激光、高压静电场克服羽衣甘蓝自交不亲和及其分子机制的研究

利用激光、高压静电场对自交不亲和的羽衣甘蓝的花粉进行处理,以期克服其自交不亲和。通过对处理后的花粉的表面结构和蛋白酶活性及其萌发情况的研究,进一步分析激光、高压静电场的生物效应。同时利用分子生物学手段Northern杂交技术,检测了经激光、高压静电场处理的花粉,在授粉后柱头上SLG和SRK基因表达的差异,以探讨激光、高压静电场对生殖反应作用的分子机制。结果表明:通过适宜剂量的激光、高压静电场处理,羽衣甘蓝的花粉萌发率提高,成熟花粉水溶性总蛋白,α-淀粉酶活力,总淀粉酶活力均不同程度的提高,同时自交亲和指数和结籽率提高。从花粉的表面结构的电镜显微观察分析,花粉壁的雕纹受到了伤害,网脊线有轻微断裂,网眼变大。授粉后,取不同时间间隔的柱头样品提取总RNA,利用Northern杂交技术检测SLG和SRK基因的表达量,授粉后24 h激光处理和高压静电场处理与对照比较,SLG和SRK基因的表达量均降低。     

青篱柴通过促进亲和花粉生长而提高传粉精确性

异型花柱植物的适应意义在于提高亲和花粉的传递, 从而促进异交, 但是有不少研究发现柱头上落置了大量不亲和花粉。目前, 很少有人研究柱头是否有利于亲和花粉的萌发和花粉管伸长, 以及通过去雄处理排除花内和植株内不亲和花粉干扰从而验证二型花柱植物是否可以促进异交。本研究以亚麻科青篱柴属(Tirpitzia)的二型花柱植物青篱柴(T. sinensis)为研究对象, 分居群调查了青篱柴长、短柱型的植株数量, 测量不同柱型的花粉与柱头大小以及观察其表面纹饰, 测定不同开花时间长、短柱型的柱头活性与花粉活力, 统计自然状态下柱头上落置的不同表型花粉比例, 进一步统计花内、株内去雄和自然对照下柱头上落置的不同表型花粉比例, 计算型间、型内和混合授粉花粉管长度和花粉萌发率, 人工授粉检测其是否型内异交不亲和与自交不亲和。结果表明, 自然居群中长、短柱型青篱柴植株数量没有显著性差异; 短柱型青篱柴花粉体积显著大于长柱型, 且二者花粉表面纹饰不同, 但不同柱型的柱头表面积与表面纹饰无差异; 青篱柴开花第一天的花粉活力显著高于开花第二天, 而柱头活性在开花前两天无显著性差异; 自然状态下柱头上落置的不亲和花粉比例显著高于亲和花粉; 在长柱型青篱柴中, 花内和株内去雄显著提高了柱头上亲和花粉的落置比例; 柱头上授型内花粉, 其花粉萌发率和花粉管的长度都显著低于授型间花粉; 授粉结果表明青篱柴为型内异交不亲和与自交不亲和。二型花柱植物通过促进亲和花粉的萌发和花粉管的伸长而有利于型间授粉, 从而显著提高其传粉精确性。     

光敏核不育水稻短日照植株的雄性器官和育性异常

采用形态学方法比较观察了 10个水稻 (OryzasatavaL .)雄性核不育系的雄性器官的发育状况 :1)雄性核不育系短日照植株的自交结实率和花粉可育度均显著低于对照 ;2 )程度不同地存在花药开裂和散粉障碍 ,有多寡不等的柱头无任何花粉附着 ,且附着在不育系柱头上的花粉萌发力弱 ;3)胚囊发育状况及异交结实率均未见异常。说明光敏核不育水稻短日照植株自交结实率低下乃因雄性核不育基因表达所致。     

怀庆地黄胚珠试管受精的研究

怀庆地黄为自交系不亲和植物。为了克服其自交不亲和性,1978—1981年我们对其进行了胚珠试管受精研究,成功地克服了其自交不亲和的障碍,获得了试管受精的种子、幼苗和植株。试管受精所得的植株为二倍体。未授粉的带胎座的胚珠未形成种子和植株。完整雌蕊进行离体自花授粉,不能克服其自交不亲和性。通过胚珠试管受精,可消除雌性孢子体的柱头和花柱对花粉萌发和花粉管生长的抑制作用。     

斑块大小对油松授粉期花粉量以及结实的影响

景观破碎化随着人类活动的增强而日益严重, 因此理解其对物种的影响程度显得尤为重要。选取北京城市种植的14 个不同大小和隔离度的油松斑块, 通过斑块内花粉量观察、结实量分析并佐以自交率的分析, 回答斑块大小和隔离度对花粉量的影响, 以及花粉量对结实和自交率的影响。研究发现花粉量随着斑块增大而显著升高, 但与隔离度没有显著关系。花粉量大的斑块中每个球果得到的总种子数和饱籽率趋于更多。5 个斑块的自交率分析表明大斑块具有很低的自交率, 而小斑块的自交率取决于花粉量, 花粉量大的斑块具有较高的自交率, 而花粉量小的斑块以异交以及斑块间花粉流为主。研究表明小斑快具有花粉量限制和自交率升高的双重风险, 并因此导致繁殖适合度的下降。在森林物种保护和管理中, 这些小斑块值得特殊关注。     

植物交配系统的进化、资源分配对策与遗传多样性

影响植物自交率进化的选择力量主要体现在两个方面：当外来花粉量不足时,自交可以提高植物的结实率,即雌性适合度（繁殖保障）;而如果进行自交的花粉比异交花粉更易获得使胚珠受精的机会,那么自交也可以提高植物的雄性适合度（自动选择优势）。但是,鉴别什么时候是繁殖保障、什么时候是自动选择优势导致了自交的进化却是极其困难的。花粉贴现降低了自交植物通过异交花粉途径获得的适合度,即减弱了自动选择优势,而近交衰退既减少了自动选择优势也减少了繁殖保障给自交者带来的利益。具有不同交配系统的植物种群将具有不同的资源分配对策。理论研究已经说明,自交率增加将减少植物对雄性功能的资源分配比例,但将使繁殖分配加大,而且在一定条件下交配系统的改变甚至可以导致植物生活史发生剧烈变化,即从多年生变为一年生。文献中支持自交减少植物雄性投入的证据有很多,但是对繁殖分配与自交率的关系目前还没有系统的研究。资源分配理论可以解释植物繁育系统的多样性,尤其是能够说明为什么大多数植物都是雌雄同体的。自交对植物种群遗传结构的影响是减少种群内的遗传变异,增加种群间的遗传分化。长期以来人们一直猜测,自交者可能会丢掉一些长期进化的潜能,目前这个假说得到了一些支持。     

小报春不同授粉组合亲和性研究

利用小报春‘红星’、‘紫霞’、‘罗兰香’3个品种分别设置8种授粉组合,统计了不同授粉组合的结实情况和单果种子数量,并对‘红星’品种部分授粉组合的花粉萌发与花粉管伸长过程进行荧光显微观察。结果显示:(1)3个品种的结实率和单果种子数量均表现为异型植株授粉>长花柱同型异株授粉、长花柱自交>短花柱同型异株授粉、短花柱自交,不同授粉组合间单果种子数量差异极显著,异型植株授粉类型结实率均达到100%,单果种子数量为44～181粒,显著高于自交组合和同型异株杂交组合;以异型致死花粉作为蒙导对短花柱同型异株授粉组合的结实有一定促进作用,但对长花柱同型异株授粉组合的结实没有一致的促进作用;3个品种中‘红星’的结实率和单果种子数量最高。(2)荧光显微观察表明,异型授粉组合花粉在柱头上大量萌发并在花柱中伸长,授粉144h后花粉管开始进入子房;同型授粉组合授粉12h后花粉开始萌发,但直到授粉后144h花粉管还没有进入花柱;自交授粉组合授粉后144h仍无花粉萌发。实验结果说明,小报春存在明显的自交不亲和性,且短花柱类型的自交不亲和性比长花柱类型强。     

植物交酸系统的进化、资源分配对策与遗传多样性

影响植物自交率进化的选择力量主要体现在两个方面：当外来花粉量不足时,自交可以提高植物的结实率,即雌性适合度（繁殖保障）;而如果进行自交的花粉比异交花粉更易获得使胚珠受精的机会,那么自交也可以提高植物的雄性适合度（自动选择优势）。但是,鉴别什么时候是繁殖保障、什么时候是自动选择优势导致了自交的进化却是极其困难的。花粉贴现降低了自交植物通过异交花粉途径获得的适合度,即减弱了自动选择优势,而近交衰退既减少了自动选择优势也减少了繁残给自交者带来的利益。具有不同交配系统的植物种群将具有不同的资源分配对策。理论研究已经说明,自交率增加将减少植物对雄性功能的资源分配比例,但将使繁殖分配加大,而且在一定条件下交配系统在改变甚至可以导致植物生活史发生剧烈变化,即从多年生变为一年生。文献中支持自交减少植物雄性投入的证据有很多,但是对繁殖分配与自交率的关系目前还没有系统的研究,资源分配理论可以解释植物繁育系统的多样性,尤其是能够3说明为什么大多数植物都是雌雄同体的,自交对植物种群遗传结构的影响是减少种群内的遗传变异,增加种群间的遗传分化,长期以来人们一直猜测,自交者可能会丢掉一些长期进化的潜能,目前这个假说得到了一些支持。     

青藏高原晚期开花植物线叶龙胆的传粉生态学

线叶龙胆(Gentiana lawrencei var. farreri)主要分布在青藏高原, 在晚秋和早冬开花。为了探明线叶龙胆繁育系统特点, 探讨其对环境的繁殖适应特征, 对其传粉生态学过程进行了连续3年的观察。线叶龙胆自然状态下的结籽率很低, 存在严重的花粉限制。雌雄异位和不完全雌雄异熟的花特征表明其结实必须依赖昆虫传粉。繁育系统实验表明, 部分套袋花也能结实, 这可能主要是由蓟马(Thripidae spp.)和蚂蚁(Formica spp.)等小昆虫协助自交所致。克什米尔熊蜂(Bombus kashmirensis)和苏氏熊蜂(B. sushikini)是线叶龙胆的有效传粉昆虫, 但其访花频率非常低, 分别为0.006和0.005 time·flower^-1·h^-1。线叶龙胆花持续期和柱头可授能力都长于其他已报道的龙胆类植物, 从而在温度低、传粉昆虫少的情况下提供了更多传粉机会。线叶龙胆同时具有协助自交和杂交的繁殖现象, 以及较长的花持续期和柱头持续能力, 这可能是其在青藏高原地区赖以存活和延续的一个重要原因。     

异果芥的花部综合征及其繁育系统

异果芥Diptychocarpus strictus是十字花科中为数不多的在同一花序上具有两种不同形态果实的短命植物。对其花部综合征及繁育系统的研究结果表明：（1）具有白色花与紫红色花两种不同花色的植株,且其花色是稳定遗传的。两种植株的比例基本上接近1：1。（2）两种植株花序上、下部发育成不同形态果实的花在形态特征上存在差异,同时不同花色植株的花在形态特征上也存在差异。（3）紫红色和白色花植株花序上、下部花的单花花粉量分别为7589.07±976.64、5428.93±900.45、7044.73±557.37和5138.60±813.48;胚珠数分别为31.83±3.36、25.03±3.72、32.03±3.43和25.70±2.61;P/O值分别为241.31±41.85、222.33±52.51、222.19±27.80和201.84±37.52。花粉败育率很低且两种花色植株花序上、下部花的长、短雄蕊之间的花粉败育率均差异显著（P〈0.05）。同一花中短雄蕊花粉量比长雄蕊的多。（4）两种花色植株花序上、下部花之间的长、短雄蕊每花药花粉数、单花花粉数、胚珠数均存在极显著差异（P〈0.01）,均是上部花比下部花的大。（5）两种植株花中长、短雄蕊花粉活力动态变化曲线相似,花粉寿命与柱头可授期具高度的同步性,其花粉活力最高的时期正是柱头的最佳可授期。（6）P/O值、套袋试验、传粉媒介观察和花粉萌发的荧光显微观察结果表明,该物种是以自交为主、异交为辅,具有兼性自交的繁育系统。     

过表达AtchyB基因提高洋桔梗光胁迫耐受性的研究

类胡萝卜素尤其是叶黄素循环类物质在植物抵抗由强光照引起的非生物胁迫中发挥着重要的作用,为了提高洋桔梗对强光照的抗性,从拟南芥中克隆了类胡萝卜素生物合成途径中参与叶黄素循环关键酶——β-胡萝卜素羟化酶基因(AtchyB),利用农杆菌介导法将其转入洋桔梗中,最终得到遗传转化植株2个株系,研究发现,转基因植株中总类胡萝卜素含量高于对照组,且叶黄素循环池被不同程度地放大。在不同光照强度下,转基因洋桔梗植株对光照耐受性明显强于对照组,且转基因植株生物量也明显提高。表明过表达AtchyB基因使洋桔梗光胁迫耐受性有所增强。     

VARIATION IN POLLEN SIZE,FERTILIZATION ABILITY,AND POSTFERTILIZATION SIRING ABILITY IN ERYTHRONIUM GRANDIFLORUM

The mean volume of pollen grains and total pollen production varied both within and among plants of Erythronium grandiflorum. The second flowers of two-flowered plants tended to produce smaller and fewer grains than first flowers, but there was no overall relationship between mean pollen grain size and production per flower. I evaluated the effects of pollen size differences within and among plants on two components of male reproductive success: pollen tube growth and postfertilization siring ability. Pollen tubes grown in media were longer for second flowers, but were not correlated with the mean size of pollen grains, suggesting that (1) internal resource content of pollen (i.e., carbohydrates plus lipids) was not associated with the hydrated size of pollen, and that (2) pollen from second flowers contained more resources. I analyzed the growth rate and the fertilization ability of pollen growing in styles. Growth rate differed among donors and recipients, but no effects of pollen or donor characters (i.e., pollen production, grain size, and flower position) were detected. In single donor pollinations, pollen size was negatively correlated with fertilization ability across donors, and positively correlated with postfertilization siring ability of donors. A second experiment used pairs of donors; within-plant differences in pollen size and flower position had effects similar to the single donor experiment on fertilization ability, but among-plant differences were not significant. The results corroborate earlier experiments that suggest that the growth of pollen tubes in the style is probably controlled by the recipient, since donor characters had minimal effects on pollen fertilization ability. Postfertilization siring ability was not affected by within-plant differences in mean grain size and production. For among-donor differences, the number of seeds set for each donor was positively correlated with the mean grain volume, and when a donor producing large pollen fertilized ovules in an ovary, there was increased seed abortion for seeds in the same ovary sired by a second donor. In addition, the total number of seeds produced by a fruit was decreased when both donors had large pollen, apparently due to increased postfertilization abortion. Postfertilization processes appear to be influenced by paternal differences that are expressed through competition among developing seeds for maternal resources.     

洋桔梗体细胞胚性愈伤组织诱导过程中超氧化物歧化酶和酯酶变化

通过转移洋桔梗非胚性愈伤组织到含有1.0mg/L2,4-D的MS培养基(ecIM)上诱导了洋桔梗胚性愈伤组织形成,而非胚性愈伤组织在含1.0mg/L2,4-D和0.5mg/LKT的MS培养基(necSM)上继代培养。本研究比较分析了洋桔梗愈伤组织在ecIM和necSM上的超氧化物歧化酶(SOD)活性及其同工酶酶谱、酯酶同工酶酶谱随着培养天数的变化。实验结果表明在ecIM和necSM上培养的洋桔梗愈伤组织的超氧化物歧化酶(SOD)活性在培养早期较低,然后随着培养天数增加而升高,维持在较高水平上,但SOD活性变化无明显规律性;另一方面,SOD同工酶在第4天后出现一新的同工酶谱带;此外,在ecIM和necSM上培养洋桔梗愈伤组织的酯酶(EST)同工酶在培养至第16~20天期间呈现显著缺失。     

Ectopic expression of carpel-specific MADS box genes from lily and lisianthus causes similar homeotic conversion of sepal and petal in Arabidopsis

Two MADS box genes, Lily MADS Box Gene 2 (LMADS2) and Eustoma grandiflorum MADS Box Gene 1 (EgMADS1), with an extensive similarity to the petunia (Petunia hybrida) FLORAL BINDING PROTEIN 7/11 and Arabidopsis AGL11, were characterized from the lily (Lilium longiflorum) and lisianthus (Eustoma grandiflorum). The expression of LMADS2 and EgMADS1 mRNA was restricted to the carpel and was absent in the other flower organs or vegetative leaves. LMADS2 mRNA was detected mainly in ovules and weakly in style tissues of the carpel, whereas EgMADS1 mRNA was only expressed in the ovules. Transgenic Arabidopsis plants ectopically expressing LMADS2 or EgMADS1 showed similar novel phenotypes resembling 35S::AGAMOUS plants by significantly reducing plant size, flowering early, and losing inflorescence indeterminacy. Ectopic expression of these two genes also generated similar ap2-like flowers by inducing homeotic conversion of the sepals into carpel-like structures in which stigmatic papillae and ovules were observed. In addition, the petals were converted into stamen-like structures in the second whorl of 35S::LMADS2 and 35S::EgMADS1 transgenic Arabidopsis. Our data indicated that LMADS2 and EgMADS1 are putative D functional MADS box genes in lily and lisianthus with a function similar to C functional genes once ectopically expressed in Arabidopsis.     

Morphological variation and female reproductive success in two sympatric Trillium species: evidence for phenotypic selection in Trillium erectum and Trillium grandiflorum (Liliaceae)

I investigated the mating systems and phenotypic variation of two sympatric spring ephemerals, Trillium erectum and T. grandiflorum (Liliaceae), and phenotypic selection acting through female reproductive success for 11 morphological characters in five sympatric populations of the two species. I examined the degree of self-compatibility, pollinator-visitation rates, and pollen limitation of fruit and seed production in both species. Both Trillium species were self-compatible, but outcrossed flowers produced more successful fruits and seeds than self-pollinated flowers. Pollinator-visitation rates to the two species were low compared to other insect-pollinated spring ephemerals. In addition, both T. erectum and T. grandiflorum experienced pollen limitation in fruit and/or seed production; however, levels of fecundity in both species may be influenced by resource availability as well. I found significant phenotypic variation in 11 morphological characters within and among the five study populations. The sizes of all morphological characters were positively correlated. In general, larger T. erectum and T. grandiflorum produced more seeds. Phenotypic selection analysis revealed that direct and indirect selection acted on the size of morphological characters for both species. But there was no detectable selection acting on plant shape. This study reveals that variation in plant size exists within and among populations of both species, and this variation is associated with variance in female reproductive success. Spatial and temporal variation in pollinator and/or resource abundance may play a role in the phenotypic variation exhibited by both Trillium species.     

Phylogeny of the Afro-Madagascan Aristea (Iridaceae) revisited in the light of new data on pollen morphology

Scanning and electron microscopic studies of the pollen grains of several species of the sub-Saharan African and Madagascan genus Aristea of c . 50 species, supplement data from an earlier study and enable us to include these species in a phylogenetic analysis. TEM examination of a range of pollen grains of representative pollen types in Aristea makes it possible to reinterpret past SEM results so that apertures covered with exine masses and previously called sulculate, are now seen to be either zonasulculate or dizonasulculate. Revised and expanded data are combined in a matrix together with new data for seed morphology in the genus, which like the capsules is remarkably diverse, including angular seeds with reticulate sculpturing, lamellate or triangular-columnar seeds with smooth or reticulate surfaces and with smooth or papillate or areolate margins. This new phylogenetic analysis suggests that Aristea should remain treated as comprising three subgenera. In subgenus Eucapsulares we add a new section Latifolieae for A. latifolia , which seems an isolated relic restricted to the mountains of the Cape Region of South Africa, an area of winter rainfall. Species with similar unspecialized capsule and seed morphology occur only in eastern south and tropical Africa and Madagascar, but they have derived pollen morphology whereas the pollen of A. latifolia is plesiomorphic. This species appears to be the closest living ancestor of the genus. In subgenus Aristea we continue to recognize three sections, sect. Racemosae , sect. Singulares and sect. Aristea. Nesting of subgenus Pseudaristea within section Racemosae of subgenus Aristea is probably an artefact of the analysis and does not receive bootstrap support, and hence we continue to recognize this group of species at subgeneric rank.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 41–68.     

外源ALA、SNP和Spd对NaCl胁迫下桔梗种子萌发特性的影响

以药用植物桔梗为研究对象,通过测定不同浓度的ALA、SNP和Spd对NaCl胁迫下桔梗种子发芽势、发芽率、萌发指数和平均根长等萌发指标的影响,寻找提高桔梗种子及幼苗在盐胁迫条件下抗性能力的途径.实验结果表明,75 mmol·L-1 NaCl胁迫下的桔梗种子萌发受到显著抑制,但是用不同浓度的ALA、SNP和Spd对桔梗种...     

Reduced glutathione is a novel regulator of vernalization-induced bolting in the rosette plant Eustoma grandiflorum

The transition from the vegetative rosette stage to the reproductive growth stage (bolting) in the rosette plant Eustoma grandiflorum has a strict requirement for vernalization, a treatment that causes oxidative stress. Since we have shown that reduced glutathione (GSH) and its biosynthesis are associated with bolting in another rosette plant Arabidopsis thaliana, we here investigated whether a similar mechanism governs the vernalization-induced bolting of E. grandiflorum. Addition of GSH or its precursor cysteine, instead of vernalization, induced bolting but other thiols, dithiothreitol and 2-mercaptoethanol, did not. The inductive effect of vernalization on bolting was nullified by addition of buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, without decreasing the plant growth rate. BSO-mediated inhibition of bolting was reversed by addition of GSH but not by cysteine. These indicate that vernalization-induced bolting involves GSH biosynthesis and is specifically regulated by GSH. Plant GSH increased during the early vernalization period along with the activity of gamma-glutamylcysteine synthetase that catalyzes the first step of GSH biosynthesis, although there was little change in amounts of GSH precursor thiols, cysteine and gamma-glutamylcysteine. These findings strongly suggest that vernalization stimulates GSH synthesis and synthesized GSH specifically determines the bolting time of E. grandiflorum.     

Analysis of the clinal variation pattern inSilene latifolia (Caryophyllaceae) pollen morphology

Reticulate and microechinate pollen forms withinSilene latifolia (S. alba, S. pratensis) were first described from N. America, where the species is an introduced weed. A previous study showed that the two forms also exist in Europe and intergrade along a zone roughly congruent with intergradation zones in seed morphology and flavone glycosylation genotypes. The present survey of pollen from herbarium specimens is more extensive and covers localities from nearly the whole of the species' native Eurasian and North African range. The first axis of a detrended correspondence analysis (DCA) of qualitative characterstate data for 11 pollen morphological characters shows a gradient between the two extreme exine types, reticulate and microechinate. When mapped, the co-ordinates of pollen samples on this axis indicate a broad zone of intergradation which coincides approximately with the somewhat sharper transition between low- and high-tubercle seeds in C. and N. Europe, but becomes diffuse in Italy and the Mediterranean region and diverges from the seed transition zone in SW. Asia and the Middle East. The biological significance of the pollen morphs is unknown; the variation pattern in pollen morphology, unlike that in seeds, is not consistently correlated with macroclimate.