以‘绿岭’、‘辽宁1号’、‘香玲’、‘上宋6号’、‘中林1号’和‘清香’6个核桃品种为试材，于2013年4月15日取样测定各品种叶片和子房的过冷却点、结冰点及电解质渗出率，计算低温半致死温度，4月20-21日调查各品种的霜冻害受冻指数。结果表明：‘绿岭’、‘香玲’、‘辽宁1号’、‘上宋6号’、‘中林1号’和‘清香’的霜冻害受冻指数分别为41.97%，52.65%，54.88%，67.58%，74.93%，98.67%，‘绿岭’受冻指数极显著低于其他品种。‘绿岭’、‘香玲’、‘辽宁1号’、‘上宋6号’、‘中林1号’和‘清香’叶片的过冷却点分别为-4.40，-4.27，-3.87，-3.73，-3.53，-3.23℃，结冰点分别为-3.83，-3.27，-3.10，-3.30，-2.47，-2.43℃；子房的过冷却点分别为-3.71，-3.68，-3.53，-3.24，-2.72，-2.31℃，结冰点分别为-3.12，-2.83，-2.61，-2.53，-1.87，-1.73℃；其中‘绿岭’、‘香玲’叶片、子房的过冷却点，子房结冰点均极显著低于其他品种，‘绿岭’叶片结冰点极显著低于其他品种。‘绿岭’、‘香玲’、‘辽宁1号’、‘上宋6号’、‘中林1号’和‘清香’叶片的低温半致死温度分别为-3.33，-2.96，-2.81，-2.63，-2.31，-2.25℃，其中‘绿岭’极显著低于其他品种；子房的低温半致死温度分别为-2.62，-2.58，-2.39，-2.05，-1.80，-1.07℃，‘绿岭’与‘香玲’无显著差异，但极显著低于其他品种。对各品种过冷却点、结冰点、电解质渗出率、低温半致死温度分析及田间抗霜冻结果均表明，6个品种的抗霜冻能力由高到低为‘绿岭’、‘香玲’、‘辽宁1号’、‘上宋6号’、‘中林1号’、‘清香’。%In order to investigate the frost resistance and the mechanism,6 walnut cultivars,‘Lvling’,‘Xiangling’,‘Liaoning NO. 1’,‘Shangsong NO. 6’,‘Zhonglin NO. 1’and‘Qingxiang’,were used as materials to determine their supercooling point,freezing point and electrolyte leakage rate in leaves and ovaries in April 15th,and to calculate the semi-lethal temperature. Their frost freezing indexes in April 20 ~21th were investigated. The results showed that the frost freezing indexes of‘Lvling’,‘Xiangling’,‘Liaoning NO. 1’,‘Shangsong NO. 6’,‘Zhonglin NO. 1’and‘Qingxiang’ were 41. 97%,52. 65%,54. 88%,67. 58%,74. 93%,and 98. 67%,respectively. The frost freezing indexes of‘Lvling’was very significantly lower than those of the other cultivars. The supercooling points in leaves of‘Lvling’,‘Xiangling’,‘Liaoning NO. 1’,‘Shangsong NO. 6’,‘Zhonglin NO. 1’and‘Qingxiang’were -4. 40 ℃,-4. 27 ℃,-3. 87 ℃,-3. 73 ℃,-3. 53 ℃ and -3. 23 ℃,respectively,and the freezing points were -3. 83 ℃,-3. 27 ℃,-3. 10 ℃,-3. 30 ℃,-2. 47 ℃ and -2. 43 ℃,respectively. The supercooling points in ovaries were -3. 71 ℃,-3. 68 ℃,-3. 53 ℃,-3. 24 ℃,-2. 72 ℃ and -2. 31 ℃,respectively,and the freezing points were -3. 12 ℃,-2. 83 ℃,-2. 61 ℃,-2. 53 ℃,-1. 87 ℃ and -1. 73 ℃,respectively. The supercooling points in leaves and ovaries,the freezing points in ovaries of‘Lvling’and‘Xiangling’were very significantly lower than those of the other cultivars. The freezing point in leaves of‘Lvling’was very significantly lower than those of the other cultivars. The semi-lethal temperatures in leaves of‘Lvling’,‘Xiangling’,‘Liaoning NO. 1’,‘Shangsong NO. 6’,‘Zhonglin NO. 1 ’ and‘Qingxiang’was -3. 33 ℃,-2. 96 ℃,-2. 81 ℃,-2. 63 ℃,-2. 31 ℃ and -2. 25 ℃,respectively,and that of in leaves of‘Lvling’was very significant lower than those of the other cultivars. The semi-lethal temperatures in ovaries of the 6 cultivars were -2. 62 ℃,-2. 58 ℃,-2. 39 ℃,-2. 05 ℃,-1. 80 ℃ and -1. 07 ℃,respectively. There was no significant difference in the semi -lethal temperature between‘Lvling’and‘Xiangling’,but theirs were very significantly lower than those of the other cultivars. The analyses of supercooling point,freezing point,electrolyte leakage rate and the frost resistance in the field all indicated that the frost resistance of the 6 cultivars from high to low was‘Lvling’,‘Xiangling’,‘Liaoning NO. 1’,‘Shangsong NO. 6’,‘Zhonglin NO. 1’,and‘Qingxiang’.
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