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1.
M. Sedgley 《Euphytica》1979,28(1):25-35
Summary Results are presented showing number of pollen tubes in the pistil, and ovule penetrations in crosses involving the avocado varieties Edranol, Ryan, Hass, Reed, Talbot, Jalna, Fuerte, Bacon and Sharwil. Between 5% and 100% of the ovules in each cross were penetrated by a pollen tube. The female parent exerted more control than the male on numbers of tubes and ovule penetrations and the results for type A varieties were more consistent than those for type B varieties. Penetration of an ovule by two tubes was observed in all varieties except Reed and Fuerte and penetration of an ovule by three tubes was observed in the variety Edranol only. With the possible exception of the variety Bacon as female parent there was no difference between pollination with pollen from type A or B varieties. 相似文献
2.
Summary A microscopical investigation has been carried out to find the causes of the failure of the species cross between scaled and unscaled Rhododendrons species. It was found that pollen germination on the stigma and pollen tube growth in the style proceed normally, but that difficulties occur when the pollen tubes reach the ovary. A small number of pollen tubes enters an ovule, but only in a few cases is seed setting effected (2–4 seeds per fruit). The majority of the tubes do not reach an ovule; the tubes have often thickened tips or, when they continue growth, they start to coil without penetrating into an ovule.Samenvatting
Kruisingen tussen geschubde en ongeschubde rhododendronsoorten, een microscopisch onderzoek
Door middel van een microscopisch onderzoek is nagegaan waarom de kruisingen tussen geschubde en ongeschubde rhododendronsoorten mislukken.Gebleken is dat de kieming van de stuifmeelkorrels op de stempel evenals de groei van de pollenbuizen in de stijl normaal verlopen, maar dat de moeilijkheden optreden, wanneer de pollenbuizen het vruchtbeginsel bereiken. Een gering aantal pollenbuizen dringt in een zaadknop, hetgeen slechts in enkele gevallen (2–4 zaden per vrucht) tot zaadvorming leidt. Het merendeel blijft steken vóór de zaadknop; het buiseinde is vaak verdikt of er vormt zich een kluwen van de doorgegroeide maar niet in de zaadknop binnendringende pollenbuis. 相似文献
3.
The effect of cut style and placental pollination on fertilization efficiency was studied for compatible Aechmea fasciata plants. These alternative in vitro pollination techniques resulted in lower penetration rates of the ovules by pollen tubes in comparison to pollination on
the stigma. An explanation was found in the intervention of the normal pollination process,through which less pollen-pistil
interactions were built up. After cut style pollination the percentage of ovule penetration by pollen tubes increased when
a longer style part was left at the ovary. Probably fewer factors that control pollen tube growth are present in the lower
style part. Pollen germinated on the ovules after placental pollination but only rarely penetration of the micropyle by a
pollen tube occurred. Activation of the ovary, induced by in vivo prepollination for 6 hours, and pollination two days after anthesis did not increase the fertilization percentage. Grafting
a style with active growing pollen tubes to ovules on the placenta (placental grafted style pollination) resulted in a higher
fertilization percentage. Pollen tube growth through the style was essential for pollen tube guidance to the ovules and penetration
of the micropyle.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Summary The nature and process of ovular incompatibility in Gasteria verrucosa was studied. Using different crossing programs and following the pollen germination and ovule penetration histochemically, an ovular gametophitic incompatibility system based on two or more loci is affirmed. Pollen tubes after self-and cross-pollination penetrate the micropyle. Although the percentage of seed setting reached about 60% after cross pollination no clear differences could be seen between the germination and ovule penetration of cross and self pollen.In the ovules, multiple penetration of micropyles and a preference for the first position ovules was observed. Results of semi-compatible crossings and mixed crossings indicated a gametophytic two or more loci incompatibility system. Ovular incompatibility was manifested by the degeneration of the sporophytic ovular tissues. In Gasteria verrucosa the system of ovular incompatibility does not seem to be restricted to the ovule. 相似文献
5.
Differences in fruit-set success reputed to exist between Heveabrasiliensis genetic clones were verified by an analysis of breeding recordsfor the clones PB 5/51, RRIM 600 and PR 107. Although the bestfruit-set success was obtained with PB 5/51 following artificial (hand)pollination, this clonal trait was not reflected in terms of greater numbersof pollen tubes developing it the styles of hand-pollinated PB 5/51 femaleflowers. It was observed, however, that more pollen tubes reached theovules in PB 5/51 than in RRIM 600 or PR 107. Significantly, PB 5/51female flowers required fewer pollen tubes to effect penetration of all threeof its ovules. As fruit formation in Hevea is dependent on all threeovules of the flower being successfully fertilised, PB 5/51 female flowershave hence a greater propensity for successful fruit-set. In all the threeclones studied, the frequency distribution of female flowers with 0, 1, 2 or3 of the ovules penetrated by pollen tubes did not conform to binomialexpectations. Flowers with no ovule penetrated and flowers with all threeovules penetrated were greatly over-represented. One explanation for thisnon-random distribution is the existence of `receptive' female flowers thatfavour successful fertilisation whereas `non-receptive' flowers tend to remainunfertilised even when hand-pollinated. 相似文献
6.
G. Coppens d'Eeckenbrugge 《Euphytica》1990,48(1):17-23
Summary Pollen germination and tube growth were studied following compatible, incompatible and pseudo-compatible pollinations in chicory. Pollen germination begins 3 minutes after compatible pollinations. The earliest pollen tubes reach the ovary 17 minutes later. Many of the later germinating pollen tubes are arrested and burst at the stigma papillae. In the transmitting tissue inhibitional effects due to negative interactions between pollen tubes are frequently observed. Complete self-incompatibility results in total inhibition of germination. In case of pseudo-self-compatibility, some pollen germinate but germination and stigma penetration are delayed and often result in pollen bursting. There is no self-incompatibility reaction in the transmitting tract but if the pollen tubes reaching this tissue are relatively numerous, negative interactions between them occur as after compatible pollinations. An hypothesis is presented which attributes the negative interactions between pollen tubes to the diffusion of a substance from the growing pollen tubes. This substance would also provoke pollen bursting on the stigma. 相似文献
7.
Storage of avocado pollen 总被引:4,自引:0,他引:4
Margaret Sedgley 《Euphytica》1981,30(3):595-599
Summary Avocado pollen was stored at a range of temperatures and relative humidities (RH) for up to one year and the pollen was tested for viability in vivo.Pollen stored for one month was capable of germination on the stigma and penetrating the ovule when stored at 4°C with <1,23,55 and 75% r.h. and at -196°C with 0% r.h. Most pollen samples stored at 25 and -15°C at a range of r.h. would germinate on the stigma but none would penetrate the ovule.After one year of storage, pollen at 4°C and <1 and 23% r.h. would germinate on the stigma but would not penetrate the ovule. There was no germination of pollen stored at 4°C and 55 and 75% r.h. Only pollen stored at -196°C and 0% r.h. would penetrate the ovule, but thawing and refreezing once during the year destroyed the viability. 相似文献
8.
A gene action model to explain gametophytic self-incompatibility 总被引:1,自引:0,他引:1
Peter D. Ascher 《Euphytica》1966,15(2):179-183
Gametophytic self-incompatibility in flowering plants can be explained in terms of recent concepts of gene action. The S alleles may be assumed to be regulators which produce monomers of a dimer repressor controlling a high rate of growth operon in the pollen tube. Similarity between monomers in the style and pollen tube produce a functional dimer repressor which inhibits this operon. A low velocity growth operon yielding pollen tube growth typical of incompatible pollen tubes would function when the high velocity operon is inactive. 相似文献
9.
Summary A quantitative examination of pollen grain germination and pollen tube growth within the overy wall was made in selected wheat × tetraploid H. bulbosum hybridizations, to investigate the effect of the wheat and the H. bulbosum genotype on these characters. As expected, variation at the known crossability loci had no effect on pollen grain germination. The frequency of pollen tube penetration of the ovary wall was, however, severely reduced when the dominant alleles were present. Pollen tube penetration was nevertheless observed in 3 of the 110 ovaries examined of the non-crossable cultivar Highbury. The H. bulbosum genotype had a much smaller effect on these characters, but significant differences between the clones were observed in the numbers of pollen tubes initially penetrating the ovary wall. Although two H. bulbosum genotypes showed no significant differences in the number of ovaries with pollen tubes at the base of the ovule, significant differences in the frequency of fertilization were observed. The possible cause of this discrepancy is discussed.The frequency of fertilization in crossable wheat × H. bulbosum hybridizations was improved by the application of gibberellic acid within 10 minutes of pollination, and reduced by an increase in the ambient temperature from 20°C to 26°C. Fertilization following the pollination of non-crossable wheat genotypes was not affected by either of these factors. 相似文献
10.
Summary The ovary of Pelargonium species is composed of 5 carpels, each of which contains 2 ovules. Usually, one of the two ovules develops and the other shrivels. The developed ovule is either on the upper side or on the lower side in the carpel. Intervarietal or interspecific difference was observed with respect to the position of the developed ovules. In order to determine the mechanism of fertilization, the behaviour of pollen tubes was observed under the fluorescence microscope and the developmental process of ovules was anatomically examined by using two cultivars, Bourbon 4x (2n=154) and Prince Rupert (2n=22). In both cultivars, many pollen grains germinated on the stigmas, but pollen tubes which reached ovaries were few. Eventually only one tube could enter the ovule in each carpel. In Bourbon 4x the ovules which were penetrated by the pollen tubes were always the upper ones. In Prince Rupert about 70% of the total fertilized ovules were on the upper side. The dying off of embryos occurred rarely. It is concluded that the intervarietal difference in the rate of the upper ovules which develop is genetical and is determined by fertilization. 相似文献
11.
The applicability of ovule culture was examined in reciprocal crosses between the diploid species D. grandiflorum L. and the tetraploid cultivar D. hybridum ‘Galahad’. An interspecific hybrid plant of D. hybridum ‘Galahad’ × D. grandiflorum was obtained,and hybridity was confirmed by chromosome counting. The hybrid was different from the parents in flower color
and size but intermediate between the parents in leaf shape. The hybrid showed low pollen fertility and failed to produce
viable seeds by either self- or backcross-pollination using fertile pollen grains from its parents. The applicability and
efficiency of the ovule culture technique for genetic improvement of the genus Delphinium through interspecific hybridization between different ploidies is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Summary The self-incompatible pear cultivar Doyenne du Comice was selfed with the aid of the mentor pollen technique (self pollen mixed 1:1 with compatible pollen) and the pioneer pollen method (compatible pollen applied 14 h in advance of the self pollen). Observations on tube growth in the style showed that inviable methylated pollen was ineffective either as mentor or pioncer pollen, having no effect on the performance of the self pollen which stopped growing at about one quarter of the style from the stigma. Calculations made on the basis of the obtained data indicated that the viable untreated or irradiated pioneer and mentor pollen, the former somewhat better than the latter, aided the self pollen tubes to reach the base of the style. 相似文献
13.
海岛棉半配生殖品系有性过程的胚胎学观察 总被引:4,自引:0,他引:4
半配生殖品系VSg自交或以VSg作母本与海岛棉标准系3-79杂交,花粉能在柱头上萌发,花粉管能在花柱组织中生长并能进入胚珠到达胚囊。精核与极核融合、初生胚乳核分裂,以及胚乳游离核形成均表现正常,但精卵融合不同于3-79。突出表现在一部分胚囊中,进入卵细胞的精核迟迟不与卵核融合,未融合的二核(♀+♂)“合子”经过一段比3-79稍长些的“休眠期”后,各自独立分裂,形成各种类型的嵌合胚。 相似文献
14.
Pratik Satya 《Plant Breeding》2012,131(5):648-655
Use of interspecific hybridization in genetic improvement of kenaf (Hibiscus cannabinus), a multipurpose crop, is limited by low cross‐compatibility. Previous hybridization studies suggest that part of incompatibility barrier is prezygotic. Pollen germination, stigma receptivity and growth of alien pollen on kenaf pistil were studied using wild relatives of kenaf. Four wild and semi‐domesticated species, H. surattensis, H. acetosella, H. radiatus and H. vitifolius, were used as pollen donors in the present experiment. H. radiatus exhibited highest pollen germination (65.89%) on H. cannabinus stigma. For closely related species (H. surattensis, H. acetosella, H. radiatus), stylar incompatibility was noticed, while for distantly related species H. vitifolius, the incompatibility was stigmatic. Number of pollen tubes entering ovule of H. cannabinus pistil was higher for H. radiatus (1.30). Alien pollen growth and penetration of pollen tube through ovule were higher in species sharing same genome of H. cannabinus. High callose deposition was observed in incompatible crosses, suggesting a general mechanism for prezygotic incompatibility in Hibiscus section Furcaria. Callose deposition in incompatible crosses increased with time. 相似文献
15.
Summary In genetically-heterogeneous outcrossing species, there is the opportunity for selection based on the male gamete. Buckwheat (Fagopyrum esculentum Moench) is self-incompatible with one ovule per flower, so pollen competition at each ovule can be studied. The occurrence of selection among pollen parents was determined, as well as the relative importance of prezygotic and post-zygotic selection. Mixed pollinations from two donors produced nonrandom paternity, with one of the donors being favored about 2:1 on several females. Individual plants showed significant variation in the speed of pollen-tube growth. Therefore, prezygotic selection is likely to have occurred based on the speed of pollen tube growth. In single-donor pollinations, donors had equal success as expected in the absence of post-zygotic selection among donors. However, a significant male x female interaction was found, consistent with postzygotic selection against particular parental combinations. To test whether male fitness is reduced by increased allocation to seed filling during pollen production, large- and small-seeded lines were compared, both as pollen donor and as pollen recipient. The large-seeded line was better in both roles, thus there was no evidence that greater allocation to seeds reduced the quality of the pollen. 相似文献
16.
花粉中微管与花粉管伸长及其胞质颗粒运动的关系 总被引:2,自引:0,他引:2
采用SDS-PAGE分离花粉中的微管蛋白。并用间接免疫荧光技术观察到花粉管中存在微管,这些微管呈束状形成花粉管伸长方向分布。花粉培养在含不同微管解聚剂的培养液中,发现这些药剂对花粉萌发均有抑制作用,但其抑制的有效浓度不同。以植物微管特效解聚剂甲基氨草磷抑制的有效浓度为最低。用APM处理已萌发的花粉,还发现它能减缓花粉管中胞质颗粒运动的速度,甚至使运动停止。但这种抑制是可逆的。以上结果表明花粉管中存 相似文献
17.
玉米与摩擦禾、薏苡的杂交不亲和性 总被引:3,自引:1,他引:2
采用荧光显微技术, 对摩擦禾、薏苡花粉在玉米柱头上的萌发和生长过程进行了观察。摩擦禾花粉粒在玉米柱头上均能萌发, 花粉管在柱头中伸长并到达花柱基部, 且可将雄配子送入胚囊内, 玉米果穗顶端有受精结实痕迹, 说明摩擦禾与玉米的杂交障碍不是杂交不亲和, 而是胚囊不亲和或杂种衰亡。薏苡花粉粒在玉米柱头也能萌发, 花粉管能伸入花柱, 但玉米与薏苡杂交生殖隔离较摩擦禾严格, 杂交极其困难, 杂交障碍为胚囊不亲和或花柱不亲和。玉米与薏苡杂交时, 薏米花粉管能到达玉米花柱基部, 而川谷花粉管却在花柱中停止生长, 杂交障碍与薏苡种类有关。玉米与薏苡杂交的花粉管异常率高于玉米与摩擦禾杂交花粉管异常率, 反映了玉米与摩擦禾的亲缘关系较与薏苡近。 相似文献
18.
19.
Summary Flowers of Pisum sativum plants grown in the field and greenhouse were self-pollinated and pollinated with Vicia faba. Germination of pollen and pollen tube growth were slower in the Pisum x Vicia cross. About 2% fertile ovules in the field and 8% in the greenhouse were obtained from the Pisum x Vicia cross, compared to 26% and 48% for Pisum x Pisum. Development of the Pisum x Vicia embryo was normal in form, though much slower than the Pisum x Pisum embryo, and about the sixth day it began to collapse. The greatest difference between the two types of crosses was observed in the endosperm. While the Pisum x Pisum endosperm nuclei divided normally and endosperm developed throughout the ovule cavity and around the embryo, the Pisum x Vicia endosperm nuclei formed only scattered masses of densely stained nuclei which were not always in close proximity to the hybrid embryo. It was concluded that faillure of some ovules to develop following Pisum sativum x Vicia faba cross pollination was the result of slow germination of pollen and slow growth of the Vicia pollen tubes, with subsequent lack of fertilization. Collapse of fertilized ovules was associated with abnormal and limited development of the hybrid endosperm, possibly leading to lack of nourishment and eventual collapse of the hybrid embryo. 相似文献
20.
T. Hodgkin 《Euphytica》1977,26(2):401-408
Summary Brussels sprouts inbred plants, homozygous for the same recessive S-allele, were intercrossed in all combinations and the number of pollen tubes penetrating the stigmas of such crosses measured. The results of five such experiments showed that pollen as well as stigma is significant in determining the number of pollen tubes counted. It was also found that the capacity of a plant's stigmas to permit pollen tube penetration was independent of the capacity of its pollen to penetrate other plants' stigmas. Variation in pollen tube production between pollens of the plants tested was often greater than that between their stigmas. 相似文献