Poff K L
Michigan State University-Department of Energy Plant Research Laboratory, East Lansing 48824.
Plant Physiol. 1991;95(2):517-21. doi: 10.1104/pp.95.2.517.
Phototropic curvature has been measured for etiolated Arabidopsis thaliana seedlings with and without a preirradiation. A bilateral preirradiation with 450-nm light at a fluence greater than about 0.1 micromole per square meter causes a rapid desensitization to a subsequent 450-nanometer unilateral irradiation at 0.5 micromole per square meter. Following a refractory period, the capacity to respond phototropically recovers to the predesensitization level, and the response is then enhanced. The length of the refractory period is between 10 and 20 minutes. Both the time needed for recovery and the extent of enhancement increase with increasing fluence of the bilateral preirradiation. Based on the relative spectral sensitivities of desensitization and enhancement, these responses can be separated. Desensitization is induced by blue light but not by red light. Enhancement, however, is induced by both blue and red light. Thus, enhancement can be induced without desensitization but not vice versa. Both desensitization and enhancement affect only the magnitude of the response and do not affect the fluence threshold.
已对有或没有预辐照的黄化拟南芥幼苗的向光性弯曲进行了测量。用大于约0.1微摩尔每平方米的通量的450纳米光进行双侧预辐照会导致对随后以0.5微摩尔每平方米进行的450纳米单侧辐照迅速脱敏。在一段不应期之后，向光性反应能力恢复到脱敏前水平，然后反应增强。不应期的长度在10到20分钟之间。恢复所需的时间和增强的程度都随着双侧预辐照通量的增加而增加。根据脱敏和增强的相对光谱敏感性，可以区分这些反应。脱敏由蓝光诱导而非红光。然而，增强由蓝光和红光共同诱导。因此，可以在不发生脱敏的情况下诱导增强，但反之则不行。脱敏和增强都仅影响反应的幅度，而不影响通量阈值。
