Studies On Anatomical Structure Of Timber And Leaf And Genetic Diversity Of Magnolia Sargentiana

Magnolia sargentiana belongs to Magnoliaceae and Magnolia, and an endemicspecies of Southwest China, being an ornamental or used as timber tree, fragrance andpharmacy plant. Because of a rapid decrease in quantity and distribution area, Magnoliasargentiana was listed in the third class of the Sichuan provinces protection plant speciesin1987. In present, Magnolia sargentiana is only found in Sichuan and Yunnan provincesand the natural distribution area of M. sargentiana is very narrow, fragmentary.According to collected data and specimens and fulfilled the field investigation, thispaper studies classification and ornamental characters in garden of Magnolia sargentianaincluding their habitat diversity, the morphological anatomical features of leaves andtimber, molecular biology and soon. It will provide evidences for exploitation, utilization,effective protecting and systematic classification. The conclusions are as follows:1. Components are complex and taxa are abundan of M. sargentiana, Origin of itsflora is ancient, Characters trasfer obviously from tropic zone to temperate zone.2. The population of M.sargentiana exhibits clumped distribution, most of the marerather small. Field investigation showed that the young trees of M.sargentiana are too fewto provide enough recruitment and ageing phenomena is severely. The population size istending to decline which signified M.sargentiana species is in danger.3. M.sargentiana is suitable to cool, moist, misty, fertile and humus-riched acidicsoilwith well-drained and loose structure. As an accompany species in its communities,M.sargentiana does not have a strong competition predominance against other species.4.The anatomical character of M.sargentiana is primitive, bisexual flower, lots ofpistil and stamina, filament is much shorter than anther, M.sargentiana has no hair orcuticle; Compared with its kindred cosmopolite species M. denudata, they have muchcommon in anatomical characters. From this, it is possible to ascertain that morphologicalcharacters are not a threatening factor.5. The genetic diversity of individuals from 8 natural populations and 1 artificialcultivation population of M. sargentiana from different distribution regions was analyzedby using random amplified polymorphic DNA(RAPD). 7 primers were screened from 96 ten-bp arbitrary primers, and a total of 46 DNA fragments were amplified, among which 32were polymorphic. DNA molecular dendrograms were established for the 8 naturalpopulations based on UPGMA. The result showed: (1) M.sargentiana has a high geneticdiversity, and its adaptability to environmental change is weak; (2) The genetic diversity ofM.sargentiana among populations is higher than within a population. In addition, thegenetic diversity of M.sargentiana natural populations are primarily related to theirgeographic distribution; More distance between them, more difference.