四倍体与二倍体白桦的光合特性比较

Photosynthetic Characteristics of Tetraploid and Diploid Betula platyphylla

以4年生四倍体白桦和二倍体白桦为试材,对其光合作用日变化、光响应曲线、CO2响应曲线和叶绿素荧光参数进行测定。结果表明:①四倍体和二倍体白桦均有光合作用"午休"现象,四倍体的全天最大净光合速率极显著高于二倍体(P<0.01),较二倍体提高了24.81%。②光饱和点、光补偿点和羧化效率等指标在两者之间的差异也极显著(P<0.01),四倍体较二倍体分别提高了9.41%、20.00%和25.19%。③四倍体叶绿素荧光参数中的PSⅡ中心非环式电子传递量子产额显著高于二倍体(P<0.05),较二倍体提高了13.28%,其他参数在两者之间差异不明显(P>0.05)。上述结果表明四倍体白桦的光合作用强于二倍体。

Diurnal variation of photosynthesis,light response curve,CO2 response curve, and parameters of chlorophyll fluorescence were determined using leaves of 4-year-old tetraploid and diploid Betula platyphylla as experimental materials.Results showed that the phenomena of midday depression of photosynthesis were observed in the tetraploid and diploid B.platyphylla.The maximum net photosynthetic rate（Pmax） of the tetraploid B.platyphylla was significantly higher than that of the diploid（P0.01） during the whole daytime period,with an increase of 24.81%.There were significant variations in light saturation point（LSP）,light compensation point（LCP）,and carboxylation rate（CE） between the tetraploid and diploid（P0.01）.The LSP,LCP,CE of the tetraploid were 9.41%,20.00% and 25.19% higher than that of the diploid respectively.There was significant variation in excitation energy capture efficiency of PSⅡ（ΦPSⅡ） between the tetraploid and diploid B.platyphylla（P0.05）.The ΦPSⅡ of tetraploid was 13.28% higher than that of the diploid.There was insignificant variation in other parameters of chlorophyll fluorescence（P0.05）.The photosynthesis of the tetraploid B.platyphylla is more active than that of the diploid.