一串红胚胎发育过程中多胺含量的变化

选取发育正常和败育一串红(Saliva splendens)5个不同时期的胚胎,分别提取、测定多胺(精胺、亚精胺、腐胺与尸胺)的含量变化.通过比较一串红胚胎发育不同阶段多胺物质的变化规律,探讨多胺在一串红胚胎发育中的生理作用.结果表明,一串红的胚胎败育和胚珠中较低的多胺含量及其在发育进程中较大的降幅有关;在盛花期,胚胎发育的关键时期,正常胚珠中哑精胺的含量有一个明显的峰值,而败育的胚珠中则无,这表明亚精胺含量变化在胚胎发育中起关键调节作用.     

荔枝胚珠中多胺含量变化与胚胎发育的关系

荔枝胚胎发育与胚珠中３种多胺（ＰＡｓ）含量及其比例变化关系密切。试验结果表明：正常发育的胚珠中腐胺（Ｐｕｔ）、亚精胺（Ｓｐｄ）和精胺（Ｓｐｍ）的含量在胚胎发育的各个阶段均高于败育胚珠,并在花后７ｄ即达到最高值,其中Ｐｕｔ的含量最高,随后都呈下降趋势。但正常胚珠中Ｓｐｍ含量在花后２２至３１ｄ（球形胚至心形胚发育阶段）均有所回升,而败育胚珠无此现象。败育胚珠中的Ｓｐｄ和Ｓｐｍ在胚胎败育期的下降速度显著     

细胞质雄性不育白菜败育过程中激素和多胺含量的变化

通过对胞质雄性不育白菜败育过程中叶片和花药组织中IAA、ZRs、GAs、ABA和Put、Spd、Spm含量及IAA／ZRs比值的变化研究,发现IAA、GA、多胺尤其是Spd含量的小足,ZRs、ABA的盈积以及IAA／ZRs比值的失衡导致了白菜雄性不育系小孢子的败育。     

假单性结实无核葡萄胚败育机理研究

以Flame Seedless、大粒红无核和京可晶3个假单性结实无核葡萄品种为试材,对其胚和胚乳的发育进行了细胞学观察,并初步探索了胚败育机理.结果表明:Flame Seedless、大粒红无核和京可晶3个无核葡萄品种胚乳开始败育的时期分别为花后29、42、34 d,胚开始大量败育的时期分别为花后39、51、45 d;假单性结实无核葡萄胚的败育是由于胚乳败育、胚缺乏营养所致.     

荔枝胚胎败育与酚类抑制物质的关系

在荔枝 (LitchichinensisSonn .)胚胎败育发生期 ,以系统溶剂法从正常或败育胚珠中初步提取酚类抑制物质 ,通过TLC分离与纯化 ,用GC MS联用仪进一步分离鉴定 ,并以标准品核对。试验首次从荔枝胚珠中分离鉴定出酚类抑制物质对羟基苯甲酸 (p_HBA)。生物活性测定表明 ,p_HBA是一种很强的生长抑制物质。在败育胚珠中其含量及IAA氧化酶活性均显著高于正常胚珠 ,IAA水平则明显低于正常胚珠 (P <0 .0 1)。因此认为 ,p_HBA参与了荔枝胚胎发育的调节 ,高含量的p_HBA是通过促进IAA侧链的氧化并影响促进和抑制生长的物质之间的平衡而导致荔枝胚胎的败育     

荔枝胚胎败育与酚类抑制物质的关系

在荔枝(Litchi chinensis Sonn.)胚胎败育发生期,以系统溶剂法从正常或败育胚珠中初步提取酚类抑制物质,通过TLC分离与纯化,用GC-MS联用仪进一步分离鉴定,并以标准品核对.试验首次从荔枝胚珠中分离鉴定出酚类抑制物质对羟基苯甲酸(p-HBA).生物活性测定表明,p-HBA是一种很强的生长抑制物质.在败育胚珠中其含量及IAA氧化酶活性均显著高于正常胚珠,IAA水平则明显低于正常胚珠(P<0.01).因此认为,p-HBA参与了荔枝胚胎发育的调节,高含量的p-HBA是通过促进IAA侧链的氧化并影响促进和抑制生长的物质之间的平衡而导致荔枝胚胎的败育.     

通过对胚珠的培养来培育无籽葡萄

葡萄(如Thompson Seedless(TS)葡萄品种)的无籽特征是由于少精子型种子发育引起的——在发育早期抑制胚胎生长造成败育。这种葡萄品种很难进行杂交,因为它们仅可用作雄性亲本,必须与有种子的品种杂交。这样杂交产生的无籽葡萄的比率很低。 1983年,D.W.Cain曾报道了一种可营救无籽葡萄的胚胎而使杂交直接进行的胚珠培养方法。然而,用这种方法得到的胚胎存活率和植株发育频率也很低。     

水稻细胞质雄性不育系及其保持系幼穗发育过程中的多胺代谢

在幼穗发育过程中,不育系和保持系幼穗多胺含量先剧降后稳定或略回升,精氨酸脱羧酶活性快速下降,而二胶和多胺氧化酶活性缓慢下降。从雌雄蕊形成期到花粉母细胞形成期,不育系的多胺含量和精氨酸脱羧酶活性明显低于保持系;不过,两系二胺氧化酶和多胺氧化酶活性却差别不大。外施D-Arg抑制两系Put合成,也抑制以Put为前体的Spd的合成;外施MGBG抑制Spd和Spm的合成;同时,D-Arg或MGBG对不育系花粉育性影响不大,但明显降低保持系花粉育性,D-Arg＋MGBG对花粉育性的降低效应更强;Put和pd＋Spm可抵消（或部分抵消）D-Arg和MGBG的降低效应。且Put＋Spd＋Spm能使不育系花粉的育性得以轻度恢复。     

焦核与大核龙眼雌配子体发育、授粉受精及早期胚胎发育的比较研究

利用人工授粉,采用压片法对大核龙眼‘九月乌’和焦核龙眼‘闽焦64-1’、‘闽焦64-2’、‘白核’等的自交与杂交后花粉管的生长特性进行研究,同时应用常规石蜡切片技术对大核与焦核龙眼的雌配子体以及合子胚早期发育进行观察。结果表明,龙眼胚珠在单核胚囊形成前就开始败育,且焦核品种(系)的败育率显著高于大核品种。不同亲本组合的授粉率存在差异,所有授粉组合在授粉36～48 h后均能观察到1个花粉管生长并进入胚囊受精。焦核品种(系)的胚胎在谢花后10 d开始败育,且败育率明显高于大核品种。受精是龙眼子房发育的首要条件,胚珠败育的雌蕊在谢花后10 d不膨大,不能发育形成焦核果实。谢花后10～30 d的早期胚胎败育是形成焦核龙眼的主要原因。焦核品种‘白核’胚乳具有成胚能力。约有24%的‘闽焦64-1’胚珠在胚胎发育过程中,其助细胞、合点端细胞及胚乳发生异常,这可能与早期胚胎败育有关。     

无核荔枝假种皮发育过程的研究

无核荔枝是荔枝中较为珍贵的品系 ,种子多退化 ,故为无核品系。其胚珠在发育过程中由于胚囊败育而萎缩 ,假种皮发生于珠脊外侧及外珠被外侧 ,由于胚珠中部的表皮及表层下的几层细胞先后脱分化形成分生组织 ,而在以后的发育中经历一个由“中层”假种皮发育到“平台”假种皮的过程 ,当“平台”假种皮形成以后 ,在其外侧边缘形成一个明显的“上翘”假种皮 ;继而 ,把发育缓慢的胚珠和珠柄包埋 ,而形成“无核”。此外 ,在其发育过程中 ,外界温度对其影响较为明显 :扬花期的高温会产生大核、焦核 ,低温则产生无核 ,因此 ,无核荔枝可能是低温敏感型。     

Involvement of polyamines in gibberellin-induced development of seedless grape berries

The roles of polyamines (PAs) in the development of seedless grape berries induced by gibberellin (GA₃) was investigated. The development of seedless grape berries was stimulated by the application of putrescine (Put), but not by that of spermidine (Spd) and spermine (Spm), regardless of the presence of GA₃. At harvest, the fresh weight of seedless grape berries treated with 500 ppm Put + 25 ppm GA₃ and 500 ppm Put increased to 111 and 112%, respectively, of the control. Treatment with methylglyoxal-bis (guanyl hydrazone), a potent inhibitor of S-adenosylmethionine decarboxylase that plays a role in Spd and Spm synthesis, did not affect the development of seedless grape berries induced by 100 ppm GA₃. The application of 100 ppm GA₃ significantly increased endogenous free Put levels. Levels of free Spd and Spm were not affected by GA₃. Although the levels of endogenous perchloric acid insoluble bound PAs were higher than those of free PAs, obvious changes in the levels of bound PAs were not observed. These results indicate that free Put is implicated in the development of seedless grape berries induced by GA₃.     

The use of leaf GPI and IDH isozymes to examine the origin of polyembryony in cultured ovules of seedless grape

Isozyme analysis of young leaf tissue was performed on progeny produced from cultured ovules resulting from crosses of seedless × seedless grapes. Two polymorphic loci, Idh and Gpi-c, were found to segregate in a simple Mendelian fashion in the populations examined. Analyses of 70 seedlings indicated that most seedlings produced by this method were zygotic. Isozyme data of 11 plants from 5 polyembryonic ovules, along with data previously reported, suggest that several mechanisms may be operative in grape that give rise to polyembryony: 1) fertilization and development of more than one cell in the embryo sac, 2) adventive embryogenesis from the zygote, or 3) embryogenic development of gametic cells in addition to the zygote in the embryo sac.Fl. Agri. Exp. Sta. Journal Series No. 9112.     

氯化钠胁迫对嫁接黄瓜叶片多胺含量的影响

以日本耐盐品种‘帝王新土佐’南瓜为砧木,以’新泰密刺’黄瓜为接穗,在100 mmol·L^-1 NaCl胁迫下,对黄瓜嫁接和自根植株不同时期叶片中不同形态多胺含量的变化进行了研究.结果表明：NaCl胁迫下黄瓜嫁接植株游离态腐胺（Put）含量在胁迫2 d时与自根植株无显著差异,其余时间均显著高于自根植株;游离态亚精胺（Spd）和游离态精胺（Spm）含量在整个胁迫期间均显著高于自根植株;游离态多胺总量（PAs）在胁迫第4天出现峰值;嫁接植株游离态Put/PAs值在胁迫4 d时与自根植株无显著差异,其余胁迫时间均显著低于自根植株,而(Spd+Spm)/Put值在整个胁迫期间均显著高于自根植株;嫁接植株结合态和束缚态Put、Spd和Spm含量在整个胁迫期间均显著高于自根植株,结合态和束缚态PAs在胁迫第6天出现峰值;结合态多胺的Put/PAs值和(Spd+Spm)/Put值变化趋势与游离态多胺一致;嫁接植株束缚态Put/PAs值在胁迫6 d时与自根植株无显著差异,其余时间均显著低于自根植株,而(Spd+Spm)/Put值在整个胁迫期间均显著高于自根植株.表明黄瓜嫁接植株表现出较强的耐盐特征.     

外源钙和亚精胺对NaCl胁迫条件下玉米幼苗体内离子平衡和多胺水平的调节

研究了钙离子和亚精胺对盐胁迫条件下玉米幼苗生长状况、电解质渗漏、离子含量和多胺水平的影响。结果表明盐胁迫下,钠离子和腐胺含量升高,质膜受到严重伤害,而钾离子、钙离子、亚精胺以及精胺水平降低。外加氯化钙和亚精胺不但能逆转氯化钠带来的离子平衡失调、多胺代谢紊乱,而且还能减轻氯化钠导致的生长抑制和质膜伤害。在盐胁迫条件下,二环己基胺引起多胺含量严重下降的情况在一定程度上能被外加氯化钙处理所缓解。这些结果提示,钙、多胺代谢以及盐渍环境下玉米生长之间可能存在一定的关系。     

An improved embryo-rescue protocol for hybrid progeny from seedless Vitis vinifera grapes × wild Chinese Vitis species

A highly efficient technique of embryo rescue is critical when using stenospermocarpic Vitis vinifera cultivars (female parents) to breed novel, disease-resistant, seedless grape cultivars by hybridizing with wild Chinese Vitis species (male parents) having many disease-resistance alleles. The effects of various factors on the improvement of embryo formation, germination, and plantlet development for seven hybrid combinations were studied. The results indicated that Beichun and Shuangyou were the best male parents. The best sampling time for ovule inoculation differed among the female parents. When hybrid ovules were cultured on a double-phase medium with five different solid medium types, percent embryo formation was highest (11.3–28.3%) on a modified MM3 medium. Percentages of embryo germination (15.4–55.4%) and plantlet development (11.15–44.6%) were all highest when embryos were cultured on Woody Plant Medium?+?5.7 μM indole-3-acetic acid?+?4.4 μM 6-benzylaminopurine?+?1.4 μM gibberellic acid?+?2% sucrose?+?0.05% casein hydrolysate?+?0.3% activated charcoal?+?0.7% agar. In the absence of other amino acids, the addition of proline significantly increased embryo formation (36.1%), embryo germination (64.6%), and plantlet development (90.5%). A highly efficient protocol has been developed for hybrid embryo rescue from seedless V. vinifera grapes?×?wild Chinese Vitis species that results in a significant improvement in breeding efficiency for new disease-resistant seedless grapes.     

POLLINATION,FERTILIZATION AND OVULE ABORTION IN OXALIS MAGNIFICA

Pollination, fertilization and ovule abortion were studied in Oxalis magnifica (Rose) Knuth, a strongly self-incompatible herb that regularly matures only a fraction of its ovules. Examination of cleared ovules indicated that among 9 individuals the average number of ovules fertilized ranged from 48–92%. The remaining ovules either failed to produce female gametophytes, or more commonly contained unfertilized female gametophytes, despite large numbers of compatible pollen grains that were placed on stigmas. Abortion of fertlized ovules could be detected first by the flattened and enlarged appearance of the endosperm nuclei, followed by visible deterioration of the embryo. Among individuals the rate of embryo abortion varied from 3.4–47.9%. At lower levels of pollination an almost one-to-one relationship existed between the number of pollen grains placed on stigmas and the number of seeds matured in the capsule. No threshold number of pollen grains necessary for successful pollen tube growth and fertilization could be demonstrated. Reduction in seed number through embryo abortion provides an opportunity for selection among developing seeds. The potential for this form of selection varies widely among individuals of Oxalis magnifica, which showed a 14-fold variation in the average percentage of aborted ovules.     

枣品种耐盐性与叶片生物膜结合态多胺水平和H~＋-ATP酶活性的关系

120mmol·L^-1NaCl胁迫30d,耐盐性强的‘金丝小枣’叶片细胞质膜、液泡膜共价结合态腐胺（Put）、亚精胺（Spd）、精胺（Spm）含量及多胺（PAs）总水平与对照无显著性差异,但耐盐性弱的‘冬枣’叶片质膜共价结合态Put、Spd、Spm含量和PAs总水平及液泡膜Spd含量均显著降低;‘金丝小枣’叶片类囊体膜共价结合态Put含量、PAs总水平较对照显著降低,‘冬枣’则是Put、Spd、Spm含量及PAs总水平均显著降低。盐胁迫下,‘金丝小枣’叶片细胞质膜、液泡膜、类囊体膜非共价结合态Put、Spd、Spm含量及PAs总水平下降,但其中仅类囊体膜Spd含量显著低于对照,而‘冬枣’的3种膜上非共价结合态的这些多胺及其总水平均显著低于对照。与对照相比,盐胁迫下耐盐性不同的2个枣品种,叶片细胞质膜、液泡膜和类囊体膜H＋-ATP酶活性均降低,但降低幅度因枣品种和生物膜种类不同而异,且H＋-ATP酶活性与相应膜结合态多胺水平存在极紧密的正相关关系。结果表明,膜结合态多胺参与枣品种耐盐性的表达,调节盐胁迫下枣叶细胞中溶质的跨膜运输。