Appenroth Klaus
Institute of General Botany and Plant Physiology, University of Jena, Dornburger Str. 159, D-07743 Jena, Germany.
J Plant Physiol. 2003 Nov;160(11):1329-34. doi: 10.1078/0176-1617-01035.
The influence of daily photoperiod (8, 16, 24 h) on eight clones of Spirodela polyrhiza was tested in two different nutrient media. The number of vegetative fronds and resting turions formed after 50 days of cultivation were scored. The specific turion yield (STY; number of turions formed per vegetative frond) was used to evaluate the effectiveness of turion formation of the tested clones. All clones formed turions in both nutrient media. The STY varied substantially between the different clones, ranging from 0.22 +/- 0.03 (clone SC from Cuba) to 3.9 +/- 0.3 (clone 9256 from Finland) in continuous light. The STY increased with increasing duration of the photoperiod. This increase may have been due to the extended period of photosynthesis rather than that of a photoperiodic long-day response. Shorter photoperiods did not stimulate turion formation in any of the clones. S. polyrhiza is a day-neutral plant with respect to turion formation, as noted previously (Appenroth et al. 1990. Annals of Botany 66: 163-168). In accordance with this conclusion, no correlation was detected between the STY and the latitude at which the clones occur naturally. Environmental factors other than shortening of photoperiods seem to be effective in signalling seasonal changes of growth conditions in advance to S. polyrhiza.
在两种不同的营养培养基中，测试了每日光周期（8小时、16小时、24小时）对8个多根紫萍克隆株的影响。对培养50天后形成的营养叶状体和休眠块茎的数量进行了统计。使用特定块茎产量（STY；每片营养叶状体形成的块茎数量）来评估受试克隆株形成块茎的有效性。所有克隆株在两种营养培养基中均形成了块茎。在连续光照下，不同克隆株之间的STY差异很大，范围从0.22±0.03（来自古巴的SC克隆株）到3.9±0.3（来自芬兰的9256克隆株）。STY随着光周期时长的增加而增加。这种增加可能是由于光合作用时间延长，而非光周期长日反应。较短的光周期并未刺激任何克隆株形成块茎。如先前所述（Appenroth等人，1990年。《植物学纪事》66：163 - 168），就块茎形成而言，多根紫萍是一种日中性植物。根据这一结论，未检测到STY与克隆株自然生长地纬度之间的相关性。除光周期缩短外的环境因素似乎能有效地向多根紫萍提前发出生长条件季节性变化的信号。
