Caporn S J M, Risager M, Lee J A
School of Biological Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK.
Botanical Institute, Department of Plant Ecology, University of Copenhagen, Oster Farimagsgade 2D, DK-1353 Copenhagen K, Denmark.
New Phytol. 1994 Nov;128(3):461-468. doi: 10.1111/j.1469-8137.1994.tb02992.x.
Frost hardiness in Calluna vulgaris (L.) Hull, which had received ammonium nitrate applications in the field for 30 months, was assessed using scores of visible injury and measurements of the rate of total electrolyte leakage from excised shoots following controlled freezing treatments in the laboratory. There was good overall correlation between the two methods (Spearman correlation coefficient 0.77), but leakage measurements were more sensitive than injury scores to the effects of nitrogen. Visible injury was not significantly altered by nitrogen supply (Kruskal-Wallis non-parametric test). Ion leakage was analyzed in different ways, using either calculations of the first-order rate coefficients or expressions of relative conductivity. These analyses produced similar results with respect to the effect of frost and nitrogen. Shoots of nitrogen-fertilized (40, 80 and 120 kg ha yr ) C. vulgaris sampled in October 1991 showed significantly (P < 0.05) less leakage after overnight frosts of -15 and -20 °C than did the water-treated controls. In October the temperature which killed 50% of the shoots (LT ), derived from the leakage data, was raised by at least 4 °C by the highest nitrogen treatments compared with the control plants. Frost treatments to pot-grown C. vulgaris in November produced similar visible injury to attached and excised shoots from the same plants, both being significantly less damaged by a -18 °C frost after a 7-month exposure to an NaNO mist solution (1.0 mM, pH 4.5) than were water-misted controls. Ammonium-mist treatments also marginally reduced frost injury, but the effects were not statistically significant. These results demonstrate that frost hardiness of C. vulgaris in the field can be assessed rapidly and accurately in the laboratory by analysis of electrolyte leakage from excised shoots.
对在田间施用硝酸铵30个月的普通石南（Calluna vulgaris (L.) Hull），通过观察可见伤害得分以及在实验室进行控制冷冻处理后测量离体嫩枝的总电解质渗漏率来评估其抗冻性。两种方法之间总体相关性良好（斯皮尔曼相关系数为0.77），但渗漏测量对氮素影响的敏感性高于伤害得分。氮素供应对可见伤害没有显著影响（克鲁斯卡尔 - 沃利斯非参数检验）。离子渗漏采用不同方式进行分析，要么计算一级速率系数，要么表示相对电导率。这些分析在霜冻和氮素影响方面得出了相似的结果。1991年10月采集的施氮量为40、80和120千克/公顷·年的普通石南嫩枝，在-15和-20°C的夜间霜冻后，其渗漏率显著低于水处理对照（P < 0.05）。10月，根据渗漏数据得出的使50%嫩枝致死的温度（LT50），与对照植株相比，最高氮处理使其至少升高了4°C。11月对盆栽普通石南进行霜冻处理，同一植株的附着嫩枝和离体嫩枝产生了相似的可见伤害，在暴露于NaNO3雾溶液（1.0 mM，pH 4.5）7个月后，二者在-18°C霜冻下的受损程度均显著低于水雾对照。铵雾处理也略微降低了霜冻伤害，但效果不具有统计学显著性。这些结果表明，通过分析离体嫩枝的电解质渗漏，可在实验室中快速准确地评估田间普通石南的抗冻性。
