普通番茄四倍体与二倍体杂交的杂种不育性研究

以普通番茄的四倍体为母本与二倍体杂交时,花粉萌发、花粉管生长及双受精过程都正常;对受精的胚珠形态结构观察得知:4天前幼胚和胚乳发育正常,授粉后4天胚乳出现异常开始退化,5天时这种异常现象更明显,第7天胚乳已完全解体。幼胚在胚乳完全解体前发育正常,而胚乳解体后,幼胚也开始解体。所以普通番茄二倍体与四倍体杂交的杂种不育的原因,在于胚乳败育以及胚的死亡。     

栽培番茄×秘鲁番茄杂交后的胚胎发育

“北京早红”番茄(Lycopersicon esculentum)×秘鲁番茄(L.peruvianum)PI,128657中的8号株系杂交后杂种种子不能正常发育的原因观察。结果表明,杂种胚和胚乳发育缓慢。授粉后16天胚乳开始退化。杂种胚的分裂是随机的,没有经历正常的发育阶段。授粉后30天杂种胚开始退化,35天完全解体。授粉后4天有些珠被绒毡层出现增生。     

栽培番茄X秘鲁番茄杂交后的胚胎发育

"北京早红"番茄(Lycopersicon esculentum)X秘鲁番茄(L. peruvianum )PI,128657中的8号株系杂交后杂种种子不能正常发育的原因观察。结果表明,杂种胚和胚乳发育缓 慢。授粉后16天胚乳开始退化。杂种胚的分裂是随机的,没有经历正常的发育阶段。.授粉后30天杂种胚开始退化,35天完全解体。投粉后4天有些珠被绒毡层出现增生。     

栽培大麦×普通小麦杂种发育的胚胎学观察

对大麦与小麦远缘杂交时雌雄性核的结合及杂种胚和胚乳的发育情况进行了观察。大、小麦杂交时,可发生双受精作用、单受精作用,或受精过程失败。单受精作用发生的时间参差不齐。大小麦杂种胚的发育进程最初与大麦自交时情况相似。以后胚发育缓慢,并长期停留在原胚阶段。在授粉后12—15天,原胚发育达到高峰。仅有个别杂种胚在授粉后第18、19天进入胚分化,且胚分化不完善。同时,在整个发育过程中,原胚不时出现解体退化现象。杂种胚乳的发育仅在最初阶段形成若干游离核,此后胚乳组织转向退化。在授粉10天以后的子房中,未检查到胚乳或胚乳解体后的残留物。     

小叶杨与美杨种间杂交的胚胎发育和杂种胚珠的离体培养

1.观察了小叶杨(Populus simonii Carr.)和美杨(Populus pyramidalis Borkh.)人工杂交后从花粉粒萌发至胚分化完成的发育过程:1.大多数美杨花粉粒可以在小叶杨的柱头上萌发长出花粉管,花粉管在花柱中正常地生长并通过珠孔进入胚囊,于授粉后4—7天发生双受精作用,形成初生胚乳核和合子。胚乳的发育正常或不正常,后者表现为在游离核阶段的败育或胚乳细胞发育不良。胚在各个发育阶段尤其是球形胚和心形胚阶段,都可能败育,也可以正常发育成为分化完全的有效胚。2.将授粉后19天、22天、26天和29天含有不同发育阶段(心形期、鱼雷期、子叶伸长期)未成熟的杂种胚珠接种于人工培养基上,结果表明:1.M110培养基(1/2 MS+IAA 0.01毫克/升+BA 0.1毫克/升+蔗糖2%)是选用培养基中效果最好的;2.不同发育阶段杂种胚的胚珠可以离体培养成生长正常的小植株。     

春小麦早期胚胎发育进程及细胞融合(cytomixis)的观察

观察了小麦胚和胚乳初期的发育进程,得到如下结果:授粉后2小时,二个精子已分别进入卵核和极核;6小时,极核已经完成受精,卵核与另一精子的融合正在进行。授粉后24小时为二细胞原胚,6天时部分胚胎开始分化。授粉后3天,胚乳核开始形成细胞,至6天时,胚乳细胞充满胚囊。开花前充分发育的反足细胞授粉后开始解体,第4天已失去细胞结构,仅留下核仁和染色质团块,第8天几乎完全消失。在珠心、胚乳、子房壁和原胚以及分化胚的胚柄中都观察到细胞融合现象,而且在原胚附近出现较多。     

中棉×戴维逊氏棉胚胎发育的研究

以棉花栽培种中棉作母本,野生种戴维逊氏棉作父本进行杂交试验,并用中棉自交作对照,比较研究了杂交情况下花粉粒的萌发、花粉管的生长、受精作用及胚和胚乳的发育过程,得到以下结果:(1)中棉×戴维逊氏棉花粉粒的萌发及花粉管在异己花柱中的生长基本正常,有花粉管胚珠的频率约20％,为中棉自交的1/4左右;(2)在杂交情况下,有花粉管进入的胚珠基本上能实现受精;(3)杂种胚乳在授粉后7天发育异常,11天开始解体,16天才有部分胚珠的胚乳开始形成细胞壁;(4)杂种胚不分化或畸形分化,在授粉后11—22天坏死。     

小麦×大麦胚胎发育的研究——Ⅰ.小麦×大麦胚和胚乳发育的观察

本试验以206小麦为母本,二棱大麦旱燕3号和六棱大麦原早1号为父本进进杂交。结果表明,两个组合早期的胚胎发育基本上是正常的,前者成胚率为8.75%,后者为16.8%。胚乳核最早于授粉后3天开始形成细胞。当胚乳细胞充满囊后,很快就转入迅速解体,胚随即停止生长,没有能够进一步分化出器官来。胚乳于授粉15天后,几乎全部败育,胚亦相继夭亡。胚胎发育过程中的不正常现象普遍存在。主要是极核受精过程遭受破坏;合子和初生胚乳核发育停滞;原胚虽能正常发育而胚乳没有形成;胚乳细胞过早形成和迅速解体等。讨论了杂交不孕和胚乳败育的原因。同时,提出了幼胚离体培养的适宜时间。     

小麦×大麦胚胎发育的研究——Ⅰ.小麦×大麦胚和胚乳发育的观察

本试验以206小麦为母本,二棱大麦旱燕3号和六棱大麦原早1号为父本进进杂交。结果表明,两个组合早期的胚胎发育基本上是正常的,前者成胚率为8.75%,后者为16.8%。胚乳核最早于授粉后3天开始形成细胞。当胚乳细胞充满囊后,很快就转入迅速解体,胚随即停止生长,没有能够进一步分化出器官来。胚乳于授粉15天后,几乎全部败育,胚亦相继夭亡。胚胎发育过程中的不正常现象普遍存在。主要是极核受精过程遭受破坏;合子和初生胚乳核发育停滞;原胚虽能正常发育而胚乳没有形成;胚乳细胞过早形成和迅速解体等。讨论了杂交不孕和胚乳败育的原因。同时,提出了幼胚离体培养的适宜时间。     

普通小麦与球茎大麦杂交后受精及胚胎发育的细胞形态学研究

普通小麦(2n=6x=42)品种及其杂种F_1为母本与四倍体球茎大麦(2n=4x=28)杂交,发现属间杂交的受精过程和胚胎生长发育比小麦自交时缓慢。球茎大麦花粉给小表授粉后4小时精子进入卵接触卵核,6小时初生胚乳核开始形成。杂合子第一次有丝分裂和授粉后22小时胚乳核的分裂中出现染色体落后及微核,授粉后9天胚乳核出现解体现象,10天后幼胚局部细胞也出现解体。13天后胚囊成为空腔,已观察不到细胞轮廓。在北京田间于授粉后9—10日即须将幼胚离体培养。     

Investigation of Sexual Process in Interspecific Crosses Between Gossipium hirsutum and G. arboreum

The present investigation is the first of a series of cytological researches on inter-specific hybridization of cottons. The present report deals with the cytological behavior of sex and related cells revealed in crossing Gossipium hirsutum (female parent) with G. arboreum. Self-pollenated G. hirsutum served as control. The germination of pollen grains on the stigma and the growth of pollen tubes in the style and the entry of pollen tubes into the micropyles in crosses are in a fairly normal' manner when compared with controls. The percentages of pollen tubes entering ovules of the crossed and controls have no significant difference, being 48.2% in crosses and 54.7% in controls. Fertilization proceeds also normal in cross pollinated ovules. About 92.7% of pollinated ovules are found to have completed the fusion of sexual elements. It is thus: shown that the growth of foreign pollen tubes and fusion of female elements with foreign sperms are not the factors which cause failure in hybridization. The development of endosperm in crosses is abnormal. The number of free nuclei of hybrid endosperm is much smaller than that of controls; the formation of hybrid cellular endosperm is 6 or 7 days earlier than that of controls. The hybrid endosperm cells start to abort soon after their formation. About 14 days after pollination they become completely disintegrated. The hybrid embryo which thus far developed normally becomes arrested in its development and aborts also after that time. It may be concluded that the sterility of crosses between G. hirsutum and G. arboreum is primarily attributed to the abortion of hybrid endosperm. The sound development of the hybrids should be sought in the improvement nutrition of the hybrid embryo from resource other than their own endosperm.     

Cytological Studies on the Embryogenesis of Hybrids between Oryza sativa L.(Pennisetum sp.

(1) The pollen grains of Pennisetum can germinate normally on the stigma of rice and the pollen tubes can grow into the style and enter the embryo sacs. However, the process of double fertilization is slow and more or less abnormal and phenomenon of simple fertilization often occurs. (2) It has been found that in the majority of cases the development of the embryos is slow and stays long in the stage of globular embryos, thus, the differentiation of the embryos is very difficult and degeneration of the embryos appears many times. Simple differentiation was observed only in some embryos during 16–24 days after pollination. Normal differenting and developing embryos were not observed. The cause of the degeneration of the embryos is related to the state of endosperm development and also to the non-coordination of the genomes of both parents. (3) The development of the endosperm is abnormal. The change from the free nuclei into the cells in the endosperm is delayed as late as the 8th day after pollination. The whole endosperm tissue is composed of the cell masses which are quite different both in shape and function, a part of these endospemn cells lacks the ability to synthesize starch. The disintegration of the endosperm could be frequently observed during their development. (4) A lots of starch are accumulated in the nucellar cells near the antipodals, It is shown that there was some metabolic confusion resulted from the crossing in the embryo sacs. Based on the above mentioued results the authers consider that the failure of producing seeds by crossing is at least related to the nutrient condition which are essential for the development of embryos. If embryo culture technique is employed at the early stage of the embryo development the hybrid seeds could be obtained.     

The Histology of Seed Development following Crosses between Diploid and Autotetraploid Raspberries (Rubus idaeus L.)

Seed development was studied in crosses made between the diploidforms and autotetraploid mutants of two raspberry (Rubus idaeusL.) cultivars. Drupelet abortion did not appear to be causedby failure of fertilization; it occurred mainly between thefourth and eighth day after pollination, and manifested itselfas simultaneous cessation of growth in all tissues. In healthydrupelets at eight days after pollination, growth appeared tobe proceeding at similar rates in all the tissues except thatthe embryo seemed to be growing faster than the endosperm inthe most advanced crosses. Both diploid and tetraploid ovulesappeared to be more stimulated by pollen from tetraploid plants.Embryo differentiation differed according to the direction ofcross, especially in stunted embryos. Radicles tended to beabnormally large when diploid pollen was used and smaller thanusual with haploid pollen.     

芥菜型油菜与白菜正反杂交的胚胎学研究

利用荧光技术对芥菜型油菜(Brassica juncea)与白菜(B. pekinesis)种间正反杂交后花粉萌发和花粉管生长过程进行了观察。结果显示: 芥菜型油菜与白菜正交授粉后, 花粉在柱头上能正常萌发, 多数花粉管沿花柱到达胚珠完成受精, 且受精方式有珠孔受精、合点受精和中部受精, 少量花粉管生长不正常, 出现花粉管顶端膨大扭曲, 花粉管分支等异常现象; 反交授粉后, 花粉在柱头上萌发时柱头乳突细胞产生强烈胼胝质反应, 影响花粉管生长, 只有少量花粉管通过花柱到达胚珠完成受精。用石蜡切片技术观察了正反杂交后杂种的胚胎发育, 正交杂种胚胎发育较早, 胚和胚乳生长较正常, 杂种胚一般均能发育至成熟; 反交杂种胚发育至心型期便不能继续发育, 胚乳也停滞在游离核阶段并最终败育。综合分析 表明, 芥菜型油菜与白菜正反杂交都存在一定程度的受精不亲和性。     

芥菜型油菜与白菜正反杂交的胚胎学研究

利用荧光技术对芥菜型油菜（Brassica juncea）与白菜（B．pekinesis）种间正反杂交后花粉萌发和花粉管生长过程进行了观察。结果显示：芥菜型油菜与白菜正交授粉后,花粉在柱头上能正常萌发,多数花粉管沿花柱到达胚珠完成受精,且受精方式有珠孔受精、合点受精和中部受精,少量花粉管生长不正常,出现花粉管顶端膨大扭曲,花粉管分支等异常现象;反交授粉后,花粉在柱头上萌发时柱头乳突细胞产生强烈胼胝质反应,影响花粉管生长,只有少量花粉管通过花柱到达胚珠完成受精。用石蜡切片技术观察了正反杂交后杂种的胚胎发育,正交杂种胚胎发育较早,胚和胚乳生长较正常,杂种胚一般均能发育至成熟;反交杂种胚发育至心型期便不能继续发育,胚乳也停滞在游离核阶段并最终败育。综合分析表明,芥菜型油菜与白菜正反杂交都存在一定程度的受精不亲和性。     

Genotype effects of Brassica napus on its reproductive behavior after pollination with B. juncea

To investigate the cause of variation in the interspecific crossability of Brassica napus, three different genotypes were studied in respect of their reproductive behavior after pollination with B. juncea. There were great differences among maternal genotypes in allowing foreign pollen to germinate on and penetrate into their stigmas, leading to a wide diversity of interspecific fertilization. The division of the hybrid primary endosperm nucleus and zygote appeared normal in all combinations of crosses. While the abundant free nuclei of the endosperm developed properly and never became cellular, the embryos degenerated as early as 10 days after pollination when the cultivar Rucabo, which had the highest fertilization record with species of B. juncea, was involved. When 81007 was used as female parent, the endosperm grew a little but the embryo halted at the heart-torpedo stage. Lack of nourishment might be responsible for the observed embryo abortion. Among the sic hybrid combinations, the cross 84014A x Changyang hunagjie was the only one where endosperm tissue was observable and an abnormal embryo occurred prior to cellular endosperm formation. Apart from the three typical embryological features, significant variation was also demonstrated among each of the cross combinations. Genetic diversity appears to exist not only between varieties, but also within cultivars. In addition, methods for developing interspecific crossable lines are discussed.     

Fertilization and Embryo Development in Wheat x Maize Crosses

The fertilization and embryo development in crosses of hexaploid wheat “Kangxuan 9” X maize “SS 7700” were studied. Of 180 florets fi,ced after pollination 34(18.9%) had embryo and endosperm, 46(25.6%) had only embryo and 12(6.7%) had only endosperm. Percentages of single or double fertilization were higher than that in control (“Chinese Spring” X maize). The hybrid embryos and endosperms obtained were karyotypically unstable and characterized by rapid elimination of the maize chromosomes to produce haploid wheat embryos. The potentials for wheat haploid production and transfer of DNA segments, including transposable elements, from maize to wheat is discussed.     

On the Fertilization of Oryza sativa L. × Sorghum vulgare Pets.

1.The pollen germination of Sorghum vulgate appeared normal on the stigma of the Oryza sativa, but the pollen tubes grew slowly in the style. Some of the pollen tubes may become enlarged in their tips or sometimes bursting, while others have continued to grow and entered the embryo sacs. 2. The growth rate of the pollen tubes varied widely. A few pollen tubes were observed in the embryo sacs of the materials 2 hours after pollination, but most of them entered the embryo sacs much later. 3. The zygote associated with a paucity of endosperm nuclei was observed in the materials 1 day after pollination. The double fertilization and 8–12-celled proembryo associated with a number of the free nuclei of the endosperm appeared with a rather high frequency (10.3%) in the materials 3 days after pollination. Some of them are normal in appearance and others may show more or less abnormalities. 4. No division figure was found except in one single case in which mitoses have occurred in both the proembryo and the endosperm. It is most likely that in such case the proembryo and the endosperm if left intact might develop further. 5. A 80-celled embryo was the biggest one which appeared in the materials 5 days after pollination. In general, no cells were ever formed in the endosperm, except in one instance among the 7 days materials the endosperm became cellular in micropylar end. In all other cases the endosperm either ceased to develop early or disorganized. The disorganized endosperm materials are considered to be utilized by the embryo. 6. In certain instances the free nuclei of the endosperm were not distributed at random. They were not equal in size and might fuse into giant nuclelei. 7. The most striking feature is that in the embryo sacs, in which double fertilization or proembryo and endosperm have occurred, a dark stained pollen tube was commonly present. This fact leads us to the conviction that in general only if a healthy pollen tube entered the embryo sac, double fertilization can take place and further development can proceed. 8. In certain cases the protoplasm of the embryo cells appeared scanty. It is apparently that the normal metabolism of the embryo was disturbed owing to the lack of nutrient, and the death of the embryo ensued. 9. No differentiated embryo was observed and no mature seeds were produced. The materials fixed 12 days after pollination showed a variety of abnormalities and collapses. The authors believe that the failure of seed production of rice X kaoliang was primarily due to the fact that the pollen tubes in the style grew too slowly to reach the embryo sacs in time. The consequence is that the double fertilization took place only in a late stage while the male and female gametes may have already become unhealthy. In addition, in this late stage the stored starch in the maternal tissues having gradually disappeared, the nutrient supply to the embryo sac was therefore limited and the young embryo and endosperm were finally in starvation.     

Observation of Pollen Tube Behaviour and Early Embryogenesis Following Interspecies Pollination Between Actinidia deliciosa and A. arguta

The pollen tube behaviour in the style and early embryogenesis following interspecies pollination between Actinidia deliciosa No. 26 and A. arguta were observed by means of fluorescence and light microscopy. Pollen grains germinated on the papillate stigma and pollen tubes grew along the V-shaped open-type style. Pollen tubes showed slower growth and reached the ovules 50--60 hours later than those of the control. Several abnormalities of pollen tubes have been observed at the base of the style, including wave-like pollen tubes, pollen tubes with swollen or pointed tips, with variable diameters, and a few with irregular growth. Random deposition of callose along pollen tube wall and even the whole wall was observed. About 26.74 % of the ovules were successfully fertilized and developed into seeds, among them 68.50% of the seeds were normal and 31.50% were abortive. About 11.41% were empty seeds without embryo and endosperm. Unfertilized small ovule was 61.45 %. Normal seed and its embryo were smaller than those of the control. The development of embryo was of the Soland type. The endosperm was cellular. The zygote remained quiescent for about 12-15 days before it started to divide, eventually forming a cotyledonary embryo 50 days after pollination.