小麦黄化突变体光合作用及叶绿素荧光特性研究

Photosynthesis and Chlorophyll Fluorescence Characters of Xantha Wheat Mutants

对小麦自然黄化突变体及其突变亲本(西农1718)的叶绿素含量、光合速率及叶绿素荧光动力学参数进行比较分析.结果显示:(1)突变体金黄株、绿黄株、黄绿株的叶绿素含量均显著低于突变亲本,总叶绿素含量分别为突变亲本的17%、24%和58%,表明该突变体为叶绿素缺乏突变体;3个突变体叶绿素a与叶绿素b的比值(Chl a/Chl b)均小于突变亲本,而且突变体叶绿素含量越低,Chl a/Chl b比值越小,说明该突变体Chl a下降幅度大于Chl b.(2)金黄株净光合速率在孕穗期、开花期仅为突变亲本的5.7%、2.4%;绿黄株净光合速率显著低于突变亲本,为突变亲本的57.7%、43.3%;而叶绿素含量仅为突变亲本一半的黄绿株,其净光合速率接近突变亲本,表明该黄化突变体叶绿素含量在一定范围内单位叶绿素含量的光合效率较高.(3)突变体Fo均显著低于突变亲本;金黄株、绿黄株的Fm,Fv,qP,qN显著低于突变亲本;金黄株Fv/Fm比值(0.671)显著低于突变亲本.研究表明,叶绿素含量在一定范围内减少,未引起突变体叶绿素荧光动力学参数(Fo除外)显著改变,而当叶绿素含量较大程度减少时,这些荧光参数会急剧降低.

The chlorophyll contents,photosynthetic rates and chlorophyll fluorescence kinetic parameters of xantha wheat mutants and its parent （Xinong 1718） were comparatively studied. It was shown that （1） The total chlorophyll contents in golden, greenish-yellow and yellowish-green mutants were significantly lower than that of the parent, accounting for 17%,24% and 58% of that of the latter, and this indicated that the mutants were a chlorophyll-deficient mutants; the Chl a/Chl b ratios in the three mutants were lower that in the parent and the lower the chlorophyll contents in the mutants the smaller the Chl a/Chl b ratios,which indicted that in these chlorophyll-deficient mutants the Chla decreased more than the Chl b; （2） The net photosynthetic rates of golden mutant at the booting and flowering stages accounted separately for only 5.7 % and 2.4% of that of the parent and the net photosynthetic rate of green-yellow mutant at the two stages was significantly lower than that of the parent and accounted separately for 57. 7% and 43.3% of that of the parent;although the chlorophyll content of yellow-green mutants contained one half of that of the parent, its net photosynthetic rate approached to that of the parent, which indicated that in the mutant,the photosynthetic efficiency per unit chlorophyll kept higher within the certain limits of chlorophyll content; （3） The Fo in the mutants were significantly lower than that in the parent and the Fm,Fv, qP and qN in golden and greenish-yellow mutants were significantly lower than those in the parent;the Fv/ Fm in golden mutants （0. 671） was significantly lower than that in the parent,indicating that the chlorophyll content varied within certain limits and this decrease did not cause the chlorophyll fluorescence kinetic parameters （except Fo） to vary significantly and if the chlorophyll content decreased greatly these parameters would sharply decreased.