Department of Horticulture, Purdue University, Lafayette, Indiana.
Plant Physiol. 1968 Feb;43(2):151-6. doi: 10.1104/pp.43.2.151.
The role of light in cold acclimation of Hedera helix L. var. Thorndale appears to differ from that reported for winter annuals. Although light greatly enhances the degree of hardiness attained, cold acclimation is not obligatorily linked to a light requirement. Photoperiods, varying from 8 to 24 hours, received during the cold acclimation period were equally effective in promoting maximum hardiness. Relatively low light intensities and short photoperiods stimulated maximum hardiness, and proportional increases in hardiness in response to increased photoperiods were demonstrated only in stems of prestarved plants. Exclusion of CO(2) and high concentrations of photosynthetic inhibitors decreased hardiness, but in no instance was hardiness reduced to the level of the dark control. The data are only compatible with a photosynthetic role of light if it is assumed that only a small portion of the total photosynthates are required to elicit maximum hardiness. Alternatively, the light stimulation which was elicited by low light intensities, short photoperiods, in the absence of CO(2), and in the presence of photosynthetic inhibitors, may be a light signal similar to a phytochrome response.
山麦冬在低温驯化过程中对光的作用似乎与冬季一年生植物所报道的不同。虽然光极大地增强了所达到的抗寒程度，但低温驯化不一定与光照要求有关。在低温驯化期间接受的从 8 到 24 小时不等的光周期对促进最大抗寒能力同样有效。相对低的光强度和短的光周期刺激最大的抗寒能力，并且仅在饥饿植物的茎中证明了对增加的光周期的抗寒能力的比例增加。CO（2）的排除和高浓度的光合作用抑制剂降低了抗寒性，但在任何情况下，抗寒性都不会降低到黑暗对照的水平。如果假设只需要总光合产物的一小部分就可以产生最大的抗寒能力，那么这些数据仅与光的光合作用作用兼容。或者，在没有 CO（2）和存在光合作用抑制剂的情况下，由低光强度和短光周期引起的光刺激可能是类似于光敏色素反应的光信号。
