Study On The Key Techniques In Seedling Cultivation Of Zanthoxylum Bungeanum Maxim

Zanthoxylum bungeanum is one of the important woody spices,medicinal materials and leaf vegetables in China,whereas the fine species breeding of Z.have been made a breakthrough recent years.And,a number of new and excellent pepper varieties with high yield,good quality,and less or no thorns have laid a good foundation for promoting the forest manufacture development.However,there is still lack of intensive research on the key breeding technologies at present,which could be the major impacts on the pepper plantation.For example,one side,the seed harvest time could not only affect the yield and quality of pepper bark,but also influence the development of seed embryo and germplasm germination ability;on the other side,for some pepper species that with fewer even no thorns on the branches,the developed prickles,the existed defect in seedling and young tree stage could be limited factor under the condition of regular seed propagation;otherwise,for the stingless pepper,the expected characters could get very good heredity by the cutting or grafting propagation.The effects on embryo development and germination ability induced by the collecting time of pepper seeds,the influences on seedling growth caused by different sowing seasons and cultivation density,also the rooting mechanisms resulted by the cuttage breeding were all investigated,similarly,the different grafting time and methods were tested in pepper grafting at our study.The aims of our paper were to explore the main factors on the pepper breeding.And the conclusions in our experiments could provide theoretical basis and technical support for the pepper breeding.The results were as follows:?1?The height diameter growth curve of 1-year-old Z.bungeanum seedlings was fitted using Logistic equation,and the growth inflection point of seedling height process was determined.Hence,the four stages of seedling height growth were divided,they were seedling emergence,early growth stage,peak growth period and late growth stage.Also,the characteristics and differences of height and diameter were determinded.?2?With the extension of seed collection period,the 1000-grain weight,the peel and embryo rate of pepper seeds increased gradually,whereas the seed vigor,experimental germination rate and field emergence rate peaked to the maximum value on August 30^th and then started to slight decreases.At the same time,the seedling height,diameter and total biomass in fresh weight got a gradually increase and reached to the maximum values on August 30^th,and they were of 117.06 cm,10.60 mm,and 79.78 g,respectively.?3?The results in the comparison of seedling experiment indicated that the emergence time was about 10 days earlier and the emergence rate increased by 0.81%under autumn sowing compared to that of the spring sowing,whereas there had no significant effect on seedling height and diameter,the same for the biomass.?4?The seedling density has a significant effect on seedling height and diameter,also for the biomass accumulation and distribution.With the density increase of?15?C1?,25?C2?,30?C3?and 38?C4?plants in per square?,the basal diameter got a gradual decrease,whereas the seedling height reached to the peak firstly at the treatment of C2,and then got to a decrease.The differences in biomass and root-shoot ratio were significant,and compared with C1,the fresh weight in leaves and stems of treatment C2 increased significantly,while the root-shoot ratio decreased,but there was no significant difference in root fresh weight.?5?The branched cuttage of pepper belonged to the type of callus rooting,and the rooting processing could be partitioned four periods,that were callus induction stage,adventitious roots formation stage,adventitious roots extension stage and late rooting stage,respectively.The results caused by the various exogenous hormones with different concentration indicated that the survival rate and rooting effect index were the highest when suffered to IAA and IBA with the concentration of 250 mg·L^-1.Likewise,the treatment of NAA with the concentration of 500 mg·L^-1 got a beneficial impact on pepper rooting.The rooting rate of softwood cuttings in different periods of growing season showed that cuttings in June were more conducive to rooting,secondly was in April,and cuttings in August performed worst.When softwood cuttings were treated as the testing materials,the rooting effect index?with 77.94%?of pepper cuttings with 6 leaflets was higher than that in the zero leaflets.For the cutting medium with different formulations,the results revealed that,the survival rate?50.67%?was highest when cuttings with perlite;similarly,survival rate got the highest of 66.67%when cultivated with the mixed substrate of perlite and peat?mixing ratio of 2:1?.Moreover,pepper cutting with the mixed substrate was significantly better than that in the single substrate.?6?It was generally found that the enzyme activity of cuttings increased in the early stage and decreased in the later stage during the rooting processing.The activities of SOD and PPO increased in the callus induction stage and adventitious formation stage of the roots,and then got a decrease in the adventitious elongation stage and late stage.Differently,the activities of POD and IAAO got a stimulation both in the stages of callus induction and roots elongation,but had a reduction in the stages of roots formation and the later period.?7?The technical elements of grafting seedlings of Z.bungeanum were evaluated by membership function method.The evaluation results of various grafting method indicated that,bud grafting performed the best,secondly was the tongue grafting,and the worst was abdominal grafting.Otherwise,‘Laiwushaoci'as scion for grafting did the best,the worst was‘Xinongwuci',and‘Hanchengwuci'manifested the moderate levels.For the grafting season,the results showed that April was the best grafting season,the second was in the June,and the worst performer was in the August.