Studies on the Cutting Propagation Technology and Rooting Mechanism of Chrysanthemum
|School||Nanjing Agricultural College|
|Course||Ornamental Plants and Horticulture|
|Keywords||Chrysanthemum Cutting Propagation Technique Rooting Mechanisms|
Chrysanthemum,as one of the famous traditional flowers in China,was widely used as cut flower,potted plant and garden ornamental flowers.Cuttage Propagation,as one of the main asexual propagation methods,was widely used in seedling production of chrysanthemum. There are huge differences in cutting rooting ability in different cultivars, which restrict the application of production. For evaluating and inproving the rooting capability,exploring rooting mechanism about chrysantheme,the cutting propagation technique,rooting mechanism have been studied. The main result showed that:1.Seven morphological indexes related to rooting ability of cuttings (rooting formation day,maximum root length,average root length,root diameter,adventitious root number,root dry weight,rooting rate) from 20 chrysanthemum cultivars were comprehensively evaluated using the method of synthetical weight analysis.Synthetical weights of indexes were calculated by method of analytic hierarchy process (AHP) and principal components analysis.The comprehensive evaluation function was built up.Twenty cultivars were divided into three groups according to the scores of comprehensive evaluation of rooting ability,6 cultivars(’Jinling Chunmeng’,’Yuhua Xingchen’,’Aoyun Zixia’,’Shuoguo’,’Zhongshan Jinyu’,’Jinba’)are included in group with strong rooting ability,9 cultivars(’Aoyun Jingguang’,’Jiman Daihua’,’Fengyunli’, ’Maoyan’,’Jinling Fenyulan’,’Jiuyuehuang’,’Nanjing Gongfen’,’Jinling Zhiguang’, ’Jinlian)in group with middle rooting ability,the remaining 5 cultivars(’Nanjing Guan’, ’Zhongshan Fendai’,’Tianzhui Yulu’,’Xiangbinzi’,’Jiuyuebai’)were included in the group showing poor rooting ability.2.6 matrix treatment contained vermiculite,grass charcoal,pearlite,vermiculite and perlite(volume ratio 1:1)mixed,grass charcoal and perlite(volume ratio 1:1)mixed and vermiculite and grass charcoal(volume ratio 1:1)mixed were used to studied the effect of cutting matrix on the cutting propagation of. chrysanthemum cv’Huoju’.Through index of the maximum root length,average root length,adventitious root number,root fresh weight,rooting rate and the subordinate functions value based the 5 index to evaluate those matrix,the results showed that the best cutting matrix is vermiculite and grass charcoal and perlite(volume ratio 1:1)take the second place in the experiment.3.The effects of IBA and NAA (each at 0,100,500 and 1000 mg·L-1)and their combinations(100 IBA+100 NAA,100 IBA+500 NAA,100 IBA+1000 NAA,500 IBA+100 NAA,500 IBA+500 IBA,500 IBA+1000 NAA,1000 IBA+100 NAA,1000 IBA+500 NAA,1000 IBA+1000 NAA mg·L-1)on the maximum root length,average root length,number root,fresh weight of chrysanthemum cuttings were investigated.when IBA treated singly, the root length was increased linely with increasing IBA concentration at 100～500 mg·L-1 treatments when IBA treated singly,when the density was increased up to 1000 mg·L-1,the effect had a trend of decline,but the root number and root weight increased significantly. The root length and root weight was increased linely with increasing NAA concentration at 100～1000 mg·L-1 treatments when NAA treated singly, but has no influence on root number.The best treat concentration is 1000 mg·L-1 when use IBA or NAA individually.treatment The rooting efficiency. was better when IBA and NAA were combined,100 mg·L-1 IBA+500 mg·L-1 NAA and 500 mg·L-1 IBA+100 mg·L-1 NAA were.most effective among the treatments.4. The cuttings of’Yuhua Xingchen’were storaged at 4℃for 2week,4week and 6week,then the cuttings rooting ability were evaluated.The change of cutting weight and content of chlorophyl,soluble protein, ASA、MDA were test as well during the cold storage. The result showed that the maximum storage period for cuttings could be up to 4 weeks at 4℃,after 6 weeks storage,the cutting rooting ability decreased,the cutting survival rate decreased significantly.The 2 weeks treatment was benefit to rooting to some extent, through the content of chlorophyl,soluble protein and ASA has dropped remarkable at this time.The content of MDA kept rising during the storage.5.The anatomical observations on the cuttings’Yuhua Xingchen’and’Tianzhui Yulu’ were carried out by means of paraffin section method.The result showed that the root primordium of chrysanthemum belonged to induced primoridum,which was orginated from the cambium cell touching with the pith ray. Sclerenchyma was not found in the stem of difficult to root cultivar’Tianzhui Yulu’.Root primordium initial cells were observed on day 6(’Yuhua Xingchen’)and day 14(’Tianzhui Yulu’),respectively. 6.Studied on the physiology during adventitious root formation of two cutivars’Yuhua Xingchen’and’Tianzhui Yulu’:The activity of POD and PPO in leaves and stems during the rooting were determined, the activities’increased after cutting in both cutivars and organs,between leaves and stem barks The activity of POD and PPO were quite different both in different organs of the same cultivars and in the same organs of different cultivars.Higher dissoluble sugar content and lower nitrogen content was found in the cuttings’Yuhua Xingchen’during the rooting. The ratio of sugar to nitrogen ratio could be a judgement standard for rooting ability of cuttings to some extent. Changes in carbohydrate content overall showed a’V’shape trends during rooting, i.e., carbohydrate content decreased firstly,then increased,whereas declined after rooting.The nitrogen content decreased constantly throughout the process of rooting.Moreover,cuttings of the cultivar easy to root showed higher ratio of sugar to nitrogen both in leaves and stems.Preferential accumulation of photosynthetic assimilates in stems caused an earlier rise in C/N ratio in stem than in leaves during rooting. After rooting,the C/N ratio in the stem was significantly higher than that in leaves in two cultivars.It argues that sink-source relation changed between the stems and leaves changed during the rooting,The rooting rate had a positive correlation with dissoluble sugar content, carbohydrates content,C/N value,but had a negative correlation with the total nitrogen content.The content of amylum could be a judgement standard for rooting ability of cuttings.Most of the content of nutritive substance declined with the emergence of callusing and rooting.The conventional rule of C/N value is suit for Taxodium distichum(L.).In addition,the content of endogenous hormones changed greatly during the process of rooting.IAA and ABA content increased remarkably during the root primordium formation,however,the ratio of IAA to ABA remained relatively stable during the whole process of rooting.The ratio of IAA to ABA was higher in the cultivar easy to root compared with the other one,and in GA3/ABA ratio rose at early stages,but decreased in both cultivars after root primordium formed.iPA content kept decreasing throughout the whole process,and as a result,the ratio of IAA to iPA increased correspondingly.