华南地区五种蕨类植物耐荫性的研究

Shade-tolerance of Five Ferns From South China

以华南地区5种耐荫性蕨类植物,华南毛蕨、乌毛蕨、蜈蚣蕨、线羽凤尾蕨和普通针毛蕨为研究对象,在模拟生态环境条件下,研究了这5类蕨类植物在全光照及透光率分别为25.00%、6.25%和1.56%下,其株高、冠幅、叶片数、叶绿素含量和光合参数等指标的变化。结果表明:随着遮荫程度的不断增加,普通针毛蕨和蜈蚣蕨的叶片数减少,冠幅降低;线羽凤尾蕨和华南毛蕨的叶绿素相对含量则随着透光率减少呈先升高后降低的趋势,其它3种蕨的叶绿素相对含量均随着透光率减少而呈阶梯状增加的趋势。5种参试蕨光补偿点呈先下降后上升,线羽凤尾蕨在透光率6.25%环境下光补偿点达到最低,华南毛蕨在透光率1.56%环境下达到最低,其它3种蕨类的光补偿点均在透光率25.00%时达到最低。但最大净光合速率变化差异较大,其中蜈蚣蕨的最大净光合速率可达到参试蕨的最高值为8.33μmol·m^(2)·s^(1),乌毛蕨其次为7.85μmol·m^(2)·s^(1),其余3种蕨的最大光合速率均在5.50μmol·m^(2)·s^(1)以下。通过计算比较各指标的表型可塑性指数(PPI)和耐荫临界值(STT),评价了5种蕨类植物的耐荫性,普通针毛蕨和线羽凤尾蕨为耐荫蕨,华南毛蕨次之,乌毛蕨和蜈蚣蕨具有一定耐荫性;耐荫性强弱排序为普通针毛蕨>线羽凤尾蕨>华南毛蕨>乌毛蕨>蜈蚣蕨。

The shade-tolerance of Cyclosorus parasiticus,Blechnum orientale,Pteris vittata,Pteris linearis and Macrothelypteris torresiana in south China were researched.Indexes of growth and physiological were measured under four kinds of different light invironments（100%,25.00%,6.25%,1.56%）,including height,crown diameter,leaf number,chlorophyll contents and photosynthetic parameters.The results showed that as shadow treatment strengthened,the crown diameter of M.torresianaand P.vittata narrowed down as well as the quantity of leaf.The SPAD of C.parasiticus and P.linearis increased at first then decreased as euphotic index diminished.Meanwhile the others increased gradually.All the light compensation point of five ferns decreased firstly and then increased.The light compensation point of P.linearis reached the lowest under 6.25%light environment,while C.parasiticus touched the bottom under 1.56%light environment,and the others reached the lowest under 25.00% light environment.The Pmax changed a lot.P.vittata reached the highest point at about 8.33μmol·m^（2）·s^（1）,followed by B.orientale at about 7.85μmol·m^（2）·s^（1）,the others were blower 5.50μmol·m^（2）·s^（1）.Phenotypic plasticity index（PPI）and shade-tolerant threshold（STT）were used for shade-tolerance evaluation,and a comprehensive evaluation on shade-endurance abilities of five ferns was given according to membership function method.P.linearis and M.torresiana had good shade-endurance,C.parasiticus took the second place,B.orientale and P.vittata were the lowest,and the shade-endurance abilities of five ferns were ranked as M.torresianaP.linearisC.parasiticusB.orientaleP.vittata.