Some plants, such as sunflowers, are vulnerable to frostbite and need special protection.
Some plants, such as Chinese rose, are cold-tolerant, so it has no effect.
The harm of low temperature to flowers;
Low temperature refers to the sudden cooling caused by cold current. This low temperature will reduce the physiological activity of flowers and lead to death in severe cases. There are three common kinds of low temperature injury: freezing injury, freezing injury and freezing injury. Here is a brief introduction;
Frostbite; Cold damage, also known as cold damage, refers to the damage of low temperature above 0℃ to warm flowers. The affected flowers are mainly tropical and subtropical flowers. Low temperature destroyed the activity of enzymes in this kind of flowers, which made protein's metabolism disorder. Low temperature inhibited the absorption of water by the roots of these flowers, but the transpiration of leaves changed little, so the balance of water metabolism was out of balance. The common symptoms of flowers after frostbite are discoloration, necrosis or spots on the surface.
Woody flowers will also appear bud wilting, top wilting, broken skin, fallen leaves and other phenomena.
Freezing injury; Freezing injury means that when the air temperature or ground temperature drops to freezing point, the supersaturated water vapor in the air condenses into white crystals, that is, frost. Because of the frost, the flowers are hurt, which is called freezing injury, and soon fall off. Wood flower buds often turn black after being damaged, flower organs are invaded by water, and petals become discolored and fall off.
Frostbite; Freezing injury refers to the damage caused by low temperature below 0℃ to flowers. When the temperature drops below 0℃, the flowers are frozen inside, which is called freezing injury. The formation of ice crystals in tissues will rupture the plasma membrane of cells and denature and inactivate protein. After freezing injury, herbaceous flowers often freeze to death, and some woody flowers have cracked bark, withered branches and injured roots. Severe freezing injury leads to plant death.