【作者】 欧立军；

【导师】 陈良碧；

【作者基本信息】 湖南师范大学 ， 植物学， 2008， 博士

【摘要】 标810S是怀化职业技术学院从温敏核不育水稻810S群体中发现的株叶形态与810S基本相同的淡黄绿叶色突变体。本研究以810S为对照,对淡黄绿叶色突变体标810S的光合特性以及杂交后代叶色和光合特性变化规律进行了研究,并利用SSR分子标记对突变基因进行了初步定位。主要结果如下:1、突变体标810S与野生型810S的光合色素含量存在显著差异。标810S的叶绿素a和b含量下降50%左右。叶绿素含量下降是标810S叶片呈淡黄绿叶色的根本原因。2、标810S的颖花数、柱头外露率和开花时间与对照基本相当,与恢复系D100和R96-1配制的杂交组合农艺性状与用810S配制的相应推广组合无明显差异,表明标810S可替代810S应用于两系杂交水稻,其淡黄绿叶色性状可应用于杂交制种田的不育系群体除杂,同时可根据幼苗期淡黄绿叶色性状植株的比例用于鉴定杂交组合中不育系的混杂率。3、弱光条件下标810S的光合速率低于810S,强光条件下标810S光合速率比对照高,且标810S在光强2400μmol·m^-2·s^-1以下没有光饱和点和“午休”现象。而810S在光强1500μmol·m^-2·s^-1达到光饱和点。标810S的CO₂补偿点低于对照,气孔导度大于810S。4、与810S相比,标810S的Fv’/Fm’、ΦPSⅡ和qP高,PSⅡ天线色素吸收光能并用于光合电子传递的量子产额较大,非环式电子传递速率、光能转换效率和原初光能捕获效率较高,NPQ较低,PSⅡ天线色素吸收的光能以热形式耗散的部分较少。5、标810S的PEPCaSe和NADP-ME的活性显著高于对照,分别是对照的189.94%和178.48%。6、标810S与正常叶色水稻杂交的F₂代群体其正常叶色与淡黄绿叶色植株的分离比例符合3:1的比值,表明淡黄绿叶色性状属于单基因隐性遗传。用标810S/日本晴的F₂群体进行SSR分子标记的连锁分析,获得了二个与该突变基因紧密连锁的SSR标记RM3838和18457,遗传距离分别为4.2cM和10.6 cM。根据RM3838和18457在水稻基因组上的位置,将该淡黄绿突变基因定位在第5染色体上。7、标810S的杂交后代淡黄绿叶色植株在黄色的程度上存在分离,叶绿素含量的变化范围为0.90-1.70 mg.g^-1FW。分离群体的光合特性存在差别,其中叶色最绿、光合色素含量最高的类型光合速率为28.38μmol CO₂·m^-2·s^-1,叶色最黄、光合色素含量最低的类型光合速率为21.27μmol CO₂·m^-2·s^-1,而叶色和光合色素含量为中间类型的光合速率高,最高达30.43μmolCO₂·m²·s^-1。综上所述,标810S的淡黄绿叶色是叶片中叶绿素含量下降所致。由于叶片中叶绿素含量比对照少,捕获光的能力降低,因此在弱光下标810S光合速率比对照低;而标810S在自然强光条件下,没有明显的光饱和点,这种高光效生理特点可能与其光合膜上电子传递速率高、PEPC活性高以及气孔导度大等有关。这种高光效生理特点可能是弥补叶绿素含量减少,使植株生长基本正常的根本原因,这也是淡黄绿叶色性状可用于杂交水稻育种的生理基础。淡黄绿叶色性状虽然为单基因隐性遗传,但杂交后代叶色黄绿程度存在差异,其光合速率也不尽相同。本文研究认为,以淡黄绿叶色较明显（不能过黄）、光合速率高、生长量大的植株作为不育系选育对象为宜。更多还原

【Abstract】 A mutant named Biao 810S was founded in thermo-sensitive genie male sterile rice 810S populations in Huaihua Vocational and Technical College.It has yellow green leaf,gets the normal growth and has the same leaf structure with 810S.In this research,compared with 810S,the photosynthetic characteristics as well as the ultrastructure and protein of chloroplast of this mutant were investigated,and a systematical analysis of agronomy attributes was also carried out.We have also mapped the causative gene of this mutant using SSR markers and discussed the principle of screening sterile strains from segregated populations of hybrid progenies.The main results are as follows:1、There were significant difference in the total photosynthetic pigment content between the mutant Biao 810S and wild type 810S. Compared with 810S,the total photosynthetic pigment content of Biao 810S was aabout 50%lower;which was the main cause of the yellow green leaf.2、The spikelet numbers,stigma exsertion rate and flowering time of Biao 810S were same as that of 810S.There were no significant difference of the agronomic traits between the the cross combination which came from the maintainers D100 and R96-1 and the combination from 810S.3、The photosynthetic rate of Biao810S was higher than 810S under strong light and lower under weak light.Biao 810S had no light saturation point and‘Midday depression’ phenomenon in some scope of intensity(2400μmol·m^-2·s^-1) while 810S got the light saturation point when the intensity was 1500μmol·m^-2·s^-1.Compared with 810S,the CO₂ compensate point of Biao 810S was lower while the stomatal conductance was highly increased.4、The Fv’/Fm’,ΦPSⅡand qP of Biao 810S were significantly higher than that of 810S,which indicated that the light energy conversion and primary light capture of photosystemⅡof Biao 810S were much higher than 810S.It also suggested that the quantum yield of PSⅡwhich was used to absorbing light and transporting photosynthetic electron was bigger and non cyclic electron transport was higher.At the same time,the NPQ of Biao 810S was much lower,which means that the portion of light intensity being dissipated in form of heat energy from PSⅡwas little.5、The activity of PEPCase and NADP-ME of Biao 810S were significantly higher than 810S,which were respectively 189.94%and 178.48%of that of 810S.6、The separate ratio of leaf color in the F₂ populations which came from Biao 810S and some other varieties was 3:1,through which the yellow green leaf mutant had been defined to be controlled genetically by single recessive gene.Further linkage analysis of rice SSR markers in F₂ populations（Biao 810S/Nipponbare） were carried out,from which two SSR markers-RM3838 and 18457 were obtained.Both RM3838 and 18457 were tightly linked to yellow green leaf mutant gene with genetic distances of 4.2 cM and 10.6cM,respectively.According to the position of this two markers,we located the mutant gene on chromosome 5.7、The hybrid offspring populations of Biao 810S/Nipponbare has separated in to groups by the different leaf colors,and the total photosynthetic pigment content changed from 0.9 to 1.70 mg.g^-1FW,so the photosynthetic characteristics and agronomic traits were also differentiated in to 3 groups:the group which was the best green and had highest photosynthetic pigment content got the photosynthetic rate at about 28.38μmolCO₂·m^-2·s^-1,the group which was the best yellow and had lowest photosynthetic pigment content got the photosynthetic rate at about 21.27μmolCO₂·m^-2·s^-1,while the photosynthetic rate of the group which was the intermediate type was the biggest,with the maximum value 30.43μmolCO₂·m^-2·s^-1.All the analysis indicated that the main cause of the yellow green leaf was the decline of the chlorophyll content.The photosynthetic rate of Biao810S was lower than 810S because of the fewer Chlorophyll Content and decreases in capacity of chloroplasts capturing lights of Biao 810S.But under strong light Biao810S got no light saturation point,this physiological characteristics of high photosynthetic efficiency might be related to high electron transport rate on the photosynthetic membrane, higher PEPC activity and increased stomatal conductance.This physiological characteristics might make up for the deficiency of chlorophyll so that the plant could grow normally,and this also the physiological basis for the breeding usage of this yellow green leaf.Although the yellow green leaf mutant had been defined to be controlled genetically by single recessive gene,here were differences in the yellow-green degree of leaf colour and photosynthetic rate of hybrid offsprings populations of Biao 810S/Nipponbare.As a result the plants which had obvious yellow green leaf color（but not to yellow）,high photosynthetic rate and larger growth increment were considered to be the breeding object of sterile line.更多还原