| Mulberry is the only source of feed for domesticated silkworm, Bombyx mori to live on, and is also the important material basis for sericulture. Therefore, the study on wide adaptability and high survival rate of mulberry fast propagation technique has important practical significance. That is, different ecological zones of sericulture can quickly breed fine varieties of mulberry saplings which are suitable for local conditions, to achieve a real sense of the mulberry varieties, to reduce the costs of the planting of mulberry, and to improve the quality and yield of mulberry.In this study, related technologies of Prof. Jia-Ling Cheng patent "a method and its seedling nursery three-dimensional product" (Application No.: 200710132106.7) is used to carry out the softwood cutting propagation test of mulberry, and for the first time, the new mechanism of softwood cutting lenticels-derived rooting has been discussed in a more systematic way, with a view to provide technical and theoretical basis for further improvement of the survival rate of cutting propagation of mulberry.The main findings are as follows:(1)The anatomical study on the process of softwood cutting rooting of mulberry found that: in this study, the roots formed by cutting propagation are mostly adventitious roots, and its root primordium induced histological origins on the vascular cambium cells. About 9 days after cutting, young adventitious roots knock out the cortex in two ways--from the lenticels department and the incision at the top. Compared with the conventional methods of softwood cuttings roots initialed from callus, the time of periderm-derived rooting shortened about 4 days, and amount of roots per cutting reached 30 to 40, with increase of 2 times.(2) The selection of cuttings and cutting time are very important for softwood cutting rooting of mulberry. Here is the comparison of the rooting results of 5 mulberry varieties. The rooting effect of yu711 is the best, rooting rate is 91.1% and the amount of roots per cutting is 49.1, followed by husang32, xuan792, da10. Xiang7920 is the worst among them. The rooting rate and root number of cuttings of husang32 and yu711 in different parts and with different lengths are the central part>lower part >upper part, 15cm>18cm>12cm.Yu711 used as experimental materials, the effect of cutting is the best on July 20th and August 10th, rooting rate is more than 90%, and 74.5% on September 1st. Therefore, the cutting propagation can be done 2 ~ 3 times continuously from July to September. (3) The research on the physiological basis of softwood cutting of mulberry showed that: in the process of cutting rooting, the contents of soluble protein and soluble sugar have a significant decrease in the earlier stage. Later, with the metabolism speeding up, there are varying degrees of increasing; however, in the period of root elongation growth, the contents of soluble protein and soluble sugar reduced again. IAAO, POD and PPO have a close connection with the cutting rooting of mulberry. IAAO and POD can both oxidize IAA, and then lower the levels of it, which is good for root induction. Meanwhile, the improvement of the activity of POD has also strengthened the resistance of cuttings, which is beneficial for cutting rooting. During the later part of rootage, the activities of IAAO and POD are reduced to varying degrees, which is beneficial to the accumulation of the content of IAA, promoting root elongation. PPO activity in softwood cuttings of different parts of bough presented downward first and then an upward trend after cutting. The reduction of the content of phenols compounds during the stage of cutting rooting indicates that they're the necessary material for rooting. The correlation between the physiological indicators and the rooting rate in different mulberry varieties and different parts of bough in same variety to show distinct, expected to further research. |
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