Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was con- structed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geo- graphic origin.

美国海岸红杉在中国发展的现状与前景

海岸红杉[Sequoia sempervirens(D. Don) Endl.]是常绿针叶树,植物界的活化石。1972年,美国总统尼克松把一株海岸红杉树苗作为国礼带到中国。中国采用扦插法,共繁殖了大约4 000株苗木,分送各地种植。实践表明,海岸红杉适应性强,在中国亚热带的南方生长良好,且无论其生长速度、木材品质,或观赏价值均超过了南方主要的栽培树种杉木、柳杉、水杉和池杉等。但海岸红杉的种子繁殖和扦插繁殖都存在困难。从2014年起,作者采用建立"萌条采穗圃",从地面下割取萌条扦插的方法繁殖海岸红杉获得了成功。试验表明:萌条扦插成活率可达90%以上;苗本直立生长,无偏斜现象;1年可育苗2或3次,可大量生产苗木;育苗成本低于组培法的1/3;技术简单,易于推广。红杉不仅对中国的木材生产、山区造林、城市居民区绿化、发展观光旅游业等,甚至对红杉木材的生产以及碳吸收发挥重要的作用。文中对中国发展红杉种植提出了若干重要建议。