The Research On Sprout Physiological Property And Cutting Propagation Technique About Slonea Hemsleyana

Sloanea hemsleyana,Elaeocarpaceae,is an evergreen tree with straight trunk and luxuriant branches and leaves.It is native to China and mainly distributes to Sichuan,Yunnan,Hubei,Hunan,and etc.The plant is not only cultivated as an ornamental and timber plantation,but also a valuable biological energy resource because of its oil quality and high yield.Its fine wood could be used to produce top-class furniture.The supply of Sloanea hemsleyana seeds is limited because of lower yield,low seed viability,low emergence rate,and storage difficulty.To address these problems,cuttings from various positions and sizes were collected during growing seasons,treated with different types and concentrations of rooting hormones,and placed on the several rooting media.The dynamic of physiological characteristics were monitored during rooting and anatomy of adventitious root initiation was documented with paraffin section.Enzyme activity of seeds and seedlings were measured after injecting different quantity of nitrogen ion to them.Under different fertilizer regime,physiological changes and enzyme activities,as well as phenology of S.hemsleyana seedlingswere recorded.The findings of above experiments provided fundamental understanding and technical explanation of S.hemsleyana cutting propagation and seedling growth and could be summarized as the following:1.High rooting percentage and better quality roots were produced by cuttings collected from upper portion of the plants.Cutting position from the same branch had significantly influenced on rooting rate and ones from the middle of branch yielded the highest rooting percentage of 40%.Cutting length at 15cm had better rooting rate of 30%.The highest rooting rate of 75%was found from stem cuttings with diameters of 0.3?0.6cm and high quality roots were from cuttings with 2?3 half-trimmed leaves.Cuttings with oblique notch(?)reached the rooting rate of 91.7%.Rooting hormone of K-IBA at 3000 mg/kg significantly increased rooting rate,which was nearly 50%more than that of the control.Cuttings should be collected in September to produce 70%or higher rooting percentage.The cuttings rooted early with high rooting rate in the placed in mixed medium shortened rooting time and increased rooting rate.2.The soluble sugar,total nitrogen,protein and C/N in cuttings varied during rooting.In the callus induction period,above indexes went down to support cell dedifferentiation,cell division and new cells formation.After callus formation,these indexes went up and provide nutrients for adventitious root induction and formation.3.During rooting,the activities of SOD and POD enzymes increased firstly,reaching to the highest level after 20 days,and then decreased.MDA,which could damage cells,varied in the same trend with SOD enzyme activity.Rooting hormone application could significantly reduced MDA content and promoted rooting.4.Anatomy of rooted cuttings indicated that Sloanea hemsleyana did not have existing root primordium,but induced primordium later.Adventitious roots mainly originated from cortical cells and vascular cambium cells.5.As injecting nitrogen ion went up,the activities of SOD,POD and CAT enzymes increased firstly,and then decreased.The three enzyme activities all increased between 3×101 ions/cm2 and 9×101 ions/cm2 and reached to their maximum at 9×101 ions/cm.There were high enzyme activities,which was conductive to coordinate the free radical content to stay in a low level in 9×1016 ions/cm2?12×1016 ions/cm2.When being injected more than 12×1016 ions/cm2 the activities decreased.The study showed that a certain amount of nitrogen ion could activate the ability of forming radical scavenging enzymes,making cells safe from free radical.6.Low-energy nitrogen ion beam made MDA content and electrolyte leakage rate of Sloanea hemsleyana increase firstly,and then decrease.Compared with control,MDA and electrolyte leakage rate decreased to different level from 3×1016 ions/cm2 to 9×1016ions/cm2,and reached to the minimum at 9×16 ions/cm2.It indicated that lipid peroxidation was cut down because of the biology repair system.Additionally,MDA rose along with the ion content increased.High dose of ion aggrandized membrane permeability,resulting in exosmose of a large quantity of ion,damage of cell adjusting ability and normal membrane system,and accumulation of lipid peroxidation production.7.Fertilizer experiments concluded that:(1)Treatment 4 improved the seedling height and treatment 3 and treatment 8 improved seedling strength.(2)Treatment 4 increased leaf chlorophyll content,the activities of SOD and CAT enzymes.Compared with other treatments,MDA content and electrolyte leakage rate in treatment 4 were significant lower,which indicated that seedlings under treatment 4 had better adaptation to stress.(3)Leaf chlorophyll content of fertilized Sloanea hemsleyana were higher than that of the control during all growing stages.The chlorophyll content increased firstly,reaching to the maximum in late August,and then decreased.(4)For all treated seedlings,the activity of protective enzyme increased firstly,reached to the peak,and then decreased.MDA content and electrolyte leakage rate increased during growing season,but variable under different environments and leaf maturation.(5)Chlorophyll content and SOD activity has positive linear relationship.In early growing period,fertilizer enhanced the photosynthetic capacity to produce a great quantity of oxygen radicals and improved the activity of SOD enzyme to avoid leaves injuring from radical.In late growing period,leaves had less chlorophyll content,which ledto lower photosynthetic capacity and SOD activity.