Study On Cutting Breeding Of Rhododendron ’Yujinzhu’ And Application Of Anti-Transpiration Agent

In this paper,the propagation techniques of Rhododendron species ’Yujinzhu’(Rhododendron simsii ’Yujinzhu’)cuttings were systematically investigated in terms of exogenous hormone screening,cutting substrate selection,spike selection and spike leaf retention,and the effects of anti-transpiration agents on the rooting of Rhododendron cuttings were experimentally studied.The effect of transpiration inhibitors on the rooting of Rhododendron cuttings was studied experimentally.At the same time,the relationship between the changes in the activity of enzymes related to IBA treatment and the occurrence and growth of adventitious roots of cuttings was analyzed.The results of the study were as follows:1.Different substrates,spike selection and spike leaf retention methods had different effects on the rooting of cuttings.The substrate mixture of coconut bran and peat soil with a volume ratio of 1:1 was the best choice of substrate for rooting ’Yujinzhu’ azalea cuttings.On this basis,the best rooting effect was achieved by selecting the spike with the middle 3 cm length node of the current year branch of ’Yujinzhu’ azalea and retaining one leaf,with the rooting rate reaching 60%,the average number of roots being 5.92,the average root length reaching 5.13 cm,the longest root length 6.22 cm,and the incidence of new leaves of the spike being 66%.2.After determining the optimal substrate and optimal spike nodes,the experiment was conducted on the spikes with different growth regulator treatments and the azalea cuttings showed different rooting performance.As for the way of growth regulator application,IBA solution with a concentration of 0.10 g/L was sprayed on the foliage of the spike once a week,and the treatment with a small arch cover resulted in 85% rooting rate,with an average number of 10.96 roots,a mean root length of 7.13 cm and a longest root length of 5.24 cm,which was significantly different from the other treatments.3.In the experiment of ’Yujinzhu’ azalea with the application of Crown Cun antitranspirant in combination with growth hormone,it was found that when the spike was sprayed with a combination of 6 g/L Crown Cun antitranspirant plus 0.15 g/L IBA treatment,the root growth rate of the spike reached 62% and the average root length was 6.04cm;The rooting rate was 14% higher and the root length was 0.79 cm longer than the control treatment with 0.15 g/L IBA.The results showed that the combination of antitranspirant plus growth regulator was effective in rooting cuttings and adventitious root growth under mild drought conditions.4.The physiological experiments on azalea cuttings after cutting revealed that the superoxide dismutase,peroxidase and polyphenol oxidase activities in ’Yujinzhu’ azalea cuttings during the rooting process of IBA sprayed cuttings were closely related to the rooting of ’Yujinzhu’ azalea cuttings.After IBA treatment,the SOD and POD activities of rhododendron cuttings decreased and were positively correlated with the occurrence of adventitious roots;the POD activity of cuttings increased and was positively correlated with the growth of adventitious roots;the PPO activity was positively correlated with the occurrence as well as the growth of adventitious roots.