CHANGING SENSITIVITY TO LIGHT AND NITRATE BUT NOT TO GIBBERELLINS REGULATES SEASONAL DORMANCY PATTERNS IN SISYMBRIUM-OFFICINALE SEEDS
CHANGING SENSITIVITY TO LIGHT AND NITRATE BUT NOT TO GIBBERELLINS REGULATES SEASONAL DORMANCY PATTERNS IN SISYMBRIUM-OFFICINALE SEEDS
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DOI：
10.1111/j.1365-3040.1993.tb00894.x
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发表时间：
1993-06-01
影响因子：
7.3
通讯作者：
KARSSEN, CM
中科院分区：
文献类型：
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作者：
DERKX, MPM;KARSSEN, CM
药用五味子Sisymbrium office inale(L.)斯考普。在自然条件下埋藏在土壤中的植物每年都会通过休眠的季节性变化模式。休眠在秋冬季节被打破，在夏季重新诱导。为了阐明该物种在自然条件下的休眠规律，对其对相关萌发因子的敏感性变化进行了详细的分析。用Logistic剂量响应曲线拟合的发芽数据表明，对光和硝酸盐的敏感性随季节而变化。光和硝酸盐需求的变化模式非常相似。一次休眠和二次休眠解除后，敏感度增加，诱导二次休眠时，敏感度则相反。在1991年春季解除初级休眠期间，磁通响应曲线呈现双相特征，响应既发生在极低磁通范围内，又出现在低磁通范围内。硝酸盐剂量反应数据都可以用单相曲线来拟合，尽管反应也可能发生在两个不同的范围内。根据曲线参数的解释，推测休眠是由光敏色素和硝酸盐受体数量的变化，受体结合特性的变化和/或由配体-受体相互作用引发的反应链的变化来调节的。在这个反应链的某个地方，赤霉素(GAs)的生物合成受到刺激。通过使用GA生物合成抑制剂四环素，间接证明了合成气体的能力确实随着季节的变化而变化。从埋葬开始，对气体的敏感性逐渐增加，与休眠的变化没有特别的关系。因此，除了埋藏的头几个月，GA敏感性可能不被视为控制该物种休眠的限制因素。
Seeds of Sisymbrium officinale (L.) Scop. that are buried under natural conditions in soil pass annually through a seasonal pattern of changes in dormancy. Dormancy is broken in autumn-winter and re-induced in summer. To elucidate dormancy regulation in this species under natural conditions, a detailed analysis of the changes in sensitivity to some relevant germination factors was carried out. Germination data fitted as logistic dose response curves showed that sensitivity to light and nitrate, both indispensable stimuli for germination of this species, varied with the seasons. Patterns of shifts in requirement for light and nitrate were remarkably similar. Sensitivity increased when both primary and secondary dormancy were alleviated, and it was reversed during induction of secondary dormancy. During alleviation of primary dormancy in spring 1991, the fluence response curves exhibited a biphasic character with responses occurring both in the very-low-fluence-range and in the low-fluence-range. The nitrate dose response data could all be fitted as monophasic curves, although responses might have occurred in two distinct ranges as well. From interpretation of curve parameters, it is postulated that dormancy is regulated by changes in the number of phytochrome and nitrate receptors, in shifts in the binding characteristics of the receptors and/or in shifts in the response chain initiated by the ligand-receptor interaction. Somewhere in this response chain, biosynthesis of gibberellins (GAs) is stimulated. By use of the GA biosynthesis inhibitor tetcyclasis, it was indirectly proven that the capacity to synthesize GAs indeed varied with the seasons. Sensitivity to GAs gradually increased from burial onwards and was not particularly related to changes in dormancy. Thus, except for the first few months of burial, GA sensitivity may not be regarded as a limiting factor in controlling dormancy in this species.