不同光照强度对赤皮青冈幼苗光合特性的影响  

Effects of shading on the photosynthetic characteristics of Cyclobalanopsis gilva seedlings

作　　者：夏婵 李何 王佩兰[1] 李志辉[1] 王波 朱中华 XIA Chan;LI He;WANG Peilan;LI Zhihui;WANG Bo;ZHU Zhonghua(College of Forestry,Central South University of Forestry and Technology,Changsha 410004,Hunan,China;Jiangxi Academy of Forestry,Nanchang 330032,Jiangxi,China;YouXian Forestry Bureau,YouXian 412300,Hunan,China)

机构地区：[1]中南林业科技大学林学院,湖南长沙410004 [2]江西省林业科学院,江西南昌330032 [3]攸县林业局,湖南攸县412300

出　　处：《中南林业科技大学学报》2021年第7期72-79,共8页Journal of Central South University of Forestry & Technology

基　　金：中央财政推广项目“珍贵树种赤皮青冈优良家系良种繁育及造林技术推广与示范”(2018XT07);国家“十二五”科技支撑计划项目(2012BAD21B03);湖南省交通运输厅项目(201706)。

摘　　要：【目的】赤皮青冈是兼具园林观赏、生态绿化与工业用材等多功能用途于一体的珍贵乡土树种,天然起源的赤皮青冈优势群落现存量稀少,而光照强度是影响幼苗繁育及林下幼苗更新的关键环境因素,因此对不同光照强度下赤皮青冈幼苗的光适应规律进行探究显得尤为重要。研究旨在了解赤皮青冈对光照的需求及适应规律。【方法】以1年生赤皮青冈幼苗为材料,设置5个光照强度,分别为:CK(全光照)、T1(30%遮阴)、T2(50%遮阴)、T3(70%遮阴)、T4(90%遮阴),探究赤皮青冈幼苗在5种光照强度下光合特性的变化趋势。【结果】光照强度对赤皮青冈幼苗光合色素含量、光合参数及叶绿素荧光参数均有显著影响。1)赤皮青冈幼苗光合色素含量随遮阴程度的加深而逐渐增加,T4处理下叶绿素a(Chl a)、叶绿素b(Chl b)、总叶绿素(Chl t)和类胡萝卜素(Car)含量均达到最高且Chl a/b达到最低,表现出积极的适应特征。2)与CK相比,赤皮青冈幼苗在T2处理下光补偿点(P_(LC))和暗呼吸速率(R_(d))达到最低且最大净光合速率(P_(nmax))达到最高,说明适度遮阴条件下赤皮青冈幼苗对低光量子密度的利用效率达到最大程度,营养物质得到有效积累,进而光合强度显著提高。3)T3和T4处理下,净光合速率(P_(n))均显著降低,表明此时光照强度已低于赤皮青冈幼苗光合作用所需,产生弱光胁迫。4)赤皮青冈幼苗在T1和T2处理下通过提高PSⅡ反应中心光化学活性以及降低热耗散来提高光能转化效率。【结论】50%遮阴是赤皮青冈幼苗最适生长的光照条件。【Objective】Cyclobalanopsis gilva is a precious native tree species with multiple functions including landscaping,ecological service,and industrial timber.The dominant community of C.gilva originated naturally is limited.The light intensity is a key environmental factor that affects seedling reproduction and understory seedling regeneration.Therefore,it is particularly important to explore the light adaptation law of C.gilva seedlings under different light intensities.【Method】In order to understand the needs of C.gilva for light and the law of adaptation,1-year-old C.gilva seedlings were treated with five light intensities including CK(full light),T1(30%shading),T2(50%shading),T3(70%shading),and T4(90%shading)in this study.The change trend of photosynthetic characteristics of C.gilva seedlings was investigated.【Result】The light intensity had a significant effect on the photosynthetic pigment content,photosynthetic parameters,and chlorophyll fluorescence parameters of C.gilva seedlings.1)As the shading intensity increasing,C.gilva seedlings showed gradually increased photosynthetic pigment content.The highest chlorophyll a(Chl a),chlorophyll b(Chl b),total chlorophyll(Chl t),and carotenoid(Car)contents while the lowest Chl a/b were observed on the seedlings under T4 treatment.This indicated that C.gilva showed positive adaptation characteristics in a shaded environment;2)Compared with CK,C.gilva seedlings had the lowest light compensation point(P_(LC))and dark respiration rate(R_(d))while the highest maximum net photosynthetic rate(P_(nmax))under T2 treatment,meaning that the utilization efficiency of C.gilva seedlings with low light quantum density reached the maximum and the nutrients were effectively accumulated under moderate shading conditions,the photosynthetic intensity was therefore significantly improved.3)Under T3 and T4 treatments,the net photosynthetic rate(P_(n))was significantly reduced,which indicated that the light intensity under these treatments was lower than that required for photosy

关 键 词：光照强度 赤皮青冈 光合色素含量 光响应曲线 叶绿素荧光参数 

分 类 号：S792.16[农业科学—林木遗传育种]