Fixed sample plots were set up for researching competition relationships between Manglietia yuyuanensis and Cunninghamia lanceolata in 17-year-old M.yuyuanensis stands mixed wiht C.lanceolata. The interspecific compet...Fixed sample plots were set up for researching competition relationships between Manglietia yuyuanensis and Cunninghamia lanceolata in 17-year-old M.yuyuanensis stands mixed wiht C.lanceolata. The interspecific competition intensity in different mixed stands was determined by using the competition indexes constructed with diameter of breast height, the volume of tree crown and distance between trees, through Hegyi’s Competition Index Model. The results showed that the spatial distribution of M. yuyuanensis in mixed stands was stochastic, the numbers of M. yuyuanensis and C. lanceolata around each M. yuyuanensis increased with the increase of the distance. Under the steady density, the ratios of C.lanceolata to M. yuyuanensis directly affect the interspecific competition and the growth. When the ratios of C.lanceolata to M. yuyuanensis were in the scope of 9-1 to 7-3, M. yuyuanensis had the obvious increase production trend compared with its pure stand. When the ratio was 9-1, the tree height and the diameter of breast height of M. yuyuanensis increase by 22.3% and 69.3% respectively; likewise, when the ratio was 8-2, they increase by 23.2% and 56.9% respectively, because at this ratio, the number of M. yuyuanensis in mixed stand was so low that its competition was mainly the interspecific competition from C.lanceolata. The competition index of M. yuyuanensis was 1.67 times lower than that in pure stand, especially the competition index constructed by the tree-crown volume was 21 times lower. however, when the ratios were in the scope of 6-4 to 5-5, M. yuyuanensis obviouly decreased production compared with pure stand, the intraspecific competition of M. yuyuanensis becomes stronger when its number increased. Based on the mechanism of stemwood cultivation, initial planting density of M. yuyuanensis trees should be reduced properly and higher ratio of C.lanceolata to M. yuyuanensis should be 8-2 or small higher in order to realize the cultivation goal of large timber of M. yuyuanensis .展开更多
Genetic diversity and genetic differentiation of 11 Manglietia yuyuanensis provenances from main distribution area were analyzed using ISSR molecular markers.A total of 108 amplified loci were detected by 9 primers,of...Genetic diversity and genetic differentiation of 11 Manglietia yuyuanensis provenances from main distribution area were analyzed using ISSR molecular markers.A total of 108 amplified loci were detected by 9 primers,of which the proportion of polymorphic loci was 86.11%.A high degree of genetic diversity in M.yuyuanensis was detected,and the genetic diversity index in species level was 0.282 7,which was markedly higher than that of M.decidua and M.patungensis,the rare and endangered species belonging to the same genus with M.yuyuanensis.The result showed that there was significant difference in genetic diversity among provenances.Provenances from north and north-west Fujian province and the nearby area,including Shaxian,Jian’ou,Wuyishan of Fujian and Longquan of Zhejiang,had higher genetic diversity,which were the dominant regions to be protected and utilized. Small population effect brought by habitat fragmentation and distance isolation effect resulted in high genetic differentiation among provenances,which contributed to 25.89% of total genetic variation,and the differentiation within provenances contributed to 74.11% of total genetic variation.Results also showed that the genetic distance amog provenances was not significantly related to the geographical distance amog provenances.Based on the Nei’s unbiased genetic distance,11 provenances might be obviously divided into 3 clusters.Shaxian and Jian’ou of Fujian with high genetic diversity and large nature population was clustered into one group.The genetic distance among Huangshan of Anhui,Longquan and Kaihua of Zhejiang,Wuyishan,Shaowu and Liancheng of Fujian,and Lichuan and Longnan of Jiangxi was small,then the above provenances were clustered.Quannan of Jiangxi,located at the south of distribution area,was an individual provenance.Based on the characteristic of its wider leaves,it was conferred that Quannan provenance was mistaken for M.fordiana Oliv.in the course of seed collection.展开更多
文摘Fixed sample plots were set up for researching competition relationships between Manglietia yuyuanensis and Cunninghamia lanceolata in 17-year-old M.yuyuanensis stands mixed wiht C.lanceolata. The interspecific competition intensity in different mixed stands was determined by using the competition indexes constructed with diameter of breast height, the volume of tree crown and distance between trees, through Hegyi’s Competition Index Model. The results showed that the spatial distribution of M. yuyuanensis in mixed stands was stochastic, the numbers of M. yuyuanensis and C. lanceolata around each M. yuyuanensis increased with the increase of the distance. Under the steady density, the ratios of C.lanceolata to M. yuyuanensis directly affect the interspecific competition and the growth. When the ratios of C.lanceolata to M. yuyuanensis were in the scope of 9-1 to 7-3, M. yuyuanensis had the obvious increase production trend compared with its pure stand. When the ratio was 9-1, the tree height and the diameter of breast height of M. yuyuanensis increase by 22.3% and 69.3% respectively; likewise, when the ratio was 8-2, they increase by 23.2% and 56.9% respectively, because at this ratio, the number of M. yuyuanensis in mixed stand was so low that its competition was mainly the interspecific competition from C.lanceolata. The competition index of M. yuyuanensis was 1.67 times lower than that in pure stand, especially the competition index constructed by the tree-crown volume was 21 times lower. however, when the ratios were in the scope of 6-4 to 5-5, M. yuyuanensis obviouly decreased production compared with pure stand, the intraspecific competition of M. yuyuanensis becomes stronger when its number increased. Based on the mechanism of stemwood cultivation, initial planting density of M. yuyuanensis trees should be reduced properly and higher ratio of C.lanceolata to M. yuyuanensis should be 8-2 or small higher in order to realize the cultivation goal of large timber of M. yuyuanensis .
文摘Genetic diversity and genetic differentiation of 11 Manglietia yuyuanensis provenances from main distribution area were analyzed using ISSR molecular markers.A total of 108 amplified loci were detected by 9 primers,of which the proportion of polymorphic loci was 86.11%.A high degree of genetic diversity in M.yuyuanensis was detected,and the genetic diversity index in species level was 0.282 7,which was markedly higher than that of M.decidua and M.patungensis,the rare and endangered species belonging to the same genus with M.yuyuanensis.The result showed that there was significant difference in genetic diversity among provenances.Provenances from north and north-west Fujian province and the nearby area,including Shaxian,Jian’ou,Wuyishan of Fujian and Longquan of Zhejiang,had higher genetic diversity,which were the dominant regions to be protected and utilized. Small population effect brought by habitat fragmentation and distance isolation effect resulted in high genetic differentiation among provenances,which contributed to 25.89% of total genetic variation,and the differentiation within provenances contributed to 74.11% of total genetic variation.Results also showed that the genetic distance amog provenances was not significantly related to the geographical distance amog provenances.Based on the Nei’s unbiased genetic distance,11 provenances might be obviously divided into 3 clusters.Shaxian and Jian’ou of Fujian with high genetic diversity and large nature population was clustered into one group.The genetic distance among Huangshan of Anhui,Longquan and Kaihua of Zhejiang,Wuyishan,Shaowu and Liancheng of Fujian,and Lichuan and Longnan of Jiangxi was small,then the above provenances were clustered.Quannan of Jiangxi,located at the south of distribution area,was an individual provenance.Based on the characteristic of its wider leaves,it was conferred that Quannan provenance was mistaken for M.fordiana Oliv.in the course of seed collection.
