| Castanopsis tibetana Hance is a precious timber species in China which has high ornamental and economic value. It is a tall evergreen broad-leaved tree which is often used as shade tree in landscape construction. The red-brown wood is hard, corrosion resistant and anti-hitting, which is widely used as upscale home furniture material. Nuts are rich in nutrients and taste sweet. In order to solve the problems of low nuts production and less survival rate of seedlings, the devised strategy is to reduce the breeding period that will also reduce the cost, so that to promote the exension and utilization of Castanopsis tibetana in landscaping and new generation artificial forest adjustment and construction.In this study,2-year old Castanopsis tibetana seedlings were used to check the effect of different rooting agents and different parameters such as, lignified degrees, cutting length, the number of leaves, cutting medium, incision styles and different ways of sprinkler irrigation on the rooting of Castanopsis tibetana cuttings were studied. Data such as, rooting rate (%), average root length (cm), average root number (a) and callus root ratio of each treatment (%) were collected 60 days after treatment. Moreover, the changes of physiological indexes like nutrient materials, rooting related enzyme activities, endogenous plant hormones were analyzed during the rooting of Castanopsis tibetana cuttings, so that to get more insights in the physiological mechanisms of Castanopsis tibetana rooting. The results are as follows:1. Research on key technology of cuttage reproduction(1) For different rooting hormones:GGR, IB A and KNAA, two different concentration:low concentration soaking (100 mg/L、300 mg/L、500 mg/L), and high concentration dipping (1000 mg/L、3000 mg/L、8000 mg/L) were designed. The results showed that IBA (500 mg/L) revealed best values at low concentration soaking treatments and KNAA (1000 mg/L) works best in the high concentration quick dipping treatments. However in general, low concentration rooting agent treatments work better than the higher ones.(2) The best cutting material:half-lignified Castanopsis tibetana cutting, which is 15cm long with two half leaves on the top and horizontal incision on the bottom has the highest rooting ability.(3) For the cutting environment:The traditional plastic shed and modern mechanized sprinkler irrigation were used, the results showed that the rooting rate under traditional plastic shed was 79.5% which was much higher than that of the cuttings treated by mechanized sprinkler irrigation (26.7%).2. Research on the mechanism of adventitious root organogenesis.(1) By observing the process of rooting, we found that Castanopsis tibetana belongs to mixed rooting type, the rooting mainly from callus and also from primordiums were also observed. The rooting process can be roughly divided into three stages: ① 0～14d was the differentiation stage of adventitious roots; ② 14～35d was the adventitious root formation and the occurrence period; ③ After 35d was the adventitious root elongation and puberty period.(2) At the early stage of rooting, the soluble sugar contents and total protein contents showed decreasing trends, while in contrast, the enzyme activities (POD, PPO and IAAO) and hormonal contents (ABA, ZR and GA) showed increasing trends. At the medium stage of rooting, the soluble sugar contents, total protein contents and the POD and PPO activities start to increase, but ABA, GA and ZR contents decreased for a short term and then tend to increase. All the tested materials tend to be stable at the late stage of rooting. Cuttings treated with IB A (500mg/L) and KNAA (1000 mg/L) have the best rooting ability, they have remarkably higher rooting rate and root numbers compared to other treatments and the control. Moreover, their soluble sugar contents and total protein contents, the POD and PPO activities and the IAA contents changed with higher pace and larger range than other treatments and the control. |
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