沙地植物长柄扁桃抗寒性的研究

Studies on cold-resistance of sand A.pedunculata Pall.

【目的】通过试验确定长柄扁桃的抗寒程度,筛选出其抗寒鉴定指标,为长柄扁桃在北方的生产推广区域提供重要理论参考。【方法】以沙地濒危植物长柄扁桃1年生枝条为试验材料,以从美国引进的抗性较强的扁桃品种"先锋"1年生枝条为对照,研究了不同冷冻处理条件下扁桃枝条的相对电导率、超氧化物歧化酶(SOD)活性、游离脯氨酸和丙二醛(MDA)含量,利用Logistic方程计算出2个扁桃品种的低温半致死温度(LT50),并对测定结果进行了抗寒性分析。【结果】长柄扁桃1年生枝条的低温半致死温度(LT50)为-31.05℃,对照品种为-21.03℃,两者的抗寒性差异明显,这与实际观察结果一致。2个扁桃品种的游离脯氨酸和MDA含量均随着处理温度的逐渐降低而呈现上升趋势,耐寒性强的长柄扁桃在低温时能保持较高的SOD活性和游离脯氨酸含量以及较低的MDA含量。说明除相对电导率外,SOD活性、游离脯氨酸和MDA含量在一定程度上也能反映长柄扁桃抗寒性的大小,可作为其抗寒性评价指标。【结论】长柄扁桃可在"先锋"栽培的区域和陕北部分地区顺利越冬,温度可能不是造成其冬季在沙地自然死亡的惟一原因。

[Objective] The study confirmd A. pedunculata Pall. ＇s cold resistance, screening identification indexes of its cold resistance through experiment and provided theory basis for northern production and extension region. [Method] With one-year-old branches of sand A. pedunculata Pall. and the introduced cultivated almond variety ＂Xian feng＂ by different low temperature treatments used as the experimental materials, the relative leakage of electrolytes, the contents of Proline, Malondialdehyde（MDA） content and Super oxide dimutase（SOD） activity were measured and compared. According to these S-shaped curves and the Logistic equation, it could be calculated the semi-lethal temperature（LT50） of them. [Result] The result showed that cold resistance of the two varieties had conspicuous differences, which were similar to the reality observed. The LT50 of the A. pedunculata Pall. and cultivated Almond variety separately were -31.05 and -21.03 ℃. The contents of Proline and MDA turned out to have similar trend of increasing,but the A. pedunculata Pall. had higher activity of SOD and high contents of Proline,and lower MDA content. Besides LT50 ,activity of SOD and the contents of Proline and MDA could be used as indexes to judge the ability of cold resistance in A. pedunculata Pall. [Conclusion] A. pedunculata Pall. can live through winter in the areas that variety ＂Xian feng＂ is cultivated and in some areas of North Shaanxi. Temperature is possiblly not the only reason that causes its natural death in sandy land.