The coke-edge and heart-burning of Chinese cabbage leaves are due to the fact that the individual leaves of the Chinese cabbage leaf ball are dried and yellowed from the leaf edge first. After being harmed by the infected bacteria, the dry rot turns into wet rot, and finally decays, deteriorates and deodorizes. Chinese cabbage coke edge, heart disease caused by calcium deficiency caused by internal metabolic disorders of cabbage. The main factors causing Ca deficiency in Chinese cabbage are the following: 1, improper fertilization. The main reason is the application of N fertilizer is too high, resulting in plant malnutrition; the application of unripe fertilizer, resulting in burning roots, destroying the root absorption capacity; one-time fertilization is too much, affecting plant water and calcium absorption. 2, improper watering. There are two main reasons: First, it is impossible to water in time after drought or fertilization; second, uneven watering. 3, soil salt content increased. The salt content in soil cannot be higher than 0.2%. When the content is more than 0.2%, the disease condition will intensify as the soil salt content increases. 4, the soil is dry. Drought years, especially in the rosette stage and the ball stage, are caused by less rainfall and can not be promptly filled with water, which often causes difficulties in calcium absorption in Chinese cabbage roots. 5, some varieties are not anti-focus, heartburn. The following are the main preventive measures: First, use resistant varieties; Second, reasonable fertilization; Third, the application of high calcium fertilizer; Fourth, timely irrigation, evenly pouring enough water. A Pipette (sometimes spelled pipet) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the style. Pipette Tips,Eppendorf Pipette Tips,Gilson Pipette Tips,Yellow 200Ul Pipette Tips Unimedsume Trading Co., Ltd , https://www.ums-labmed.com