The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. As light intensity increased from 200 to 2000 photosynthetic photon flux density (PPFD), fraction of light absorbed in photosystem (PS) II and PRI values in all plants were strongly lowered, but fraction of light absorbed in PSII dissipated via thermal energy dissipation and non-photochemical quenching (NPQ) values in all plants wereremarkably elevated.When plants were exposed to 200 PPFD, the values of fraction of light absorbed in PSII, utilized in photosynthetic electron transport(p), andfraction of light absorbed excitation energy in PSII dissipated via thermal energy dissipation (D), remained stable regardless of the changes in levels of Chla + b. Under 800 and 1200 PPFD, the values of p and electron transport rate (ETR) decreased, but D and NPQ increased as Chla + bcontent decreased, suggesting that decrease inChla + bcontent led to lower PSII efficiency and it became necessary to increase dissipate excess energy. On the contrary, in 2000 PPFD, leaves with lower Chla + bcontent had relatively higher p and electron transport rate (ETR) values and lower D level, as well as tended to increase more in NPQ but decrease more in PRI values. The consistent relations between PRI and NPQ suggest that NPQ is mainly consisted ofthe xanthophyll cycle-dependentenergy quenching.Yellow-green cultivar showed lower Chla + bcontent but high carotenoids/Chla + b ratio and had high light protection ability under high PPFD. The precise management of photosynthetic parameters in response to light intensity can maximize the growth and development of Chinese kale plants.

中文翻译：

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不同光照强度下黄绿色，绿色和深绿色芥蓝（Brassica oleracea L. var。alboglabra Musil。）光合作用的生理特性。

这项工作的目的是研究三个羽衣甘蓝品种的色素差异叶片的生理特性和光合装置。响应变化的光强度，在绿色，黄绿色和深绿色品种中测定叶绿素（Chl）荧光和光化学反射指数（PRI）。随着光强度从200增加到2000，光合作用光子通量密度（PPFD），所有植物在光系统（PS）II和PRI值中吸收的光分数都大大降低，但在PSII中吸收的光因热能消散而散失所有植物的光化学猝灭（NPQ）值均显着升高。当植物暴露于200 PPFD时，PSII中吸收的光分数用于光合作用电子传递（p），并且无论Chla + b的水平如何变化，PSII中通过热能耗散（D）消散的光吸收激发能的分数都保持稳定。在800和1200 PPFD下，随着Chla + b含量的降低，p和电子传输速率（ETR）的值降低，但D和NPQ升高，这表明Chla + b含量的降低导致PSII效率降低，因此有必要增加耗散多余的能量。相反，在2000 PPFD中，Chla + b含量较低的叶片具有较高的p和电子传递速率（ETR）值，而D较低。级别，以及NPQ趋于增加但PRI值趋于降低。PRI和NPQ之间的一致关系表明NPQ主要由叶黄素循环依赖的能量猝灭组成。黄绿色品种在较高的PPFD下，其Chla + b含量较低，但类胡萝卜素/ Chla + b比例较高，并且具有较高的光防护能力。响应光强度对光合作用参数的精确管理可以使芥蓝植物的生长和发育最大化。