embryos; however, the embryogenic potential decreases during germination. In Arabidopsis, LEAFY COTYLEDON (LEC) genes are expressed during the embryonic stage, and must be repressed to allow germination. Treatment with the histone deacetylase inhibitor trichostatin A (TSA) causes de-repression of LEC genes. ABSCISICACID3 (ABI3) and its Zeamays ortholog VIVIPAROUS1 (VP1) act together with the LEC genes to promote embryo maturation. In this study, we have asked the question whether TSA treatment in a conifer affects the embryogenic potential and the expression of embryogenesis-related genes. We isolated two conifer LEC1-type HAP3 genes, HAP3A and HAP3B, from Picea abies and Pinus sylvestris. A comparative phylogenetic analysis of plant HAP3 genes suggests that HAP3A and HAP3B are paralogous genes originating from a duplication event in the conifer lineage. The expression of HAP3A is high, in both somatic and zygotic embryos, during early embryo development, but decreases during late embryogeny. In contrast, the expression of VP1 is initially low but increases during late embryogeny. After exposure to TSA, germinating somatic embryos of P. abies maintain the competence to differentiate embryogenic tissue, and simultaneously the germination progression is partially inhibited. Furthermore, when embryogenic cultures of P. abies are exposed to TSA during embryo maturation, the maturation process is arrested and the expression levels of PaHAP3A and PaVP1 are maintained, suggesting a possible link between chromatin structure and expression of embryogenesis-related genes in conifers

The cytohistological basis of apospory in Hypericum perforatum L

none6siSt. John’s wort (Hypericum perforatum L., 2n=4x=32) is a medicinal plant that produces pharmaceutically important metabolites with antidepressive, anticancer and antiviral activities. It is also regarded as a serious weed in many countries. H. perforatum is furthermore an attractive model system for the study of apomixis. Natural populations of H. perforatum are predominantly composed of tetraploid individuals, although diploids and hexaploids are known to occur. It has been demonstrated that while diploids are sexual, polyploids are facultative apomictic whereby a single individual can produce both sexual and apomictic seeds. Despite our increasing understanding of gamete formation in sexually reproducing species, relatively little is known regarding the cytological basis of reproduction in H. perforatum. Here, we have studied embryo sac formation and the genetic constitution of seeds by means of staining-clearing of ovules/ovaries, DIC microscopy and flow cytometric seed screening (FCSS) of embryo and endosperm DNA contents. Comparisons of female sporogenesis and gametogenesis between sexual and apomictic accessions have enabled the identification of major phenotypic differences in embryo sac formation, in addition to complex fertilization scenarios entailing reduced and unreduced male and female gametes. These data provide new insights into the production of aposporous seeds in H. perforatum, and complement ongoing population genetic, genomic and transcriptomic studies.noneGALLA G; BARCACCIA G.; SCHALLAU A; PUENTE MOLINS M; BAUMLEIN H; SHARBEL T.FGalla, Giulio; Barcaccia, Gianni; Schallau, A; PUENTE MOLINS, M; Baumlein, H; Sharbel, T. F

Identification and genetic analysis of the APOSPORY locus in Hypericum perforatum L.

The introduction of apomixis \u2013 seed formation without fertilization \u2013 into crop plants is a long-held goal of breeding research, since it would allow for the ready fixation of heterozygosity. The genetic basis of apomixis, whether of the aposporous or the diplosporous type, is still only poorly understood. Hypericum perforatum (St John\u2019s wort), a plant with a small genome and a short generation time, can be aposporous and/or parthenogenetic, and so represents an interesting model dicot for apomixis research. Here we describe a genetic analysis which first defined and then isolated a locus (designated HAPPY for Hypericum APOSPORY) associated with apospory. Amplified fragment length polymorphism (AFLP) profiling was used to generate a cleaved amplified polymorphic sequence (CAPS) marker for HAPPY which co-segregated with apospory but not with parthenogenesis, showing that these two components of apomixis are independently controlled. Apospory was inherited as a dominant simplex gene at the tetraploid level. Part of the HAPPY sequence is homologous to the Arabidopsis thaliana gene ARI7 encoding the ring finger protein ARIADNE7. This protein is predicted to be involved in various regulatory processes, including ubiquitin-mediated protein degradation. While the aposporous and sexual alleles of the HAPPY component HpARI were co-expressed in many parts of the plant, the gene product of the apomict\u2019s allele is truncated. Cloning HpARI represents the first step towards the full characterization of HAPPY and the elucidation of the molecular mechanisms underlying apomixis in H. perforatum

The Employment and Output Effects of Changing Patterns of Afforestation in Scotland

This paper considers the economy-wide output and employment effects of the shift in forest expansion away from coniferous plantations towards broadleaf and native species. Four different woodland types are distinguished within a Scottish input-output table and demand and supply multipliers estimated to show the total effects on the economy of a 100 hectare increase in the land area devoted to each type as well as a switch in land from agriculture. Results suggest that the output and employment effects of new native woodlands and farm woodlands are greater than those generated by planting additional coniferous woodlands of equivalent size. In addition, an increase in the area of these policy-driven woodland types is likely to have positive effects, even when the expansion impinges onto agricultural land of average productivity. It is thus argued that the traditional economic objectives of forestry policy have not been compromised in the drive towards multi-benefit woodlands

Managing young forests in the Douglas-fir region : symposium held June 15-18, 1970

These are the proceedings of the third short course in the management of young Douglas-fir and western hemlock con­ducted by the School of Forestry, Oregon State University, June 15-18, 1970. The course included one day of lectures and discussion on the campus of Oregon State University, two all-day field trips to observe management, and one day of a "sound-off" session in which all participated. The 53 registrants came from Oregon, Washington, and California. The opportunities in young-growth management are great. European foresters have managed Douglas-fir successfully longer than foresters in the Pacific Northwest and, even though both the economics and ecological conditions in Europe differ from ours, foresters in the Pacific Northwest will profit from knowing about their experiences. Administration and operation of partial cuttings are more complicated than final harvest cuttings and the economics of the management program have not been determined com­pletely. The knowledge and experience, then, of foresters active in research and management of young forests are especially relevant. But young-growth management not only must be finan­cially sound but also ecologically safe and esthetically accept­able. For instance. red alder, a valuable species economically, is also valuable biologically because it fixes nitrogen in the soil. And it may play an important role in the control of Poria weirii, a serious root rot of Douglas-fir. Skillful management can maintain or improve esthetic qualities of the forest. This short course was oriented toward those goals