Phenotypic Observation Of Inflorescence Variation Of Autotetraploid Robinia Pseudoacacia

Autotetraploid Robinia pseudoacacia (4x) is formed by doubling somatic chromosome of diploid (2x) in Korea, and it shows many advantages, such as fewer stipular thorns and higher contents of nutrient (such as crude protein and mineral) than those of diploid. To understand the laws and mechanism of inflorescence variations in autotetraploid Robinia pseudoacacia, from 2007 to 2009, the whole development of inflorescence was researched, which is in Yanqing country, Beijing. The research contents and main conclusions are as follows.By phenotypic observation, the variations in inflorescence architecture, growth pattern, and the proportion of inflorescence types among different individuals and years were studied. A new inflorescence type-later inflorescence was found, whose phenological phase was changed but structure was not, and it was instable.. The growth patterns of inflorescence types in autotetraploid were not found different, but different with that of diploid. The development asynchrony and structure mutation were in the floret, which is on the second inflorescence axis.Through the methods of botanical microtechnique and plant morphology, growth phases in the whole inflorescence development process were detected. As a result, the whole growth process was divided into nine phases. The crucial phase for variation was detected, which is later first axis primordium phase, and new meristem was found in this phase, which finally differentiation into mutated structure; and the flowering time in autotetraploid was 15d longer than that of diploid.To illuminate the mechanism of these variations in Autotetraploid Robinia pseudoacacia,5-acazC was used to treat the buds, which is in first axis primordium phase, and the floral meristem identity genes were cloned from Autotetraploid Robinia pseudoacacia first time. In the 5-acazC treating test, the germination rate of buds, inflorescence growing and variations were all obviously restrained, and the phenomenon of.early flowering was observed. Partly DNA sequence of LFY and TFL1 homologous genes were cloned, and no difference of sequence was found. The homology of two genes with other Leguminosae plant is 90%,.