Abstract: Using Tarocco blood oranges were used as materials,a plastic greenhouse was set up in Taroko Blood Orange Garden in winter （December-February of the following year） to study the temperature change and its effects on the quality of citrus fruits. The results showed that the daily minimum temperature in the greenhouse was increased by 0.2~3.6 ℃, and the daily maximum temperature in the greenhouse was also significantly increased by 0.5~10.8 ℃. The diurnal temperature difference in the greenhouse was larger than that outside, and the temperature differences during cold wave and fine weather were more obvious. The coloring effect of Taroko blood orange outside was better than that in greenhouse. The greenhouse effectively increased the edible rate, juice yield, soluble solids and sugar content of Taroko blood orange, decreased the total acid content and increased the solid-acid ratio.

Key words: citrus, greenhouse, antifreeze, fruit quality