Study On Seed Morphology And Germination Characteristics Of Macrocarpium Officinalis

The thesis studies the relationship between four characteristics (length, width, size andshape) of cornus officinalis seeds of7different provenances, and that between thecharacteristics and the environment. Meanwhile, it also attempts to find the reason of thedormancy of the seeds and methods of breaking the dormancy, which leads to thefollowing findings:(1) The four characteristics of the seeds vary considerably in length, width, size and shape.(2) The relativity between the width and size is high (F=0905), while that between thelength and size is medium (F=0756).(3) The size of the seeds is positively correlative to the longitude and average annualtemperature, and so is the width; the size of the seeds is highly positively relative to thelatitude, while the width is highly negatively relative to that.(4) The fitting of width against longitude, size against latitude are the best under the trendsurface analysis by a linear equation with longitude-latitude as the variables andcharacteristics of the seeds as the dependent variable. The fittings are respectively0826and0971.(5) The seeds of7provenances are studied as two clusters, with the seeds from Foping andHanzhong of Shaanxi Province, and Luanchuan of Henan Province as the northern cluster;those from Ningguo, Huangshan and Jingde of Anhui Province, and Zhenjiang of JiangsuProvince as the southern cluster.(6) The dormancy of the seeds can be broken by the gibberellin solution; stratification caneffectively break the dormancy; the germination percentage after a three-monthstratification shows that alternating temperature stratification is the most effective, lowalternating temperature stratification together with alternating temperature stratification isthe second, and the low temperature stratification is not obviously effective; with a seven-month low temperature stratification the germination percentage of the cornusofficinalis seeds reaches40%.(7) A combination of gibberellin solution with stratification will effectively break thedormancy of the cornus officinalis seeds. It is concluded that after an immersion in500mg L-1GA3for more than24hours, alternating temperature stratification can effectivelybreak the dormancy of the cornus officinalis seeds.(8) Evidence that the seeds of different provenances respond to the treatment shows thatseeds of different provenances have varied degrees of dormancy. Seeds from the northhave higher degree of dormancy than those from the south.(9) Changes of anatomical structures of the seeds indicate that the reason of the seeds'dormancy lies in the mechanical restraint effect (physical dormancy) and the inhibitorysubstances within the seed coat (physiological dormancy). Besides, the embryo hasmorphological dormancy. Therefore, the dormancy of the cornus officinalis seeds is acomplex and combinational dormancy with multiple factors.