Study On Branch Cold Resistance Of Peach,apple,wine Grape In Ningxia

In order to explore the cold resistance ability of the main fuit trees in Ningxia,this experiment select annual shoots of three peach varieties(Jing Long 7,Zhong Youtao 14,Okubo),three apple cultivar(Golden Delicious,Huimin Fuji,Qin Guan),four wine grape breeds(Bei Hong,Cabernet Sauvignon,Syrah,Vidal)as test materials.Designing three treatments,paraffin sections,different low-temperature stress and different time of low-temperature stress,to determine the content of relevant stress resistance indicators in those shoots.Finally,comprehensively analyze and compare the cold resistance capability of grapes,apples and peach trees of different varieties.By the membership function method to comprehensively analyze and rank all the experimental results,and based on the research results,the regional classification of overwintering disaster risk levels in Ningxia is provided,which provides a theory for the winter protection and industrial development of three common fruit trees in Ningxia.The results showed that:1)In cold-resistant fruit tree varieties,the diameter of the duct molecules,the area of the xylem,and the ratio of the area of the xylem to the area of the vascular bundles in the new shoots of the branches were larger.2)In different low-temperature stress treatments,the relative electrical conductivity of the annual branches of each cultivar increased with decreasing temperature and showed an "S"-shaped change curve;in different freezing time treatments,the relative electrical conductivity of the branches of each variety increased first and then no longer rise.Undergoing 6 h treatment,the increasing trend tended to be flat.3)The LT50 of the three types of peaches are Okubo(-24.41?)?Zhong Youtao 14(-24.13?),and Jing Long 7(-21.89?);the LT50 of the three types of apples are Qin Guan(-32.98?),Huimin Fuji(-29.66?),Golden Delicious(-27.70?);LT50 of the four wine grapes are Bei Hong(-29.57?),Vidal(-27.26?),Cabernet Sauvignon(-23.99?),Syrah(-14.10?).4)Varieties with strong cold resistance have high soluble sugar and protein content and little change in content.Above a certain temperature range,the content of soluble sugar and protein no longer rises,and the temperature range that different varieties have different toleration,which is based on their variety characteristics.5)The activities of SOD,POD,CAT all increased or increased firstly then decreased,with the decrease of temperature and prolonged low temperature time.The protective enzyme activity in the branches of the varieties with strong cold resistance ability was higher.The MDA content showed a change characteristic compatible with the protective enzymes.The varieties with strong cold resistance had low MDA content,and the contents changed little with the deepening of low temperature stress.6)Regardless of the cold resistance ability,the moisture content of the shoots decreases with the decrease of temperature and the extension of the low temperature time.The magnitude of the decrease can reflect their cold resistance capcility.In the extreme low-temperature environment of-30?,6 h is the critical time for cold damage of most varieties.7)The order of the cold resistance ability of 3 peach varieties is Okubo,Zhong Youtao 14,and Jing Long 7;the rank of the cold resistance capcility of 3 apple varieties is Qin Guan,Golden Delicious,and Huimin Fuji;4 wine grapes are sorted according to cold resistant ability by Vidal,Bei Hong,Cabernet Sauvignon,and Syrah.The results of cold resistance ability ranking are related to the semi lethal temperature of tested materials.The semi lethal temperature calculated by the relative conductivity combined with the logistic equation can accurately judge the cold resistance of tested fruit trees.8)The northern part of Shapotou District and the eastern part of Yanchi County are low in temperature and are at high risk of overwintering frozen damage to peach trees.Apples can be widely planted throughout Ningxia and the risk of overwintering frozen injury is low.Wine grapes must be soil-buried in winter.Otherwise,there is a moderate and severe risk of overwintering frozen damage.