植物覆盖技术保护潮湿地区土遗址探讨

潮湿地区降雨量大,土遗址普遍风化严重,室外保护难度大,表面防风化技术还不成熟。基于土遗址表面普遍生长有茂盛植被的现象,充分发挥植物对遗址的保护作用,减少不利影响,采用植物覆盖技术保护遗址十分必要且可行。本工作通过调查植物对遗址影响和植物覆盖技术保护实践的分析,论证了植物覆盖技术的可行性,提出针对封土、墙体等不同遗址,充分考虑遗址风化程度和保存状态,选用适合植物物种实施植物覆盖技术,植物物种选择应首选当地适宜优势物种,应充分评估植物对土遗址的不利影响。研究结果表明,植物覆盖技术保护遗址十分必要且可行。     

Improved methodology for extraction and amplification of DNA from single grains of charred wheat

Comparisons were made between two commonly used methods for the extraction of ancient DNA from charred plant remains. Using artificially charred wheat seeds, we show that silica-binding is the most efficient method for extraction of DNA. We describe a improved silica-binding procedure, including pre-incubation with N-phenacylthiazolium bromide and increased washing of bound DNA, which yields amplifiable DNA from seeds heated at 200 °C for up to 8 h, conditions which promote the formation of Maillard products which often copurify with aDNA and inhibit subsequent PCRs. We believe that this method will be effective in ancient DNA extraction with most types of charred archaeobotanical material. Both cold- and hot-start PCR procedures gave good amplicon yields with extracts prepared in this way, but cold-start PCRs also resulted in synthesis of short artefact products. Addition of bovine serum albumin to PCRs, an inert carrier substance thought to enhance amplification efficiency by binding contaminants, had no advantageous effect and in fact reduced amplicon synthesis.