Scale Cutting Propagation Technology And Carbohydrate Metabolism In Lilium Cv. 'Elite'

Lily scale cutting propagation is essential to the process of lily bulb commercial production.In spite of scholars have done a great deal of research,the propagation technology is still not perfect,in particular on the substance metabolism during lily scale cutting propagation.With Lilium cv.'Elite' as material,the research studied the effects of exogenous GA₃,IBA,as well as sawdust,peat on scale cutting propagation via different culture methods and 'starch—sucrose' metabolism and its relationship with bulblet formation during scale cutting propagation.The purposes of these experiments are to provide theoretic basic for in-depth metabolism research and improve the lily bulb propagation system,and then accelerating lily bulb production in China.The main results are as follow.1.The result showed that medium and culture method affected the scale propagation significantly.Scales cutting embedded in sawdust had the highest scale propagation coefficient and produced the most roots number,while scale cutting planted in sawdust produced larger bulblet and had more sprouted bulblets.2.Effects of exogenous GA₃ and IBA on scale cutting propagation were investigated.The specie,treatment duration and the concentration in order affected the scale propagation.IBA notably promoted the forming of bulblets and roots,and both of the organs developed simultaneously with IBA treatment.GA₃ favored the larger,well-formed bulblet development,however,the amount of bulblets and roots were less than that treated with IBA,and the roots initiated one week later after bulblets occurred.In addition,GA₃ significantly promoted the sprouting of bulblets at 18℃.The consumption process of storage substances in mother scales varied in different treatments.Scales of IBA treatment appeared rot on the bulblets after 60 d at 20℃,which suggested the scales should be transplanted timely to prevent from rotting,while GA₃ treatment could keep the scales healthy up to 80 d.Control also could achieve similar bulblets with GA₃ treatment,but longer culture time at the optimum temperature were needed.3.After transplanted,majority of bulblets come into leaf and only few generated stem.Starch content of bulblets was less in treatment which bulblet sprouting rate was high.Starch in bulblet was consumed for leaf growth.4.With the bulblets developing,starch and total soluble sugar in mother scales were consumed seriously and decreased most quickly in the middle part.At early stage of cultivation,the activity of SP(starch phosphorylase) ascended with the degradation of starch.SP decomposed starch during scale cutting propagation.5.In mother scales,sucrose content declined and reducing sugar content was lower than sucrose but increased and accounted for a large proportion in total soluble sugar at late stage.Growth and development of bulblets needed plenty of reducing sugar.6.At early stage of cultivation,the activities of SS(sucrose synthase) and SPS(sucrose phosphate synthase) in mother scales were high and then descended.These illustrated reducing sugar produced by starch degradation were used to synthesize sucrose under the action of SS and SPS. 7.In bulblets,starch accumulated gradually;total soluble sugar and sucrose content changed little and has been maintained at a low level.Reducing sugars were exploited to synthesize starch for bulblets enlargement.The activities of SP,SS and SPS were lower than in mother scales.8.At late stage of cultivation,carbohydrates in mother scale were less and soluble protein decomposed for bulblets development.Protein continuously synthesized in bulblets enlargement process after formation.9.Growth regulators promoted the storage substance break down earlier in mother scales.Contents of starch,total soluble sugar,sucrose and total soluble protein in mother scales of IBA treatment decimated fastest and activities of SIC,and SS were highest.The activity of SPS in GA₃ treatment was highest.Growth regulators improved activities of related enzymes to accelerate the reserve substance metabolism.These caused more or bigger bulblets were formed.10.The middle part of mother scale had more nutrition and carbohydrate content changed greater than other parts.In base of mother scale,contents of starch and total soluble protein content,the activities of SS, SPS and SP were higher.These conjectured substances in top and middle parts of mother scale were utilized early.The base part was metabolic center and the mother scale provided a material basis for bulblets development.11.In mother scales during scale cutting propagation,SP activity ascending impelled starch decomposed to reducing sugars.They synthesized sucrose under the actions of SS and SPS for the growth of bulblets and roots.At late stage,carbohydrates were short and protein decomposed for bulblets further development.In bulblets,protein was synthesized and reducing sugars were exploited to synthesize starch for bulblets enlargement.