Plasticity in Photosynthesis and Functional Leaf Traits of Meconopsis horridula var. racemosa in response to Growth Irradiance

總狀綠絨蒿（Meconopsis horridula var. racemosa）是世界著名的高山花卉和藥用植物。在喜馬拉雅地區，它既能生長於光照強烈的高山流石灘上，也能棲息在低光強的灌木林下。為了瞭解這種植物如何適應不同的光環境，我們研究了葉片性狀和生理在其光適應中的相對作用。與生長在低光強下的植株相比，總狀綠絨蒿在高光強下表現出更高的光合速率、單位面積葉氮含量、比葉重、葉綠素a／b比值和CO2擴散導度，但是光合氮利用效率及單位品質的葉氮含量在處理間相對穩定。不同生長光強下光合速率的變化與單位面積的葉氮含量、CO2擴散導度和比葉重相關。我們的研究表明總裝綠絨蒿對光強表現高的光合適應塑性，且在高光照下光合表現更好。研究結果對於總裝綠絨蒿栽培策略的制定有重要意義。

關鍵字

葉綠素螢光；生長光強；比葉重；葉氮；光合作用

並列摘要

Meconopsis horridula var. racemosa, a valuable horticultural and medicinal plant, grows in the high mountains of the Himalayas under a range of light intensities, from bright illumination on the screes to low light in the understory of shrubs. To understand how this species adapts to these various environments, we examined the relative significance of leaf traits and physiology on photosynthetic light acclimation. Compared with plants exposed to low growth irradiance, those under greater irradiance exhibited a higher photosynthetic rate, leaf nitrogen content per unit area (N(subscript a)), leaf dry mass per unit area (LMA), chlorophyll a/b ratio and CO2 diffusion conductance. However, photosynthetic nitrogen-use efficiency and leaf N content per unit mass remained relatively constant regardless of light regime. This change in photosynthetic rate under different light conditions was linked to N(subscript a), LMA and CO2 diffusion conductance. Our results show that M. horridula has high photosynthetic plasticity in response to growth irradiance, and that photosynthetic performance is better from plants grown under brighter illumination. Such findings will be beneficial when developing a cultivation strategy in commercial production.

並列關鍵字

Chlorophyll fluorescence ； Growth irradiance ； Leaf mass per unit area ； Leaf nitrogen ； Photosynthesis

國際替代計量

Plasticity in Photosynthesis and Functional Leaf Traits of Meconopsis horridula var. racemosa in response to Growth Irradiance

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