Morphological and Physiological Acclimation Responses to Contrasting Light and Water Regimes in Primula sieboldii
Morphological and Physiological Acclimation Responses to Contrasting Light and Water Regimes in Primula sieboldii
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DOI：
10.1111/j.1440-1703.2004.00642.x
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发表时间：
2004-05
影响因子：
2
通讯作者：
H. Noda;H. Muraoka;I. Washitani
中科院分区：
文献类型：
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作者：
H. Noda;H. Muraoka;I. Washitani
以三叶报春花为研究对象，研究了光照（高、中、低）和土壤水分（湿、干）对三叶报春花形态和生理性状的影响。三叶报春花是一种生长于开阔草地和栎林林下的春季植物。对来自不同光照和土壤水分利用度的自然微生境的3个基因进行了生长试验。在弱光条件下（相对光子通量密度R-PPFD为5%）生长的1个高光湿微生境品种的光饱和光合速率比高光条件下（R-PPFD为61%）低41%，暗呼吸速率低50%，落叶早。每日光合作用的估算表明，叶片气体交换中的光驯化响应有助于整个植物的有效碳增益，而与实验光条件无关。水分胁迫增加了根重比，降低了分株叶面积、叶柄长度和光合能力。水分胁迫的这些形态效应在高、中光条件下比弱光条件下更大。上述反应的结果在品种的相对生长速率中得到了确认。高光加湿条件下的相对生长率是弱光加湿条件下的4倍，是高光加干条件下的1.5倍。然而，即使在低光照和/或干燥的环境下，品种也保持了正的相对增长率，并成功地产生了黄麻。我们没有发现基因间生长反应的显著差异。本研究揭示的高光合可塑性应该使三叶报春花能够在广泛的光和土壤水分可用性中生存。
The effects of the availability of light (high, medium and low) and soil water (wet and dry) on morphological and physiological traits responsible for whole plant carbon gain and ramet biomass accumulation were examined in a splitter-type clonal herbaceous species Primula sieboldii, a spring plant inhabiting broad range of light environments including open grassland and oak forest understory. Growth experiments were conducted for three genets originated from natural microhabitats differing in light and soil water availability. Ramets of a genet from high light and wet microhabitat, which were grown in low light (relative photon flux density: R-PPFD of 5%) showed 41% less light-saturated photosynthetic rate, 50% less dark respiration rate and earlier defoliation than the ramets in high light (R-PPFD of 61%). The estimation of daily photosynthesis revealed that the light acclimation response in leaf gas exchange contributes to efficient carbon gain of whole plants, irrespective of experimental light conditions. Water stress increased root weight ratio, decreased ramet leaf area, petiole length and photosynthetic capacity. These morphological effects of water stress were larger in high and medium light regimes than in low light regime. The consequence of the above responses was recognized in the relative growth rate of the ramets. The relative growth rate of the ramets in high light with wet regime was four-fold of that in low light plus wet regime, and was 1.5-fold of that in high light plus dry regime. However, even in low light and/or dry regimes, ramets kept positive relative growth rates and produced gemma successfully. We could not detect significant variation in growth responses among genets. The high photosynthetic plasticity revealed in the present study should enable Primula sieboldii to inhabit in a broad range of light and soil water availability.