作 者：
陈乾;邓智文;黄丽婷;刘凯;荣俊冬;陈礼光;郑郁善
关键词：
福建柏;遮荫;生理特性;叶绿素荧光特性;
摘 要：
为探讨遮荫对苗期福建柏生长的影响,本试验以1.5年生福建柏播种苗为研究对象,设置4种遮荫强度,分别为自然光（对照）、透光率50%、透光率25%、透光率12.5%,采用容器土培法研究不同遮荫强度对苗期福建柏叶绿素含量、渗透调节物质、抗氧化酶活性及叶绿素荧光特性的影响.结果表明:遮荫造成苗期福建柏叶绿素含量和主要荧光参数值增大,渗透调节物质含量和抗氧化酶活性降低.随着遮荫强度增强,叶绿素a（Chl a）、叶绿素b（Chl b）及总叶绿素（Chl a+b）含量均增加,PSⅡ最大光化学效率（Fv/Fm）、PSⅡ潜在的光化学活性（Fv/Fo）、PSⅡ电子传递效率（Fm/Fo）、光适应下PSⅡ实际光量子产额（YⅡ）、光抑制时最大光合电子传递效率（ETR）、光化学猝灭系数（qP）则先升后降,过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）活性、可溶性蛋白、脯氨酸含量则先降后增,非光化学猝灭系数（qN）、可溶性糖含量逐渐降低.各处理间叶绿素含量存在极显著差异（P<0.01）,Fv/Fm、Fv/Fo、Fm/Fo在自然光与透光率50.0%、25.0%之间,自然光YⅡ、ETR与其他3个遮荫处理间均存在显著差异（P<0.05）,抗氧化酶活性、渗透调节物质含量在自然光与遮荫处理间也均存在显著差异（P<0.05）;Fv/Fm、Fv/Fo、Fm/Fo、YⅡ、ETR、qP均在透光率50%处理时最高,CAT、POD、SOD活性、可溶性蛋白、Pro含量最低.研究表明,遮荫环境下,苗期福建柏光合能力、抗氧化酶活性和渗透调节物质含量发生了相应变化,其中,透光率50%遮荫最有利于福建柏苗期生长,说明适度遮荫可以改变福建柏幼苗生理特性,提高光合能力,促进生长.
作 者：
CHEN Qian;DENG Zhiwen;HUANG Liting;LIU Kai;RONG Jundong;CHEN Liguang;ZHENG Yushan;College of Forestry, Fujian Agriculture and Forestry University;
关键词：
Fokienia hodginsii;;shading;;physiological characteristics;;chlorophyll fluorescence characteristics
摘 要：
To investigate the effects of shading on the growth of Fokienia hodginsii at seedling stage, 1.5-year-old F.hodginsii seedlings were subject to 4 shading intensities in pot experiment, including 50%, 25% and 12.5% light transmittance and the control. Chlorophyll content, osmoregulation substance, antioxidant enzyme activity and chlorophyll fluorescence characteristics of F.hodginsii seedlings were monitored. The results showed that chlorophyll content and the main fluorescence parameters of F.hodginsii seedlings overall increased under shading, and the contents of osmotic regulator and antioxidant enzyme activity decreased. With the increase of shading intensity, chlorophyll a, chlorophyll b and total chlorophyll contents showed uprising trends; maximal quantum yield of PSⅡ(Fv/Fm), potential activity of PSⅡ(Fv/Fo), electron transport rate of PSⅡ(Fm/Fo), actual photosynthetic efficiency of PSⅡ(YⅡ), maximum photosynthetic electron transport rate in photoinhibition(ETR) and coefficient of photochemical quenching(qP) all increased first and then decreased; catalase(CAT), peroxidase(POD), superoxide dismutase(SOD) activities, soluble protein and proline contents firstly declined and then increased; non-photochemical quenching coefficient(qN) and soluble sugar content gradually reduced. There were significant differences in chlorophyll content among the 4 treatments(P<0.01). Fv/Fm, Fv/Fo and Fm/Fo varied significantly between 50.0% and 25.0% light transmittance and the control. YⅡ and ETR were significantly different between the control and all the treatment groups(P<0.05). Fv/Fm, Fv/Fo, Fm/Fo, YⅡ, ETR and qP were all the highest under 50% shading, while CAT, POD, SOD activities, soluble protein, proline content were the lowest. To summarize, under shading the photosynthetic capacity, antioxidant enzyme activity and osmoregulation substance content all changed accordingly in the leaves of F.hodginsii seedlings. Among them, moderate shading of 50% light transmittance contributes the most to the growth of F.hodginsii seedlings, resulting in improved physiological characteristics and photosynthetic capacity.
