| Eucalyptus is the main afforestation tree species of fast-growing forest with the characteristics of fast growing, high yield, strong adverse resistance, adapted to poor, good stem shape and wide adaptability in southern of China. Fertilization is one of the main measures to promote the production of Eucalyptus.Humic acid fertilizer is a kind of organic inorganic fertilizer with variety of functional groups which has strong adsorption capacity, ion exchange capacity and coordination ability. The application of humic acid fertilizer on the tissue culture seedling of E.urophylla×E.grandis DH3229 was studied with a potting experiment. To study the absorption and utilization of nutrients, contrast the difference of growth, physiological and photosynthetic characteristics under the application of special Eucalyptus fertilizer and humic acid fertilizer. Detecting the nutrient elements and 7 kinds of phenolic acids in pot media, evaluating humic acid fertilizer efficiency, discussing the growth mechanism of Eucalyptus.To provide theoretical basis for optimizing the application technology of fertilizer. The main research conclusions are as follows:1. Fertilization could significantly promote the growth of height and ground-diameter and dry matter accumulation of E.urophylla×E.grandis seedlings, especially to the root. The effect of two kinds of humic acid fertilizer Eucalyptus special fertilizer on promoting the ground-diameter growth of Eucalyptus seedlings is better than conventional compound fertilizer during the 3 months study period. The difference of dry matter accumulation is not obvious among four fertilization treatments and the effect of two kinds of humic acid no significant effect on the distribution of dry matter in plants.2. Fertilization especially humic acid fertilizer can significantly improve the maximum net photosynthetic rate (Amax), dark respiration Rate (Rday), light saturation point (LSP), light compensation point (LCP), photosynthetic active radiation intensity range, photosynthetic rate (Pn) and transpiration rate (Tr), increase stomatal conductance of leaves cell and carbon dioxide-use efficiency. The effect of two kinds of humic acid fertilizer on promoting the Photosynthesis of Eucalyptus seedling leaves is better than Eucalyptus special fertilizer. As a whole, Effect of weathered lignite humic acid fertilizer on photosynthetic Characteristics was higher than that of the peat humic acid. The growth, biomass has a significant positive correlation with Amax, LSP, LCP, Tr in E.urophylla×E.grandis seedlings leaves, and has a significant negative correlation with Ci.3. Humic acid fertilizer significantly enhance the physiological metabolism of E.urophylla×E.grandis seedling leaves, especially improve APX, PPO and SOD activity, and soluble protein content. It must be noted that the content of malondialdehyde (MDA) and catalase CAT activity with the treatments of CK were significantly higher than 4 other fertilization treatments in the leaves of Eucalyptus DH3229 seedlings. Result shows that adequate nutrient conditions could significantly decrease the MDA content and CAT enzyme activity of antioxidant protective system in leaves.4. Fertilization significantly promoted the absorption of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, Na, in the root, stem and leaf of Eucalyptus seedlings, and the utilization rate of N, P, K by humic acid fertilizer were lower than the treatments of eclycuptus special fertilizer and conventionalcompound fertilizer. Correlation analysis showed that the growth, biomass has a significant positive correlation with the utilization rate of N, P, K in E.urophylla×E.grandis seedlings.5. Fertilization especially humic acid fertilizer significantly increased the total content of N, P, K, Ca, Mg, Mn, Cu, Zn, ammonia nitrogen, nitrate nitrogen, available phosphorus, available potassium and trace elements in the pot soil. Humic acid could significantly improve the soil nutrient conditions of plant growth, the effect of the wheathered lignite humic acid is more obvious.6. The content of seven kinds of phenolic acids was different among four fertilization treatments. Benzoic acid and pcoumaric acid can degrade under humic acid fertilizer treatments, and the conventional compound fertilizer treatment can increase the accumulation of ferulic acid, pcoumaric acid and salicylic acid in pot media. Correlation analysis showed that the growth, biomass has a significant nagetive correlation that the correlation coefficient over 0.563 with content of benzoic acid in potted media, and not significant with ferulic acid, pcoumaric acid and salicylic acid. |
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