Abscisic acid, gibberellin and cell viability in cereal aleurone

The aleurone layer of cereals is a secretory tissue whose activity is regulated by abscisic acid (ABA) and gibberellins (GAs). Whereas GA triggers enzyme synthesis and secretion and initiates a program that culminates in cell death, ABA prevents enzyme production and cell death. Reactive oxygen species (ROS) are key players in regulating cell viability and GA sensitizes the aleurone cell to ROS. Sensitivity of GA-treated cells results in part from a reduction in steady-state amounts of mRNAs encoding enzymes that scavenge ROS. mRNAs encoding catalase, superoxide dismutase and ascorbate peroxidase are almost undetectable in aleurone layers 24 h after incubation in GA. For layers incubated in ABA, however, the amounts of these mRNAs increase. Western blotting and enzyme activity assays confirm that GA but not ABA reduced the amount and activity of ROS scavenging enzymes (Fath et al., 2001b). Substantial amounts of ROS are produced by enzymes engaged in lipid metabolism, and by the electron transport chain in the mitochondria. Aleurone layers contain abundant stores of triglycerides and ROS are produced as these lipids are rapidly converted to sugars. We hypothesize that the ROS produced in GA-treated aleurone cells bring about cell death by disrupting the plasma membrane. Aleurone cells incubated in ABA, on the other hand, are better able to maintain redox balance. ABA does not initiate rapid triglyceride metabolism, and the activities of ROS-scavenging enzymes remain high in ABA-treated cells. We conclude that GA initiates a metabolic cascade in aleurone cells that results in death from ROS. ABA maintains viability by keeping ROS under control. This revised version was published online in August 2006 with corrections to the Cover Date.     

Gibberellins as gametocides for the common onion (Allium cepa L.). III. GA4+7 and pollen viability

Summary The gametocidal effect of GA₄₊₇ in onion is strong in respect of pollen production but very weak or absent in respect of pollen viability. Large scale application of GA₄₊₇ for the production of onion hybrid seed is still impossible because of low seed yield and high costsof required chemicals. On a small scale, however. GA₄₊₇ can be used very well to emasculate breeding material.Because of switching over to the gibberellin terminology of plant physiologists, this title slightly deviates from that of the two previous articles.     

Comparison of different pollen viability assays to evaluate pollen fertility of potato dihaploids

Summary The main obstacle in breeding potato (Solanum tuberosum L.) dihaploids is the severe limitation of male fertility. To determine pollen viability assays that correlate well to fertility in crosses, results of five different pollen viability assays were compared by correlation analysis with fruit and seed set characters in test crosses, and to pollen tube growth in situ (PL-test). The methods used were: staining the pollen cells with carmino acetic acid (CAA-test); in vitro pollen germination (PG-test); and detection of pollen staining rates after incubation with fluoresceine diacetate (FDA-test), 2-3-5-triphenyle tetrazolium chloride (TTC-test), and 5-bromo-4-chloro-3-indolyle--galactoside (X-Gal-test).The results of test crosses and pollen tube growth in situ correlated with the results of all other assays with the following ranking, from highest to lowest: enzyme activity assays (X-Gal-test, FDA-test, TTC-test), in vitro pollen germination (PG-test), and pollen staining by CAA. The newly developed X-Gal-test for monitoring -galactosidase activity showed the least variation of all assays investigated. Thus, this highly reproducible simple procedure is recommended for male fertility screening.Abbreviations B/F Berries obtained per 100 flowers - CAA Carmino acetic acid - FDA Fluoresceine diacetate - PG Pollen germination rate in vitro - PL Pollen tube growth in situ - S/B Seeds per berry - S/F Seeds per pollinated flower - TTC 2-3-5-triphenyle tetrazolium chloride - X-Gal 5-bromo-4-chloro-3-indolyle--galactoside     

磁场处理水对蔬菜种子发芽影响的初步研究

本研究采用0.025T、0.05T、0.1 T(T:特斯拉)剂量的磁场处理水对结球甘蓝、白尖叶莴苣和短叶十三萝卜的种子进行浸种处理.结果表明:不同剂量的磁场处理水浸泡蔬菜种子与对照(非磁场处理水浸泡种子)在发芽率和发芽势上存在显著的差异,其中以0.1T磁场处理水浸泡蔬菜种子的效果为最好.     

玉米与玉米近缘种可杂交性研究

本文对玉米与其近缘种及它们的杂交或回交后代的可杂交性进行了研究。结果表明，玉米近缘种的多数材料都能与玉米杂交结实，它们的杂种F1均表现出强的杂种优势和光敏反应；远缘杂交亲和性的母本效应较大，且与物种间遗传距离直接相关。此外，还对玉米近缘材料在玉米遗传育种中的应用进行了探讨。     

棉花植株和花粉耐盐性的鉴定

本研究对８个耐盐性不同的棉花品种（系），利用水培的方法对其整体植株进行了耐盐性鉴定，利用液滴培养技术对其花粉的耐盐性进行了鉴定，并分析了棉花整体植株和花粉耐盐性的相关性，结果表明，在水培盐胁迫条件下，棉花叶片总面积和叶片鲜重减少的百分数是反映棉花整体植株耐盐性的指标。在液滴培养盐胁迫条件下，棉花花粉粒萌发的百分率是反映其耐盐性的可靠指标，而花粉管的长度不能反映棉花的耐盐性。棉花整体植株的耐盐性和花     

Summary of Influencial Factors on Pollen Viability and Its Preservation Methods

植物花粉贮藏技术研究是开花生物学特性研究中的一项重要内容。在此，就植物花粉生活力的影响因素、花粉生活力的测定方法、花粉的贮藏步骤、方法进行了概述，列出了部分植物的花粉在不同条件下所能贮藏的时间和贮藏一定时间后的生活力状况，并指出了今后花粉贮藏的方向。     

TTCH定量测定辣椒种子的活力及活力丧失原因的探讨

本文以辣椒种子为材料,测定了不同贮存年限的辣椒种子发芽率,用TTCH测定了其活力,结果表明活力指标与发芽率相关极显著,华椒1号的相关系数达0.8912,华椒17号的相关系数达0.9277。实验表明辣椒种子活力下降的内在因素是膜的破坏、活性物质减少及毒素积累等因素引起的。     

水稻雄性不育突变体012S-3的遗传分析和基因定位

雄性不育是水稻杂种优势利用的重要资源,对雄性不育现象的研究具有重要理论意义和实践价值。本研究以自然突变的水稻雄性不育突变体012S-3为试验材料,对其表型特征和花粉育性等进行调查,并构建遗传群体,利用分子标记对目的基因进行初步定位,然后应用基因组重测序技术对其进行精细定位。结果表明,012S-3是一个典型的无花粉普通型雄性不育材料,其不育性状受1对隐性核基因控制。初步定位分析目的基因与SSR标记RM6081存在连锁关系,其遗传距离约为34.4 c M;进一步的精细定位分析,找到3个候选基因:LOC_Os07g35880、LOC_Os07g35920和LOC_Os07g35940,其中LOC_Os07g35880和LOC_Os07g35940编码β-淀粉酶,属于水稻中新发现的花粉致死基因。该不育基因的成功定位为其进一步的分离克隆及其在水稻分子设计育种中的应用奠定了基础。     

小麦种子在不同贮存条件下保存10年后生活力的差异

冬小麦农大139含水量为6.7%和11.8%。分别密封保存于室温和0～5℃冰箱。10年后,测定其发芽势,发芽率等指标,结果表明:①在室温条件下,含水量为11.8%的种子全部死亡,含水量为6.7%的种子有近50%的发芽率同保存前种子发芽率相比明显下降。②在0～5℃冰箱保存的种子,两种含水量均达到80%左右的发芽率,同保存前相比没有明显差别。统计分析表明,贮存温度及贮存温度和种子含水量的互作对贮存种子活力的影响达到极显著水平。