氮改性褐煤的特性及其在退化土壤造林中的应用研究

通过研究褐煤在氧化氨解反应后特性的变化及其在退化土壤造林中的应用效果,旨在探索褐煤高效利用的有效途径.结果表明:氧化氨解工艺能有效地提高褐煤的阳离子交换量、腐殖酸总量和富里酸含量,降低胡敏素含量.反应生成的氮改性褐煤,全氮含量为5.8%,且呈不同形态(铵态、酰胺态和紧密有机态氮态)的分布,能在土壤中保存较长的时间.半干旱退化土壤中的应用试验表明,在土壤中掺入氮改性褐煤(每株137 g或274 g)可使樟子松林分造林成活率提高20%～25%,而施用相应含氮量的尿素对林木成活率几乎没有作用.随着立地条件的改善和植被的恢复,施用氮改性褐煤林分的土壤碳汇、土壤微生物总量以及脱氢酶、脲酶、β-葡糖苷酶、碱性磷酸酶等的活性都有明显的提高,证实了氮改性褐煤可以作为一类生态和环保的土壤改良剂.     

Hormone-sensitive lipase: sequence, expression, and chromosomal localization to 19 cent-q13.3

Hormone-sensitive lipase, a key enzyme in fatty acid mobilization, overall energy homeostasis, and possibly steroidogenesis, is acutely controlled through reversible phosphorylation by catecholamines and insulin. The 757-amino acid sequence predicted from a cloned rat adipocyte complementary DNA showed no homology with any other known lipase or protein. The activity-controlling phosphorylation site was localized to Ser563 in a markedly hydrophilic domain, and a lipid-binding consensus site was tentatively identified. One or several messenger RNA species (3.3, 3.5, or 3.9 kilobases) were expressed in adipose and steroidogenic tissues and heart and skeletal muscle. The human hormone-sensitive lipase gene mapped to chromosome 19 cent-q13.3.     

The ectomycorrhizal status of European larch (Larix decidua Mill.) seedlings from bare-root forest nurseries

In this paper, we report molecular investigation of an ectomycorrhizal fungi (EMF) community of European larch (Larix decidua Mill.) seedlings grown in a bare-root nursery. In total, we surveyed 32 nurseries that were each active in supplying planting stocks to restock forests and for afforestation of post-agricultural land. Sequence-based approach was used to identify EMF taxa, quantify EMF richness, and document differences in the relative abundance of individual taxa. We identified seven fungal species that might contribute to the mycorrhizal community structure of 1 to 3-year-old L. decidua seedlings. The species richness in the examined larches varied between one and four fungal taxa, depending on both the nursery stock samples (NSS) and age class of the seedlings. The average was 1.4 for 1-year-old seedlings and 2.3 for 2- and 3-year-old plants. The dominance of Ascomycota over Basidiomycota and the prevalence of two species, Wilcoxina mikolae and Suillus grevillei, as EMF partners were characteristic features of nursery-grown L. decidua seedlings. S. grevillei was the only one basidiomycetes colonized roots of tested seedlings. The rest of the mycorrhizal pool from forest nurseries was typically dominated by pioneer fungal ascomycetes. W. mikolae was the most common mycorrhizal ascomycete present at a high frequency on NSS from both age classes and with very high abundance (average 90%) on 1-year-old seedlings. Some other ascomycetes (Pezizales 1, Pezizales 2 and Pezizales 3) appeared on tested larches at a low frequency, but sometimes in high abundance. Tuber spp. appeared at a low frequency and low abundance. The relative abundance of S. grevillei was positively correlated with the age of seedlings, while W. mikolae was negatively correlated with age. Tuber sp. 1 and 2, Pezizales 2, and W. mikolae were positively associated with the basic soil pH values. However, forward selection of the environmental variables showed that only the age of the larch seedlings contributed significantly (F = 11.45, P = 0.02) to the variance in the ECF community.     

Backshoring and nearshoring: An overview

Increasingly, economies that have traditionally benefited from offshoring are losing some of their strategical advantages, with a consequent increase in backshoring by developed economies. This paper describes the phenomenon and tries to shed light on the current challenges, trends, and debates in the area, and on the main determinants of backshoring. A new phenomenon known as nearshoring is also analysed—this consists of relocating some previously offshored manufacturing activities so that they are now close to previous core locations, but not so close as to suffer from disagglomeration effects. This combines the advantages of offshoring and backshoring.     

Development of colchicine‐induced tetraploid St. Augustinegrass (Stenotaphrum secundatum) lines

St. Augustinegrass is well suited for lawns and commercial landscapes. While many genotypes are cross‐fertile, all cultivars are propagated vegetatively in sod production. To ensure varietal purity, development of sterile triploid hybrids by crossing tetraploid and diploid genotypes has been successfully used in other warm‐season turfgrasses. Applying this model in St. Augustinegrass would be beneficial to sod producers and turf managers who require purity for certification and uniformity for performance, respectively. This study was conducted to develop colchicine‐induced tetraploid lines of St. Augustinegrass. Seeds of cultivar ‘Raleigh’ were treated with four colchicine concentrations at four exposure times. A non‐treated control was included among the treatments. Seedlings that germinated were screened for genome size changes using flow cytometry. Line DSA 13005 and two progeny lines derived through selfing, DSA 16001 and DSA 16016, were corroborated as tetraploids (2n = 4x = 36) through chromosome counts. These lines will be used in future breeding efforts to attempt development of sterile triploid cultivars of St. Augustinegrass.