Supercooling and Cold-hardiness of Acclimated and Deacclimated Buds and Stems of Persian Walnut Cultivars and Selections
Supercooling and Cold-hardiness of Acclimated and Deacclimated Buds and Stems of Persian Walnut Cultivars and Selections
复制标题
DOI：
10.21273/hortsci.45.11.1662
复制
发表时间：
2010-11-01
期刊：
影响因子：
1.9
通讯作者：
Leslie, Charles
中科院分区：
文献类型：
--
作者：
Aslamarz, Asadolah Aslani;Vahdati, Kourosh;Leslie, Charles
为了研究波斯核桃品种和选材的抗寒性，采用了三种方法进行比较：1)热分析；2)控制冷冻后组织健康评价；3)隆冬严寒后的野外观测。收集了8个波斯核桃基因型（4个商业品种和4个有前途的伊朗品种）的茎段和芽。使用热电模块（TEM）进行热分析，以测量水和组织冻结时产生的高（HTE）和低（LTE）温度放热。当样品温度以2℃/h的速率下降时，记录TEM信号。在控制温度下评估组织损伤，使用预先冷冻的茎段，在2摄氏度/小时的温度下冷却至-5到-30摄氏度，然后在这些温度下保存16小时。冷冻样品解冻并视觉评估损伤的严重程度。在一个异常严重的冬季冻结后，对现场条件下的冷损害进行了评估。在2月中旬和4月，从受影响的树木上移除细枝，并根据损伤程度和恢复能力进行目视评估。通过组织褐变评估，ltte的发生与组织死亡相关。品种和选材的过冷能力和抗寒能力均随季节累积而增加，接近春蕾时下降。热分析表明，芽和茎在休眠高峰时表现出多个lte的趋势。根据抗寒性将品种和选材分为三类：敏感型（‘Z（30）’和‘Serr’）、半耐寒型（‘Z（53）’和‘Z（67）’）和耐寒型（‘Lara’、‘Hartley’、‘Z（63）’和‘Pedro’）。
To study the cold-hardiness of Persian walnut cultivars and selections, three methods were compared: 1) thermal analysis; 2) evaluation of tissue health after controlled freezing; and 3) field observations after a severe midwinter freeze. Stem segments and buds were collected from eight Persian walnut genotypes (four commercial cultivars and four promising Iranian selections). Thermal analysis was conducted using thermoelectric modules (TEM) to measure the high (HTE) and low (LTE) temperature exotherms produced when water and tissues freeze. TEM signals were recorded as the temperature of the samples was decreased at a rate of 2 degrees C/h. Tissue injury under controlled temperatures was evaluated using pre-chilled stem segments cooled at 2 degrees C/h to set temperatures ranging from -5 to -30 degrees C and then held at these temperatures for 16 h. Frozen samples were thawed and visually evaluated for severity of injury. Cold damage under field conditions was evaluated after an unusually severe winter freeze. Twigs from affected trees were removed in mid-February and in April and visually rated for extent of injury and ability to recover. The occurrence of LTEs was correlated with death of the tissues as assessed by tissue browning. Both the capacity to supercool and the cold-hardiness of cultivars and selections tested increased with accumulated seasonal chilling and decreased as they approached spring budbreak. Thermal analysis showed a tendency for buds and stems to exhibit multiple LTEs at peak dormancy. The cultivars and selections were classified into three groups based on their cold-hardiness: sensitive ('Z(30)' and 'Serr'), semihardy ('Z(53)' and 'Z(67)'), and hardy ('Lara', 'Hartley', 'Z(63)', and 'Pedro').