同源四倍体水稻与非洲栽培稻杂交的胚胎学观察

以同源四倍体水稻(Oryza sativa,2n=4x=48)和二倍体水稻(Oryza Sativa,2n=2x=24)为母本,以非洲栽培稻(Dryza glarri,2n=2x=24)为父本进行远缘杂交配组,对其杂交结实的胚胎学机理进行了研究。结果表明,非洲栽培稻的花粉粒能在二倍体水稻的柱头上萌发,但萌发频率仅为0．18％～0．56％,花粉管在花柱内的伸长速度比较慢,发生受精的频率比较低,因而二倍体水稻与非洲栽培稻杂交的结实率比较低。然而,非洲栽培稻的花粉粒在同源四倍体水稻的柱头上萌发频率高达12．81％～14．65％,花粉管在花柱内的伸长速度比较快,发生受精的频率比较高,因而同源四倍体水稻与非洲栽培稻杂交的结实率比较高。在同源四倍体水稻与非洲栽培稻的杂交中发现,其受精作用比较特殊,其中包括精细胞与卵细胞的单受精作用,精细胞与次生极核的单受精作用和正常的双受精作用,总受精率和总成胚率分别为7．49％～9．28％和6．61％～8．64％。     

同源四倍体水稻与非洲栽培稻杂交的效果

以4份同源四倍体水稻(Oryza sativa,2n=4x=48)和4份二倍体水稻(Oryza sativa,2n=2x=24)为母本,以4份非洲栽培稻(Oryza glaberrima,2n=2x=24)为父本进行远缘杂交配组,共配制32个杂交组合。研究结果表明,非洲栽培稻分别与亚洲栽培稻中的两种倍性水平的水稻品系进行杂交均表现出一定的可交配性,生殖隔离并不很严格。然而,不同倍性的亚洲栽培稻与非洲栽培稻杂交,其结实率表现出明显的差异。二倍体水稻与非洲栽培稻不容易杂交,其结实率比较低(0．32％—1．93％),而同源四倍体水稻与非洲栽培稻较容易杂交,其结实率比较高(1．22％—8．86％,)。由此认为,利用同源四倍体水稻为母本与非洲栽培稻杂交更容易将后者的遗传物质引入亚洲栽培稻。     

同源四倍体水稻与狼尾草杂交结实的胚胎学证据

在以6份同源四倍体水稻为杂交母本与狼尾草进行属间杂交中发现,其结实率达到0.84%～2.06%,而在以二倍体水稻为母本的属间杂交中却没有获得结实种子.利用激光扫描共聚焦显微技术对属间杂交结籽的特殊生殖现象进行了观察研究,试图寻找其杂交结实的胚胎学证据.结果表明,狼尾草的花粉粒不能在二倍体水稻的柱头上萌发,说明二倍体水稻与狼尾草的生殖隔离很严格,两者很难杂交.然而,狼尾草的花粉粒在同源四倍体水稻的柱头上能萌发,花粉管能在花柱中伸长并能将雄配子送入胚囊内与雌配子融合成受精卵.同源四倍体水稻与狼尾草的受精作用比较特殊,包括精细胞与卵细胞的单受精作用、精细胞与次生极核的单受精作用和正常的双受精作用,总受精率和总成胚率分别为6.36%～11.68%和4.11%～9.44%.试验结果为解释同源四倍体水稻与狼尾草杂交结籽的特殊生殖现象提供了有力的胚胎学证据.     

同源四倍体水稻光合特性初步研究

利用2份同源四倍体水稻和相应的二倍体水稻为试验材料,在大田试验和盆栽试验条件下对其光合生理特性进行了研究。结果表明,同源四倍体水稻生育后期(乳熟期)的光合速率高于相应的二倍体水稻;在土壤干旱条件下,与相应的二倍体水稻相比,同源四倍体水稻的光合速率表现出一定的优势,其剑叶的叶绿素含量、Fv/Fm和ФPSⅡ保持较高的水平。     

同源四倍体水稻雌雄配子体多态性的研究

同源四倍体水稻（２ｎ＝４ｘ＝４８）由于其细胞内染色体数的倍增而导致其生殖性状发生了明显的变化。在其雄配子体中存在着比较少的正常花粉粒（１３．３５％￣１７．４９％）和比较多的败育花粉粒（８２．５１％￣８６．６５％）。在败育花粉粒中包括典败,园败和染败花粉粒。在同源四倍体水稻ＡＰＩＶ的成熟胚囊内存在着正常蓼型胚囊（４３．０％）,退化型胚囊（３６．０％）和变异型胚囊（２１．０％）,在变异型胚囊中包括双卵     

稻芒及其在杂交后代表现的调查

芒在野生稻中是普遍存在的。该性状以防卫和种子传播的功能被自然选择。在栽培稻中 ,除了一些为防鸟兽类危害而保留下来的较原始有芒品种 ,芒成了农民极讨厌的性状。芒是稻种的一个遗传性状。《中国水稻》[1 ] “芒的遗传”中论述 :“在水稻品种中 ,芒为显性性状。在有芒品种 /无芒品种杂交组合中 ,F1 表现为有芒 ,F2 有芒与无芒的分离比例有 3∶1、 1 5∶1、 9∶7、 9∶6∶1、 63∶1(管相相等 ,1 946) ,由此可见控制芒的基因位点肯定不止一个 ,二个或三个基因参与作用的遗传情况也是常发生的 ,故国外学者也往往认为是三个基因的累加作用。…     

同源四倍体水稻与狼尾草杂交的效果

利用A P IV (4)、IR36(4)、紫血稻(4)、测64(4)、明恢63(4)、IR28(4)、测90(4) 和桂99(4) 等8 个同源四倍体水稻(Oryza sativa, 2n= 4x= 48) 为杂交母本, 以狼尾草(P ennisetum alopecuroides, 2n= 2x= 18) 为杂交父本进行杂交, 获得了实粒种子。但是, 在以A P IV (2)、测90(2) 和紫血稻(2) 这3 个二倍体水稻(Oryza sativa, 2n= 2x= 24) 为杂交母本, 以狼尾草为杂交父本的杂交组合中却没有获得实粒种子。在授粉后狼尾草的花粉粒能诱导杂交母本的子房发生明显膨大。在同源四倍体水稻中的子房膨大效应比二倍体水稻中的子房膨大效应更加明显。在以同源四倍体水稻为杂交母本的杂交组合中, 可以获得一些实粒种子, 但是, 如果在授粉前利用DH 溶液对同源四倍体水稻的去雄颖花进行处理后再授狼尾草的花粉粒则能获得更多的实粒种子。结果暗示由于同源四倍体水稻具有比较弱的有性生殖能力, 在远缘杂交中它们是比较好的杂交母本。     

栽培稻种间杂交改良云南粳稻品种研究

为引入非洲栽培稻的有利基因以丰富云南粳稻的遗传基础以达到培育高产、抗病、抗逆云南粳稻品种的目的,利用179个非洲栽培稻品种作母本与6个云南粳稻杂交,并用相应父本回交后形成F1、BC1F1、BC2F1、BC2F2群体,同时对滇粳优1号作轮回亲本的组合在BC2F1中每组合随机用5~10株回交至BC3F1。研究表明,F1及BC1F1的自交结实率为0,种间杂种不育是非洲栽培稻与亚洲栽培稻种间杂交最主要的生殖障碍;但回交至BC2F1自交结实率即达到7.9％, BC3F1的平均结实率为14.6％,在BC2F1选结实率在10％以上的植株自交1次,BC2F2的结实率即为42.8%,变幅15%~80%;表明杂种不育模式符合“单位点孢子体 配子体互作不育”。在BC2F2群体中,10.7％的组合的综合表现优于轮回亲本。大规模育种实践表明,通过两次回交,再自交2~3代,种间杂种不育的障碍基本可得到克服,并可引入非洲栽培稻的有利基因。     

不同倍性栽培稻与药用野生稻种间杂交不结实性的比较胚胎学观察

以栽培稻(Oryza sativa)品种L202二倍体（L202 2x）及其同源四倍体（L202 4x）作母本分别与药用野生稻（Oryza officinalis）杂交,比较了两个杂交组合的杂交结实性及影响结实性的杂种胚胎发育细胞学。两个杂交组合所取得的一致结果是：杂交授粉后30 d所有杂交小穗均干枯死亡,不能结实;种间杂交不结实的原因在于受精和杂种胚胎胚乳发育异常。两个杂交组合的受精和杂种胚胎胚乳发育虽然均存在双受精、单受精和未受精类型,但就受精率而言,L202 2x作母本的平均总受精率为59.45％,略高于L202 4x（54.87％）; L202 4x的单受精率（24.60％）则高于L202 2x的单受精率（15.30％）。两个杂交组合的杂种胚胎胚乳发育均严重异常,虽然在授粉后1 d形成小的球形胚;到授粉后3 d,胚胎发育停滞并开始解体;至授粉后5 d,只有二倍体杂交组合的极少数胚胎可发育到梨形胚时期,四倍体组合的胚胎则基本全部解体。双受精胚囊内胚乳发育更为异常,在授粉后1 d,游离胚乳核就开始解体退化,到授粉后3 d不能形成细胞化胚乳或细胞化过程异常。与L202 2x作母本的杂交相比,以L202 4x作母本所得杂种胚胎发育更为滞后,且退化严重,形成的游离胚乳核少,解体早,不能进行细胞化。因此,利用同源四倍体栽培稻与药用野生稻杂交获得种间杂种的难度更大。     

同源四倍体水稻花粉的发育特征

利用激光扫描共聚焦显微技术观察了同源四倍体水稻紫粳 4x花粉的发育过程及其败育时期和方式。在成熟花粉中正常花粉只占45.5％,还有54.5％的花粉在发育过程中发生败育。在小孢子母细胞减数分裂过程中出现了一些异常现象,如染色体不能正常配对、形成异常二分体及二分体分裂不同步等现象。绝大部分花粉败育发生在单核小孢子期和二胞花粉晚期。在败育花粉中典败花粉粒占21.4％,圆败花粉粒占5.0％,染败花粉粒占28.1％。导致紫粳 4x花粉败育的原因可能是由于其染色体数目加倍,在减数分裂过程中有些染色体不能正常配对,从而进行异常分裂造成的。     

Grain Protein Content of Interspecific Progenies Derivedfrom the Cross of African Rice (Oryza glaberrima Steud.) and Asian Rice (Oryza sativa L.)

Abstract

The protein contents of the grain of 50 interspecific progenies developed from the cross between WAB56-104, an Oryza sativa variety, and CG 14, an Oryza glaberrima line, were investigated. In contrast to the higher protein content of O. glaberrima than O. sativa on the average, the protein content of CG 14 was always lower than that of WAB56-104. However, judging from the average of three seasons, 72% of the interspecific progenies had a higher protein content than the mid-parent and 50% of them had a higher protein content than WAB56-104. Although the actual values of protein content of the interspecific progenies were significantly different among the seasons, a highly significant correlation was always observed in protein content between any two of the three seasons. Protein content therefore was considered character of each interspecific progeny though it was also affected by environment. A significant correlation was not observed between paddy yield and protein content in any season; several interspecific progenies showed higher protein content and paddy yield than the mid-parents. A low paddy yield is likely to be associated with high protein content through physiological regulation without a genetic linkage between the two traits. However, the results suggest that the transgressive segregation of protein content observed in the interspecific progenies is attributed not to this physiological regulation but to a certain mechanism to concentrate protein in grains with a genetic background.     

远缘杂交在水稻遗传育种中的应用

水稻种内基因资源的充分利用为我国粮食增产作出了巨大贡献。为进一步挖掘种间、属间及亚远缘物种的有利基因,维持栽培稻遗传多样性,实现水稻超高产、优质和多抗育种,本文综述了远缘杂交所涉及的分子机理及水稻远缘杂交育种的思路,概述了水稻种间和属间远缘基因资源的研究成果、远缘杂交障碍及克服途径、多种技术在水稻远缘杂交方面的发展概况等,为加快远缘物种基因资源在水稻育种上的应用提供参考。     

栽培稻种间近等基因系杂种育性研究

 为了研究亚洲栽培稻与非洲栽培稻种间杂种不育的遗传基础，以亚洲栽培稻品种WAB56-104为测验种与来自种间回交组合WAB56-104/CG14//WAB56-104///WAB56-104的14个种间近等基因系测交，对亲本及杂种的花粉及小穗育性研究表明，这14个近等基因系带有来自非洲栽培稻品种CG14的3个互不等位的配子消除位点和2个互不等位的花粉不育基因位点, 其中至少有2个配子消除位点未曾报道过。     

栽培稻种间近等基因系杂种育性遗传及其基因定位

 用粳型亚洲栽培稻品种WAB56-104与来自种间回交组合WAB56-/104/CG14∥WAB56-104///WAB56-104的3个栽培稻种间近等基因系杂交、回交，对3个BC1F1群体的花粉及小穗育性遗传研究表明，育性遗传符合单位点孢子体-配子体互作模型，来自非洲栽培稻的不育基因在与相同位点的亚洲栽培稻等位基因互作时，导致携带亚洲栽培稻等位基因的雌雄配子败育，而形成花粉及小穗的半不育，但本研究的3个组合中，并未导致所有携带亚洲栽培稻等位基因的雌配子完全败育，其作用介于配子消除与花粉灭杀之间。用微卫星标记对这3个群体的育性基因定位表明，它们都位于第6染色体短臂末端，但WAB450-2、WAB450-8携带的不育位点与紧密连锁的微卫星标记RM190、RM133共分离，且很可能与S1等位，而WAB450-7的不育基因则与位于相邻区间的RM253呈松散连锁，可能与WAB450-2、WAB450-8的育性位点不同。     

Relationship between Shoot Elongation and Dry Matter Weight During Submergence in Oryza sativa L. and O. glaberrima Steud. Rice Cultivars

Abstract

Rice plants are damaged by flash floods with a rapid increase in water level caused by a heavy rain. However, rice plants cope with the flash floods either by an “escape strategy” involving rapid shoot elongation or by a “quiescence strategy” involving surviving under water with minimal activity. As we found in previous experiments, Saligbeli cultivar adapted well to flash floods through rapid shoot elongation. To understand the vigorous growth process during submergence, we studied the relationship between shoot elongation and changes in dry matter weight (DMW) during submergence. O. glaberrima Steud. cv. Saligbeli and O. sativa L. cv. Ballawé and IR 49830-7-1-2-2 were used. Saligbeli and Ballawé exhibit shoot elongation, and IR 49830-7-1-2-2 exhibits flash-flood tolerance due to the presence of the Sub-1 gene. Twelve-day-old seedlings were submerged for 7 days and the plant length and DMW were measured. The plant length ratio of submerged to control plants in Saligbeli was higher than that of other cultivars during 2-6 days of submergence but IR 49830-7-1-2-2 shoot elongation was inhibited by submergence. In all three cultivars, the elongation of the developing leaf sheath conferred shoot elongation during submergence. The plant length of all submerged plants showed a strong positive correlation with DMW of the leaves developed during submergence. Submerged Saligbeli and Ballawé showed strong negative correlations between DMW of the leaves developed before and during submergence (r = –0.786 for Saligbeli and –0.772 for Ballawé , P < 0.05), suggesting that the enhancement of shoot elongation during submergence is accomplished by using dry matter of the leaves developed before submergence. However, the correlation was not observed in the submerged IR 49830-7-1-2-2. Further details from studies using isotopes are also needed to understand the plant growth during submergence.     

分离和纯化水稻(O.sativa)总信使RNA及其体外翻译

信使 RNA 是传递 DNA 遗传信息的工具,它也可以通过逆转录酶的催化合成互补 DNA(cDNA),用作分子杂交的探针,以分离特定的基因。本文选用10日龄水稻幼苗提取总 mRNA,52.6g 新鲜组织中获得6.5mg 总 RNA,根据 A260/A280=1.69,说明 RNA 中含极少量蛋白质。采用多聚尿苷酸-琼脂糖柱层析,从总的 RNA 中分离到88μg 总的 mRNA,免网织红细胞溶胶体外翻译体系产物表明,分离的 mRNA 具有生物功能。     

Comparative Embryological Studies on Infertility of Interspecific Hybridizations Between Oryza sativa with Different Ploidy Levels and O. officinalis

As maternal parents, diploid (L202-2x) and autotetraploid (L202-4x) of Oryza sativa cv. L202 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. There were no mature hybrid seeds obtained because all the hybridized spikelets died 30 days after pollination. The main reasons for no seed set were abnormal fertilization and development of the embryos and endosperms in the interspecific hybrids. There were double- fertilization, egg cell single-fertilization and non-fertilization in these crosses. Although 59.45% and 54.87% of hybrid embryos produced in the crosses of L202-2x/O. officinalis and L202-4x/O. officinalis, respectively, hybrid embryos ceased to develop or degenerated and plenty of free endosperm nuclei were in disaggregating state without developing cellular endosperms three days after pollination. Besides, some embryological differences in these two crosses were found, that is, the rate of double-fertilization and total rate of double- and single-fertilization in L202-2x/O. officinalis were higher than those in L202-4x/O. officinalis. The embryo and endosperm of hybrids developed more slowly, and embryos and free endosperm nuclei were more severely degenerated in L202-4x/O. officinalis than in L202-2x/O. officinalis. Five days after pollination, a few of embryos in L202-2x/O. officinalis developed into pear-shaped ones, however, embryos in L202-4x/O. officinalis were all degenerated. Therefore, it is more difficult to obtain interspecific hybrids by wide crosses between autotetraploid of O. sativa and O. officinalis.