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1.
中国樱桃与甜樱桃花粉原位萌发及花粉管生长的差异   总被引:10,自引:4,他引:6  
以‘垂丝’、‘东塘’(中国樱桃)和‘莫利’、‘拉宾斯’(甜樱桃)为试材,分别于自花、异花授粉后不同时间切取花柱,用FAA固定,荧光染色后压片观察。结果显示,中国樱桃和甜樱桃的自花、异花花粉均能在柱头萌发,且其花粉管在花柱中表现为“极快—慢—快—稳定”的动态变化过程。但甜樱桃花粉萌发率高于中国樱桃,异花高于自花。中国樱桃自花、异花都有花粉管到达花柱基部;甜樱桃‘莫利’ב拉宾斯’和‘拉宾斯’自交有花粉管到达花柱基部,而‘莫利’自交的花粉管在花柱中上部已停止生长。结果表明,中国樱桃表现自交亲和性,而甜樱桃除人工诱变导致自交亲和的‘拉宾斯’等品种外,表现典型的植物配子体自交不亲和性。  相似文献   

2.
异型花柱是一种受遗传因素控制的花型多态性现象,包括二型花柱和三型花柱两种类型.本文以茜草科艳丽耳草(Hedyotis pulcherrima)为实验材料,通过对其野外居群的花型、花部形态及花粉特征等观察,发现艳丽耳草野外居群同时存在长花柱型花和短花柱型花,长/短花柱型花的数量比例为1∶1.两型花具有精确的交互式雌雄异位特征,并且该特征与花冠长度相关性显著.长/短花柱型花的柱头裂片长度、花粉大小及淀粉含量等具有二型性.花粉体外培养时花粉萌发率及花粉管生长速率无显著性差异.人工授粉后,艳丽耳草长/短花柱型花型间异交花粉管生长形态正常,授粉24 h后花粉管均已进入子房.而长/短花柱型花在自交及型内异交下均表现为不亲和,花粉管生长停止于柱头,花粉管顶端累积胼胝质并膨大.艳丽耳草没有无融合生殖现象,型间人工辅助异交授粉结实率为100%,显著高于自然结实率.本研究结果表明,艳丽耳草是典型的二型花柱植物,并具有异型自交不亲和系统.  相似文献   

3.
花柱和花粉胞外钙调素对花粉萌发和花粉管伸长的影响   总被引:6,自引:0,他引:6  
以烟草为材料,通过半体内实验,就花柱和花粉胞外钙调素对花粉萌发和花粉管伸长的影响进行了观察。发现用EGTA及钙调素抗血清处理柱头或花粉均可抑制花粉在柱头上的萌发;向花柱引导组织中显微注射纯化钙调素可促进花粉管束伸长,而注射钙调素抗血清可抑制花粉管束伸长;同时证实玉米花柱和花粉细胞壁中均存在钙调素及钙调素结合蛋白,而且花粉和花柱细胞壁中钙调素结合蛋白的种类有差异。结果表明存在于花粉和花柱细胞外的钙调素对花粉萌发和花粉管伸长均有促进作用。  相似文献   

4.
梨远缘花粉原位萌发及生长特性   总被引:5,自引:2,他引:3  
应用荧光标记方法对梨远缘花粉在‘丰水’和‘噢嗄二十世纪’柱头上萌发及花粉管生长特性进行观察,结果表明:(1)梨远缘花粉均能在柱头上萌发,但其萌发率不同,授粉后24 h,在‘丰水’柱头上‘红叶桃’花粉萌发率最高,达62.8%,而‘盖县大李’花粉萌发率仅为12.0%,各种远缘花粉在‘丰水’柱头萌发率均高于‘噢嗄二十世纪’柱头。(2)各种远缘花粉管在梨柱头或花柱内生长情况也有差异,‘红叶桃’等核果类花粉管在梨柱头上均表现为扭曲、盘绕等现象,不能穿过柱头;‘红星’和‘红富士’花粉管虽然有少量穿过柱头,但不能进一步在花柱内生长,表现为扭曲变形、先端膨大等不亲和性现象。因此,梨与远缘果树杂交不亲和在柱头上就已发生,这与梨自交不亲和反应发生在花柱内的现象不同。  相似文献   

5.
本文介绍了近年来在花粉—雌蕊相互作用的控制机理及发育调控中取得的一些进展。花粉与雌蕊的识别由一系列不亲和基因所控制的专一性糖蛋白所介导。在花成熟后期这些基因开始表达,合成大量的S蛋白质,从而植物获得自交不亲和的特性。雌蕊S蛋白质位于柱头或花柱中,它们能抑制自交不亲和花粉管生长。  相似文献   

6.
以‘大五星’枇杷退化种子少核株系‘川农1号’(C1)为试材,以‘大五星’枇杷自花授粉为对照,采用荧光显微技术,对枇杷少核株系自花、异花授粉后花粉管生长情况进行观察。结果表明:(1)C1株系异花授粉后花粉能在柱头上萌发,并伸入中央花柱道,在授粉后48h左右到达花柱基部。(2)C1株系自花授粉后,花粉萌发与花粉管的伸长速度相对于异花授粉滞后,自花授粉后36h大多数花粉管到达花柱的中上部并停止生长,且伴随产生花粉管顶端形态异常、荧光异常明亮等现象,最终只有极少数花粉管能到达花柱基部。研究表明,C1株系为配子体自交不亲和,C1株系的自交不亲和性是引起其少核的重要原因之一。  相似文献   

7.
梨花柱S-RNase对花粉管内CaM分布的影响   总被引:2,自引:1,他引:1  
采用免疫胶体金定位和电子显微技术研究了离体条件下梨花柱S-RNase对自花、异花花粉管中钙调素(CaM)分布的影响.结果显示:(1)花粉管中CaM主要分布在质膜附近,在细胞壁上也有少量分布.(2)不亲和(自花)花柱S-RNase处理后花粉管远离质膜的位置发现CaM,处理24h后在花粉管中部出现CaM,且CaM位置向花粉管内部移动;而亲和(异花)S-RNase处理后花粉管的CaM分布没有明显变化.研究表明,CaM参与了自交不亲和反应过程.  相似文献   

8.
以砂梨(Pyrus pyrifoliaNakai)品种今村秋(Imamuraaki)和丰水(Hosui)为材料,分别用光学显微镜和荧光显微镜观察了离体和半活体条件下微丝骨架解聚剂细胞松弛素B(cytochalasin B,CB)和稳定剂鬼笔环肽(phalloidin)对梨花粉萌发和花粉管生长的影响.结果表明:(1)低浓度(10μg/mL)鬼笔环肽能促进花粉萌发和花粉管生长,但高浓度对花粉萌发和花粉管的生长具有抑制作用;CB抑制花粉萌发和花粉管生长,且抑制效应随其浓度的增加而增强.(2)鬼笔环肽处理柱头后进行自花授粉,可明显促进自花花粉萌发和花粉管的生长,而CB处理柱头后异花授粉则抑制异花花粉萌发及其花粉管生长.可见,微丝骨架参与了梨花粉萌发和花粉管生长过程,并参与了梨自交不亲和反应的调节.  相似文献   

9.
百合远缘杂交花粉萌发及花粉管生长过程观察   总被引:14,自引:0,他引:14  
利用荧光显微镜对百合远缘杂交组合Bernini×Pollyanna花粉萌发及花粉管生长过程进行观察研究,结果显示,授粉后3~30 h内花粉萌发形成花粉管,且花粉管生长速度由快到慢,48~51 h内花粉管停止生长,花粉管最后深入到花柱的1/3处,并观察到一些异常的花粉管形态;花粉管生长过程中还伴随着一系列的胼胝质反应,出现的部位依次是乳突细胞、花粉管、花柱通道细胞、胚珠中的胚囊.结果表明该杂交组合不亲和.研究认为Berni-ni柱头乳突细胞是阻碍Pollyanna花粉管生长的第一道屏障,花柱通道细胞是抑制花粉管在花柱内生长的第二道屏障.  相似文献   

10.
植物的生殖讲座(五):被子植物的自交不亲和性   总被引:8,自引:0,他引:8  
方瑾 《生物学通报》1996,31(7):28-30
自交不亲和性广泛存在于被子植物中,同形花与异型花均存在自交不亲和性。受精的障碍可发生在花粉萌发、花粉管进入柱头、花粉管在花柱中生长及进入胚囊中等不同阶段和部位。不亲和性由孢子体系统或配子体系统控制。用转基因技术研究发现甘蓝的SLG启动子能控制配子体型和孢子体型的表达。配子体自交不亲和的S基因产物具有核酸酶的活性,能选择性地破坏不亲和花粉管的RNA。本文简介了克服自交不亲和性的方法及自支不亲和性的利用。  相似文献   

11.
12.
The self-incompatibility (SI) reaction in the Solanaceae involves molecular recognition of stylar haplotypes by pollen and is mediated by the S-locus from which a stylar-localized S-RNase and several pollen-localized F-box proteins are expressed. S-RNase activity has been previously shown to be essential for the SI reaction, leading to the hypothesis that pollen rejection in incompatible crosses is due to degradation of pollen RNA. We used pollen expressing the fluorescent marker GFP, driven by the LAT52 promoter, to monitor the accumulation of mRNA and protein in pollen after compatible and incompatible pollinations. We find that GFP mRNA and protein gradually accumulate in pollen tubes until at least 18-h post-pollination and, up to this time, are only slightly more abundant in compatible compared with incompatible crosses. However, between 18- and 24-h post-pollination, pollen tube GFP mRNA and protein levels show a dramatic increase in compatible crosses and either remain constant or decrease in incompatible crosses. In contrast to these molecular correlates, the growth rates of compatible and incompatible pollen tubes begin to differ after 6-h post-pollination. We interpret the changes in growth rate at 6-h post-pollination as the previously described transition from autotrophic to heterotrophic growth. Thus, while pollen rejection is generally considered to result from the cytotoxic effects of S-RNase activity, this time course reveals that a difference in the growth rate of compatible and incompatible pollen appears prior to any marked effects on at least some types of pollen RNA.  相似文献   

13.
Background and Aims The integrity of actin filaments (F-actin) is essential for pollen-tube growth. In S-RNase-based self-incompatibility (SI), incompatible pollen tubes are inhibited in the style. Consequently, research efforts have focused on the alterations of pollen F-actin cytoskeleton during the SI response. However, so far, these studies were carried out in in vitro-grown pollen tubes. This study aimed to assess the timing of in vivo changes of pollen F-actin cytoskeleton taking place after compatible and incompatible pollinations in Nicotiana alata. To our knowledge, this is the first report of the in vivo F-actin alterations occurring during pollen rejection in the S-RNase-based SI system. Methods The F-actin cytoskeleton and the vacuolar endomembrane system were fluorescently labelled in compatibly and incompatibly pollinated pistils at different times after pollination. The alterations induced by the SI reaction in pollen tubes were visualized by confocal laser scanning microscopy. Key Results Early after pollination, about 70 % of both compatible and incompatible pollen tubes showed an organized pattern of F-actin cables along the main axis of the cell. While in compatible pollinations this percentage was unchanged until pollen tubes reached the ovary, pollen tubes of incompatible pollinations underwent gradual and progressive F-actin disorganization. Colocalization of the F-actin cytoskeleton and the vacuolar endomembrane system, where S-RNases are compartmentalized, revealed that by day 6 after incompatible pollination, when the pollen-tube growth was already arrested, about 80 % of pollen tubes showed disrupted F-actin but a similar percentage had intact vacuolar compartments. Conclusions The results indicate that during the SI response in Nicotiana, disruption of the F-actin cytoskeleton precedes vacuolar membrane breakdown. Thus, incompatible pollen tubes undergo a sequential disorganization process of major subcellular structures. Results also suggest that the large pool of S-RNases released from vacuoles acts late in pollen rejection, after significant subcellular changes in incompatible pollen tubes.  相似文献   

14.
Pear ( Pyrus pyrifolia L.) has a S-RNase-based gametophytic self-incompatibility (SI) mechanism, and S-RNase has also been implicated in the rejection of self-pollen and genetically identical pollen. No studies, however, have examined the extent of organelle alterations during the SI response in Pyrus pyrifolia . Consequently, this study focused on the alterations to mitochondria and nuclear DNA in incompatible pollen tubes of the pear. Methylthiazolyldiphenyl-tetrazolium bromide was used to evaluate the viability of pollen tubes under S-RNase challenge. The results showed that the viability of the control and compatible pollen tubes decreased slightly, but that of the incompatible pollen and pollen tubes began to decline at 30 min. The mitochondrial membrane potential (Δ ψ mit) was also tested with rhodamine 123 30 min after SI challenge, and was shown to have collapsed in the incompatible pollen tubes after exposure to S-RNase. Western blotting 2 h after SI challenge confirmed that the Δ ψ mit collapse induced leakage of cytochrome c into the cytosol. Swollen mitochondria were detected by transmission electron microscopy as early as 1 h after SI challenge and the degradation of nuclear DNA was observed by both 4,6-diamidino-2-phenylindole and transferase-mediated dUTP nick-end labeling. These diagnostic features of programmed cell death (PCD) suggested that PCD may specifically occur in incompatible pollen tubes.  相似文献   

15.
Plants have many ways to regulate the type of pollen that arrives on the stigma surface. Once there, further control mechanisms regulate compatibility. The latter controls are largely based on biochemical interactions that support compatible pollination and prevent incompatible matings. S-RNase-based self-incompatibility (SI) systems are the most phylogenetically widespread mechanisms for controlling pollination. Studies of Nicotiana establish a firm link between SI and unilateral interspecific incompatibility. Although implicated in both inter- and intraspecific compatibility, S-RNase operates through at least three distinct genetic mechanisms that differ in their dependence on non-S-RNase factors. Identification and characterization of these non-S-RNase factors is currently an area of active research. Searching for genetic and biochemical interactions with S-RNase can identify candidate non-S-RNase factors. HT-protein is one factor that is required for S-allele-specific pollen rejection in the Solanaceae. Major style arabinogalactan proteins such as TTS interact biochemically with S-RNase. These glycoproteins are known to interact with compatible pollen tubes and have long been suggested as possible recognition molecules. Their binding to S-RNase implies a link between stylar systems for compatibility and incompatibility. Thus, genetic and biochemical studies suggest a highly networked picture of pollen-pistil interactions.  相似文献   

16.
Most species of Dalechampia have expanded stigmatic surfaces that extend from the stylar tip part way down the sides of the elongated styles. Pollen grains landing at the stylar tip grow tubes directly down the style to the ovary. Pollen grains landing on the lateral stigmatic surfaces, however, exhibit indirect pollen-tube growth: the tubes grow first to the stylar tip, bend 180°, and then grow to the ovary. Indirect pollen-tube growth appears to be reproductively important: more than half the arriving pollen lands on the lateral stigmatic surfaces, and virtually all of these grains produce tubes that grow indirectly to the ovary; pollen on the lateral surface fertilizes seeds about as effectively as pollen at the tip (with direct tube growth). Indirect pollen-tube growth may be the result of a correlated response to selection for expanded stigmatic surfaces in Dalechampia, or it may be an adaptation to increase the intensity of pollen competition.  相似文献   

17.
以‘丰水’和‘幸水’梨花柱及花粉为试材,用激光共聚焦显微技术,研究了离体条件下G蛋白活性调节剂和花柱S-RNA酶对花粉管生长及其游离Ca~(2 )浓度的影响。结果表明:G蛋白激活剂CTX可促进花粉管生长,且可解除花柱S-RNA酶对自身花粉管生长的抑制作用;G蛋白抑制荆PTX和花柱S-RNA酶共同处理使异体的花粉管生长受到抑制。CTX处理使花粉管尖端区的[Ca~(2 )]_i明显升高,花柱S-RNA酶处理引起自身花粉管尖端区的[Ca~(2 )]_i梯度消失;CTX和花柱S-RNA酶共同处理则使自身花粉管内的[Ca~(2 )J_i表现出两者单独处理时的综合特征;而花柱S-RNA酶和PTX共同处理后,异体的花粉管内[Ca~(2 )]_i表现出先升高后下降的趋势。  相似文献   

18.
The specificity of S-RNase-based self-incompatibility (SI) is controlled by two S-locus genes, the pistil S-RNase gene and the pollen S-locus-F-box gene. S-RNase is synthesized in the transmitting cell; its signal peptide is cleaved off during secretion into the transmitting tract; and the mature “S-RNase”, the subject of this study, is taken up by growing pollen tubes via an as-yet unknown mechanism. Upon uptake, S-RNase is sequestered in a vacuolar compartment in both non-self (compatible) and self (incompatible) pollen tubes, and the subsequent disruption of this compartment in incompatible pollen tubes correlates with the onset of the SI response. How the S-RNase-containing compartment is specifically disrupted in incompatible pollen tubes, however, is unknown. Here, we circumvented the uptake step of S-RNase by directly expressing S2-RNase, S3-RNase and non-glycosylated S3-RNase of Petunia inflata, with green fluorescent protein (GFP) fused at the C-terminus of each protein, in self (incompatible) and non-self (compatible) pollen of transgenic plants. We found that none of these ectopically expressed S-RNases affected the viability or the SI behavior of their self or non-self-pollen/pollen tubes. Based on GFP fluorescence of in vitro-germinated pollen tubes, all were sequestered in both self and non-self-pollen tubes. Moreover, the S-RNase-containing compartment was dynamic in living pollen tubes, with movement dependent on the actin–myosin-based molecular motor system. All these results suggest that glycosylation is not required for sequestration of S-RNase expressed in pollen tubes, and that the cytosol of pollen is the site of the cytotoxic action of S-RNase in SI.  相似文献   

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