| Mei, one of famous flowers native to continental China, has been nominated China national flower for many times, so it is very important to speed up the winter-hardy species propagating and make it rapid promotion in Beijing. Grafting is an important means for cold-resistant Mei multiplication, but it is easy to find incompatibility during the breeding. In addition, the hardwood cutting is not ideal for winter-hardy cultivars. Softwood cutting within the superiority of fast reproduction, high efficiency, economic space occupation, easy operating and low costing that has been used for many woody plants propagation. Establishing an efficient protocol preliminary for softwood cutting propagation of Mei are the objective of this study. The softwood cutting propagation technique and the related physiological and biochemical changes during rooting, and annual growth rules of cuttage seedlings were studied, which could provide theoretical support and technical guidance for Mei propagation. The main results and conclusions are as follows:The softwood cutting propagation technique of hardiness Mei was studied in this work, the findings indicates that, (1) cutting in May was beneficial to rooting, root count and root length than that in August. (2) IBA had dominant influence on rooting of three cultivars, and the type of medium, branch had different effects on rooting with different cultivars and cutting dates. In May, it was favorable for P.mume ’Meiren’ to choose medium 3:1(peat:perlite) and P.mume ’Sanlun Yudie’ to choose medium 2:1(peat:perlite), while substrate had no effect on rooting of P.mume ’Dan Fenghou’ in May and all three species in August. The IB A concentration from 1500 to 2500 mg·L-1 were all conducive to improve the rooting rate and rooting quality, while the cuttings with higher IBA concentration would be with growth inhibition effect. ABT1 had little promotion effect for P.mume’Meiren’ and P.mume ’Sanlun Yudie’, so it should be careful to put into use in production. In addition to the slender branches, the upper and middle parts of branch would make help for rooting rate and root quality. (3) the cuttings with length of 8 cm was better for the rooting rate and rooting length, and too short(6 cm) or too long(10 cm) were all unfavorable to root. (4) there were significant or extremely significant correlations between root traits, so rooting percentage, an easy measured property, could selected to look for the better treatment. (5) among the nine species of Mei, the P.mume’Danfen’, P.mume ’Longtan Yudie’ and P.mume ’Fen Yue Xiang’ had higher rooting index, which could be expanded propagation in production.The effects of different cutting dates on softwood cutting rooting and related physiological and biochemical changes during rooting of P.mume ’Meiren’ were studied. Contents of soluble sugar, starch, soluble protein and activities of POD, PPO, IAAO in the rooting area and needles at various rooting phase were measured in a simple random replication experiment. It shows that, (1) in different seasons, the adventitious root displayed three distinct phases:induction (0-10 d), expression (10-30 d) and elongation (30-40 d). (2) IBA treatment had an obvious effect on accelerating rooting and cutting in May was better than that in August, which with rooting percentage of 83%, mean root number per cuttings of 21, and mean root length of 8 cm. (3) in different cutting dates, the content of soluble sugar and activity of PPO and POD in the rooting area of stock showed positive linear response to rooting percentage, while the IAAO activity in the rooting area and needles of stock showed a negative linear response to rotting rate, that might cause cutting dates effects. (4) the contents of nutrients and activities of oxidases in the rooting area and needles showed significant changes during the process of rooting, it showed as follows:the soluble sugar content and the activity of oxidases in the rooting area in May were higher than that in August during expression phase; the peak of the content of soluble sugar and starch during the cutting in the needles in August compared with that in May existed hysteresis, and in August the POD activity was lower and IAAO activity was higher; during the rooting process, the activity of PPO in the needles and rooting area changed on the contrary in May and August. All of these changes might have influence upon on rooting. IBA treating would accelerate the accumulation of nutrients and make the POD activity show obvious double peaks, the IAAO activity in a lower level during induction and continuous elevate during expression, which may be favored for rooting.The annual growth rules of cuttage seedlings of P. mume ’Meiren’ were studied, it shows that:(1) height growth curve of P. mume ’Meiren’ cutting seedling could be fitted into ’S’ curve. (2) the net growth of height and ground diameter reached the maximum on July and August. The cutting seedling should be managed intensively during June to August. |
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