Development and experiment of cold resistance tester for grape roots and branches

With the rapid development of wine industry in China, wine brewing cultivation moves to the west and north on a large scale. The cold and droughty weather of northern winter frequently causes the frost even death of dormant grape plants. There exist obvious differences among different grape varieties, breeds and cold-resistance of organs. In particular, the cold-resistance of roots is the weakest. Therefore, choosing comparatively improved cold-resistant breeds becomes an important task of scientific workers. In order to accurately and conveniently measure the cold-resistance of grapes, it is necessary to develop a tester to measure the cold-resistance of grape roots and branches in the laboratory. The tester mainly consists of STM32 MCU, off-chip ADC, temperature transmitter, and thermoelectric module. It has the function of measuring the cold-resistance grape roots and in the laboratory with a precision of 0.96%.The tester controlled the temperature transmitter by MCU and measured the real-time temperature within the test box. Meanwhile, thermoelectric module is controlled to measure the heat release of tissue cells belonging to the roots and branches when they freeze and the measurement data are transmitted to the MCU through serial port. The LT50 is obtained through the way of processing these data. Finally, the experiment result and storage data are showed by the epistatic machine system. Within the test box which can imitate the change of natural temperature, an experimental study is conducted to measure the cold-resistance of various grape roots and branches by using this apparatus. The experiment result indicates that Gloire Riparia and Vidal roots which LT50s are below -6.0℃ have the stronger cold-resistance. The branch of Gloire Riparia has the strongest cold-resistance and its LT50 is between -28.1 and -30.7℃. This apparatus operates in a stable way which can meet the cold-resistance test requirement of grape roots and branches and also provide a basis for the cultivation of new cold-resistance breeds.