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运用常规石蜡切片法和细胞学压片法,对焕镛木[Woonyoungia septentrionalis (Dandy) Law]小孢子发生、雄配子体发育以及花粉萌发进行观察分析.结果显示:焕镛木花单性,雄花的雄蕊多数、离生,每一花药具4个花粉囊,花药壁5~7层.腺质绒毡层具1~2层细胞;小孢子形成时胞质分裂方式为修饰性同时型;四分体排列方式以四面体型为主,并有交叉型和左右对称型,偶见T型和直线型;成熟花粉粒为二细胞型花粉粒.小孢子发生和雄配子体发育过程中存在变形及败育现象.花粉萌发率为79.89%~80.62%.结合焕镛木花粉粒数目和萌发率的分析认为,雄配子体发育中的败育不是影响焕镛木濒危的主要因素. 相似文献
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利用常规石蜡切片法和细胞学压片法,对异型花柱植物滇丁香的长花柱型植株的小孢子发生、雄配子体发育及花粉萌发进行观察。结果表明:(1)长花柱型滇丁香具5枚花药,花药4室。(2)花药壁由1层表皮、1层花药内壁、2层中层和1~3层绒毡层组成;花药壁发育方式为基本型,绒毡层类型为腺质绒毡层。(3)小孢子母细胞减数分裂的胞质分裂为同时型,四分体排列方式为四面体型,偶有左右对称型;不同药室间小孢子母细胞减数分裂不同步。(4)成熟花粉粒为二细胞型。(5)小孢子发生和雄配子体发育过程正常,表明长花柱型滇丁香属于发育正常的两性花。(6)授粉4h后,长花柱型滇丁香的花粉在长、短两种花柱柱头上的萌发率分别达(91.8±1.6)%和(93.2±1.1)%,且两者间无显著性差异(t=1.585,df=8,p=0.152),表明长花柱型滇丁香的成熟花粉粒在长、短两种花柱柱头上的萌发均正常。 相似文献
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小盐芥小孢子发生和雄配子体发育研究 总被引:4,自引:4,他引:0
在显微水平上研究了小盐芥的小孢子发生及雄配子体发育过程,以及不同阶段与花蕾外部形态的相关性.本实验报道的小孢子发生及雄配子体发育的研究结果表明:雄蕊为四强雄蕊,每个花药具4个花粉囊.小孢子母细胞减数分裂属同时型,小孢子在四分体中的排列方式属四面体型.成熟花粉粒属3-细胞型,有3个萌发沟.花粉囊壁发育属双子叶型,由4层细胞构成——表皮、药室内壁、中层和绒毡层.绒毡层为腺质绒毡层.植株花蕾肉眼可见时,雄性孢原细胞开始分化.花蕾露白即蕾长1.1~1.7 mm时,形成成熟的雄配子体,即3-细胞花粉粒. 相似文献
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在显微水平上对丹参小孢子发生和雄配子体的发育过程及其与不同发育阶段花蕾的外部形态的相关性进行了研究。结果表明:丹参有2枚雄蕊,每个花药具2个花粉囊.小孢子母细胞减数分裂属同时型,小孢子在四分体中的排列属四面体型。成熟花粉粒属3细胞型并有6个萌发沟。花粉囊壁发育属双子叶型,由4层细胞构成,即表皮、药室内壁、中层和绒毡层。绒毡层细胞为腺质,二核。植株花蕾肉眼可见,大小在1~1.5mm时雄蕊孢原细胞开始分化;花蕾长至9~12mm。即从钟型花萼的钟口肉眼可见乳白色花瓣时.形成成熟的雄配子体,雄配子体具有3细胞的花粉粒。 相似文献
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采用常规胚胎学方法,对香港木兰(Magnolia championii Benth.)小孢子形成及雄配子体发育过程进行了研究。结果显示,香港木兰花药具4个小孢子囊,小孢子囊壁5—6层,其中腺质绒毡层1—2层;小孢子减数分裂时胞质分裂方式为修饰性同时型,四分体排列方式为四面体型或左右对称型,偶为交叉型,成熟花粉粒为二细胞型。在次生造孢细胞、小孢子母细胞、四分体时期都会出现败育,且在很多成熟花药中全部是败育的单核花粉。PAS染色后发现,相对正常发育的小孢子囊,在这种小孢子囊壁中仍有大量淀粉粒残留,可能是药隔中的营养物质不能及时从药隔组织转移到小孢子囊壁以供给小孢子发育所需的营养,使整个药室内的小孢子发育都停滞在单核期。通过不同生境植株花粉萌发率的对比,推断空气湿度是影响香港木兰小孢子正常发育的一个重要因素。 相似文献
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采用石蜡切片法对观光木(Tsoongiodendron odorum Chun)的小孢子发生和雄配子体发育进行了解剖学研究.观光木的花药由花药原基发育而来,具4个小孢子囊,花药壁由表皮、药室内壁、2~3层中层和1~2层绒毡层组成.中层在小孢子四分体时期开始解体,最终消失;绒毡层为腺质绒毡层,细胞具1~2核,在花药发育过程中不断分泌各种物质,提供小孢子发育,直到花粉成熟绒毡层才自溶消失.初生造孢细胞分裂形成次生造孢细胞,次生造孢细胞再转化为小孢子母细胞,小孢子母细胞减数分裂的胞质分裂为修饰性同时型,四分体排列方式为交叉型、对称型或"T"型(极少),成熟花粉粒二细胞型,开花时散出.观光木的成熟花粉粒存在严重的败育现象. 相似文献
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利用常规石蜡切片技术对柠条锦鸡儿小孢子发生及雄配子体发育的过程进行了观察,为柠条锦鸡儿生殖生物学提供基础资料。结果表明:(1)柠条锦鸡儿雄蕊花药4室,花药壁完全分化时,由外到内依次是表皮、药室内壁、中层和绒毡层,花药壁发育为基本型;表皮细胞1层,发育过程中始终存在;药室内壁在花药成熟时形成带状纤维层加厚;幼小花药壁的中层1~2层细胞,在花药发育成熟时退化消失;绒毡层1层细胞,腺质绒毡层,花药成熟时消失。(2)小孢子母细胞减数分裂过程中的胞质分裂为同时型,产生四面体型和左右对称型小孢子。(3)成熟花粉粒为二细胞型,扫描电镜下观察其成熟花粉粒为圆球形,外壁近光滑。(4)花粉母细胞分裂后形成的四分体小孢子中出现多核仁现象,核仁数在2~6个范围变化,推测这可能和末期Ⅱ核仁融合的不彻底有关。研究发现,柠条锦鸡儿小孢子发生和雄配子发育过程没有发现异常现象。 相似文献
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Lidiya V. Kovaleva Alla Dobrovolskaya Alexander Voronkov Viktor Rakitin 《Journal of Plant Growth Regulation》2011,30(1):64-73
The time courses of 1-aminocyclopropane-1-carboxylic acid (ACC) content and ethylene production in developing anthers of petunia
fertile and sterile lines and the effects of exogenously applied ethylene and an inhibitor of ethylene action, 2,5-norbornadiene
(NBD), on male gametophyte development and germination were investigated. Fertile male gametophyte development was accompanied
by two peaks of ethylene production by anther tissues. The first peak occurred during microspore development simultaneously
with degeneration of both tapetal tissues and middle layers of the anther wall. The second peak coincided with maturation
and dispersal of pollen grains. The mature pollen is characterized by a high ACC content (up to 300 nmol/g). Exogenously applied
ethylene (1–100 ppm) induced degradation of gametophytic generation at the meiosis stage. NBD completely inhibited anther
development at the early stages of its development and delayed anther dehiscence. In anther tissues of the petunia sterile
line, tenfold higher ethylene production was observed at the meiosis stage compared to that in fertile male gametophytes and
this correlated with degeneration of both microsporocytes and tapetal tissues. In vitro male gametophyte germination was accompanied
by an increase of ethylene production, whereas NBD completely blocked male gametophyte germination. These results suggest
that ethylene is an important factor in male gametophyte development and germination. 相似文献
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L. V. Kovaleva G. V. Timofeeva G. B. Rodionova E. V. Zakharova V. Yu. Rakitin 《Russian Journal of Developmental Biology》2013,44(2):69-77
We investigated dynamics of the content of 1-aminocyclopropane-1-carboxylic acid (ACC) and ethylene production in male gametophyte development and germination in fertile (self-compatible and selfincompatible) and sterile clones of petunia. Fertile male gametophyte development was accompanied by two peaks of ethylene production by anther tissues. The first peak occurred during the microspore development simultaneously with the degeneration of both the tapetal tissues and the middle layers of the anther wall. The second peak coincided with dehydration and maturation of pollen grains. In the anther tissues of the sterile line of petunia, tenfold higher ethylene production was observed at the meiosis stage compared with that in fertile male gametophytes. This fact correlated with the degeneration of both microsporocytes and tapetal tissues. Exogenously applied ethylene (1–100 ppm) induced a degradation of the gametophytic generation at the meiosis stage. According to the obtained data, ethylene synthesis in germinating male gametophyte is provided by a 100-fold ACC accumulation in mature pollen grains. The male gametophyte germination, both in vitro, on the culture medium, and in vivo, on the stigma surface, was accompanied by an increase in ethylene production. Depending on the type of pollination, germination of pollen on the stigma surface and the pollen tube growth in the tissues of style were accompanied by various levels of ACC and ethylene release. The male gametophyte germination after self-compatible pollination was accompanied by higher content of ACC as compared with the self-incompatible clone, whereas, after the self-incompatible pollination, we observed a higher level of ethylene production compared with compatible pollination. For both types of pollination, ACC and ethylene were predominantly produced in the stigma tissues. Inhibitor of ethylene action, 2,5-norbornadiene (NBN), blocked both the development and germination of the male gametophyte. These results suggest that ethylene is an important factor in male gametophyte development, germination, and growth at the progamic phase of fertilization. 相似文献
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The low fertility of naked seed rice (NSR) was investigated by the following observations: somatic chromosome constitute, behavior of pollen mother cells (PMCs), the germination of mature pollen grains, the development of male and female gametes and the structure of the anther opening. The results indicated that somatic chromosomal number was 2n = 24, behavior of PMCs were normal and most of pollen grains could regularly develop further to mature male gametophytes in NSR. And dehiscence chamber and thickened endothecium cell (TEC) in numerous anthers of the NSR were developed abnormally after dicaryotic phase, result in few anthers complete opening and most partly opening or failure to opening, therefore much fewer of pollen grains attach on the stigma as compared with normal variety. Furthermore most of embryo sacs possessed abnormal structure and were sterile. All of above illustrated that the failure of the anther opening and the abortion of female gametophyte were main factors controlling the low seed-setting rate of the NSR. 相似文献
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B. Phuangrat N. Phironrit A. Son-ong P. Puangchon A. Meechai S. Wasee W. Kositratana P. Burns 《Tropical plant biology》2013,6(4):210-216
The quality and quantity of pollen from three types of flowers; elongata, reduced elongata and staminate from the commercialized Thai papaya cultivar ‘Khak Nual’ were determined using pollen morphology, pollen physical characters and pollen development processes. Pollen development progressed at the same pace in the three types of pollen-producing flowers and was consistent with pollen development in many angiosperms. Pollen morphology showed that papaya pollen grains are tricolporate, with three apertures, and there is no significant difference in diameter (25.18–25.72 μm) and weight (11.76–15.45 ng) among pollen sources. The staminate flower shows the lowest amount of pollen, with 12,368 pollen per anther, but higher viability and germination rates of 95.53 % and 53.64 %, respectively. In contrast, the elongata type shows the highest amount of pollen grains with 14,884 pollen per anther and the lowest viability and germination rates, 93.06 % and 46.33 % respectively. The physical characteristics of pollen grains from reduced elongate and elongate flowers are similar. Reduced elongate flower type can donate pollen without self-pollinating. 相似文献
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丹参雄性不育系Sh-B的鉴定与花粉发育过程的解剖学研究 总被引:1,自引:0,他引:1
在显微水平上对新发现的丹参雄性不育系Sh-B花药发育过程进行了解剖学观察,并对其花粉活力和结实率进行了鉴定。结果显示:根据花器官及花药的形态、大小以及花丝的长度,可以将Sh-B不育株分为3个不育类型,即Sh-B1、Sh-B2和Sh-B3。这3种不育类型均属于雄性不育,其花丝不到正常可育株的1/2,花药干瘪而瘦小,内无花粉粒或花粉无活力;其根、茎、叶以及种子形态结构与正常可育植株基本相似。产生雄性不育的主要原因有:花粉囊药室内壁纤维层加厚,影响花药壁开裂;小孢子母细胞周围不产生胼胝质或产生的胼胝质很少;绒毡层细胞延迟解体;花粉粒畸形。在其花药发育的小孢子母细胞时期、四分体形成前期、单核期、双核期均可能产生雄性不育的小孢子或花粉粒。 相似文献
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Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations.Rice (Oryza sativa) is the world's major staple food,and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield.Towards a better understanding of the mechanisms controlling rice male reproductive development,we describe here the cytological changes of anther development through 14 stages,including cell division,differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis.Furthermore,we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana.Additionally,we describe the key genes identified to date critical for rice anther development and pollen formation. 相似文献
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Using an X-ray microanalysis system fitted with variable-pressure scanning electron microscopy, we noted that many calcium crystals accumulated under the stomium in the anther of Petunia. When the anther was dehisced and pollen grains were released from the stomata, the calcium crystals adhered to pollen grains and moved to the stigma together with pollen grains. In contrast, an X-ray microanalysis of the stigma surface before pollination detected no calcium emission on the stigma surface. Furthermore, pollen germination and pollen tube growth in medium without Ca occurred as in complete medium. However, after the pollen grains had been washed with abundant germination medium without calcium, pollen germination in the medium without Ca was inhibited. These results show that the calcium crystals dissolved in the aqueous drop under the exudate on the stigma and supplied calcium ions for pollen germination. In addition, calcium crystals were produced not only in the anther of Petunia but also in Nicotiana, suggesting that calcium crystals supply pollen grains with the calcium ions required for pollen germination and serve to improve reproduction efficiency in Solanaceae. 相似文献