| Summary: | 碩士 === 國立中興大學 === 園藝學系所 === 98 === Recently, consumers have gained lots of attention in the safety of food and human health. As media reported that many cases of kidney patients had died after ingested carambola, consumers lost will to buy carambola and made big damege of carambola industry. This study focused on the oxalic acid in carambola, which may cause kidney diseases, and processed selection of varieties and breeding to lower the oxalic acid content in carambola.
We measured the organic acid content of 30 varieties kept in Fengshan Tropical Horticultural Experiment Branch and the results indicated that ‘Tart’, ‘Yan Pu Tart’ and ‘Gloden star’ carambola fruits had high content of oxalic acid, which were not suitable for the maternal plant as low-oxalic-acid carambola breeding. On the other side, ‘Shih Cian’, ‘Malaysia 8’, ‘Tainoung No.2’, ‘Jin Long’, ‘CTND03’, ‘Zhu Ye’ and ‘Cing Cian Hou’ carambola fruits had the lowest content of oxalic acid, which were suitable for the maternal plant as low-oxalic-acid carambola breeding.
The content of oxalic acid in leaf and fruit had no significant correlation, so it would be not appropriate to select low-oxalic-acid varieties according to the content of oxalic acid in leaf. One should take the content of oxalic acid in fruit as selecting standard. The content of oxalic acid in carambola fruit had significant correlation with both titratable acidity and the content of ascorbic acid. Both could be the selecting index of low-oxalic-acid varieties. The content of oxalic acid had significant difference during fruit development and had correlation between the oxalic acid of young and ripe fruit. Overview the development of carambola fruit, as the maturity raised, macro elements had the trend of decrease. Considering of keeping macro elements as the selecting standard, the correlation would be higher after the green-ripe stage.
We offered fertilizers with the same content of total nitrogen to bolt-planting ‘Malaysia’carambola. Compared with serving only ammonia, the mixture of nitrate and ammonia had the effect of decreasing the content of oxalic acid in carambola fruit. The activity of glycolate oxidase, which related to oxalic acid simulation, also lowed, and the accumulation of total soluble suger increased. Using nitrate fertilizer duing plant growing had obvious effect of lowering the content of oxalic acid in carambola fruit. It should process further study to achieve the biggest benefit.
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