光照和氮交互作用对3种彩叶玉簪光合作用及荧光特性的影响

Effects of Light Intensity and Nitrogen Interaction on Photosynthesis and Chlorophyll Fluorescence Characteristics in Three Species of Colorful Hosta

在2种光照强度和4种氮素处理下,研究3种彩叶玉簪叶片光合速率和荧光参数对其周围环境变化的响应。结果表明:在光照强度L1(遮阴50%)和L2(遮阴70%)条件下,3种彩叶玉簪叶片叶绿素a、叶绿素b、总叶绿素、类胡萝卜素质量分数随供氮量的增加呈先增加后降低趋势,转折点分别出现在氮素处理水平N2(9.6 g.盆-1)和氮素处理水平N1(3.2 g.盆-1);同时氮素增加也显著提高3种彩叶玉簪叶片光合有效速率;Fv/Fm(PSⅡ最大光化学效率)、ФPSII(PSII电子传递量子效率)和qP(光化学碎灭系数)的变化趋势与其色素质量分数变化相似,其中在L1条件下N2处理对金鹰玉簪的荧光参数影响较为显著,在L2条件下N1处理水平利于黄金叶和金头饰玉簪光化学效率提高,光照和氮处理对3种彩叶玉簪叶片Fv/Fm、qP上均具有显著交互作用(p<0.05)。研究发现,光照强度L1与氮水平N2、光照强度L2与氮水平N1处理组合能提高3种彩叶玉簪的光能利用率,并有利于其光合产物的积累。

An experiment was conducted to study the responses of leaf photosynthetic rate and chlorophyll fluorescence of three species of colorful Hosta to the changes in surrounding environment under the treatments of two levels of light intensities and four levels of nitrogen supply. Results showed that, under the conditions of light intensity L1 （ 50% shade） and L2 （70% shade） , the contents of leaf chlorophyll a, chlorophyll b, total chlorophyll and carotenoid in the three species of colorful Hosta first increased, then decreased with increasing nitrogen supply. The turning points for the levels of nitrogen treatments were in N2 （9.6 g/basin） and N1 （3.2 g/basin） respectively. The net photosynthetic rate of the leaves of color- ful Hosta significantly increased with increasing nitrogen supply. The changing tendencies in maximum quantum efficiency of photosystem （Fv/Fm ）, actual photochemical efficiency （φPSII ） and coefficient of photochemical quenching （qP） were similar to the change in pigment content. Under the L1 conditions, the effect of Nz treatment on the fluorescence parameters of Hosta ＇ Gold Edger＇ was significant, while N1 treatment could increase the photochemical efficieneies of Hosta ＇ Siehold- iana Gold＇ and Hosta ＇ Golden Tiara＇ under the light intensity L2. Light intensity and nitrogen supply had a significant interaction on the Fv/m and qP （at the level of 0.05 ）. The combinations of light intensity L1 （50% shade） and nitrogen level N2（9.6 g/basin） as well as light intensity L2（70% shade） and nitrogen level N1（3.2 g/basin） could improve the light utilization efficiency and increased the amount of dry matter accumulation in the three species of colorful Hosta.