Pinus radiata D. Don, native to a Californian coastal environment, has been introduced to many parts of the world as an exotic species for afforestation. It is now a major plantation species in the Southern Hemisphere...Pinus radiata D. Don, native to a Californian coastal environment, has been introduced to many parts of the world as an exotic species for afforestation. It is now a major plantation species in the Southern Hemisphere. In 1990, it was introduced to the heavily degraded, dry Min river valley area in Aba prefecture of Sichuan Province, P. R. China. Survival and growth of young trees planted at several sites appear to be reasonable. This review is to serve as an introduction to the large body of literature on P. radiata for forest scientists in China. It covers the following aspects: P. radiata in its native environment and in ex situ plantations, provenance and genetic variations, environmental limitations and climate niche, diseases and pests, lessons from unsuccessful introductions, and the use of P. radiata for ecological restoration. The early growth of P. radiata planted in the dry river valley area is briefly described. Potential problems associated with the introduction of P. radiata in Aba and future research needs are also identified.展开更多
Panax ginseng C. A. Meyer is an important traditional herb in eastern Asia. It contains ginsenosides, which are primary bioactive compounds with medicinal properties. Although ginseng has been cultivated since at leas...Panax ginseng C. A. Meyer is an important traditional herb in eastern Asia. It contains ginsenosides, which are primary bioactive compounds with medicinal properties. Although ginseng has been cultivated since at least the Ming dynasty to increase production, cultivated ginseng has lower quantities of ginsenosides and lower disease resistance than ginseng grown under natural conditions. We extracted root RNA from six varieties of fifth-year P. ginseng cultivars representing four different growth conditions, and performed Illumina paired-end sequencing. In total, 163,165,706 raw reads were obtained and used to generate a de novo transcriptome that consisted of 151,763 contigs(76,336 unigenes), of which 100,648 contigs(66.3%) were successfully annotated. Differential expression analysis revealed that most differentially expressed genes(DEGs) were upregulated(246 out of 258, 95.3%) in ginseng grown under natural conditions compared with that grown under artificial conditions. These DEGs were enriched in gene ontology(GO) terms including response to stimuli and localization. In particular, some key ginsenoside biosynthesis-related genes, including HMG-Co A synthase(HMGS), mevalonate kinase(MVK), and squalene epoxidase(SE), were upregulated in wild-grown ginseng. Moreover, a high proportion of disease resistance-related genes were upregulated in wild-grown ginseng. This study is the first transcriptome analysis to compare wild-grown and cultivated ginseng, and identifies genes that may produce higher ginsenoside content and better disease resistance in the wild; these genes may have the potential to improve cultivated ginseng grown in artificial environments.展开更多
Abstract The author introduces the w-function defined on the considered spacelike graph M. Under the growth conditions w = o（log z） and w = o（r）, two Bernstein type theorems for M in Rm^n＋m are got, where z and r...Abstract The author introduces the w-function defined on the considered spacelike graph M. Under the growth conditions w = o（log z） and w = o（r）, two Bernstein type theorems for M in Rm^n＋m are got, where z and r are the pseudo-Euclidean distance and the distance function on M to some fixed point respectively. As the ambient space is a curved pseudo- Riemannian product of two Riemannian manifolds （∑1,g1） and （∑2,g2） of dimensions n and m, a Bernstein type result for n =2 under some curvature conditions on E1 and E2 and the growth condition w = o（r） is also got. As more general cases, under some curvature conditions on the ambient space and the growth condition w = o（r） or w = o（√r）, the author concludes that if M has parallel mean curvature, then M is maximal.展开更多
基金This paper is part of a project funded by Australian Centre for International Agricultural Research (ACIAR), State Forests of New South Wales, Australia and Department of Forestry, Sichuan Province China.
文摘Pinus radiata D. Don, native to a Californian coastal environment, has been introduced to many parts of the world as an exotic species for afforestation. It is now a major plantation species in the Southern Hemisphere. In 1990, it was introduced to the heavily degraded, dry Min river valley area in Aba prefecture of Sichuan Province, P. R. China. Survival and growth of young trees planted at several sites appear to be reasonable. This review is to serve as an introduction to the large body of literature on P. radiata for forest scientists in China. It covers the following aspects: P. radiata in its native environment and in ex situ plantations, provenance and genetic variations, environmental limitations and climate niche, diseases and pests, lessons from unsuccessful introductions, and the use of P. radiata for ecological restoration. The early growth of P. radiata planted in the dry river valley area is briefly described. Potential problems associated with the introduction of P. radiata in Aba and future research needs are also identified.
基金supported by the International Science and Technology Cooperation of China(2011DFA32730)
文摘Panax ginseng C. A. Meyer is an important traditional herb in eastern Asia. It contains ginsenosides, which are primary bioactive compounds with medicinal properties. Although ginseng has been cultivated since at least the Ming dynasty to increase production, cultivated ginseng has lower quantities of ginsenosides and lower disease resistance than ginseng grown under natural conditions. We extracted root RNA from six varieties of fifth-year P. ginseng cultivars representing four different growth conditions, and performed Illumina paired-end sequencing. In total, 163,165,706 raw reads were obtained and used to generate a de novo transcriptome that consisted of 151,763 contigs(76,336 unigenes), of which 100,648 contigs(66.3%) were successfully annotated. Differential expression analysis revealed that most differentially expressed genes(DEGs) were upregulated(246 out of 258, 95.3%) in ginseng grown under natural conditions compared with that grown under artificial conditions. These DEGs were enriched in gene ontology(GO) terms including response to stimuli and localization. In particular, some key ginsenoside biosynthesis-related genes, including HMG-Co A synthase(HMGS), mevalonate kinase(MVK), and squalene epoxidase(SE), were upregulated in wild-grown ginseng. Moreover, a high proportion of disease resistance-related genes were upregulated in wild-grown ginseng. This study is the first transcriptome analysis to compare wild-grown and cultivated ginseng, and identifies genes that may produce higher ginsenoside content and better disease resistance in the wild; these genes may have the potential to improve cultivated ginseng grown in artificial environments.
文摘Abstract The author introduces the w-function defined on the considered spacelike graph M. Under the growth conditions w = o（log z） and w = o（r）, two Bernstein type theorems for M in Rm^n＋m are got, where z and r are the pseudo-Euclidean distance and the distance function on M to some fixed point respectively. As the ambient space is a curved pseudo- Riemannian product of two Riemannian manifolds （∑1,g1） and （∑2,g2） of dimensions n and m, a Bernstein type result for n =2 under some curvature conditions on E1 and E2 and the growth condition w = o（r） is also got. As more general cases, under some curvature conditions on the ambient space and the growth condition w = o（r） or w = o（√r）, the author concludes that if M has parallel mean curvature, then M is maximal.
