Study On Seed Germination And Seedling Shading Treatments Of Corydalis Yanhusuo

Corydalis yanhusuo is an excellent ornamental plant,study on seed dormancy characteristicand breaking methods and plants’ shading tolerance, these can provide theoretical and referencefor reproduction and to be used under the condition of complex landscape. This experiment firststudied Corydalis yanhusuo seeds’ biological characteristics and effects of temperature,concentration of light and exogenous GA3treatment on its seed germination, then throughdifferent shading treatments to research its seedlings’ shading tolerance. The main resultsshowed as follows:Corydalis yanhusuo seed dormancy, belonged to embryo-after-seeds. Its seeds containedamount of germination inhibitor, poor permeability of the seed coat，but after dormancycharacteristic analysis showed that kind of skin barrier was not the leading cause of seeddormancy.After stratification treatments five months, its internal embryo different and formcompletely and dormancy breaking. Seeds stored mixed with wet sand was a better way ofstorage. As the stratification of time extension, SOD and starch content in the seeds showed atrend of gradually reduce, soluble protein and sugar content showed a trend of "down-up-down",free proline content showde the tendency of "rise and fall".Appropriate temperature and exogenous GA3could effectively promoted Corydalisyanhusuo seed germination. Temperature were10℃and15℃,GA3concentration of1500mg/L,2500mg/L,3000mg/L, the germination rate were higher, the highest was in15℃-2500mg/L,41.33%; Temperature was15℃, GA3concentration were1500mg/l,2500mg/l, the germinationwas higher;Temperature was15℃,GA3concentration of1000mg/L,2500mg/L,3000mg/Lwerethe most favourable for the growth of root and stem;Corydalis yanhusuo germination rate washigher under lighting condition than the dark condition and2000lx light conditions conducivedto its germination.Under four shading treatments, the Corydalis yanhusuo seedlings’content of chlorophyllhad an increment than that of full sunshine. Chlorophyll content increased with the increase ofshading degree, under shading degrees of75%reached the highest, and the shading degrees of75%and90%was significantly higher than other processing, and the chlorophyll a/b decreasedgradually with the increase of shading degree;Soluble sugar content increased with the increaseof shading degree showed a trend of "rise and fall". Under shading degrees of75%, solublesugar content was higher than other treatments; Free proline content roughly showed"down-up" trend with the increase of the shading degree, under shading degrees of50%and75%, the content was lower.Different light intensity conditions significantly influenced the Pn, Ci, Tr and Gs and WUEof Corydalis yanhusuo seedlings. The changes in the Pn and WUE show"twin peaks" curveunder full sunshine shading degrees of25%and50%, shading degrees of75%and90%showed "single-peak"curve. Pn and WUE under shading degrees of75%was higher than the other threetreatments; Under each treatment, Ci characterized by downward trend; under full sunshine andshading degrees of25%, Tr characterized by"double peak"curve, other treatments showed"single-peak"curve; The Gs was roughly showed continuous downward trends under alltreatments;On the whole, the Fv/Fm and Fv/Fo with the increase of shading intensity, showed atrend of "rise and fall", and under shading degrees of75%was higher, under full sunshine,Fv/Fm and Fv/Fo were significantly lower than other treatments.