Research On Selection And In-Vitro Rapid Propagation Of Cold-Resistant Sympodial Bamboos

Effect of simulated and natural low temperature environment on leaf conductivitie, protective enzyme (SOD, POD, PPO), soluble protein and sugar content and leaf membrane fatty acid content of different sympodial bamboos in middle and north subtropical zones was studied. A preliminary evaluation system of cold-resistant sympodial bamboos was constructed according to relationship between physicochemical indexes and cold tolerance of sympodial bamboos. The system of in-vitro rapid propagation of Dendrocalamus latiflorus has been optimized and in-vitro rapid propagation of cold-resistant sympodial bamboo Dendrocalamus minor var amoenus was successfully completed. Results showed that:1. Enzyme activity (SOD, POD, PPO), soluble protein, soluble sugar content and membrane unsaturated fatty acid content in leaves of tested sympodial bamboos increased during cold acclimation period. While low temperature stress aggravated leaf electrolyte leakage. And SOD, PPO activity, soluble protein and sugar content of tested sympodial bamboos decreased during low temperature stress. Enzyme activity, soluble protein, soluble sugar content and membrane unsaturated fatty acid content in leaves of acclimated seedlings were higher than that of unacclimated seedlings, while the leaf electrolyte leakage was reverse.2. Generallly relative leaf conductivities of cold-resistant sympodial bamboos were lower than that of cold-sensitive sympodial bamboos. In contrast, the enzyme activity, membrane unsaturated fatty acid content in leaves of cold-resistant sympodial bamboos were higher than that of cold-sensitive sympodial bamboos. Relative leaf conductivities and index of unsaturated fatty acid could be used as evaluation index for cold tolerance of sympodial bamboos. But the soluble protein and sugar content in leaves of tested sympodial bamboos was not closely related to cold tolerance of them.3. Comprehensive evaluation of cold tolerance of sympodial bamboos in middle and north subtropical zones showed that, Bambusa textilis var. fasca McClure, B. rihida Keng et Keng f, B. textilis cv. Maculata, B. chungii McClure, Neosinocalamus affinis cv.Viridiflavus,et al. could be introduced to northern cultivation margin of sympodial bamboos.4. Medium 3/4MS+BA2.0mg/ml+KT0.5mg/ml+CW50ml/l was relative suitable subculture medium for Dendrocalamus latiflorus. And medium 1/3MS+IBA4.5mg/l+NAA3mg/l was relative suitable subculture medium for rooting culture of Dendrocalamus latiflorus. Lique medium was beneficial for improvement growth condition and proliferation rate of clump shoot.5. The best month for explant collection of Dendrocalamus minor var amoenus is May and June. And the best position for explant collection is middle-upper part knot of semi-lignification branch. The clump shoot could be induced in medium with BA3-6mg/L,KT0.5-1.5 mg/L. Medium 3/4MS+ BA2.3mg/l+ KT1.0mg/l+ CW100mg/l was relative suitable subculture medium for Dendrocalamus minor var amoenus. Medium 1/5MS+IBA8mg/l+NAA4.5mg/l+KT0.1mg/l was relative suitable rooting medium for Dendrocalamus minor var amoenus, with the rooting method of synchronized treatment first and then rooting. 6. The clump shoot could be transplant when the root was 2-7cm long after hardening-seedling for 5-7 days in natural scattered light. Generally, the survival rate of seedlings could be more than 90% in substrate of peat soil: fine river sand=1:3. The survival rate of rooting seedlings could be higher when prolonged the cultivation time in rooting medium.