| Maize is the only one MAYS genus of gramineae ZEA, whose phyllotaxy often presents alternate. The maize with opposite is one new mutation, which is an important genetic resource with great research value for its characters such as more female spikes, larger leaf area, and so on. The leaf development mechanism of opposite phyllotaxy is very complex and currently it is rare for the report on that. In this study, taking ELISA(enzyme-linked immuno sorbent assay) and HPLC(high performance liquid chromatography) as detecting methods and utilizing materials with many couples of opposite maize and their near isogenic lines alternate maize, the correlation between different endogeneous hormone contents at different temperatures and the opposite ratio of maize were studies through the comprehensive field experiments. The metabolism mechanisms of CTK(cytokinin) and IAA(auxins) of opposite maize were studied through detecting the activities of CKX(cytokinin oxidase) and IAAO(auxin oxidase) through analyzing the correlation between the activities and their corresponding hormones. How to breed the high-yield hybridization combinations was also studied, taking different inbred lines of opposite maize as parents, through analyzing and comparing the influencing of genotype, environment and their interacting to the yield traits of different inbred lines. Results were shown as follows.1.Taking different opposite maize as materials such as H4D,8701D, Dan3D, LiuD, ChangD and wumD, the experiments were finished by growing in different areas and years, seeding by stages in the same area and sowing in open and membrance overed fields, respectively. The results indicated that, comparing with other main environment factors such as light and moisture, temperature had significant positive correlation with the opposite ratio of maize. But when it reached 27℃, the opposite ratio of some inbred lines started to decline.2. For the growth and development of maize was controlled by the endogeneous hormone. In order to study the effects of the change of hormone on leaf primordium, the correlations were analyzed between the hormone contents and opposite ratio of maize at different temperatures. Except GA and CTK, the endogeneous hormone contents of ABA and IAA of opposite maize were influenced heavily by temperature. The correlations were negative between the contents of GA, ABA and IAA and the opposite ratios of maize, but it was reverse to CTK. The changes of maize opposite ratio were controlled by not only one hormone but multiple hormones. And the study indicated that the kickpoint was the nineth day, after that, the content of different maize kept in a relative stable range. The opposite ratios of maize were mainly influenced by the ratio of CTK/IAA. The inbred lines with higher opposite ratio was less influenced by temperature, but it was reverse to the one with lower opposite ratio. At the same temperature, the ratio of CTK/IAA of opposite maize was significant higher than that of its near isogenic lines alternate maize.3. In order to know which was the key one among the total CTKs, five CTKs and IAA were detected by the method of HPLC. Among the cytokinines, Z, ZR and DHZR were the important hormones influencing the total CTKs content, and Z was the key one. The ratio of Z/IAA and (Z+ZR+DHZR)/IAA had close correlation with maize opposite ratios. Among all the CTKs, IP and IPA took obvious effects at 21℃. DHZR played an important role in the inbred-line of wumD, but not in the others.4. In order to make clear that how CKX and IAAO took effects on CTK and IAA respectively, the activities of CKX and IAAO were detected by UV. The results indicated that the CKX activity played a key role in the CTK content of maize, especially at higher temperature, which had lower effects on the opposite maize at the lower temperature. Temperature had great impact on the IAAO activity of opposite maize. The IAA content was influenced not only by IAAO, but maybe also by POD(peroxidase) and CAT(patalase). At the same temperature, the IAAO activities of opposite maize were markedly higher than that of its near isogenic lines alternate maize, so the IAA content of the latter being less. Both the activities of CKX and IAAO kept in a stable level after nine days.5. Better inbred lines must have outstanding traits such as stable and high opposite ratio, higher yield, and better combining ability so on. The yield traits of maize were influenced by many factors such as genotype, environment and their interacting. The yield traits such as ear height, leaf width, ear diameter, ear length, ear rows and row grains were mainly influenced by genotype. As far as the inbred lines were concerned, the genotypic variability square was over 59.27% in the total variation square, up to a maximum of 84.60%. But to the new cross combination, the square was more than 53.68%, up to a maximum of 83.05%. The traits of leaf length and yield were mainly affected by both genotype and location. And bald length was greatly influenced by the environment factor.In order to match different cross combinations, taking different inbred lines of opposite maize as parents, the results showed that it was better for the agronomic characters of the varieties of 2 and 8, whose yields were over 5000g, and the highest one (variety 8) reached 5534.17g. In addition to this, varieties 3 and 5 were also important combinations with great application worth.In conclusion, the experiments confirmed that the forming of opposite character had the inseparable correlation with CTK/IAA of the growing point of maize stem tip which played an important role in Phyllotaxy differentiation. And it was the key factor which controlled the types of leaf primordium. The environment factors, especially the temperature, could affect the ratio of CTK/IAA which control the ratios of opposite maize. The mechanism metabolism of CTK and IAA were studied through analyzing the correlation between CTK and CKX, IAA and IAAO, respectively. The experiments provided a new path to breed the new maize varieties with high yield and special application. |
PDF Full Text Request