不同光强对加拿大一枝黄花生长和叶绿素荧光的影响

Growth Characters and Chlorophyll Fluorescence of Goldenrod(Solidago canadensis) in Different Light Intensities

以外来入侵种加拿大一枝黄花(Solidago canadensis)为研究对象,在4种光照强度处理下,对其光合色素含量、叶绿素荧光特性、比叶重、植株的生长特征和生物量分配等指标进行了测定分析.结果表明:(1)随着光照强度的减弱,加拿大一枝黄花叶片的Chla、Chlb和Chl(a+b)均上升,Chla/Chlb下降,4种光强处理下叶片的初始荧光(Fo)、光系统Ⅱ实际光化学效率(ФPSⅡ)、光系统Ⅱ最大光能转化效率(Fv/Fm)日变化曲线相似,高光强下的Fo、ФPSⅡ和Fv/Fm均小于中、低和弱光强下的,这说明加拿大一枝黄花能适应较大的光强幅度,同时对低、弱光强有一定的抗逆性.(2)生长在高(RI为100%)、中(RI为60%)光强下的加拿大一枝黄花植株正常生长,生长于低(RI为20%)弱(RI为5%)光强下的植株生长不良,表现为植株矮小,茎秆细弱.中度的遮荫对它的生长没有明显影响,但在严重遮阴下生长受抑.(3)生长在高、中光强下的总生物量、地下部分生物量明显增多,低、弱光强处理下的叶生物量比显著增加.结果表明,加拿大一枝黄花在高、中光强下对生长最有利,能够适应较大幅度的光照变化,但在严重遮阴下生长明显受抑,说明该入侵植物不易入侵到密林等光照强度比较弱的生境.

Photosynthetic pigment contents, chlorophyll fluorescence characteristics, special leaf weight, the growth and biomass allocation character of Solidago canadensis, as an invasive species in China, were studied by ecophysiological techniques at different irradiances （RI：100%, 60% ,20% and 5 %）. The result indicated that：（1） The content of chlorophyll a, chlorophyll b and chlorophyll （a＋b） of S. canadensis increased with the decrease of light intensity,while the ratio of chlorophyll a/b decreased. The diurnal changes of Fo,ФPS Ⅱ and Fv/Fm had the similar curves. The diurnal change of Fo,ФPS Ⅱ and Fv/Fm stabilized and had higher value at shading treatment （RI：60% ,20% and 5%） ,while the diurnal changes of Fo, ФPS Ⅱand Fv/Fm fluctuated sharply under highest light intensity （RI. 100%）. This implying that S. canadensis could adapt broad range of light intensities and tolerate low light intensity and weak light intensity. （2）The plant grow natural under highest light intensity （RI.100%） and moderate light intensity （RI.60%）,while the plant grow unnatural under low light intensity （RI.20%） and weak light intensity（RI： 5%）. It was indieated that moderate shading has no signifieant influenee on its growth and development, but severe shading inhibits the growth of S. canadensis. （3） The S. canadensis has the highest RMR,R/C and total biomass under highest light intensity （RI.100%） and moderate light intensity （RI.-60%）,There was no signifieant differenees between the two kinds of treatment,while the treatments under low light intensity （RI.20%） and weak light intensity （RI.5%） had the highest LMR and LMF. In summary,S, canadensis ean adapt more variety of light intensity by morphologieal and physiologieal plastieity, while the growth of this plant was inhibited under severe shading. Thus we ean infer that it is hard to invade the bushy forest and other environment under severe shading for S. canadensis.