Analysis of Chloroplast Ultrastructure, Stomatal Characteristic Parameters and Photosynthetic Characteristics of Chlorophyll-Reduced Mutant in Brassica napus L.
[Objective] In order to discuss the yellowing mechanism and provide a theoretical basis in rape breeding practice,the relationship between chloroplast ultrastructure,stomatal characteristic parameters,photosynthetic pigment content and photosynthetic characteristics of the spontaneous chlorophyll-reduced mutant NY in B.napus L.were studied.[Method] Taking the rape mutant NY,wild type NG,F1 (NY×NG) and rF1(NG×NY) as research materials,the heart-leaf and the flatten-leaf at five-leaf stage were used for chloroplast ultrastructure observation,stomatal characteristic parameters investigation,photosynthetic pigment content determination,photosynthetic characteristics measurement and agronomic traits investigation.[Result] In general,the chloroplast development degree in yellow heart-leaf and yellow-green flatten-leaf from mutant NY was worse than that of wild type NG,F1 (NY×NG) and rF1(NG×NY) from chloroplast ultrastructure; the chloroplast numbers of heart-leaf in a lower epidermis stoma guard cell from mutant NY was decreased about 40％,whereas the number in yellow-green flatten-leaf was close to that of the wild-type NG in stomatal characteristic parameters; the Chla,Chlb,Chl(a+b),carotenoids and the net photosynthetic rate of mutant were significantly lower than those of the same period of wild-type and F1,rF1 in content and composition of photosynthetic pigment as well as photosynthetic characteristics.Correspondingly,the growth period delayed,economic traits deteriorated and grain yieldper plant decreased,which happened in the mutant,but the above agronomic traits and photosynthetic characteristics from F1 and rF1 were restored to normal levels.[Conclusion] The mutant NY is one of total chlorophyll deficiency type caused by chloroplast structure developmental defects.Abnormal chloroplast structure,less grana and grana lamella and lower chlorophyll content are main reasons for mutant lower net photosynthetic rates and worst agronomic traits.
国家科技期刊平台
NSTL
万方数据
维普
