摘要
用遮光法获得5%、1%、0.5%、0.1%、0.05%全光照共5个不同光照强度的水体,将菹草(Potamogeton cripus)萌发幼苗置于上述水体,观测幼苗生长发育状况,并利用水下饱和脉冲荧光仪(DIVING-PAM)测定其光合荧光特性。结果表明:(1)不同光照强度对菹草幼苗生长发育影响显著;随光强减弱,菹草幼苗株高、叶片数、生物量增长率显著降低(P<0.01);(2)菹草幼苗的最大光化学量子产量(Fv/Fm)随光强减弱而降低,实验第16天时,0.5%、0.1%、0.05%实验组Fv/Fm值仅为对照组的65%、53%和42%;(3)随光强减弱,幼苗吸收光能用于光化学电子传递的份额(qP)减少,第16天时,0.5%、0.1%、0.05%实验组的qP值为对照组的68%、67%、53%;(4)光强减弱导致0.5%实验组qN先升高后降低,0.1%、0.05%实验组的qN值则表现出显著下降趋势,表明幼苗在较低光强条件下,叶片PSII光能转换效率显著下降,进入PSII光化学过程的激发能减少,热耗散激发能也相应减少;(5)光强减弱导致电子在光合链中的传递速率(ETR)显著下降,第16天时,1%、0.5%、0.1%、0.05%实验组ETR分别为对照的70%、63%、56%、36%,导致参与CO2的电子减少,光合作用降低。快速光响应曲线测定结果表明,幼苗ETRmax随光强减弱呈下降趋势,光响应能力随光强的减弱显著下降。
Light is a crucial factor for the growth of submerged macrophytes. Its influence on seeding growth and photosynthetic fluorescence characteristics of Potamogeton cripus were studied in this study.The seeding of Potamogeton cripus were transplanted into the waters with 5%, 1%, 0.5%, 0.1% and 0.05% sunlights respectively. The sunlight intensity was controlled by a Shading-net. The growth of Potamogeton cripus seeding were investigated, Meanwhile, some photosynthetic fluorescence characteristics were determined by a developed, submersible, pulse-amplitude modulated （PAM） fluorometer, Diving-PAM. The results were shown as followings： （1） The seeding of Potamogeton cripus had a significant change in growth by the different irradiance densities. The seeding heights, leaf numbers and fresh weights increase rate decreased significantly with the light decreasing; （2）The photochemical efficiency （Fv/Fm ratio） of seedings exhibited apparent difference by the different irradiance densities, and the Fv/Fm by 0.5%,0.1%,0.05% were 65%,53% and 42% than that of CK in the 16th day; （3）The photochemical quenching（up） of seeding exhibited apparent also difference by the different irradiance densities, and the qP by 0.5%,0.1%,0.05% were 68%,67%,53% than that of CK at the end of experiment; （4）The qN by 0.5% increased in the beginning experiment and reduced significantly in the late experiment, however, the qN by 0.1%, 0.05% were decreased significantly during the experiment, which indicating that the photochemical efficiency of PSI I reduced at the low intensity and excitation energy entering PSII decreased, and the heat dissipation decreased; （5） The Electron-transport rate（ETR） of seeding exhibited apparent significantly decreased by the different irradiance densities, the ETR by 1%, 0.5%, 0.1%, 0.05% were 70%, 63%, 56%, 36% than that of CK an the end of experiment and the photoresponse capacity of seeding had a significant changes by the different irradiances densities.
出处
《生态环境》
CSCD
北大核心
2008年第4期1342-1347,共6页
Ecology and Environmnet
基金
教育部科技创新工程重大项目(705824)
江苏省重点科技专项(BM2002701)
关键词
光照
菹草
生长发育
荧光参数
light
seeding ofPotamogeton cripus
growth
fluorescence chorophyblI parameters
