The Studies On Selection Of Hevea Rubber Seedling Of Different Sensitivity To Ethrel Injury

At present, the ethrel stimulation tapping system is a primary tapping system and it greatly enhance the production benefit. There are many evident showing that the stimulation not only caused plant biochemical change in stem (scion) but also in rootstock and even cause the change of root environment. It is very important to study the effect of ethrel stimulation tapping on plant biochemistry of the rootstock of rubber budding tree that would result in selection and grow the rootstock which favorable to ethrel stimulation tapping system and helpful to realize the sustainable production under the stimulation tapping system.The external injury symptom and internal plant physiologic change were studied by observing injury symptom and measuring physiological and biochemical parameters in different growth period of rubber seedling after treated with ethrel and a selection method for rubber seedling of different sensitivity to ethrel injury was presented. The main results are as follows:1. Rubber seedling would be injured when it was sprayed with ethrel and the injury symptom is different to that of acid.2. The sensitivity to ethrel injury among rubber seedlings are significantly difference and it change with the growth period and concentration of ethrel.3. According to the characters of different sensitivity to ethrel injury among rubber seedlings, the rubber seedlings which different sensitive to ethrel injury would be selected by using different concentration of ethrel in different growth period.4. The plant physiological and biochemical parameters of rubber seedlings of different sensitivity to ethrel injury are different and also change in different growth period.5. The mechanism of different sensitivity to ethrel injury maybe that the activities of SOD, CAT and APX of the non-sensitivity rubber seedling are higher that of the sensitivity rubber seedling.6. It is proposed to select the different sensitivity rubber seedlings in the extend-period and stable-period of whorl of leave. The method for selection different sensitivity rubber seedlings is respectively 0.5% ethrel X4h in extend period and 0.5% ethrel X 72h in stable period for sensitive seedling; 2.5% ethrel X 72h in extend period and 2.5% ethrel X 120h in stable period for non-sensitive seedling.