Studies On The Clonal Selection On And Mass Propagation By Tissue Culture And Somatic Embryogenesis Of Platanus Occidentalis

In 1999,forty seven open pollination Platanus occidentalis families (in which 12 provenince were involved) were introduced from United States of America, under the help of Dr. Sam Land, Jr. and Dr. Jeame Tang. In 2000, we lied out a nursery testing and first selection within each family was made according to height growth performance. And then one extra nursery testing was conduced for the selected. In 2001, we transplanted these genetic materials in five testing sizes, which were located in Songjian Shi of Shanghai, Zhengjiang Shi of Jiangsu, Sixian County of Anhui, Nanyang Shi of Henan and Dongying Shi of Shangdong, respectively. Depend upon the 5th and 8th growth performance, 50 clones were selected both among and within provenience/families. In this study, all the selected clones were taken as experimental materials to study rooting ability, rooting characters, growth performance, salt tolerance, drought hardiness. And second selection was made by these traits. And 8 clones were chosen as more superior clones, at meantime, tissue culture characteristics of these clones, and somatic embryogenesis was studied also. The main conclusions were as follows:I. The cutting survival rate, rooting time, roots number, total root length among 50 clones both in pot cutting and nursery cutting were in a very significant (P, 0.01) differences;II. The growth traits such as tree height, stem diameter above ground and stem volume of three-year-seedlings among clones were in a very significant (P, 0.01) differences also, which indicated that more fast-growing clones could be chosen from these 50 clones.III. In order to evaluate the salt and drought tolerant, the leaves POD, CAT, SOD activity and glycinebetaine, sugar alcohol contents of clones, after process of salt stress, was increased 2.45 times, 2.5 times, 2.75 times, 9.52 times, 1.92 times respectively; the photosynthesis characteristic A value, Gs value and Tr value of potted clones under the process of water stress were all presented downward trends, Ci showed a descendent-ascensive trend; fluorescence parameter Fv/Fm,â–³F/Fm and qP of clones all decreased, qN presented a upward trend; except GA showed a declining trend, ABA, IAA, ZR and GA contents of clones presented interval fluctuate state, which showed a complex expression form of phytohormone on water stress.IV. By integrated the performance of rooting character, growth trait, salt tolerance, drought hardiness of the 50 Platanus occidentalis clones in nursery testing and 8yr field testing, there were eight clones to be chosen as superior clones SJ8, NY44, SJ36, DY36, ZJ29, DY10, SX1 and SX36, for further large scale testing and utilization.V. The tissue culture experiments of re-selected clones of Platanus occidentalis was performed and the results showed that: the MS basic medium supplied with NAA 0.1 mg/L, 6-BA 0.5 mg/L or KT 0.3 mg/L for bud multiplication; 1/2 MS medium with NAA 0.02 mg/L, 6-BA 0.1 mg/L, KT 0.05 mg/L or IBA 1.0 mg/L for stem explants directly rooting inducing; and MS basic medium with 6-BA 0.1 mg/L or IBA 1.0 mg / L for the root induction, are suitable combinations.VI. The somatic embryogenesis of Platanus occidentalis was investigated also, and the best medium conbinations were , using 2nd or 3rd position leaves from the top and dark culture, MS medium with sucrose 30 g/L, agar 6 g/L, pH 5.7, NAA 0.2 mg/L, IBA 0.3 mg/L or 6-BA 0.3 mg/L, for callus inducing; MS medium with sucrose 40 g/L, agar 6 g/L, pH 5.7, supplied the hormone mixture and active C, organic matter TC 4 mg/L, casein acids hydrolysate 400 mg/L for somatic embryonic mass induction; MS medium with sucrose 40 g/L, agar 6 g/L, pH 5.7, supplement ABA 3 ~ 6 mg/L, organic matter TC 4 mg/L, for somatic embryogenesis, respectively.