Responses of the Physiological and Biochemical Characteristics of Alfalfa Roots with Different Root Collar Diameters to Low Temperatures Under Simulated Winter Irrigation

作者：Ai-Min Zhu, Qingxin Zhang, DU Xiao-yan, Xianguo Wang, Yuxia Zhang, Baiming Cong, Yonglei Tian · 发表于：Research Square · 年份：2021 · DOI：10.21203/rs.3.rs-583000/v1 · 被引用次数：1 · 研究领域：Plant Water Relations and Carbon Dynamics、Wheat and Barley Genetics and Pathology、Plant Stress Responses and Tolerance

Abstract Background: Due to the frequent occurrence of extremely low temperatures in northern China, the problem of alfalfa mortality during overwintering requires urgent solutions to support the development of large-scale alfalfa production in the region. Understanding the effects of winter irrigation and the alfalfa root collar diameter on physiological and biochemical cold resistance mechanisms in alfalfa will be of great significance to finding such solutions. Methods: In this study, alfalfa roots with different root collar diameters (3.50±0.10 mm, 5.25±0.10 mm, 7.00±0.10 mm) were subjected to simulated winter irrigation (0 ml, 20 ml, 40 ml) and different low-temperature stress treatments (4°C, -10°C, -15°C, -20°C) in the laboratory. The relationships between alfalfa root collar activity, relative conductivity and the nonstructural carbon and nitrogen contents and antioxidant enzyme activity in the collar were explored. Results: Low-temperature stress was the most important factor causing significant changes in the physiological and biochemical indexes of the alfalfa root collar, followed by the root collar diameter. Low-temperature stress and the root collar diameter had significant effects on nonstructural carbon and nitrogen levels and enzyme activity (except POD activity) in alfalfa root collars, and winter irrigation had extremely significant effects on the nonstructural nitrogen contents of alfalfa root collars. The larger the diameter of the root collar was, the hi...