为研究玉米干种子搭载返回式卫星后，叶片光合色素含量及叶绿体结构的变异，采用两种玉米自交系干种子：遗紫２４、遗１４１。每个系干种子分成两份，一份用作对照，另一份搭载于１９９６年１０月２０日发射的返回式科学实验卫星，飞行共１５ｄ，分别用分光光度计测定室内发芽后１３ｄ幼苗和田间播种后６０、７０、９０ｄ植株叶片丙酮提取液的吸收光谱。种子萌发后第４ｄ，剪取处理与对照同位置小区叶片，切成１ｍｍ２小块，经过前固定、后固定、洗涤、脱水、包埋，在超薄切片机上切片，用柠檬酸铅和醋酸双氧铀双染，在ＪＥＭ１００型电镜下观察照相。结果表明：空间诱变后，叶绿素ａ＋ｂ的含量比对照明显降低，其中叶绿素ｂ的下降幅度远大于叶绿素ａ，说明前者对诱变更敏感；空间诱变后，叶绿体的外形发生改变，出现长形、圆形、不规则变形虫形等类型。内部结构的变异类型主要有：叶绿体发育不完全，有的被膜出现缺刻；叶绿体内基粒垛数及单个基粒垛内类囊体数明显减少，甚至有的基粒片层模糊不清；基质片层扭曲，排列紊乱，常以模糊的基粒为中心呈辐射状排列；也有类囊体只沿叶绿体长轴平行排列，并不垛叠成基粒，一些类囊体肿胀，使得基质片层间距加大。处理与对照在维管束鞘细胞叶绿体结构上最明显? In order to study the variation of photosynthetic pigment content and chloroplast structure of dry corn seeds after returning to satellites, two kinds of maize inbred lines were used for dry seeds. Each line of dry seeds was divided into two parts, one for control and the other for the return-type scientific experimental satellite that was launched on October 20, 1996. The flight was for 15 days. The indoor germination on the 13th day after inoculation was measured by spectrophotometer and Absorption Spectra of Acetone Extracts from Plant Leaves at 60, 70 and 90 Days after Sowing. After the seeds were germinated, the leaves of the same plot were cut and cut into 1mm2 pieces at 4 days after the seeds were germinated. After fixed, fixed, washed, dehydrated and embedded, the slices were sliced ​​on an ultrathin microtome with lead citrate and bis Uranyl double staining, observed under the JEM100 electron microscope photography. The results showed that the content of chlorophyll a + b decreased significantly after space mutagenesis, and the decrease of chlorophyll b was much more than that of chlorophyll a, which indicated that the former was more sensitive to mutagenesis. After the spatial mutagenesis, the appearance of chloroplast changed, , Round, irregular deformation worm-shaped and other types. The main types of variation in the internal structure are: incomplete development of chloroplast and lack of envelopment of some of the membranous membranes. The number of basal pallets and the number of thylakoids in single basal pallets decreased significantly in chloroplast, and some basal lamina were vague. Laminar twist, disorderly arrangement, often fuzzy base grain as the center of the radial arrangement; also have thylakoid only along the long axis of the chloroplast arranged in parallel, not stack stacked into the base, some thylakoid swelling, making the stromal lamellae Increased spacing. The most obvious chloroplast structure of bundle sheath cells was observed in treatment and control.