| Pogostemon cablin (Blanco) Benth is one of the traditional Chinese medicinalmaterials commonly used, with properties of acridness and tepidity. Its aboveground partcan be used as medicine. Apart from the destruction of patchouli’s Geo-authentic habitatscaused by the development of the cities around in recent years, asexual reproduction,high incident of pests and diseases, serious continuous cropping during the plantingperiod also lead to a series of problems, such as a lack of gene diversity and qualityreduction. P. cablin‘Shipai’ and P. cablin ‘Gaoyao’, which can be used as medicine, areon the verge of extinction, while P. cablin ‘Hanan’, which contains volatile oil, becomesthe main cultivated variety. Therefore, fostering a high production, fine quality newspecies with stable genetic characters of P. cablin is the task of top priority. One of thenew ways to explore and utilize medicinal plants is to cultivate polyploidy plants, whichare believed to have higher biomass, stronger resistance with more active ingredientsthan those haploidy ones. This study concentrates on the seed-selecting of polyploid P.cablin strains. After confirming the chromosome numbers of three different varieties ofpatchoulis, using P. cablin ‘Shipai’ from local varieties as the breeding female parent.We successfully induced a large number of patchoulis with colchicin, identified5treatment (13Strains in all) autooctoploid strains, evaluated and analyzed the stability of heredity and quality, and finally got the breeding material of patchouli octoploidy. Belowis the main result:(1) P. cablin polyploidy inductionAdding colchicin to the rapid reproduction tissue of P. cablin, we’ve tried differentways (sessile dropping, soaking and mixed cultivating), different inducing materials(callus, cluster buds and regenerate seedings), different inducing concentrations (0.025%~0.2%) and different inducing hours (0~96h) to see the change of induced mutationrate. Through the whole experiment, soaking cluster buds with0.05%colchicin for72hours got the best result. In such an environment, induced mutation rate reached to85%(including treated seedings, tested through stomata appraising). The number ofchromosomes of variation seedings is2n=8x=128, which further proves that we acquireP. cablin octoploidy. In addition, chimaeras and abnormal plants are also acquired. Inconclusion, soaking cluster buds with colchicin is an effective way to acquire P. cablinautooctoploids.(2) P. cablin polyploidy identificationOptimizing the experiment condition of the chromosome sectioning and flowcytometry, we’ve found a practical scheme to identify the ploidy of P. cablin, combiningmorphological identification. After sifting, we finally acquired13P. cablin polyploidystrains. The study shows that identifying the ploidy of P. cablin by the sizes anddensities of its stomas and leaf shape indexes is a simple but effective way;degradationhypotonic method is used to acquire P. cablin chromosomes which have high resolutionand thus could be tallied;flow cytometry is an effective way to estimate autopolyploidsaccurately.(3) P. cablin polyploid quality Strains EvaluationMorphologically, compared with normal P. cablin plants, those polyploidy oneshave stronger stems, bigger and thicker leaves, darker colors and smaller leaf shapeindexes. Besides, stomas under the skin are larger but their densities are smaller, withmore contents of chloroplasts in guard cells. The average contents of Patehouli aleohal inthose9polyploidy strains respectively increased. The content and fluorescence of chlorophyll in octoploids both perform better than those in tetraploids. According to theanalysis, in terms of production, physiology level and contents of active ingredients,patchouli polyploidy strains perform better than tetraploids. The results still need to befurther study. |
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