Study On Influence Of Fe On Growth And Quality Of Ipomoea Aquatica Forsk

Solution culture with five Fe concentrations (10、20、30、40、50μmol·L-1) in solutions was adopted to study influence of Fe on growth and quality of three varieties of water spinach(Ipomoea aquatica Forsk) Biomass. chlorophyll content, photosynthesis. POD and CAT activities were analyzed in the experiments. Optimum Fe concentrations were suggested for best yield of different varieties. And accumulation of other minerals beside Fe in plant parts and contents of soluble protein, soluble sugar, Vc and total AA were also determined to check influence of Fe on quality of the varieties. The main results of this study are as follows:1. Appropriate concentration of Fe has a facilitating role on plant height and root length of water spinach. Under the same level of Fe concentration, plant height and fresh weight of the three varieties were expressed as the "Teng" water spinach>"Dave" water spinach>"Liuye" water spinach."Teng" water spinach shoot and root growth showed strong vigor than the other two varieties. Best yield of“Teng” water spinach was obtained in the treatment of20μmol·L-1Fe.2. The chlorophyll (a+b) content of Ipomoea species were increase at first and then decreased as the Fe concentration increase. Under the same Fe concentration, the total chlorophyll (a+b) content of "Teng" water spinach were higher than the other two. and more obvious at low Fe concentrations.3. The net photosynthetic rate of "Teng" water spinach showed a "U"-shape change with increase of Fe concentration. The appropriate increase in Fe concentration played a promoting role for net photosynthetic rate of the water spinach, but might inhibit the photosynthetic rate when Fe concentration is too high. Stomatal conductance of "Daye" and "Teng" water spinach showed a trend of increase first and then decrease with the increasing in Fe concentration. Under different Fe concentrations, intercellular CO2concentration of water spinach is not significantly different. Transpiration rate of "Teng" water spinach is changed more obviously with the increasing Fe concentration and in the case of the same Fe concentration Ipomoea vine transpiration rate is lower than the other two varieties.4. As the Fe concentration increasing."Liuye" water spinach POD activity was decreased."Daye" water spinach was parabola with increasing Fe concentration and POD activity was the highest at Fe concentration of30μmol·L-1."Teng" water spinach POD activity was the highest in the Fe concentration of40μmol-L-1. In the same Fe concentration, the "Teng" water spinach CAT activity was higher than the other two varieties; the average CAT activity of "Liuye’" water spinach was the lowest. With the Fe concentration increasing."Liuye" and "Daye" water spinach CAT activity was raised first and then decreased, the highest at the Fe concentration of30umol·L-1.5. Under the same treatment. Fe in all varieties are mainly accumulated in the above ground edible parts, the Fe content in the stem was the lowest. Fe content in the leaves of the "Teng" water spinach was the highest and significantly higher than the other two varieties about91.2%-364.5%. which imply it is the Fe-rich varieties. K content had varied little on parts of the Ipomoea. Ca content in leaves and stems of "Daye" water spinach were higher, Na content in "Liuye" water spinach and "Teng" water spinach were higher. Mg content in "Liuye" and "Daye" water spinach leaves and stems were higher. Zn content in spinach was decreasing with increased Fe concentration, Zn content in above ground parts of "Teng" water spinach was the highest compared with other varieties.6. Improving Fe nutrition enhanced protein synthesis. Soluble protein content in "Liuye" water spinach leaves was gradually increased with increasing Fe concentration. However, soluble sugar content of all varieties did not change significantly with variation of Fe treatments. As the Fe concentration increasing, vitamin C content in "Teng" water spinach was gradually increasing and higher than the other two varieties; this means "Teng" water spinach had better quality. The total amino acid content of water spinach was varied with different Fe treatments, which showed a sharp rise and then a quick decline in the change.