Allometric growth reflects different allocation patterns and relationships of different components or traits of a plant and is closely related to ecosystem carbon storage. As an introduced species, the growth and carbon storage of Sonneratia apetala are still unclear. To derive allometric relationships of the mangrove S. apetala and to estimate carbon storage in mangrove ecosystems, we harvested 12 individual Sonneratia apetala trees from four different diameter classes in the Futian National Nature Reserve, Guangdong, China. Allometric growth models were fitted. The results showed that diameter at breast height (DBH) and wood density were better variables for predicting plant biomass (including above- and below-ground biomass) than plant height. There were significant power function relationships between biomass and DBH, with a mean allometric exponent of 2.22, and stem biomass accounted for 97% of the variation in S. apetala total biomass. Nearly isometric scaling relationships were developed between stem biomass and other biomass components. To better understand the carbon stocks of the S. apetala ecosystem, we categorized all trees into five age classes and quantified vegetation carbon storage. The S. apetala vegetation carbon storage ranged from 96.48 to 215.35 Mg C ha?1, and the carbon storage significantly increased with stand age. The allometric equations developed in this study are useful to estimate biomass and carbon storage of S. apetala ecosystems.
High mammalian gene expression was obtained for more than twenty different proteins in different cell types by just a few laboratory scale stable gene transfections for each protein. The stable expression vectors were constructed by inserting a naturally-occurring 1.006 kb or a synthetic 0.733 kb DNA fragment (including intron) of extremely GC-rich at the 5′ or/and 3′ flanking regions of these protein genes or their gene promoters. This experiment is the first experimental evidence showing that a non-coding extremely GC-rich DNA fragment is a super “chromatin opening element” and plays an important role in mammalian gene expression. This experiment has further indicated that chromatin-based regulation of mammalian gene expression is at least partially embedded in DNA primary structure, namely DNA GC-content. 相似文献
We isolated a bovine viral diarrhea virus (BVDV) from commercial fetal bovine serum and designated it HLJ-10. The complete genome is 12,284 nucleotides (nt); the open reading frame is 11,694 nt, coding 3,898 amino acids. Phylogenetic analysis indicated that this strain belongs to BVDV group 2. 相似文献