Germination Characteristics And Analysis Of Germination Promoting Factors Of Magnolia Soulangeana Seed

Using the Magnolia soulangeana seeds as experimental material, we observed the usualbiological character, and detected the physiological and biochemical changes during seedgermination. Meanwhile, we explored the differences of seed vigor, seed’s embryo configuration,reserve substance, and endogenous hormones content during cold and variable temperaturestratificationand exogenous hormonal treatments. And we also investigated how the promotingfactors influenced on the seed germination rate and seedling growth. The results were shown asfollows:(1) The shape of Magnolia soulangeana seed was triangular obovoid,8.1±1.25mm long,8.2±1.53mm wide,4.0±0.63mm thick, and the thousand seed weight was133.58±1.71g. Themesosperm with goodpermeability although it was bony hard, thereby, it still could offernecessary permeable condition for seed germination. Hence the water content increased graduallyduring seed germination. The content of soluble sugar and soluble protein in seed decreasedgradually when the amylase and acid phosphatase activity enhanced. In the same way, thecrudefat and starch degraded into small molecular substances under the action of enzymes. It tookabout30d from sowing to reveal the radicle, and about70d the first true leaf grows up afterMagnolia soulangeana seeds germination.(2) Magnolia soulangeana seed had dormancy characteristic. Although the embryo organhad developed completely at harvest, the size of embryo was tiny and could still grow up duringcold stratification. Meanwhile, the water content increased gradually during cold stratification,soluble sugar content reduced first and then remained stable, soluble protein content reducedafter rising first, starch and crude fat decline speed slowed down with stratification prolonging,α-amylase and acid phosphatase activity weakened, β-amylase activity enhanced. The content ofendogenous IAA, GA, ZR increased to varying degrees in the process of cold stratification, andthe ABA content increased first and then decreased.(3) Compared the influence on seed germination rate from different stratification treatments,we could conclude that cold stratification could effectively slow down the seed vigor dropscompared to room temperature stratification, cold stratification had better effect on breaking theseed dormancy compared to room temperature stratification, while variable temperaturestratification was more effectively, and could make the seed germination rate up to82.2%.(4) Exogenous hormonal treatment could effectively promote the Magnolia soulangeanaseed germination. Promote-inhibit matter content ratio of endogenous hormones showed a trendof rising with exogenous hormone treatments during seed germination., andthe seed germinationrate was improved evidently. After analysis the sprouting factors synthetically, we speculated that120d stratification, GA500mg/Land6-BA200mg/L soaked for24h was the best choice forthe seed germination rate. Not only was higher seed germination rate, but also improved seedlinggrowth effectively, such as seedling height, root length, root-stem ratio, and the seedling wasmore robust.