共查询到18条相似文献，搜索用时 171 毫秒
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在人工授粉条件下,观察了小叶杨有性生殖过程的形态发育及其持续时间,结果如下:除正常花粉外,有异常和败育花粉,但不影响传粉和受精。胚珠倒生,单珠被,厚珠心,蓼型胚囊,珠孔受精,核型胚乳,胚的发育属柳叶菜型,种缨由胎座表皮细胞发育而成,柱头属湿型,花柱是实心的。人工授粉后4小时,花粉粒90％以上萌发,授粉后48小时,花粉管到达胚囊,双受精作用发生在授粉后3—6天,胚乳游离核时期持续约15—18天,但从胚乳游离核到胚乳细胞全部形成只需2—3天,合子“休眠”6—10天,原胚期约10天,心形期和鱼雷期各约2天,幼胚后期发育迅速,胚体由占种子内全长的1/3至充满整个种子只需5—6天。从授粉到种子成熟,历时约一个月。 相似文献
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毛白杨胚胎学观察 Ⅱ．胚珠、胚囊的构造，受精作用及胚的发育 总被引：2，自引：0，他引：2
董源 《北京林业学院学报》1984,(1):83-94
本文是毛白杨胚胎学研究的第二部分，研究了毛白杨胚珠、胚囊的构造，受精作用及胚的发育过程；找出了授粉前后花序的外部特征与胚珠发育情况之间的关系。子房由二心皮合成。柱头四裂；花柱为开放型，基生胎座，上生2－4枚胚珠，通常1－2枚发育，其余败育，胚珠倒生型， 珠柄发达；单珠被；厚珠心，直列式四分体；珠孔受精，双受精现象发生在授粉后40小时至6天之间，核型孔乳，胚的发育为简化的“十字花型”。对珠被的特点，胚囊的发育类型，受精的方式以及胚的发育类型予以讨论。 相似文献
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鹅掌楸属两种植物花粉品质和花粉管生长的研究 总被引：24，自引：0，他引：24
应用ＦＤＡ荧光染色法、离体和活体培养及看护培养等方法检验了鹅掌楸属两种木本植物花粉的品质，观察了开花期间花粉品质的变化，同时也观察统计了自然和人工授粉情况下，花粉在柱头上萌发及花粉管在花柱中生长的情况。研究结果表明：在离体条件下，柱头和子房对花粉的萌发和花粉管的生长有明显的促进作用；花粉在自己或异己的柱头和胚珠上萌发均良好，是亲和的，但花粉管通过花柱的比率较低，仅２４％。与本课题前期工作的研究结果相一致。并从数量调查和活体观察两个方面，再一次证实雄配子体的发育水平是影响结籽率的重要因子之一，花柱是不亲合性反应的发生区域。 相似文献
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【目的】水晶蜜柚原产于马来西亚,是海南柚类的主栽品种之一,但有关水晶蜜柚果实无籽的原因未见报道,探究水晶蜜柚果实无籽原因可为蜜柚高效栽培和育种提供理论依据。【方法】从水晶蜜柚的花粉活力与萌芽率、花粉母细胞减数分裂,花粉管伸长荧光显微观察、杂交实验、胚胎胚囊石蜡切片观察等细胞学角度研究水晶蜜柚果实的无籽机理。【结果】水晶蜜柚活力强的花粉76.58%,萌芽率88.48%;花粉母细胞减数分裂正常,但出现异常二分体和三分体现象;水晶蜜柚杂交的花粉管能伸长至子房并到达胚珠,完成受精作用,而自交的花粉管只能伸长到花柱中下部,到达不了子房,不能完成受精作用;水晶蜜柚胚胎胚囊石蜡切片显示不做处理和自交的胚胎发育一致,前期发育正常,能观察到胚胎从幼胚发育到鱼蕾形胚,鱼雷形胚时胚囊出现中空异常状态,珠柄消失;杂交的胚胎能从幼胚正常发育到子叶胚,珠柄未消失,有发育成种子的迹象;水晶蜜柚与三红蜜柚杂交的坐果率为21%,其自交和去雄套袋不授粉的坐果率只有3%和2%;杂交所得的果实的种子为饱满可育的种子,其自交和去雄套袋不授粉的种子为败育和退化的种子。【结论】水晶蜜柚花粉育性正常,花粉母细胞减数分裂正常,胚囊正常... 相似文献
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观察了胡杨的受精过程以及胚乳和胚的发育,结果如下:湿型柱头,表皮细胞具腺质特征,传粉期分泌脂滴。在光学显微镜下,子房腔中花粉管内的精细胞质和精核内的核仁清晰可见。受精作用发生于授粉后8—13d,精核核膜与雌性核膜正在融合而界限尚未消失时,精核内染色质已经分散,核仁更加明显。核型胚乳,在球形胚时期细胞化,在胚生长过程中被吸收,至胚成熟时消耗殆尽。胚珠和胚的生长均呈S形曲线,但胚珠的迅速生长期早于胚的迅速生长期。胚达到最终长度(0.8—1.0mm)10d后,种子方才散出。从传粉至种子散出约两个半月。 讨论了杨属柱头的异形性、雌雄性核融合过程中精核的状态以及胚珠、胚和胚乳生长的相关性。 相似文献
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人工辅助授粉对鹅掌楸结籽率的影响 总被引：9，自引：0，他引：9
介绍了鹅掌楸属种内、种间杂交的人工辅助授粉技术及其与结籽率的关系。中国马Ｇｕａ木（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｃｈｉｎｅｎｓｅ （Ｈｅｍｓｌ．）Ｓａｒｇ．）和北美鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎ ｔｕｌｉｐｉｆｅｒａ Ｌ．）的柱头可授期都很短，仅１￣２天，且不同步，授粉技术是影响人工辅助授粉成败的关键。在南京林业大学校园人工栽培的中国马Ｇｕａ木群体中，其自然结籽率不到１％，用黄山种源中国马Ｇｕａ木的 相似文献
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鹅掌楸花粉保存条件的比较研究 总被引：19，自引：0，他引：19
研究比较了鹅掌楸花粉的几种保存条件。结果表明：（１）新鲜花粉在超低温（－１９６℃，ＬＮ２）条件下可保持５ｄ。花粉存活率（７６．５１％）与对照（新鲜花粉）几乎相同（７５．５５％）。在电镜下观察其超微结构无异常变化。而保存１５ｄ的花粉细胞超向结构发生严重损伤，内膜系统及细胞器降解。２５ｄ后几乎观察不到存活的花粉。（２０在－２５℃保存条件下，以二甲基亚砜为保护剂，添加蔗糖作为辅佐剂保存效果较好。（３）４ 相似文献
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植物磺肽素(PSK),是近年来发现的一种新型植物肽类生长调节物质,具有促进单细胞的分裂增殖等生理功能.以杂交鹅掌楸未成熟胚来源的体胚发生体系为材料,探索PSK-α在植物体胚发生中的作用.研究发现PSK-α能够促进细胞分裂和增殖,有利于胚性细胞的形成.在杂交鹅掌楸体胚发生初期添加0.1 mg·L-1的PSK-α可提高未成熟胚的脱分化率并能有效改善培养细胞的状态;0.5 mg·L-1的PSK-α能够促进胚性愈伤组织的形成和增殖;体胚形成后期添加0.8 mg·L-1的PSK-α利于其正常发育以及再生植株的培养. 相似文献
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文冠果授粉习性和果实发育规律的研究 总被引：3，自引：0，他引：3
以人工控制授粉方式对文冠果授粉特性、落果规律以及果实和种胚的发育规律进行试验,研究其落果原因。结果表明:文冠果不孕花新鲜花粉的活力可达93%以上,花粉在柱头上萌发及花粉管在花柱中的伸长均正常,但自花授粉的果实在早期败育;人工授粉的正常果实发育与自然授粉果实发育相比,存在生长速度慢、果实小的现象;种胚发育的球形胚阶段与果实发育的转折点存在对应关系。推测:文冠果落果与是否完成受精作用以及后期的营养竞争有关,而球形胚时期是营养竞争和果实发育的关键时期。 相似文献
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Floral biology and breeding behavior were studied in the bamboo Dendrocalamus strictus Nees. The inflorescence in this species is a large branching panicle. Fertile florets are intermixed with smaller sterile ones. There are six stamens. The ovary is stipitate and turbinate. The style is long and the stigma is bifid and plumose. Dendrocalamus strictus is typically dichogamous and protogynous. The gynoecium matures 3-4 days before the androecium, effectively preventing self pollination. Flower bloom, which took place over a period of 2 to 3 h, was dependent on air temperature and only occurred between 0600 and 1300 h. Dendrocalamus strictus is anemophilous. Flowers in the male phase were visited by insects. These insects completely neglected the flowers at the female phase. The insects fed on the pollen and were not pollen vectors. When wind was excluded by enclosing the inflorescences in bags there was no seed set, indicating that cross pollination by wind is necessary for fertilization and that parthenocarpy and apomixis are not occurring in this species. Pollen fertility was about 98% as indicated by staining fresh pollen at the time of anther dehiscence and pollen release with Alexander's stain (Alexander 1969). When placed on a modified Brewbaker-Kwak medium containing 1% glucose, the pollen grains germinated well, and the pollen tubes grew to 15-20 times the diameter of mature pollen grains. Although profound protogyny has its disadvantages in times of sporadic flowering, it can be useful in breeding programs because it eliminates the need for emasculation. 相似文献
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Rong H. Ho 《Forest Ecology and Management》1984,9(3):161-171
Three to five ramets were selected from each of five white spruce clones for the study. Seed cones (megastrobili) were pollinated once and some were sampled at the different stages of development to study the pollination mechanism, seed-cone receptivity, and seed production potential.The proximal end of a seed cone emerged from the bud scales and was the area to be receptive first. As the seed cones continued to develop, the margins of the cone scales became reflexed to increase the surface area and to funnel pollen along the margins of two adjacent scales onto the micropylar arms. Pollen was transferred to a deep depression in the nucellus and it germinated in the depression a weel after pollination. Another week later the micropyle was sealed by the ingrowth and divisions of the cells in the micropylar canal. Receptivity of a seed cone lasted for about 10 days and the end of receptivity was signalled by the closure of cone scales.The optimal receptivity appeared to occur when seed cones approached the end of receptivity and this coincided with the peak of pollen shedding. It was evident that seed cones pollinated at this stage produced the most filled seeds, an average of 41.6 from a seed production potential of 88 seeds per cone. Total cone scales averaged 67.7 per cone of which 43.6 scales were fertile and located at the mid-portion of a cone. 相似文献
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The objective of the study was to investigate in vivo interspecific pollination success between Pinus radiata, P. maximinoi, P. oocarpa and P. tecunumanii. Pinus radiata was control pollinated with pollen lots of P. maximinoi, P. oocarpa and P. tecunumanii in a P. radiata seed orchard at Karatara (Southern Cape, South Africa). Pollination success was determined by counting the number of visible ovules, pollen grains inside and outside P. radiata ovules, as well as pollen tubes visible inside P. radiata ovules. Conelets were harvested and studied at eight time intervals, including 24 h after pollination, and weekly for 7 weeks after pollination. Histology studies with a standard fixation-dehydration-embedding sequence and paraffin wax method were used to determine the number of visible pollen grains inside versus outside the ovules and number of pollen tubes. Results indicated that pollen grains did sift through the cone scales within 24 h after pollination. However, P. radiata differed significantly (time by type of cross interaction) from the other three hybrid combinations in terms of number of visible ovules, visible pollen grains inside and outside of the ovules as well as pollen tubes, confirming limited interspecific hybridisation success. Future studies need to determine the percentage of fertile ovules in cross combination as a tool in predicting pollination success. 相似文献
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华北落叶松传粉生物学的研究 总被引：7，自引：1，他引：7
本文研究了华北落叶松雌雄球花在树冠上的分布和树冠周围花粉密度变化规律、传粉机制、胚珠接收花粉量及结实状况等。雌球花主要分布在树冠中上部2－4龄枝上，雄球花分布范围较广，且常与雌球花混生；树冠周围花粉密度与雄球花的分布密切相关，中部最大，依次向上下两端减少。依据雌球花形态特征的变化，可将传粉期为5个阶段，整个期间无传粉滴出现，由球被顶端大裂片的珠被毛接收花粉。最佳传粉期约为2天。胚珠平均接收4粒花粉，虽然胚珠接收的花粉数与饱满种子的产量有一定的关系，但并不是造成空粒的主要原因。此外，讨论了不同授粉方式对种子产量的重要意义。 相似文献
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落叶松种间交配结实力变异和自交衰退的研究 总被引：5，自引：1，他引：5
落叶松种间杂交的结实率普遍较高，但不同种之间有一定差异，其中日本落叶松与兴安落叶松交配结实率最低。种内自由授粉和自交的对比试验显示，示粒种子产生的主要原因是自交。本文讨论了自交不孕无性系的可能利用途径。在不同交配组合下研究了华北落叶松捕捉花粉的过程，确定在传粉期花粉和雌性生殖器官存在一定的相互作用，但无特异性。传粉后约4周，珠心顶端破裂，分泌物进入珠孔道，并与珠被分泌物共同作用于花粉，使花粉向珠心移动。组织化学分析表明，从传粉到受精期间，蛋白质的分布发生区域性变化，传粉期蛋白质几乎分布于整个胚珠，而在受精期则主要集中在颈卵器之上的珠心组织中。初步确定在花粉萌发和受精期，华北落叶松中存在花粉识别与选择系统。 相似文献