冠果草种子萌发过程的组织化学动态

冠果草的种子中没有胚乳,营养物质贮藏在胚中,其成分主要是淀粉和蛋白质。胚各部分的物质积累情况差异较大,子叶和下胚轴细胞中的淀粉粒、蛋白体数目多、体积大,胚芽和胚根分生细胞中则只贮藏少量的淀粉粒、蛋白体。在种子萌发过程中,胚各部分的淀粉粒逐渐解体,至二叶幼苗期全部消失。蛋白体的降解有严格顺序,远离胚芽的细胞中蛋白体降解较早,胚芽附近细胞中的降解较晚,而且胚芽细胞中还有新的蛋白体形成。单个蛋白体的降解     

植物贮藏蛋白体的形成与发育及其调控

植物贮藏蛋白体由质体、内质网及液泡发育而来。贮藏蛋白体的形成和发育受贮藏蛋白质组分,蛋白质多肽携带信号,植物凝集素及一些细胞器的调控。贮藏蛋白体是由单层膜包围的亚细胞结构,其主要成份是贮藏蛋白质,植酸、植物凝集素,一些酶及无机离子如K~+Mg~(2+)等。贮藏蛋白体的形成与发育研究受到了人们的注意。本文将介绍一些这方面的进展。一、贮藏蛋白体的形成与发育贮藏蛋白体被认为是由质体,内质网和液泡发育而来,更多的资料支持后两种观点。 1、质体Graham发现玉米贮藏蛋白体形成与细胞质膜有关,这些蛋白体有双层膜结构。Morton将它们称为蛋白质体。分离的蛋白质体能在体外合成贮藏蛋白质,     

水稻胚乳发育中淀粉体和蛋白体ATPase活性的动态变化

利用ATPase定位技术,对水稻品种(Oryza sativa L.cv．Minghui 63)胚乳细胞发育中后期淀粉体和蛋白体的ATPase活性进行了超微细胞化学定位。结果表明,在淀粉体内外膜上、淀粉粒间的通道上和淀粉体四周的无定形物上呈现显著的ATPase活性。蛋白体Ⅰ和蛋白体Ⅱ的膜上和四周的囊泡、小泡上均出现ATPase活性产物。另外,胚乳细胞的胞壁和质膜,糊粉层和亚糊粉层细胞的胞壁、质膜、细胞核和胞间连丝上也有定位的ATPase活性产物分布。根据ATPase活性产物分布特点,推测淀粉体内的网状通道是便于养分进入淀粉体内部的转运通道。淀粉体膜和蛋白体膜上的ATPase主要是为养分进入内部提供跨膜动力。     

水稻胚乳发育中淀粉体和蛋白体ATPase活性的动态变化

利用ATPase定位技术,对水稻品种(OryzasativaL.cv.Minghui63)胚乳细胞发育中后期淀粉体和蛋白体的ATPase活性进行了超微细胞化学定位。结果表明,在淀粉体内外膜上、淀粉粒间的通道上和淀粉体四周的无定形物上呈现显著的ATPase活性。蛋白体Ⅰ和蛋白体Ⅱ的膜上和四周的囊泡、小泡上均出现ATPase活性产物。另外,胚乳细胞的胞壁和质膜,糊粉层和亚糊粉层细胞的胞壁、质膜、细胞核和胞间连丝上也有定位的ATPase活性产物分布。根据ATPase活性产物分布特点,推测淀粉体内的网状通道是便于养分进入淀粉体内部的转运通道。淀粉体膜和蛋白体膜上的ATPase主要是为养分进入内部提供跨膜动力。     

赤霉素对蛋白质合成的调节控制作用

种子萌发时胚的生长需要营养物质。禾谷类的种子在胚乳中贮藏着丰富的养分。这些贮藏物质的动用主要受植物激素赤霉素(GA)的控制。GA是在胚中合成,经过盾片输送到胚乳周围的糊粉层细胞-GA发生作用的靶细胞。糊粉层组织由均一的、不分裂的、富含蛋白质的二到三层细胞组成,这些细胞对GA反应时合成多种水解酶如a-淀粉酶和蛋白酶。这些酶被分泌释放到胚乳中去,水解大分子贮藏物质淀粉和蛋白质等形     

黄瓜种子萌发过程中Ca~(2 )分布的变化

采用细胞化学方法 ,研究了黄瓜种子中贮藏Ca2 的分布特点及其在萌发过程中的变化动态。干种子的子叶细胞中贮藏有大量的蛋白体、油脂体 ,Ca2 沉淀颗粒大量分布于胞质、胞间隙以及细胞质膜上。大多数蛋白体中有 1至数个圆球形或椭圆体形含Ca2 的球状晶体。相比之下 ,胚芽和胚根细胞中Ca2 较少。种子萌发早期 ,子叶中的贮藏钙及晶体溶解释放出的Ca2 部分转运到生长发育中的胚芽和胚根中。随着萌发的继续 ,胚根和胚芽细胞中的Ca2 不会持续增多 ,反而下降     

黄瓜种子萌发过程中Ca^2＋分布的变化

采用细胞化学方法,研究了黄瓜种子中贮藏Ca^2 的分布特点及其在萌发过程中的变化动态,干种子的子叶细胞中贮藏有大量的蛋白体,油脂体,Ca^2 沉淀颗粒大量分布于胞质,胞间隙以及细胞质膜上,大多数蛋白体中有1至数个圆球形或椭圆体形含Ca^2 的球状晶体,相比之下,胚芽和胚根细胞中Ca^2 较少,种子萌发早期,子叶中的贮藏钙及晶体溶解释放出的Ca^2 部分转运到生长发育中的胚芽和胚根中。随着萌发的继续,胚根和胚芽细胞中的Ca^2 不会持续增多,反而下降。     

莲胚发育与核酸,蛋白质含量的变化

莲胚发育达到最大鲜重(开花后21d)前,胚轴和子叶的DNA,RNA都持续增长。开花13d后,蛋白、淀粉等贮藏物质显著积累,核酸增长速度加快。成熟胚轴的DNA和RNA含量很高,而子叶中积累大量的淀粉、可溶性糖和蛋白质。发育前期胚乳的生长速度较快,开花后16d左右鲜重和物质积累达到高峰。胚生长后期胚乳逐渐败育,贮藏物质和结构物质都减少,膨大的子叶逐步取代了胚乳的地位。 莲胚生物大分子物质含量的模式属于双子叶植物类型。讨论了莲胚细胞多倍化的问题。     

黄瓜种子萌发过程中Ca2+分布的变化

采用细胞化学方法,研究了黄瓜种子中贮藏Ca2+的分布特点及其在萌发过程中的变化动态.干种子的子叶细胞中贮藏有大量的蛋白体、油脂体,Ca2+沉淀颗粒大量分布于胞质、胞间隙以及细胞质膜上.大多数蛋白体中有1至数个圆球形或椭圆体形含Ca2+的球状晶体.相比之下,胚芽和胚根细胞中Ca2+较少.种子萌发早期,子叶中的贮藏钙及晶体溶解释放出的Ca2+部分转运到生长发育中的胚芽和胚根中.随着萌发的继续,胚根和胚芽细胞中的Ca2+不会持续增多,反而下降.     

拟南芥菜(Arabidopsis thaliana)子叶中蛋白体形成的超微结构和免疫电镜定位研究

本文对拟南芥菜(Arabidopsis thaliana)种子发育过程中贮藏蛋白的积累和蛋白体的形成进行了超微结构和免疫电镜定位的研究。常规超薄切片的电镜观察表明,在开花后第10天(10 DAF),高电子密度的蛋白质物质开始在子叶细胞的液泡中沉积。这一过程一直延续到种子接近成熟(14 DAF),这时液泡中充满了蛋白质物质,转变成为大的蛋白体。利用了该种植物主要种子贮藏蛋白之一的12 s球蛋白的单克隆抗体作为免疫探针,以蛋白质A-胶体金电镜技术对12 s种子蛋白进行了细胞内定位,证实了在液泡中积累的物质为种子贮藏蛋白。实验结果表明在拟南芥菜中,子叶细胞中的液泡是蛋白体的前体,肯定了蛋白体的发生起源于液泡的观点。本文还对应用胶体金电镜技术进行细胞内定位的某些问题作了初步探讨。     

濒危植物——长喙毛茛泽泻的雌雄配子体发育

长喙毛茛泽泻 Ranalisma rostratum stapf 小孢子母细胞的减数分裂过程为连续型,四分体为左右对称型。成熟花粉为三胞花粉。花药绒毡层为变形绒毡层。雌蕊由多数单室子房构成,每子房中含一具双珠被、薄珠心的倒生胚珠。胚囊发育为葱型。成熟胚囊中三个反足细胞退化;二个极核分别位于中央细胞的两端,其体积相差明显。这种极核分布可能与反足细胞过早退化有关。     

The Development of Male and Female Gametophyte in an Endangered Plant—Ranalisma rostratum Stapf (Alismataceae)

Ranalisma rostratum Stapf is a rare and endangered species． This paper deals with the development of its male and female gametophytes and probes the relationship between the process of reproduction and the cause which made this species endangered． The meiosis of microspore mother cells is successive cytokinesis and the microspore tetrads are isobilateral． Pollen grains are 3-celled when shed． The ovule is anatropous,bitegmic and tenuinucellate． The micropylar dyad cell usually desenerates soon after its formation, and the chalazal dyad cell develops into a Allium type embryo sac． During the development of embryo sac both polar nuclei are respectively located at the two ends of central cell,and they maintain this situation until the micropylar polar nucleus takes part in fertilization． Features of the embryo sac of Ranalisma rostratum Stapf are discussed．     

濒危植物——长喙毛茛泽泻的受精作用及胚和胚乳的发育

长喙毛茛泽泻Ranalisma rostratum Stapf的配子融合开始较早,但精核与极核融合速度较快。精核与珠孔极核融合后即移向胚囊合点端与另一极核再融合形成初生胚乳核。初生胚乳核第一次分裂后形成两个细胞,以后珠孔端胚乳细胞再进行游离核分裂,胚乳发育属于沼生目型。开花后两天,合子分裂,八分体呈4层,每层呈两个细胞方式排列胚胎发生属于石竹型。     

The Fertilization and the Development of Embryo and Endosperm in an Endangered Plant—Ranalisma rostratum Stapf (Alismataceae)

Ranalisma rostratum Stapf is a rare and endangered species． This paper deals with the fertilization and the development of embryo and endosperm in this plant．The embryogenesis is of Caryophyllad type and the development of endosperm belongs to Heobial type．Before fertilization,the two polar nuclei are located respectively at both ends of embryo sac. In most angiosperms with two polar nuclei,the polar nuclei may fuse eiher before fertilization to form a secondary nucleus or during fertilization called triple fusion． In Ranalisma rostratum Stapf, however, it is found that only in case when the micropylar polar nucleus is fertilized,it can move to the chalazal end and fuse with the chalazal polar nucleus．This phenomenon is very rare and the process must take more time to fulfil fertilization both polar nuclei． This feature of fusion of polar nuclei is therefore thought as a primitive character from the view of phylogeny．     

薏苡胚发育及贮藏营养物质积累的研究

薏苡（Ｃｏｉｘ ｌａｃｒｙｍ ａ－ｊｏｂｉ）胚发育分下列各期：棒形胚前的原胚期、棒形胚期、胚芽鞘期、１叶期、２ 叶期、３叶期、４ 叶期、５ 叶期及６叶期成熟胚。３ 叶期胚具１ 条不定根（种子根）,４ 叶期具２ 条,５ 叶期及成熟胚期具３ 条。不定根与胚根排成１ 纵行。营养物质最先在盾片细胞中积累。开花后９ 天的１ 叶期胚,在盾片、胚芽鞘及胚轴细胞中积累了淀粉,以后遍及成熟胚的各部分。淀粉粒含量与器官发生及生长顺序成正相关,但发育后期,盾片细胞内的淀粉粒含量下降。开花后１０ 天,盾片细胞中形成含晶体的蛋白质体,晶体含蛋白质及植酸钙镁。以后,这种蛋白质体增多、增大。同时,又形成不含晶体的蛋白质体。一定时期,含晶体的蛋白质体消失,不含晶体的蛋白质体增多,直到胚成熟。开花后１３ 天,胚芽鞘上部细胞形成蛋白质体。以后遍及成熟胚的各部分,器官发生越早,所含蛋白质体越多、越大。开花后１０ 天,盾片细胞中产生了脂体,成熟胚的盾片细胞,含有大量的脂体。还观察了胚发育各期与颖果及盾片长度的对应关系     

Studies on Embryo Development and Deposition of Storage Reserves in Coix lacryma-jobi

Embryo development in Coix lacryma-jobi is classified into the following stages: proembryo before club-shaped, club-shaped, coleoptilar, I-leafed, 2-1eared, 3-1eared, 4-1eared, 5-leafed and 6-leafed (mature embryo). The 3-, 4-, 5-leafed embryos have 1, 2 and 3 adventitious roots (seminal roots) respectively, and the matrue also has 3. These seminal roots are arranged in a longitudinal row parallelling with the radicle. The storage reserves first deposit in the scutellar cells. 9 days after anthesis (l-leafed stage), the starch grains are accumulated in cells of scutellum, coleoptile and mesocotyle. When the embryo matures, starch grains are deposited throughout its cells. The increase in size and amount of starch grains correlates with the initiation and growth order of the embryonic organs. But the amount in the scutellar cells decreases from later to mature stage. 10 days after anthesis (2-leafed stage), protein bodies containing crystals, of protein and phytin are present in the scutellar cells. They subsequently become larger and abundant druses. At the same time some protein bodies without crystals are also formed. Later, the protein bodies containing crystals disappear, while those without crystals increase until the embryo matures. 13 days after anthesis (3- leafed stage) protein bodlies are formed in the upper coleoptile cells. Protein bodies are rich in the cells of mature embryo, but the earlier the organ of embryo occurs, the more and the larger protein bodies it contains. 10 days after anthesis, lipid bodies appear in the scutellar cells and increase in size and quantity rapidly as the embryo develops. The correlation of the length of caryopsis and scutellum with embryo development is also observed.     

Fine structural observations of embryo development inPelargonium XHortorum bailey: with normal and mutant plastids

Summary The ultrastructural changes in the cotyledon, radicle and suspensor haustorium ofPelargonium, containing either normal or mutant plastids, are investigated from the heart stage of embryogenesis to the mature seed. The fine structure of parenchymatous cells from the cotyledon and radicle is essentially similar whereas that of the suspensor haustorium is very different.The cotyledon and radicle develop into one massive storage tissue possessing numerous lipid and several protein bodies per cell, and well developed starch grains. The suspensor haustorium has no storage function, rather it acts as a transitory tissue which dies off as the seed matures. The extensive chloroplast development suggests that, in addition to its traditional role, the suspensor haustorium also acts as a photosynthetic booster for the developing embryo.The development of surviving mutant embryos is similar to normal ones except that in cotyledon and radicle cells plastids develop only to vesicles, which associate into loose prolamellar bodies and sometimes small fenestrated thylakoids, and in the suspensor haustorium cells, only to small compact grana.     

十种濒危植物的种群生态学特征及致危因素分析

从保护生态学的观点出发,对10个濒危植物的地理分布、生境条件、种群数量动态、空间分布格局、种间关系、种群的生命表、生殖力表、有性生殖、无性繁殖等种群生态学特征进行了综合分析。论述了濒危植物以光合、蒸腾、呼吸为主的生理生态学规律;预测种群数量动态的Leslie矩阵、刻画种群空间分布格局的模型、刻画种群生长和数量增长的Logistic方程和多元回归模型所反映出的生态学特征。分析了濒危植物种群动态、发展趋势以及在内外因素作用下的生态学特征和过程。针对濒危植物保护研究存在的问题,从生态学角度对我国未来濒危植物保护研究应注意的问题提出了建议。     

Seed Structure and Localization of Reserves inChenopodium quinoa

The three areas of food reserves in quinoa seeds are: a largecentral perisperm, a peripheral embryo and a one to two-celllayered endosperm surrounding the hypocotyl-radicle axis ofthe embryo. Cytochemical and ultrastructural analysis revealedthat starch grains occupy the cells of the perisperm, whilelipid bodies, protein bodies with globoid crystals of phytin,and proplastids with deposits of phytoferritin are the storagecomponents of the cells of the endosperm and embryo tissues.EDX analysis of the endosperm and embryo protein bodies revealedthat globoid crystals contain phosphorus, potassium and magnesium.These results are compared with studies on other perispermousseeds published to date.Copyright 1998 Annals of Botany Company Chenopodium quinoa,EDX analysis, phytoferritin, phytin, protein bodies, quinoa, seed structure, seed reserves, starch grains.