1, different definitions
Oranges are fruits of orange trees belonging to Rutaceae and Citrus, also known as Guo Huang, Citrus, Jinhuan and Liu Ding. Citrus is a kind of citrus fruit with high edible and medicinal value. Originated in Southeast Asia. Small trees of citrus. Fruit can be peeled and eaten fresh, and pulp can be used as an additive for seasoning or other foods.
Pomelo is a kind of tree belonging to the genus Citrus in Rutaceae. The shoots, leaf backs, pedicels, calyx and ovary are all pilose, the leaves are usually dark purple, and the shoots are flat and angular. The leaves are quite thick, dark green in color and oval or oval in shape. They are cultivated in the south of the Yangtze River in China and Xinyang and Nanyang in Henan Province in the north. Southeast Asian countries have planted it.
2. Different morphological characteristics
Oranges are oblate or pear-shaped, ranging in size from 8 cm to 4 cm in diameter. There are annular protrusions and shallow radial grooves at the top of the fruit, and sometimes radial grooves at the pedicle. Rough skin, even pits, large oil cells, 2-4 mm thick skin, light yellow, easy to peel. The ladle has 9- 1 1 petal, and the capsule is thick.
Grapefruit is spherical, oblate, pear-shaped or wide-tapered, and its transverse diameter is usually above 10 cm, and it is light yellow or yellow-green. The hybrid is vermilion, with thick or thin pericarp, spongy, large oil cells, convex, soft and verified, with gourd sac 10- 15 or as many as 19 petals.
3. Different growth habits
The growth, development, flowering and fruiting of citrus are closely related to environmental conditions such as temperature, sunshine, moisture (humidity), soil, wind, altitude, topography and slope direction, among which the temperature has the greatest influence. Even if the temperature is different, sometimes there will be completely different results.
The optimum temperature for citrus growth is ~ 37℃. When flower buds differentiate in autumn, the temperature of day and night is required to be about 20℃ and 10℃ respectively. Too low a temperature will freeze oranges. In addition, oranges are shade-tolerant trees, but good sunshine is needed for high quality and high yield. Generally, areas with annual sunshine hours 1200 ~ 2200 hours can grow normally.
Pomelo trees have strong adaptability to temperature, with annual average temperature 16.6-2 1.3℃, monthly average temperature 1.4- 13.2℃, annual accumulated temperature ≥ 10℃ and absolute low temperature-65438. Low temperature, rainy weather or unusually high temperature during the flowering period of pomelo trees will affect flower quality, pollination and fertilization, aggravate physiological fruit drop, and lead to low fruit setting rate and low yield.
After the fruit enters the expansion stage, it is also greatly affected by temperature. When other environmental conditions are met, the temperature is suitable, the fruit expands quickly and the weight of single fruit is high. On the contrary, the fruit expansion is blocked, especially the high temperature accompanied by drought, which seriously affects the yield.
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