Analysis of Chloroplast Ultrastructure, Stomatal Characteristic Parameters and Photosynthetic Characteristics of ChlorophyllReduced Mutant in Brassica napus L.
Analysis of Chloroplast Ultrastructure, Stomatal Characteristic Parameters and Photosynthetic Characteristics of ChlorophyllReduced Mutant in Brassica napus L.
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发表时间：
2013
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通讯作者：
Xiao Hua-gui
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作者：
Xiao Hua-gui
【目的】研究B.napus L.自发叶绿素减少突变体NY的叶绿体超微结构、气孔特征参数、光合色素含量与光合特性的关系，探讨油菜黄化机理，为油菜育种实践提供理论依据。[方法]以油菜突变体NY、野生型NG、F1（NY×NG）和rF 1（NG×NY）为研究材料，对5叶期的心叶和倒三叶进行叶绿体超微结构观察、气孔特征参数调查、光合色素含量测定、光合特性测定和农艺性状调查。[结果]从叶绿体超微结构来看，NY突变体的黄心叶和黄绿心叶的叶绿体发育程度总体上比NG、F1（NY×NG）和rF 1（NG×NY）差; NY突变体心叶下表皮气孔保卫细胞叶绿体数减少约40%，而黄绿色叶片的气孔特征参数与野生型NG接近;突变体的叶绿素a、叶绿素b、叶绿素a+B、类胡萝卜素和净光合速率显著低于同期野生型和F1，rF 1在光合色素含量和组成以及光合特性方面表现出明显的差异，相应地，突变体生育期延迟，经济性状恶化，单株产量下降，但F1和rF 1的上述农艺性状和光合特性均恢复到正常水平。【结论】NY突变体是由叶绿体结构发育缺陷引起的叶绿素总量缺失型，叶绿体结构异常、基粒和基粒片层减少、叶绿素含量降低是导致NY突变体净光合速率降低、农艺性状较差的主要原因。
【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,rF1in content and composition of photosynthetic pigment as well as photosynthetic characteristics.Correspondingly,the growth period delayed,economic traits deteriorated and grain yield per plant decreased,which happened in the mutant,but the above agronomic traits and photosynthetic characteristics from F 1 and rF 1 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.